Air stable molybdenum alkyl kabe catalyst, process for the preparation thereof and use thereof in high

Abstract

The present invention relates to novel air-stable molybdenum alkyl Carbayer catalysts, processes for their preparation and their use in high performance alkyne metathesis.

Description

[0001] This invention relates to a novel air-stabilized molybdenum alkylidyne catalyst, its preparation method, and its use in high-performance alkyne metathesis.

[0002] Over the past two decades, alkyne metathesis has evolved noteworthy from a mere curiosity into a strategically important approach in materials science and small molecule synthesis (J. Am. Chem. Soc. 2021, 143(38), 15538-15555). This progress is naturally linked to advancements in catalyst design. Most catalysts currently in use are molybdenum-alkyl carbapenems with sufficient auxiliary ligands such as fluorinated alkoxides, amides, or silanols; however, none of these catalysts are bench-stable. Among them, molybdenum-alkyl carbapenems with triplegated silanol ligand spheres are by far the most active and selective catalysts known for alkyne metathesis (J. Am. Chem. Soc. 2020, 142, 11279-11294); they are also not bench-stable.

[0003] Despite the high level of complexity in this field, greater user-friendliness remains a pressing need that is not yet fully met; only when the best catalysts are easily handled will they be used routinely. Some milestones have been achieved in this direction in the past. While molybdenum alkyl carbamates with silanolate ligands degrade within hours when left in air, our laboratory has shown that their adducts with phenanthroline or 2,2'-bipyridine can be stored in the laboratory for extended periods (Chem. Eur. J. 2012, 18, 10281-10299). However, such adducts do not exhibit catalytic activity; they must be reactivated before use by removing the phenanthroline ligands with Lewis acid additives such as ZnCl2 or MnCl2.

[0004] This basic concept was recently expanded by the Buchmeiser team (Eur. J. Inorg. Chem. 2023, 26, e202200649; Organometallics 2021, 40, 1178-1184), which used N-heterocyclic carbene (NHC) instead of phenanthroline to form metastable adducts. In the solid state, specific complexes of this type have been found to have a laboratory lifetime exceeding one week; therefore, they can be weighed and transferred in air. Partial decomposition of the stable NHC ligand is then required in 1,2-dichloroethane under a nitrogen atmosphere at an elevated temperature (80 °C) to implement the partial decomposition of the stable NHC ligand, while no activity was observed at room temperature. Under these conditions, good turnover numbers were ensured, at least for nearly unfunctionalized substrates, with low catalyst loadings.

[0005] Therefore, there remains a need for improved alkylidyne catalysts that exhibit high stability in air in the laboratory and demonstrate high catalytic activity without requiring additional activation steps or high temperatures. Surprisingly, the inventors have discovered that such performance can be achieved using a newly designed tris-molybdenum alkylidyne tris-silanolate catalyst.

[0006] Therefore, the present invention relates to a metal-organic compound of general formula (I),

[0007]

[0008] X represents N, CR X SiR X , where R X Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl or 5-10 heteroaryl, wherein the alkyl, cycloalkyl, aromatic or heteroaromatic ring structure may be substituted with one or more heteroatoms;

[0009] R 1 R 2 and R 3 They may be the same as or different from each other, and are independently selected from H, C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, di-C1-C4 alkylamino, halogen, nitro, cyano, trifluoromethyl or -COOR 8 , where R 8 Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl, or

[0010] (R on the same benzene ring) 1 and R 2 ) or (R 2 and R 3 This forms an aromatic or heteroaromatic ring structure, which is conjugated with the benzene ring and has a total of 10-18 carbon atoms in the ring structure, of which 1-3 ring carbon atoms can be replaced by nitrogen. This aromatic or heteroaromatic ring structure can be replaced by one or more heteroatoms.

[0011] R 4 Selected from H, methyl or ethyl,

[0012] R 5 and R 6They may be the same as or different from each other, and are independently selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, and di-C1-C4 alkylamino. The alkyl, cycloalkyl, aromatic, or heteroaromatic ring structure may be substituted with one or more substituents selected from C1-C6 alkyl, 6-14 aryl, or heteroatoms.

[0013] R 7 It is selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl or 5-10 heteroaryl, and the alkyl, cycloalkyl, aromatic or heteroaryl ring structure can be substituted by one or more substituents selected from C1-C6 alkyl, 6-14 aryl or heteroatom.

[0014] In another embodiment, the present invention relates to a metal-organic compound of formula (I):

[0015]

[0016] in:

[0017] X represents N, CR X SiR X , where R X Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl.

[0018] R 1 R 2 and R 3 They may be the same as or different from each other, and are independently selected from H, C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, di-C1-C4 alkylamino, halogen, nitro, cyano, trifluoromethyl or -COOR 8 , where R 8 Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl.

[0019] R 4 Selected from H, methyl or ethyl,

[0020] R 5 and R 6They may be the same as or different from each other, and are independently selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, di-C1-C4 alkylamino, 6-18 aryl, or 5-10 heteroaryl. The alkyl, cycloalkyl, aromatic, or heteroaromatic ring structure may be substituted with one or more substituents selected from C1-C6 alkyl, 6-14 aryl, or heteroatoms.

[0021] R 7 It is selected from C1-C12 alkyl, C3-C12 cycloalkyl or 6-18 aryl, and the alkyl, cycloalkyl or aromatic ring structure can be substituted by one or more substituents selected from C1-C6 alkyl, 6-14 aryl or heteroatom.

[0022] In yet another embodiment, the present invention relates to a metal-organic compound of formula (I):

[0023]

[0024] in

[0025] X is N,

[0026] R 1 R 2 and R 3 They may be the same as or different from each other, and are independently selected from H, C1-C12 alkyl, or C3-C12 cycloalkyl.

[0027] R 4 Selected from H, methyl or ethyl,

[0028] R 5 and R 6 They may be the same as or different from each other, and are independently selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl groups. The alkyl, cycloalkyl, aromatic, or heteroaromatic ring structure may be substituted with one or more substituents selected from C1-C6 alkyl, 6-14 aryl, or heteroatoms.

[0029] R 7 It is selected from C1-C12 alkyl or 6-18 aryl groups, and the alkyl or aromatic ring structure can be substituted by one or more substituents selected from C1-C6 alkyl, 6-14 aryl or heteroatoms.

[0030] In another embodiment, the present invention relates to a metal-organic compound of formula (I):

[0031]

[0032] in

[0033] X is N,

[0034] R 1 R 2 and R 3 Independently selected from H or C1-C6 alkyl groups,

[0035] R 4 It's H.

[0036] R 5 and R 6 They may be the same as or different from each other, and represent C1-C12 alkyl or 6-18 aryl groups.

[0037] R 7 It represents a C1-C12 alkyl or a 6-18 aryl group, which can be substituted with one or more substituents selected from C1-C6 alkyl, 6-14 aryl or heteroatoms.

[0038] Based on the previously defined organometallic compounds of formula (I), the inventors have prepared 1:1 adducts of organometallic compounds of formula (I) as defined above with adduct-forming compounds selected from the following:

[0039] - A nitrogen-containing 5-10-membered heteroaryl compound, wherein the heteroaryl group is optionally substituted with one or more C1-C6 alkyl, halogen, -CN, -CF3, -N(C1-C6 alkyl)2 or -NO2 substituents, or

[0040] -PR P 3, where R P It is independently selected from C1-C6 alkyl or 6-18 aryl groups, which are optionally substituted with one or more C1-C3 alkyl, halogen, -CN, -CF3, -N(C1-C3 alkyl)2 or -NO2 substituents.

[0041] In a more specific embodiment, the present invention relates to an adduct of a metal-organic compound of formula (I) with an adduct-forming compound, wherein the adduct-forming compound is pyridine, optionally substituted with one or more C1-C6 alkyl, halogen, -CN, -CF3, -N(C1-C6 alkyl)2 or -NO2 substituents, provided that at least one of the pyridine substituents at the 2 and 6 positions is H, and the adduct with the parent pyridine is shown in formula (II):

[0042]

[0043] Where R 1 -R 7 It has the meaning as defined in any one of claims 1-4.

[0044] Within the scope of this invention, a method for preparing organometallic compounds of general formula (I) is also disclosed:

[0045]

[0046] in:

[0047] X represents N, CR X SiR X , where R X Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl or 5-10 heteroaryl, wherein the alkyl, cycloalkyl, aromatic or heteroaromatic ring structure may be substituted with one or more heteroatoms;

[0048] R 1 R 2 and R 3 They may be the same as or different from each other, and are independently selected from H, C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, di-C1-C4 alkylamino, halogen, nitro, cyano, trifluoromethyl or -COOR 8 , where R 8 Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl, or

[0049] (R on the same benzene ring) 1 and R 2 ) or (R 2 and R 3 This forms an aromatic or heteroaromatic ring structure, which is conjugated with the benzene ring and has a total of 10-18 carbon atoms in the ring structure, of which 1-3 ring carbon atoms can be replaced by nitrogen. This aromatic or heteroaromatic ring structure can be replaced by one or more heteroatoms.

[0050] R 4 Selected from H, methyl or ethyl,

[0051] R 5 and R 6 They may be the same as or different from each other, and are independently selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, and di-C1-C4 alkylamino, wherein the alkyl, cycloalkyl, aromatic, or heteroaromatic ring structure may be substituted with one or more heteroatoms.

[0052] R 7The alkyl, cycloalkyl, aromatic, or heteroaromatic ring structure is selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl groups, and may be substituted with one or more substituents selected from C1-C6 alkyl, 6-14 aryl, or heteroatoms.

[0053] The method includes the step of reacting a molybdenum complex of formula (III) with a compound of formula (IV) to produce a compound of formula (I):

[0054]

[0055] Where Z represents C1-C6 alkyl, -O-C1-C6 alkyl, -N(C1-C6 alkyl)2, -N(6-18 aryl)2, or –N[(C1-C6 alkyl)(6-18 aryl)], and where X and R 1 -R 7 It has the meaning defined above for organometallic compounds of formula (I).

[0056] In the method of this invention, the choice of solvent is not critical, as long as the solvent is selected from the following aprotic, nonpolar organic solvents: diethyl ether, aromatic solvents such as benzene, toluene, aliphatic hydrocarbon solvents having 5-8 carbon atoms such as pentane, hexane, or mixtures thereof. The reaction conditions are also not critical, and the reaction is generally carried out at a temperature of 0°C-80°C, preferably 10°C-35°C, under ambient pressure and an inert gas atmosphere.

[0057] Organometallic compounds of formula (I) as defined above and their adducts can be used to catalyze alkyne metathesis reactions. Therefore, the present invention also relates to the use of organometallic compounds of formula (I) as defined above, or any adducts thereof, as catalysts for alkyne metathesis reactions.

[0058] In the context of this invention, the meaning is as follows:

[0059] C1-C12 alkyl refers to straight-chain or branched alkyl groups having 1-12 carbon atoms;

[0060] C1-C12 alkoxy groups represent straight-chain or branched alkoxy groups having 1-12 carbon atoms;

[0061] Di-C1-C4 alkylamino means an amino group having two identical or different straight-chain or branched alkyl substituents, each having 1-4 carbon atoms;

[0062] C3-C12 cycloalkyl means a monocyclic saturated cycloalkyl group having 3-12 carbon atoms;

[0063] C3-C12 cycloalkoxy groups represent monocyclic saturated cycloalkoxy groups having 3-12 carbon atoms;

[0064] Five- to ten-membered heteroaryl groups represent monocyclic or optionally bicyclic aromatic heterocycles (heteroaromatics) having a total of 5 to 10 ring atoms, containing up to 3 cyclic heteroatoms selected from N, O, and / or S, and linked via a ring carbon atom or optionally via a ring nitrogen atom. Examples are: furanyl, pyrroleyl, thiopheneyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, isoxazolyl, isothiazolyl, triazolyl, oxadiazolyl, thiadiazolyl, pyridinyl, pyrazinyl, triazinyl, benzofuranyl, benzothiopheneyl, benzimidazolyl, benzooxazolyl, benzothiazolyl, benzotriazolyl, indolyl, inazolyl, quinolinyl, isoquinolinyl, naphridinyl, quinazolinyl, quinoxolinyl, phthalazinyl, pyrazolo[3,4-b]pyridinyl.

[0065] The heteroatoms or heterosubstituents defined according to the present invention may be selected from OH, halogens, CN, NO2, NO, NCO, -NCS, -SCN, SO3H, monohalomethyl, dihalomethyl, trihalomethyl, CF(CF3)2, SF5, aliphatic, aromatic, heteroaromatic, primary amine, secondary amine, tertiary amine or ammonium, -O-alkyl (alkoxy), -O-aryl, -O-heteroaryl, -O-SiR S 3. -SSR S -SR S -S(O)-R S -S(O)2-R S -COOH, -CO2-R S -BR S 2. -PR S 2. -OPR S 2. Amide, bonded by C or N atoms, formyl group, -C(O)-R S -COOM, where M is a metal, such as Li, Na, K, Cs, Ag. R S They may be identical or different from each other independently, and each is an aliphatic, heteroaliphatic, aromatic, or heteroaromatic group, each optionally further substituted with one or more heterosubstituents, aliphatic, heteroaliphatic, aromatic, or heteroaromatic groups; and / or optionally bridged by -O- atoms, representing halides. In the context of this invention, halogen means fluorine, chlorine, bromine, and iodine.

[0066] When listing a range of values, the goal is to include every value within that range and its subranges. For example, "C 1–6 "Intended to include C1, C2, C3, C4, C5, C6, C 1–6 C 1–5 C 1–4 C 1–3 C 1–2 C 2–6 C2–5 C 2–4 C 2–3 C 3–6 C 3–5 C 3–4 C 4–6 C 4–5 and C 5–6 .

[0067] In the context of this invention, preferred alkyl groups are straight-chain or branched alkyl groups having 1-6 carbon atoms. Exemplary and preferred are: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 1-ethyl-propyl, n-pentyl, and n-hexyl.

[0068] In the context of this invention, preferred alkoxy groups are straight-chain or branched alkoxy groups having 1-6 carbon atoms. Exemplary and preferred examples include: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, n-pentoxy, and n-hexyloxy.

[0069] In the context of this invention, preferred cycloalkyl groups are those having 3-7 carbon atoms. Exemplary and preferred are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl.

[0070] In the context of this invention, preferred cycloalkoxy groups are those having 3-7 carbon atoms. Exemplary and preferred examples are cyclopropoxy, cyclobutoxy, cyclopentoxy, cyclohexyloxy, and cycloheptoxy.

[0071] In the context of this invention, preferred di-C1-C4 alkylamino groups are the following di-C1-C4 alkylamino groups: N,N-dimethylamino, N,N-diethylamino, N-ethyl-N-methylamino, N-methyl-N-n-propylamino, N-isopropyl-N-methylamino, N-isopropyl-N-ethylamino, N-isopropyl-N-n-propylamino, N,N-diisopropylamino, N-n-butyl-N-methylamino, and N-tert-butyl-N-methylamino.

[0072] "Aryl" refers to a group in a 4n+2 aromatic ring system (e.g., having 6, 10, or 14 π electrons shared in the ring array) that provides 6–18 ring carbon atoms and zero heteroatoms ("C") in the aromatic ring system. 6–14 Aryl group (“C6 aryl”). In some embodiments, the aryl group has 6 ring carbon atoms (“C6 aryl”, e.g., phenyl). In some embodiments, the aryl group has 10 ring carbon atoms (“C6 aryl”). 10 Aryl group, such as naphthyl (e.g., 1-naphthyl and 2-naphthyl). In some embodiments, the aryl group has 14 ring carbon atoms (“C14”). 14"Aryl" (e.g., anthracene). "Aryl" also includes cyclic systems in which an aryl ring as defined above is fused with one or more carbocyclic or heterocyclic groups, wherein the group or linking point is located on the aryl ring, and in such cases, the number of carbon atoms continues to represent the number of carbon atoms in the aryl ring system. Unless otherwise stated, the aryl group is optionally substituted independently in each case, i.e., unsubstituted ("unsubstituted aryl") or substituted by one or more substituents ("substituted aryl"). In some embodiments, the aryl group is an unsubstituted C 6–14 Aryl. In some embodiments, the aryl group is a substituted C. 6–14 Aryl.

[0073] The 6- to 18-membered aryl groups typically represent monocyclic, bicyclic, or tricyclic carbocyclic aryl groups, which may also have 0-5 substituents selected from the following: C1-C12 alkyl, C1-C12 alkoxy, di-C1-C4 alkylamino, C3-C12 cycloalkyl, C3-C12 cycloalkoxy, 6- to 18-membered aryl, 5- to 10-membered heteroaryl, halogen, cyano, and nitro.

[0074] "Aryl" is a subgroup of alkyl and aryl, and refers to an alkyl group that has been optionally substituted with an aryl group. In some embodiments, the aryl group is an optionally substituted benzyl group. In some embodiments, the aryl group is a benzyl group. In some embodiments, the aryl group is an optionally substituted phenethyl group. In some embodiments, the aryl group is a phenethyl group.

[0075] In the context of this invention, preferred aryl groups are: phenyl, naphthyl, anthracene, methylphenyl, dimethylphenyl, trimethylphenyl, methoxyphenyl, dimethoxyphenyl, trimethoxyphenyl, fluorophenyl, chlorophenyl, bromophenyl, iodophenyl, pentafluorophenyl, trifluoromethylphenyl, dimethylaminophenyl, and C1-C12 alkoxycarbonylphenyl.

[0076] "Heteroaryl" refers to a group in a 5-10 membered monocyclic or bicyclic 4n+2 aromatic ring system (e.g., having 6 or 10 π electrons shared in a cyclic array), providing a cyclic carbon atom and 1-4 cyclic heteroatoms, each heteroatom independently selected from nitrogen, oxygen, and sulfur ("5-14 membered heteroaryl"). In heteroaryls containing one or more nitrogen atoms, the bonding point can be a carbon or nitrogen atom, provided the valence allows. Heteroaryl bicyclic systems may contain one or more heteroatoms in one or both rings. "Heteroaryl" includes cyclic systems in which a heteroaryl ring as defined above is fused with one or more carbocyclic or heterocyclic groups, wherein the bonding point is located on the heteroaryl ring, and in such cases, the number of ring members continues to indicate the number of ring members in the heteroaryl cyclic system. "Heteroaryl" also includes ring systems in which a heteroaryl ring as defined above is fused with one or more aryl groups, wherein the linkage point is located on the aryl or heteroaryl ring, and in such cases, the number of ring members represents the number of ring members in the fused (aryl / heteroaryl) ring system. In a bicyclic heteroaryl ring (e.g., indolyl, quinolinyl, carbazolyl, etc.) without a heteroatom in the ring, the linkage point can be located on either ring, i.e., the ring carrying the heteroatom (e.g., 2-indolyl) or the ring without the heteroatom (e.g., 5-indolyl).

[0077] Five- to ten-membered heteroaryl groups typically represent monocyclic or optionally bicyclic aromatic heterocycles (heteroaromatics) having a total of 5 to 10 ring atoms, containing up to three cyclic heteroatoms selected from N, O, and / or S, and linked via a ring carbon atom or optionally via a ring nitrogen atom. Examples are: furanyl, pyrroleyl, thiopheneyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, isoxazolyl, isothiazolyl, triazolyl, oxadiazolyl, thiadiazolyl, pyridinyl, pyrazinyl, triazinyl, benzofuranyl, benzothiopheneyl, benzimidazolyl, benzooxazolyl, benzothiazolyl, benzotriazolyl, indolyl, inazolyl, quinolinyl, isoquinolinyl, naphridinyl, quinazolinyl, quinoxolinyl, phthalazinyl, pyrazolo[3,4-b]pyridinyl.

[0078] Exemplary 5-membered heteroaryl groups containing one heteroatom include, but are not limited to, pyrroleyl, furanyl, and thiophenyl. Exemplary 5-membered heteroaryl groups containing two heteroatoms include, but are not limited to, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, and isothiazolyl. Exemplary 5-membered heteroaryl groups containing three heteroatoms include, but are not limited to, triazolyl, oxadiazolyl, and thiadiazolyl. Exemplary 5-membered heteroaryl groups containing four heteroatoms include, but are not limited to, tetrazolyl. Exemplary 6-membered heteroaryl groups containing one heteroatom include, but are not limited to, pyridinyl. Exemplary 6-membered heteroaryl groups containing two heteroatoms include, but are not limited to, pyridazinyl, pyrimidinyl, and pyrazinyl. Exemplary 6-membered heteroaryl groups containing three or four heteroatoms include, but are not limited to, triazinyl and tetraazinyl, respectively. Exemplary 7-membered heteroaryl groups containing one heteroatom include, but are not limited to, azepinyl, oxepinyl, and thiepinyl. Exemplary 5,6-bicyclic heteroaryl groups include, but are not limited to, indolyl, isoyindolyl, indazole, benzotriazolyl, benzothiophenyl, isobenzothiophenyl, benzofuranyl, benzoisofuranyl, benzoimidazolyl, benzooxazolyl, benzoisooxazolyl, benzooxadiazolyl, benzothiazolyl, benzoisothiazolyl, benzothiadiazolyl, indazinyl, and purinyl. Exemplary 6,6-bicyclic heteroaryl groups include, but are not limited to, naphthidyl, pteridyl, quinolinyl, isoquinolinyl, cenolinyl, quinoxolinyl, phthalazinyl, and quinazolinyl.

[0079] "Heteroaryl" is a subgroup of alkyl and heteroaryl, referring to an alkyl group that is optionally substituted by a heteroaryl group.

[0080] In the context of this invention, preferred heteroaryl groups are 5-10 membered heteroaryl groups that are monocyclic or optionally bicyclic and contain up to two heteroatoms selected from N, O, and / or S. Particularly preferred are 5- or 6-membered heteroaryl groups that are monocyclic and contain up to two heteroatoms selected from N, O, and / or S, such as furanyl, thiophene, thiazolyl, oxazolyl, isothiazolyl, isoxazolyl, pyrazolyl, imidazole, pyridinyl, pyrimidinyl, pyridazinyl, and pyrazinyl.

[0081] In the context of this invention, general formula R 5 R 6Examples of preferred silanol bridges for SiO- are: diphenylsilanol, dialkylsilanol, di(tert-butyl)silanol, phenylmethylsilanol, phenyl(tert-butyl)silanol, di(methoxyphenyl)silanol, di(dimethoxyphenyl)silanol, di(dimethylphenyl)silanol, di(trimethylphenyl)silanol, di(dimethylaminophenyl)silanol, di(fluorophenyl)silanol, di(difluorophenyl)silanol, di(pentafluorophenyl)silanol, di(3,5-ditert-butyl-6-methoxyphenyl)silanol, di(1-naphthyl)silanol, di(2-furanyl)silanol, and di(2-thiophenyl)silanol.

[0082] Among the possible candidates for forming adducts (amines, pyridines, quinolones, oxazoles, thiazoles, thioethers, nitriles, phosphites, phosphites, etc.), substituted pyridines are considered particularly suitable because many of them (with different donor properties and steric requirements) are commercially available.

[0083] The invention will be further illustrated by experimental details and accompanying drawings. The drawings show the following:

[0084] Figure 1 Reagents and conditions for catalyst synthesis and complex synthesis

[0085] (a) 1,3-Propanediol, pTsOH (3 mol%), toluene, reflux, 81% (R=H), 72% (R=Me)

[0086] (b) (i) i-PrMgBr (0.4 equivalents), n-BuLi (0.8 equivalents), THF, 0℃; (ii) Ph2Si(OMe)2, 0℃ RT, 85% (R=H), 70% (R=Me);

[0087] (c) HCl (6 M), THF, 0°C, 92% (R=H), 94% (R=Me);

[0088] (d) NH4OAc, NaBH(OAc)3, THF;

[0089] (e) NaOH (2 M), THF, 60% (after two steps, R=H), 65% (after two steps, R=Me)

[0090] (f) 9, Toluene, 94% (R=H), 98% (R=Me);

[0091] (g) Pyridine, CH2Cl2, 88% (R=H), 77% (R=Me);

[0092] The indicated scale refers to the single largest batch of R=Me.

[0093] Figure 2 Photograph of a sample with crystallized 16b; this sample was stored in air at ambient temperature for 8 months without any precautions. 1 The 1H NMR spectrum ([D8]-toluene, 253 K) showed a well-resolved aromatic region, revealing only trace impurities due to hydrolysis.

[0094] Figure 3 Same metathesis reaction of functionalized substrate

[0095] [a] 89% at 50°C, 91% at room temperature;

[0096] [b] Use free complex 17 instead of adduct 16a;

[0097] [c] At 110℃;

[0098] [d] Using 7 mol% catalyst at 110℃;

[0099] [e] At 90℃;

[0100] [f] at 100℃;

[0101] [g] Has added BPh3 at room temperature;

[0102] [h] MS 4 Å (instead of 5 Å); the selected catalyst loading is color-coded.

[0103] Figure 4 Macrocyclic alkyne metathesis via closed-ring alkyne

[0104] All reactions were carried out in toluene (2 mM) in the presence of MS at 5 Å using the specified catalyst; all substrates had methyl caps on their triple bonds; [a] modified “auxiliary” post-treatment was necessary to obtain pure samples.

[0105] Figure 5 Higher target molecules via the metathesis of closed-ring alkynes

[0106] (a) 16a (5 mol%), 60 °C, toluene, MS 5 Å, 81%;

[0107] (b) 16a (5 mol%), 50 °C, toluene, MS 5 Å, 65%;

[0108] (c) 16a (10 mol%), 60 °C, toluene, MS 5 Å, 94%;

[0109] (d) 16a (30 mol%), 110 °C, toluene, MS 5 Å, 71%;

[0110] (e) 16a (30 mol%), 110 °C, toluene, MS 5 Å, 81%.

[0111] like Figure 1 As illustrated in the representative examples, the preparation of the envisioned ligand is directly demonstrated in amounts of several grams. Commercially available bromobenzaldehyde 11 (R=H, Me) is converted to the corresponding acetal prior to metal / halogen exchange with i-PrMgBr / n-BuLi treatment. The resulting organometallic substance is quenched with Ph₂Si(OMe)₂, and the resulting siloxane 12 is treated with an aqueous HCl solution to simultaneously release the Si-OH groups and the aldehyde. Subsequent reductive amination 13 yields the target trisilanolate 14. However, this step is accompanied by varying degrees of intermolecular and / or intramolecular siloxane formation. Stirring the oligomer fraction with an aqueous NaOH solution in THF is sufficient to correct this problem and regenerate the desired monomer, thereby enabling the target ligand 14 to be obtained on a large scale from inexpensive starting materials in good overall yield.

[0112] In the solid state, compound 14b exhibits an “up / inward” orientation of all three silanol groups, likely a result of intramolecular hydrogen bonding between the -OH groups. These interactions require pre-organization of the ligand scaffold, which may persist in an aprotic medium; therefore, chelate formation should be favorable. Indeed, stirring solutions of 14 and 9 in toluene yields the desired complex 15 in excellent yields, which is a yellow solid. The formation of the oligomeric complex is not significantly interfered with, and washing the crude product with pentane is generally sufficient to remove trace amounts of residual substrate, thus facilitating the separation of the analytically pure form of 15. Minor procedural adjustments also yielded the ethyl variant 17 (see Experimental Section). Other ligands of this type, with additional substituents on the aromatic rings of the silicon and / or backbone, can be prepared similarly.

[0113] Adding a slight excess of pyridine to a yellow solution of 15b in CH2Cl2 at ambient temperature resulted in a deep pale purple color. Evaporation of the solvent and washing the residue with pentane to remove the excess pyridine yielded adduct 16b as a pale purple powder, which could be recrystallized, for example, from CH2Cl2 / pentane to obtain a purple single crystal suitable for X-ray diffraction. The solid-state structure confirmed the tight binding of the external pyridine ligand (Mo1-N2 2.255(1) Å), while the N atom of the tribenzyl linker was far from the metal center (Mo1 / N1 5.38 Å); it only possessed a geometric function but did not exhibit electronic effects.

[0114] In the search for potential, and even better, stable ligands, many pyridine derivatives with varying space requirements and donor capabilities have been screened. Although 2,6-dimethylpyridine does not bind to 15 at all, adducts derived from 3-bromopyridine and 3,5-dibromopyridine have proven unstable (partial loss of the outer ligand occurs when the crude material is washed with pentane). The more electron-rich 4-pyrrolidinylpyridine results in stable adducts that are almost non-prone to discomplexation at room temperature. Therefore, the choice of pyridine allows for tuning of adduct stability over a wide range. For practical purposes, inexpensive pyridine itself is a good compromise: the resulting adduct 16 can be stored for extended periods in benchtop or refrigerator and can be weighed in air, while toluene solutions exhibit excellent catalytic activity and allow for many challenging alkyne metathesis reactions at or slightly above room temperature without the need for separate pre-activation of the adduct.

[0115] With a half-life of several days, the pyridine-free complex 15b exhibits perceptible robustness when kept in air as a microcrystalline powder; although long-term storage requires inert conditions, it can be weighed and handled without special precautions.

[0116] Complexation with pyridine significantly increases stability. When adduct 16b is stored in air in crystalline form at ambient temperature for up to 8 months, as... Figure 2 As shown in the figure, through 1 H NMR showed almost no signs of degradation. Hydrolysis became more pronounced over time when stored in air as a powder (rather than as crystals) at room temperature. However, satisfyingly, the integrity of the powder sample was readily maintained even when simply stored in a desiccator or, optionally, in a screw-cap vial in a refrigerator. Under these conditions, the powder sample remained intact for several months, as demonstrated by NMR and elemental analysis; importantly, all catalytically tested reactions occurred at constant rates and efficiencies. Therefore, we conclude that pyridine adduct 16 is not completely inert to moisture and will eventually hydrolyze, but long-term storage outside the glove box under readily achievable conditions (e.g., in a desiccator and / or refrigerator) is possible. Such high stability and procedural simplicity are currently arguably mismatched. Therefore, adduct 16 is considered sufficient to utilize feasible and practical tools, even for non-experts.

[0117] When dissolved in an inert solvent such as toluene, pyridine adduct 16 exhibits perceptible catalytic activity at ambient temperature due to the spontaneous release of 15 as monitored by NMR; no separate activation is required. The metathesis reaction of 1-methoxy-4-(prop-1-yn-1-yl)benzene at 25 °C is catalyzed by pyridine adduct 16a (5 mol%) in [D8]-toluene in the absence of molecular sieves. Equilibrium composition is reached within 60 minutes. As expected, heating leads to a significant acceleration in the rate of temperature increase.

[0118] Although these results demonstrate that air-dwelling pyridine adduct 16 is itself a fully effective catalyst, requiring no pre-activation other than dissolution in an inert solvent, it can promote the reaction if needed. The addition of BPh3 (1 equivalent relative to 16) purged pyridine, thus shifting the equilibrium between 15 and 16 significantly to the free catalyst side; this was accompanied by a characteristic color change of the solution from pale purple to yellow. Under these conditions, the test reaction proceeded within minutes at ambient temperature. While promoters other than BPh3 can be conceived, this crystalline compound is considered a good choice for its ease of handling (though not entirely air-stable, but usable without any precautions) and benign properties; it retains the high affinity of trivalent boron for N-donors but exhibits mild Lewis acidity, thus potentially posing little risk in advanced applications.

[0119] The new series of chelation catalysts shows promising application prospects. Most reactions can be... 2 mol% of the storage-stable adduct 16a was used as a catalyst in toluene in the presence of MS 5 Å as a scavenger for the release of 2-butyne; however, for substrates carrying proton substituents, higher catalyst loadings (typically 5 mol%) were used. The catalysts were operated in a temperature range of at least -20 °C and +130 °C, preferably between ambient temperature and +70 °C; the optimal reaction temperature depends on the chosen substrate. In many cases, the choice of temperature is not critical and has little effect on the yield of the metathesis product; this aspect is demonstrated by the formation of product 22a at different reaction temperatures (…). Figure 4 ) and product 35 ( Figure 4 To illustrate.

[0120] A series of homometathesis reactions confirmed the broad functional group tolerance of 16. Figure 4Some entries deserve special comment. The protonated groups eventually react with the complex, replacing the silanol, and in doing so, destroy catalytic activity; therefore, they have historically marked a significant limitation for alkyne metathesis and are one of the main reasons for developing catalysts that utilize the chelation effect (J. Am. Chem. Soc. 2021, 143 (38), 15538-15555). Satisfactorily, the newly invented and user-friendly catalyst 16 has proven sufficient. They operate in the presence of primary and secondary aliphatic, benzyl and propargyl alcohols, phenols with -OH, anilines with -NH2 substituents, and secondary amines with -NH groups. However, as mentioned above, a loading of 5 mol% was used in these cases to ensure complete conversion.

[0121] The fact that the combination of external pyridine with the active molybdenum alkyl carbapenem is reversible even at ambient temperatures in toluene solution foreshadows the excellent compatibility of this new catalyst with different donor sites. In fact, catalyst 16, containing a pre-transition metal center in the highest possible oxidation state, is compatible with various heterocycles, including but not limited to: pyridine, pyrimidine, quinoline, thiophene, thiazole, oxazole, and N-alkylpiperidine; catalyst 16 is also compatible with Lewis basic sites, including but not limited to: aliphatic secondary and tertiary amines, secondary and tertiary alkyl (aryl)amines, aniline, phosphine, thioethers, and nitriles. Higher reaction temperatures are only necessary in those cases where the functional groups cause electron-deficient metathesis of the triple bond. [(tBuO)3W, a prototype of the catalytically active alkyl carbapenem complex... The comparison of CCMe3 clearly illustrates the progress, as this catalyst was previously unable to convert substrates containing thiazole rings or even pyridines with reduced basicity.

[0122] Other functional groups that have been found to be compatible with 15-17 include, but are not limited to: terminal and internal alkenes, acetals, aldols, alkyl, alkenyl and aryl halides, alkyl azides, borate esters, carbamates, carbonates, 1,2-dibromoolefins, ethers, epoxides, esters, ketones, nitriles, -NO2, -CF3, and silyl ethers.

[0123] Many closed-ring alkyne metathesis (RCAM) reactions catalyzed by 16 or 17 have yielded excellent results. Figure 4 As expected, macrocycles 34 and 35 were obtained in high yields. The reactions can, as desired, be carried out at room temperature or at elevated temperatures. Product 36 constitutes a more stringent test: due to their low reactivity, acetylacetic esters and related substrates have exceeded the range of earlier catalysts, including [(tBuO)3W, which is a landmark in the history of this field. [CCMe3]. To our knowledge, only molybdenum alkyl carbamates with silanols have been found to form macrocyclic alkynates via RCAM; the new user-friendly variant 16 retains this ability.

[0124] Cycloalkynes carrying -OR substituents at both propargyl positions, such as 37-39, are demanding targets. Figure 4 Only a few examples of such preparations via RCAM are known in the literature, which also rely on molybdenum alkyl carbamate coordinated with silanolates. Therefore, it is noteworthy that 16 and 17 can form products of this type. Results showed that product 38 and the trisilanol ligand hydrolyzed the catalyst during post-treatment co-elution in rapid chromatography, thus making product purification challenging. The N atom in the ligand backbone proved advantageous in addressing this problem. Therefore, the organic phase was washed with an aqueous HCl solution, followed by solvent evaporation, and the residue was purified by rapid column chromatography; under these conditions, the ligand was quantitatively removed. Although only sufficiently acid-stable products can be processed in this manner, such "ligand-assisted" post-treatment is indeed another advantage of this novel catalyst family.

[0125] The inventors used the selection of advanced intermediates from previous natural product synthesis activities conducted in the inventors' laboratory. Figure 5 The highly functionalized cycloalkyne 48, a precursor to the anticancer agent epochromycin C, can be readily formed using a novel, storage-stable pyridine adduct 16. Product 50 was successfully formed, which has already served as a key intermediate in the total synthesis of the alkaloid letrozole. In summary, these examples demonstrate the compatibility of the novel, storage-stable adduct 16 with a wide range of polar and nonpolar functional groups, even when presented in a dense array.

[0126] Alkyne metathesis is orthogonal to alkene metathesis because molybdenum alkyl carbapenems leave all types of double bonds unaffected. In the case of epochromycin, this is an advantageous chemoselective surface (47). 48), but with the help of the storage-stable pyridine adduct 16, it is more pronounced in the high-yield formation of 52. This product belongs to the amphidinolide V series: one of the two external methylene groups of the decorative macrocycle is part of the vinyl-epoxide and is therefore a fairly reactive functional group, while the other has a potential elimination group at the allyl position.

[0127] The compatibility of the novel catalysts with different Lewis base groups is further illustrated by the formation of product 54, a key precursor in the pathway for the formation of the marine pyridinium alkaloid epitetradehydrohalocycloamine B; in this case, macrocyclization must proceed in the presence of unhindered pyridine. In the inventors' initial report, this reaction was achieved using an air-sensitive "canopy" catalyst (Angew. Chem. Int. Ed. 2022, 61, e202209651). It is now shown that the more user-friendly, storage-stable adduct 16a is equally effective.

[0128] The high-yield formation of product 56, which comprises the base macrocycle of the nominally njaoamine I (a member of the marine alkaloid family with cytotoxic properties), is particularly instructive. While elevated temperatures are necessary for the reaction to proceed, the presence of a tertiary amine and quinoline near the reactive triple bond arguably poses a challenge to almost any transition metal reagent or catalyst. Therefore, the excellent yield achieved using 16a as a catalyst is noteworthy. In terms of efficiency, the new air-stable adduct 16a is on par with the air-sensitive molybdenum-alkyl carbapenem used in our initial study (J. Am. Chem. Soc. 2021, 143(35), 14402-14414). Generally, the combination of comparable performance with significantly improved user-friendliness marks a significant advance in the field of alkyne metathesis.

[0129] The present invention will be further illustrated by the following experimental section.

[0130] Experimental Section

[0131] Overview

[0132] Unless otherwise specified, all reactions were performed under argon atmosphere in flame-dried glassware according to standard Schlenk techniques. Solvents were purified by distillation over the indicated desiccants and transferred under argon atmosphere: tetrahydrofuran (magnesium / anthracene), toluene (NaAlEt4), benzene (CaH2), dichloromethane (CaH2), 1,2-dimethoxyethane (CaH2), acetonitrile (CaH2), diethyl ether (Na / K), and n-pentane (Na / K). Deuterated solvents were stored on molecular sieves (3 Å) for at least five days prior to use.

[0133] The molecular sieves and Celite used in this study ® Before use, in a vacuum (10) -3 It is dried at 150°C (sand bath) for 24 hours under a molten metal atmosphere and stored and transferred under an argon atmosphere.

[0134] Rapid column chromatography was performed using Merck silica gel, type 9385 (230-400 mesh, 60 Å pore size).

[0135] Unless otherwise specified, all commercially available compounds (abcr, Lancaster, Aldrich, TCI) were used as is. Substrates for alkyne metathesis reactions were prepared as described in the literature. Starting materials for the synthesis of intermediates from natural products were generously provided by Dr. D. Dalling, Dr. C. Mathes, Dr. O. Larionov, Dr. K. Gebauer, and Dr. S. Spohr.

[0136] MS (EI): Finnigan MAT 8200 (70 eV), ESI-MS: ESQ 3000 (Bruker), Precision mass determination: Bruker APEX III FT-MS (7T magnet) or Mat 95 (Finnigan). All values ​​are given in units of mass per elementary charge (m / z).

[0137] Experimental Procedure

[0138] molybdenum precursor complex

[0139] Complex [Li (Et2O) 1 / 2 [Mo(CO)5(COAr)](S1, Ar=2,6-di(methyl)phenyl)

[0140]

[0141] A 250 mL three-necked round-bottom flask equipped with a 50 mL dropping funnel and connected to a vacuum / argon manifold was flame-dried. 2-Bromo-1,3-dimethylbenzene (3.28 mL, 24.1 mmol) and diethyl ether (60 mL) were added to the flask. The solution was cooled to -40 °C, and then a tert-butyllithium solution (1.6 M n-pentane solution, 30.1 mL, 48.3 mmol) was added over 10 minutes via the dropping funnel. Stirring was continued at -20 °C for 3 h.

[0142] A 500 mL three-necked round-bottom flask equipped with a 100 mL dropping funnel and connected to a vacuum / argon manifold was flame-dried. Molybdenum hexacarbonyl (6.50 g, 24.1 mmol) and diethyl ether (60 mL) were added to the flask, and the resulting solution was cooled to 0 °C. The solution of lithium-ionized aromatics was cooled to -78 °C and transferred to the dropping funnel under argon overpressure via a low-density polyethylene (LDPE) tube, then rapidly added to the cold solution of molybdenum hexacarbonyl. Once the addition was complete, the resulting yellow-orange mixture was stirred at ambient temperature for 4 h. A glass stopper was used instead of the dropping funnel, and a solvent trap was connected to the vacuum / argon manifold. The solvent and all volatile materials were then heated under reduced pressure (10 °C). -3 Evaporation was carried out at 1000 mbar. The resulting orange solid was suspended in dichloromethane (4 × 20 mL) and passed through a celite-filled container. ® The solution was filtered using an argon filter frit mounted on a flame-dried 250 mL three-necked flask connected to a vacuum / argon manifold. The resulting filtrate was then filtered under a vacuum (10... -3 Concentrate in millibars until approximately 10 mL of solution remains.

[0143] Add 700 mL of n-pentane to a flame-dried 1 L three-necked flask equipped with an argon manifold, and add the concentrated solution dropwise while stirring vigorously. The product precipitates as a microcrystalline solid, which is collected by filtration using an argon filter sintered glass core mounted on a flame-dried 2 L two-necked flask connected to a vacuum / argon manifold. The product is washed with 3 × 20 mL of n-pentane and then subjected to high vacuum (1000 mL). -3 Drying at 1000 mbar to produce the desired complex, a diethyl ether adduct (2:1 ratio). Pale yellow microcrystalline solid material (8.76 g, 95%). HRMS (ESI) for C 14 H9O6MoLi [M-Et2O-Li] - Calculated value: 370.94587; Measured value: 370.94613. The spectral data have been found to be consistent with the data reported in the literature.

[0144] [Mo(≡CAr)Br3(dme)](S2, Ar=2,6-di(methyl)phenyl)

[0145]

[0146] A 500 mL three-necked round-bottom flask equipped with an internal thermometer and connected to a vacuum / argon manifold was flame-dried. Li was added to the flask. (Et2O) 1 / 2[Mo(CO)5(COAr)] (S1) (4.37 g, 10.6 mmol) and dichloromethane (60 mL). The resulting orange mixture was cooled to -78 °C and stirred for 15 minutes. Then, a solution of oxaloyl bromide (1.09 mL, 11.6 mmol) in dichloromethane (5 mL) was added dropwise over 5 minutes, which caused the color to turn purple. Once the addition was complete, stirring was continued at -78 °C for 15 minutes. The mixture was then warmed to -40 °C. Upon reaching this temperature, a rapid change to light brown was observed, and the mixture was rapidly cooled again to -78 °C. Stirring was stopped to allow most of the precipitate to settle.

[0147] In parallel, a 1 L three-necked jacketed cooling flask was connected to a vacuum / argon manifold and flame-dried. The cooling flask was equipped with a 25 mL pressure-balanced dropping funnel and contained Celite. ® A jacketed, cooled argon filter core (diameter: 4.5 cm; height: 20 cm; porosity: 3) with a 5 cm pad. Celite is placed in the jacketed filter core. ® The slurry was prepared with dichloromethane and tightly packaged, then the core was cooled to -78°C using a cryostat. 1,2-Dimethoxyethane (5.50 mL, 52.9 mmol) was added to the flask, which was also cooled to -78°C.

[0148] The cold, light brown reaction mixture was transferred in portions to a sintered glass core via an LDPE tube under argon overpressure. A deep red color was observed when the bright yellow filtrate was contacted with 1,2-dimethoxyethane in a 1 L receiving flask. The mixture was stirred at -78 °C for 10 min, and then a solution of bromine (0.51 mL, 10.0 mmol) in dichloromethane (5 mL) was added dropwise over 15 min via a dropping funnel. Once the addition was complete, the mixture was stirred at -78 °C for 15 min. The resulting brown-orange mixture was allowed to reach ambient temperature within 1 hour, during which time the color intensified. Stirring was continued at ambient temperature for 1 h, and then the dropping funnel and sintered glass core were replaced with a glass stopper. The brown reaction mixture was then filtered through a sintered glass core containing Celite. ® The mixture was filtered using an argon-filtered sand filter (mounted on a flame-dried 500 mL double-necked flask connected to a vacuum / argon manifold). The sand filter was replaced with a stopper, and the solvent in the filtrate was removed under vacuum to obtain the title complex as a rust-colored solid (2.30 g, 41%). Impurities were removed by washing the solid with diethyl ether. The spectroscopic data were found to be consistent with those reported in the literature.

[0149] [Mo(≡CAr)(OtBu)3](9,Ar=2,6-di(methyl)phenyl)

[0150]

[0151] [Mo(≡CAr)Br3(dme)](Ar=2,6-di(methyl)phenyl)S2 (2.05 g, 3.79 mmol) and tetrahydrofuran (23 mL) were added to a 250 mL Schlenk flask. A solution of sodium tert-butyl oxide (1.07 g, 11.2 mmol) in tetrahydrofuran (7 mL) was added dropwise via syringe at ambient temperature, with continuous stirring overnight. The solvent was then removed under vacuum to obtain a dark brown solid. The residue was suspended in n-pentane (4 × 20 mL), and the suspension was passed through a Celite filter with an argon filter core mounted on a 250 mL double-necked flask connected to a vacuum / argon manifold. ® Use a filter pad for filtration. Replace the filter cartridge with a stopper and concentrate the filtrate under vacuum (10). -3 (mbar) until the total volume is approximately 4 ml remaining. The solution was cooled to -40°C, which induced crystallization of the title complex over 4 hours. The supernatant was removed and the solution was then subjected to high vacuum (10 mbar). -3 The residue was dried at 1 mbar to obtain the desired brown powder complex (1.31 g, 3.04 mmol, 80%). The spectroscopic data were found to be consistent with those reported in the literature.

[0152] ligands

[0153] Compound S3

[0154]

[0155] 5-Bromobenzaldehyde (6.85 g, 37.0 mmol), toluene (50 mL), and propane-1,3-diol (2.94 mL, 40.7 mmol) were added to a 100 mL two-necked round-bottom flask equipped with a Dean-Stark apparatus (reflux condenser and toluene-filled distillation trap) connected to a vacuum / argon manifold. p-Toluenesulfonic acid (211 mg, 1.11 mmol) was added, and the solution was stirred overnight at reflux temperature. After cooling to ambient temperature, the organic layer was washed with aqueous sodium bicarbonate solution (2 × 50 mL) and brine (1 × 50 mL). The organic phase was dried over magnesium sulfate and filtered, and the solvent was evaporated. The residue was purified by silica gel rapid column chromatography (hexane / ethyl acetate, 19:1–9:1) to give the title compound as a yellow liquid (7.25 g, 81%). The spectroscopic data were found to be consistent with those reported in the literature.

[0156] Compound 12a

[0157]

[0158] Compound S3 (7.25 g, 29.8 mmol) and tetrahydrofuran (30 mL) were charged into a 100 mL Schlenk flask. The solution was cooled to 0 °C, and then a solution of isopropyl magnesium chloride-lithium chloride complex (1.25 M tetrahydrofuran solution, 9.18 mL, 11.9 mmol) was added dropwise. After stirring for 5 minutes, a solution of n-butyllithium (1.6 M hexane solution, 14.6 mL, 23.9 mmol) was added dropwise, and the resulting gray suspension was stirred at 0 °C for 1 hour. Dimethoxydiphenylsilane (13.5 mL, 59.6 mmol) and tetrahydrofuran (25 mL) were charged into a 250 mL double-necked round-bottom flask equipped with a pressure-balanced dropping funnel connected to a vacuum / argon manifold. The resulting solution was cooled to 0 °C. The Grignard reagent was transferred to a dropping funnel using an LDPE tube under argon pressure and then slowly added to a solution of dimethoxydiphenylsilane at 0 °C. Once the addition was complete, the mixture was allowed to reach ambient temperature and stirred overnight. The reaction was carefully quenched by adding saturated ammonium chloride aqueous solution (100 mL). The layers were separated, and the aqueous phase was extracted with ethyl acetate (3 × 75 mL). The combined organic layers were dried over magnesium sulfate and filtered, and the solvent was evaporated. The residue was purified by silica gel rapid column chromatography (hexane / ethyl acetate, 9:1) to give the title compound as a colorless oil (9.58 g, 85%). HRMS (EI) for C 23 H 24 O3SiNa [M +Na] + Calculated value: 399.13869; Measured value: 399.13871.

[0159] Compound 13a

[0160]

[0161] Compound 12a (9.58 g, 24.53 mmol) and tetrahydrofuran (245 mL) were added to a 500 mL single-necked round-bottom flask equipped with a 100 mL dropping funnel in air. The solution was cooled to 0 °C, and then hydrochloric acid (6 M aqueous solution, 62 mL, 0.37 mol) was added via the dropping funnel over 10 minutes. The mixture was warmed to ambient temperature and stirred for 1 hour. The solution was carefully neutralized with an aqueous sodium bicarbonate solution and extracted with dichloromethane (3 × 150 mL). The combined organic layers were dried over sodium sulfate and filtered, and the solvent was evaporated. The residue was purified by silica gel rapid column chromatography (toluene / ethyl acetate, 10:1) to give the title compound as a colorless solid (6.88 g, 92%). HRMS (ESI) for C 19 H 16O2SiNa [M +Na] + Calculated value: 327.08118; Measured value: 327.08071.

[0162] Ligand 14a

[0163]

[0164] Compound 13a (8.20 g, 26.9 mmol), tetrahydrofuran (270 mL), and ammonium acetate (642 mg, 8.33 mmol) were added to a 500 mL two-necked round-bottom flask connected to a vacuum / argon manifold. Sodium triacetoxyborohydride (9.10 g, 42.9 mmol) was added in portions, and the resulting suspension was stirred for 24 hours. The solution was neutralized with aqueous sodium bicarbonate solution and extracted with ethyl acetate (3 × 200 mL). The combined organic layers were dried over magnesium sulfate and filtered, and the solvent was evaporated. The residue was purified by silica gel rapid column chromatography (dichloromethane / methanol, 99:1–98:2) to give a mixture of siloxane dimers / oligomers and ligand 14a as a colorless powder. This crude material and tetrahydrofuran (400 mL) were added to a 500 mL single-necked flask in air. Aqueous sodium hydroxide solution (2 M, 400 mL) was added, and the mixture was stirred overnight. The layers were separated, and the aqueous layer was extracted with ethyl acetate (3 × 300 mL). The combined organic phases were washed with brine (300 mL), dried over magnesium sulfate, filtered, and the solvent was evaporated to produce the title compound (4.75 g, 60%) as a colorless powder. HRMS (ESI) for C 57 H 50 NO3Si3 [M - H] - Calculated value: 880.31041; Measured value: 880.31091.

[0165] Compound S4

[0166]

[0167] 5-Bromo-2-methylbenzaldehyde (11b, 15.6 g, 78.4 mmol), toluene (100 mL), and propane-1,3-diol (6.23 mL, 86.2 mmol) were added to a 250 mL double-necked round-bottom flask equipped with a Dean-Stark apparatus (reflux condenser and distillation trap filled with toluene) and an argon manifold. p-Toluenesulfonic acid (447 mg, 2.35 mmol) was added, and the solution was stirred overnight at reflux temperature. After cooling to ambient temperature, the organic layer was washed with aqueous sodium bicarbonate solution (2 × 75 mL) and brine (1 × 100 mL). The organic phase was dried over magnesium sulfate and filtered, and the solvent was evaporated. The residue was purified by silica gel rapid column chromatography (hexane / ethyl acetate, 9:1) to give the title compound as a yellow liquid (14.9 g, 72%). HRMS (EI) for C 11 H 13 O2Br [M] - Calculated value: 256.00954; Measured value: 256.00935.

[0168] Compound 12b

[0169]

[0170] Compound S4 (14.9 g, 56.7 mmol) and tetrahydrofuran (20 mL) were charged into a 100 mL Schlenk flask. The solution was cooled to 0 °C, and then a solution of isopropyl magnesium chloride-lithium chloride complex (1.25 M tetrahydrofuran solution, 18.5 mL, 23.1 mmol) was added dropwise. After stirring for 5 minutes, a solution of n-butyllithium (1.6 M hexane solution, 28.4 mL, 46.3 mmol) was added dropwise, and the resulting gray suspension was stirred at 0 °C for 1 hour. Dimethoxydiphenylsilane (26.2 mL, 116 mmol) and tetrahydrofuran (50 mL) were charged into a 250 mL two-necked flask equipped with a pressure-balanced dropping funnel connected to a vacuum / argon manifold. The resulting solution was cooled to 0 °C. Grignard reagent was transferred to the dropping funnel using an LDPE tube and argon pressure, and then slowly added to the cooled dimethoxydiphenylsilane solution. Once the addition was complete, the mixture was warmed to ambient temperature and stirred overnight. The reaction was carefully quenched with a saturated aqueous solution of ammonium chloride (50 mL). The layers were separated, and the aqueous phase was extracted with ethyl acetate (3 × 30 mL). The combined organic layers were dried over magnesium sulfate and filtered, and the solvent was evaporated. The residue was purified by silica gel rapid column chromatography (hexane / ethyl acetate, 19:1) to give the title compound as a colorless oil (15.8 g, 70%). HRMS (EI) for C 24 H26 O3Si [M] - Calculated value: 390.16457; Measured value: 390.16510.

[0171] Compound 13b

[0172]

[0173] Compound 12b (8.72 g, 22.3 mmol) and tetrahydrofuran (220 mL) were added to a 500 mL single-necked flask equipped with a 100 mL dropping funnel in air. The solution was cooled to 0 °C and hydrochloric acid (6.0 M aqueous solution, 57 mL, 0.34 mol) was added through the dropping funnel over 10 minutes. The mixture was warmed to ambient temperature and stirred for 1 hour. The solution was carefully neutralized with a saturated aqueous sodium bicarbonate solution, and the aqueous layer was extracted with dichloromethane (3 × 100 mL). The combined organic phases were dried over sodium sulfate and filtered, and the solvent was evaporated. The residue was purified by silica gel rapid column chromatography (toluene / ethyl acetate, 14:1) to give the title compound as a colorless liquid (6.68 g, 94%). HRMS (EI) for C 20 H 18 O2SiNa [M +Na] + Calculated value: 341.09704; Measured value: 341.09683.

[0174] Ligand 14b

[0175]

[0176] Compound 13b (5.00 g, 15.7 mmol), tetrahydrofuran (160 mL), and ammonium acetate (390 mg, 5.07 mmol) were charged into a 250 mL double-necked round-bottom flask connected to a vacuum / argon manifold. Sodium triacetoxyborohydride (4.99 g, 23.6 mmol) was added fractionally, and the resulting suspension was stirred for 24 hours. The solution was neutralized with aqueous sodium bicarbonate solution and extracted with ethyl acetate (3 × 75 mL). The combined organic layers were dried over magnesium sulfate and filtered, and the solvent was evaporated. The residue was purified by silica gel rapid column chromatography (dichloromethane / methanol, 50:1–5:1) to give a mixture of siloxane dimers / oligomers and ligand 14b as a colorless powder.

[0177] The crude material and tetrahydrofuran (80 mL) were added to a 100 mL single-necked flask in air. Sodium hydroxide aqueous solution (2 M, 80 mL) was added and the mixture was stirred overnight. The layers were separated, and the aqueous phase was extracted with ethyl acetate (3 × 40 mL). The combined organic layers were washed with brine (1 × 50 mL), dried over magnesium sulfate, filtered, and the solvent was evaporated to yield the title compound (3.65 g, 65%) as a white powder. HRMS (ESI) for C 60 H 56 NO3Si3 [M - H] - Calculated value: 922.35735; Measured value: 922.35784.

[0178] Compound S5

[0179]

[0180] Compound S4 (4.00 g, 15.6 mmol) and tetrahydrofuran (30 mL) were added to a 50 mL Schlenk flask. The solution was cooled to 0 °C, and a solution of isopropyl magnesium chloride-lithium chloride complex (1.25 M tetrahydrofuran solution, 4.78 mL, 6.22 mmol) was added dropwise. After stirring for 5 minutes, a solution of n-butyllithium (1.6 M hexane solution, 7.78 mL, 12.4 mmol) was added dropwise, and the resulting gray suspension was stirred at 0 °C for 1 hour.

[0181] Add Et₂SiH₂ (6.01 mL, 46.7 mmol) and tetrahydrofuran (20 mL) to a 250 mL two-necked round-bottom flask equipped with a pressure-balanced dropping funnel connected to a vacuum / argon manifold. Cool the resulting solution to 0 °C. Transfer the Grignard reagent to the dropping funnel using an LDPE tube and under argon pressure, then slowly add it to the cooled diethylsilane solution. Once the addition is complete, warm the mixture to ambient temperature and continue stirring overnight. Carefully quench the reaction with a saturated aqueous solution of ammonium chloride (40 mL). Separate the layers and extract the aqueous phase with ethyl acetate (3 × 50 mL). Dry the combined organic layers on magnesium sulfate and filter, evaporating the solvent. Purify the residue by silica gel rapid column chromatography (hexane / ethyl acetate, 12:1) to give the title compound as a colorless oil (3.88 g, 94%). HRMS (EI) for C 15 H 24 O2Si[M] + Calculated value: 264.15401; Measured value: 264.15419.

[0182] Compound S6

[0183]

[0184] Similarly, it was prepared from S3 (4.00 g, 16.5 mmol) as a colorless liquid (2.89 g, 70%).

[0185] HRMS (ESI) for C 14 H 22 O2SiNa [M + Na] + Calculated value: 273.12823; Measured value: 273.12808.

[0186] Compound S7

[0187]

[0188] Compound S5 (3.87 g, 14.7 mmol) and dichloromethane (30 mL) were charged into a 50 mL single-necked round-bottom flask in air. The solution was cooled to 0 °C, and then m-chloroperoxybenzoic acid (77% w / w, 3.62 g, 16.1 mmol) was added in portions. After stirring at ambient temperature for 5 hours, the mixture was transferred to a separatory funnel and washed with saturated aqueous sodium bicarbonate solution (2 × 60 mL) and aqueous sodium hydroxide solution (1 M, 60 mL). The organic layer was dried over magnesium sulfate and filtered, and the solvent was evaporated to yield the title compound (3.84 g, 92%) as a colorless liquid. HRMS (EI) for C 15 H 24 O3Si [M] + Calculated value: 280.14892; Measured value: 280.14896.

[0189] Compound S8

[0190]

[0191] Similarly, it was prepared from compound S6 (2.89 g, 11.5 mmol) as a colorless liquid (2.84 g, 93%).

[0192] HRMS (EI) for C 14 H 22 O3Si [M] + Calculated value: 266.13327; Measured value: 266.13357.

[0193] Compound S9

[0194]

[0195] Compound S7 (3.87 g, 13.8 mmol) and tetrahydrofuran (120 mL) were charged into a 250 mL single-necked round-bottom flask equipped with a 50 mL dropping funnel in air. The solution was cooled to 0 °C, and then hydrochloric acid (12 M aqueous solution, 17.0 mL, 207 mmol) was added through the dropping funnel over 10 minutes. After 20 minutes at 0 °C, the solution was carefully neutralized with a saturated aqueous sodium bicarbonate solution, and the aqueous phase was extracted with dichloromethane (3 × 100 mL). The combined organic layers were dried over sodium sulfate and filtered, and the solvent was evaporated to yield the title compound (2.72 g, 89%) as a colorless liquid. Compound S9 readily forms a siloxane and is immediately used in subsequent steps. HRMS (ESI) for C 12 H 18 O2SiNa [M + Na] + Calculated value: 245.09683; Measured value: 245.09693.

[0196] Compound S10

[0197]

[0198] Similarly, it was prepared from compound S8 (500 mg, 1.88 mmol) as a colorless liquid (3.22 g, 82%). This compound readily forms siloxanes and is immediately used in subsequent ligand synthesis steps. HRMS (EI) for C 11 H 16 O2Si [M] + Calculated value: 208.09141; Measured value: 208.09143.

[0199] Ligand S11

[0200]

[0201] Compound S9 (2.72 g, 12.2 mmol), tetrahydrofuran (100 mL), and ammonium acetate (304 mg, 3.95 mmol) were charged into a 250 mL double-necked round-bottom flask connected to a vacuum / argon manifold. Sodium triacetoxyborohydride (3.81 g, 18.0 mmol) was added in portions, and the resulting suspension was stirred for 24 hours. Then, additional sodium triacetoxyborohydride (1.00 g, 4.72 mmol) was added, and stirring continued for another 48 hours. For post-treatment, the solution was cooled to 0 °C and carefully neutralized with an aqueous sodium bicarbonate solution. The mixture was concentrated by rotary evaporation to a final volume of 50 mL, followed by extraction with tert-butyl methyl ether (3 × 50 mL). The combined organic layers were washed with an aqueous sodium hydroxide solution (1 M, 40 mL), dried over magnesium sulfate, filtered, and the solvent was evaporated. The residue was purified by silica gel rapid column chromatography (hexane / ethyl acetate, 5:1–4:1) to yield the title compound as a colorless powder (873 mg, 35%). HRMS (ESI) for C 36 H 56 NO3Si3[M-H] - Calculated value: 634.35736; Measured value: 634.35773.

[0202] Ligand S12

[0203]

[0204] Similarly, it was prepared from compound S10 (3.47 g, 15.3 mmol) as a colorless oil (960 mg, 33%).

[0205] HRMS (ESI) for C 33 H 52 NO3Si3 [M + H] + Calculated value: 594.32496; Measured value: 594.32459.

[0206] Complex

[0207] Complex 15b

[0208]

[0209] Ligand 14b (855 mg, 0.93 mmol) was loaded into a 250 mL Schlenk flask and azeotropically dried with benzene (2 × 4 mL) to remove any residual water. The compound was suspended in toluene (90 mL), and a solution of alkyl carbabinoid 9 (400 mg, 0.93 mmol) in toluene (10 mL) was added dropwise. After stirring for 1.5 hours, all volatile material was removed under vacuum to produce the title complex as a yellow powder (1.04 g, 98%). Orange crystals suitable for single-crystal X-ray diffraction were grown from the concentrated benzene solution. HRMS (ESI) for C 69 H 63 MoNO3Si3Na [M + Na] + Calculated value: 1158.30620; Measured value: 1158.30562.

[0210] Complex 15a

[0211]

[0212] Ligand 14a (204 mg, 0.23 mmol) was loaded into a 50 mL Schlenk flask and azeotropically dried with benzene (3 × 1.5 mL) to remove residual water. The compound was suspended in toluene (30 mL), and a solution of alkyl carbabinoid 9 (100 mg, 0.93 mmol) in toluene (8 mL) was added dropwise. After stirring for 3.5 hours, all volatile material was removed under vacuum to produce the title complex as a yellow powder (238 mg, 94%). HRMS (ESI) for C 66 H 58 MoNO3Si3 [M + H] + Calculated value: 1094.27731; Measured value: 1094.27686.

[0213] Complex 17a

[0214]

[0215] Ligand S12 (339 mg, 0.52 mmol, 90% purity) was loaded into a 100 mL Schlenk flask and azeotropically dried with benzene (2 × 2 mL) to remove residual water. The compound was dissolved in toluene (50 mL), and a solution of alkyl carbabinoid 9 (222 mg, 0.51 mmol) in toluene (6 mL) was added dropwise. After stirring for 1 hour, all volatile material was removed under vacuum to produce a brown residue. This residue was dissolved in dichloromethane (3 mL), and excess pentane (50 mL) was added. After 3 days at -78 °C, the title complex precipitated from the solution as a yellow powder, which was collected by filtration (336 mg, 81%). HRMS (ESI) for C 42 H 58 MoNO3Si3 [M + H] + Calculated value: 806.27731; Measured value: 806.27657.

[0216] Complex 17b

[0217]

[0218] Ligand S11 (300 mg, 0.47 mmol) was added to a 100 mL Schlenk flask and azeotropically dried with benzene (2 × 2 mL) to remove residual water. The compound was suspended in toluene (45 mL), and a solution of alkyl carbabinite complex 9 (204 mg, 0.47 mmol) in toluene (8 mL) was added dropwise. After stirring for 3.5 hours, all volatile material was removed under vacuum to produce a brown residue. The crude material was repeatedly ground with pentane and then dried under high vacuum to produce a toluene-free complex 17b as a yellow powder (399 mg, 99%). HRMS (ESI) for C 45 H 64 MoNO3Si3 [M + H] + Calculated value: 848.32426; Measured value: 848.32437.

[0219] adducts

[0220] adduct 16a

[0221]

[0222] Complex 15a (835 mg, 0.76 mol) and dichloromethane (15 mL) were added to a 25 mL Schlenk flask. Pyridine (80 μL, 0.99 mmol) was added to the orange solution, immediately turning the color deep purple. After stirring for 1 hour, all volatile materials were removed under vacuum to produce a purple powder, which was washed with pentane (2 × 6 mL) and dried under vacuum to produce the title adduct (787 mg, 88%). Purple crystals suitable for single-crystal X-ray diffraction were grown from the dichloromethane / pentane solution by slow solvent evaporation.

[0223] adduct 16b

[0224]

[0225] Complex 15b (98 mg, 87 μmol) and dichloromethane (2 mL) were added to a 10 mL Schlenk flask. Pyridine (11 μL, 0.13 mmol) was added to the orange solution, immediately turning the color deep purple. After stirring for 2 hours, all volatile materials were removed under vacuum to produce a purple powder, which was washed with pentane (3 × 1.5 mL) and vacuum dried to produce adduct 16b (81 mg, 77%). Purple crystals suitable for single-crystal X-ray diffraction were grown from the dichloromethane / pentane solution by slow solvent evaporation. HRMS (ESI) for C 74 H 68 MoN2O3Si3 [M] + Calculated value: 1214.35863; Measured value: 1214.35929.

[0226] 3-Bromopyridine adduct 16c

[0227]

[0228] To a 10 mL Schlenk flask, add complex 15b (49 mg, 43 μmol) and dichloromethane (1.5 mL). Add 3-bromopyridine (7 μL, 73 μmol) to the orange solution, which immediately turns the color deep purple. After 15 minutes, add pentane (7 mL) and cool the solution to -78 °C. Separate the supernatant from the precipitate as follows: transfer it to a new Schlenk flask using a filter-capped LDPE tube and argon pressurization. Remove the solvent under a constant argon flow. Wash the resulting purple solid at 0 °C with pentane (3 × 1.5 mL) and dry under a gentle argon flow to yield the title adduct (48 mg, 85%).

[0229] 3,5-Dibromo-pyridine adduct 16d

[0230]

[0231] Complex 15b (75 mg, 66 μmol) and dichloromethane (1.5 mL) were added to a 10 mL Schlenk flask. 3,5-Dibromopyridine (23 mg, 99 μmol) was added to the orange solution, immediately turning the color deep red. After stirring for 1 hour, pentane (5 mL) was added. The supernatant was then separated from the precipitate using a filter-capped LDPE tube and argon pressurization to a new Schlenk flask. The solvent was removed under a constant argon flow. The resulting purple solid was washed at 0 °C with pentane (3 × 2 mL) and dried under a gentle argon flow to yield the title adduct (75 mg, 83%).

[0232] 4-Pyrrolidinylpyridine adduct 16e

[0233]

[0234] Complex 15b (76 mg, 67 μmol) and dichloromethane (1.5 mL) were added to a 10 mL Schlenk flask. 4-Pyrrolidinyl-pyridine (15 mg, 0.1 mmol) was added to the orange solution, immediately turning the color deep purple. After stirring for 3 hours, all volatile materials were removed under vacuum. The purple powder was washed with pentane (2 × 2 mL) to yield the title adduct (71 mg, 55 μmol, 83%) containing trace amounts of free 4-pyrrolidinyl-pyridine and hydrolyzed ligands. The purity of the sample was only about 93% (NMR).

[0235] Alkyne metathesis reaction

[0236] Representative procedures for the asystological decomposition of alkynes

[0237] Compound 22a

[0238]

[0239] 1-(4-methoxyphenyl)-1-propyne (21.37 mg, 0.25 mmol), powdered molecular sieve (250 mg, 5 Å), and toluene (1.25 mL) were charged into a 10 mL Schlenk flask. Adduct 16a (6 mg, 5 μmol, 2 mol%) was weighed in air and added to the mixture in one go. After stirring at ambient temperature for 12 hours, the reaction was quenched with ethanol (1 mL), and the mixture was passed through a Celite filter. ®The mixture was filtered through a short saddle and carefully washed with ethyl acetate (20 mL) and dichloromethane (10 mL). The combined filtrates were evaporated and the residue was purified by silica gel rapid column chromatography (hexane / ethyl acetate, 70:1–50:1) to yield the title compound as a colorless solid (27 mg, 91%).

[0240] The spectral data are consistent with those reported in the literature.

[0241] Compound 22b

[0242]

[0243] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 50 °C. The title compound was purified by rapid column chromatography (hexane) as a colorless solid (35 mg, 89%).

[0244] The spectral data are consistent with those reported in the literature.

[0245] Compound 22c

[0246]

[0247] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 50 °C. The title compound was purified by rapid column chromatography (hexane / ethyl acetate, 8:2–1:1) as a colorless solid (28 mg, 85%).

[0248] The spectral data are consistent with those reported in the literature.

[0249] Compound 22d

[0250]

[0251] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 50 °C. Purification by rapid column chromatography (hexane / dichloromethane, 1:1) yielded the title compound as a colorless solid (36 mg, 98%).

[0252] The spectral data are consistent with those reported in the literature.

[0253] Compound 22e

[0254]

[0255] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 50 °C. The title compound was purified by rapid column chromatography (hexane / dichloromethane, 10:1–8:2) as a colorless solid (38 mg, 71%).

[0256] HRMS (ESI) for C 26 H 32 B2O4Na [M + Na] + Calculated value: 453.23794; Measured value: 453.23815. The spectral data are consistent with those reported in the literature.

[0257] Compound 22f

[0258]

[0259] Similarly, adduct 16a was used as a catalyst (15 mg, 13 μmol, 5 mol%) at 50 °C. Purification was performed by rapid column chromatography (hexane / ethyl acetate 12:1-3:2-1:1) to yield a crude product containing a copolar ligand. To remove impurities, the crude product was dissolved in ethyl acetate (30 mL), and the organic layer was washed with an aqueous hydrogen chloride solution (3 × 10 mL, 3 M). The organic layer was dried over magnesium sulfate and filtered, and the solvent was evaporated to yield the title compound as a colorless solid (26 mg, 91%). The spectroscopic data were consistent with those reported in the literature.

[0260] 22g of compound

[0261]

[0262] Similarly, adduct 16a was used as a catalyst (15 mg, 13 μmol, 5 mol%) at 50 °C. Purification by rapid column chromatography (hexane / ethyl acetate, 8:2–1:1) yielded the title compound as a red solid (36 mg, 98%). Spectral data were consistent with those reported in the literature.

[0263] Compound 22h

[0264]

[0265] Similarly, the preparation was carried out at 110 °C using complex 17 as a catalyst (10 mg, 13 μmol, 5 mol%). Purification by rapid column chromatography (hexane / ethyl acetate, 3:1–1:1) yielded the title compound as an orange solid (24 mg, 71%). Spectral data were consistent with those reported in the literature.

[0266] Compound 22i

[0267]

[0268] Similarly, it was prepared at 110 °C using complex 17 as a catalyst (15 mg, 17 μmol, 7 mol%). Purification by rapid column chromatography (hexane / ethyl acetate, 4:1) yielded the title compound as a yellow solid (15 mg, 45%). HRMS (EI) for C 14 H8N2O4 [M] + The calculated value is 268.04786; the measured value is 258.04825. The spectral data are consistent with the data reported in the literature.

[0269] Compound 23

[0270]

[0271] Similarly, adduct 16a was used as a catalyst (15 mg, 13 μmol, 5 mol%) at 50 °C. The title compound was purified by rapid column chromatography (dichloromethane / methanol 98:2) as a colorless solid (24 mg, 81%).

[0272] The spectral data are consistent with those reported in the literature.

[0273] Compound 24

[0274]

[0275] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 90 °C. Purification by rapid column chromatography (hexane / ethyl acetate, 3:2–1:1) yielded the title compound as a pale yellow solid (20 mg, 89%). Spectral data were consistent with those reported in the literature.

[0276] Compound 25

[0277]

[0278] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 100 °C. Purification by rapid column chromatography (dichloromethane / methanol, 95:5) yielded the title compound as a colorless solid (10 mg, 44%). Spectral data were consistent with those reported in the literature.

[0279] Compound 26

[0280]

[0281] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 50 °C. Purification by rapid column chromatography (dichloromethane / methanol, 99:1–98:2) yielded the title compound as a colorless solid (28 mg, 80%). HRMS (EI) for C 20 H 12 N2 [M] + Calculated value: 280.09950; Measured value: 280.09974. The spectral data are consistent with those reported in the literature.

[0282] Compound 27

[0283]

[0284] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 50 °C. Purification by rapid column chromatography (hexane / dichloromethane, 100:1) yielded the title compound as a colorless solid (21 mg, 88%). Spectral data were consistent with those reported in the literature.

[0285] Compound 28

[0286]

[0287] Similarly, adduct 16a was used as a catalyst (15 mg, 13 μmol, 5 mol%) at 50 °C. Purification by rapid column chromatography (dichloromethane / methanol, 99:1–95:5, using 2% triethylamine) yielded the title compound as a brown oil (31 mg, 80%). HRMS (ESI) for C 20 H 41 N2 [M + H] + Calculated value: 309.32643; Measured value: 309.32658. The spectral data are consistent with those reported in the literature.

[0288] Compound 29

[0289]

[0290] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 50 °C. The title compound was purified by rapid column chromatography (dichloromethane / methanol, (hexane / ethyl acetate, 3:1, using 5% trimethylamine) to yield a yellow oil (35 mg, 80%). Spectral data were consistent with those reported in the literature.

[0291] Compound 30

[0292]

[0293] Similarly, adduct 16a was used as a catalyst (6 mg, 5 μmol, 2 mol%) at 50 °C. Purification by rapid column chromatography (hexane / ethyl acetate, 50:1) yielded the title compound as a clear oil (24 mg, 77%). Spectral data were consistent with those reported in the literature.

[0294] Compound 32

[0295]

[0296] Similarly, adduct 16a was used as a catalyst (15 mg, 13 μmol, 5 mol%) at 50 °C. Purification by rapid column chromatography (dichloromethane / methanol, 98:2–90:10) yielded the title compound as a yellow oil (29 mg, 82%). Spectral data were consistent with those reported in the literature.

[0297] Compound 33a

[0298]

[0299] Similarly, adduct 16a was used as a catalyst (15 mg, 13 μmol, 5 mol%) at 50 °C with a 4 Å molecular sieve (250 mg) instead of a 5 Å molecular sieve. Purification by rapid column chromatography (hexane / ethyl acetate, 1:1) yielded the title compound as a colorless solid (16 mg, 65%). HRMS (ESI) for C 12 H 23 O2 [M + H] + Calculated value: 199.16962; Measured value: 199.16956. The spectral data has been found to be consistent with the data reported in the literature.

[0300] Compound 33b

[0301]

[0302] Similarly, adduct 16a was used as a catalyst (15 mg, 13 μmol, 5 mol%) at 50 °C. Purification by rapid column chromatography (hexane / ethyl acetate, 2:3) yielded the title compound as a colorless solid (25 mg, 79%). HRMS (ESI) for C 16 H 30 O2Na [M + Na] + Calculated value: 277.21387; Measured value: 277.21381. The spectral data are consistent with those reported in the literature.

[0303] Compound 31

[0304]

[0305] To a 10 mL Schlenk flask, add 59 mg (0.25 mmol) of 8-iodooct-2-yne, 250 mg (5 Å) of powdered molecular sieve, and 1.15 mL of toluene. Weigh adduct 16a (6 mg, 5 μmol, 2 mol%) in air and add it all at once. Add a stock solution of triphenylborane (0.5 mL, 5 μmol, 2 mol%) of 0.01 M toluene solution and stir the mixture at ambient temperature for 1 hour. Add 1 mL of ethanol to quench the reaction and pass the mixture through a Celite filter. ® The mixture was filtered through a short liner and carefully washed with ethyl acetate (20 mL) and dichloromethane (10 mL). The solvent was evaporated, and the residue was purified by silica gel rapid column chromatography (hexane / ethyl acetate, 95:5) to yield the title compound as a yellow oil (48 mg, 82%). The spectroscopic data were consistent with those reported in the literature.

[0306] Representative program for metathesis of closed-ring alkynes

[0307] Compound 35

[0308]

[0309] To a 10 mL Schlenk flask, add 38 mg (0.10 mmol) of di(octyl-6-yn-1-yl) phthalate, 250 mg (5 Å) of powdered molecular sieve, and 50 mL of toluene. Weigh adduct 16a (6 mg, 5 μmol, 5 mol%) in air and add it all at once. Stir the mixture at ambient temperature for 12 hours. Quench the reaction with 5 mL of ethanol and pass the mixture through a Celite filter. ®The mixture was filtered through a short liner and carefully washed with ethyl acetate (20 mL) and dichloromethane (10 mL). The solvent was evaporated, and the residue was purified by silica gel rapid column chromatography (hexane / ethyl acetate, 10:1) to yield the title compound as a yellow oil (30 mg, 91%). The spectroscopic data were consistent with those reported in the literature.

[0310] Compound 34

[0311]

[0312] Similarly, adduct 16a was used as a catalyst (2 mg, 2 μmol, 2 mol%) at 50 °C. Purification by rapid column chromatography (hexane / ethyl acetate, 9:1) yielded the title compound as a colorless oil (19 mg, 97%). Spectral data were consistent with those reported in the literature.

[0313] Compound 36

[0314]

[0315] Similarly, adduct 16a was used as a catalyst (8.5 mg, 7 μmol, 10 mol%), refluxed for 2 hours to prepare the compound. Purification by rapid column chromatography (hexane / ethyl acetate, 30:1) yielded the title compound as a colorless oil (26 mg, 98%). Spectral data were consistent with those reported in the literature.

[0316] Compound 37

[0317]

[0318] Similarly, the solution was prepared by reflux for 4 hours using complex 17b as a catalyst (17 mg, 20 μmol, 20 mol%). The complex was dissolved in toluene (1 mL) in a separate Schlenk flask, and the solution was added dropwise to a solution of diyne at 110 °C. The crude product was purified by rapid column chromatography (hexane / ethyl acetate, 10:1–7:3) to yield the title compound as a yellow oil (24 mg, 77%). HRMS (ESI) for C 18 H 32 O4Na [M + Na] + Calculated value: 335.21928; Measured value: 335.21918. The spectral data are consistent with those reported in the literature.

[0319] Compound 38

[0320]

[0321] Similarly, complex 16a was used as a catalyst (23 mg, 20 μmol, 20 mol%) to prepare the solution by reflux for 4 hours. The catalyst was dissolved in toluene (1 mL) in a separate Schlenk flask, and the solution was added dropwise to a solution of diyne at 110 °C. The crude product was washed with an aqueous HCl solution (3 M, 3 × 10 mL), the organic phase was dried over magnesium sulfate and filtered, and the solvent was evaporated. The residue was purified by rapid column chromatography (toluene / tert-butyl methyl ether, 8:2) to yield the title compound as a colorless solid (16 mg, 60%). HRMS (ESI) for C 16 H 28 NaO3 [M + Na] + Calculated value: 291.19307; Measured value: 291.19290. The spectral data are consistent with those reported in the literature.

[0322] Compound 39

[0323]

[0324] Similarly, complex 16a was used as a catalyst (23 mg, 20 μmol, 20 mol%) at reflux temperature. The complex was dissolved in toluene (1 mL) in a separate Schlenk flask, and the solution was added dropwise to a solution of diyne at 110 °C. The crude product was purified by rapid column chromatography (hexane / ethyl acetate 9:1) to yield the title compound as a colorless solid (10 mg, 46%). HRMS (CI) for C 14 H 28 NO2 [M + NH4] + Calculated value: 242.21145; Measured value: 242.21154. The spectral data are consistent with those reported in the literature.

[0325] Compound 48

[0326]

[0327] A 50 mL Schlenk flask was loaded with diyne 47 (10 mg, 13 μmol), powdered molecular sieve (250 mg, 5 Å), and toluene (7 mL). Adduct 16a (1 mg, 0.5 μmol, 5 mol%) was weighed in air and dissolved in toluene (1 mL). The catalyst solution was added dropwise to the substrate solution at 60 °C, and stirring was continued at this temperature for 2 hours. The reaction was quenched with ethanol (5 mL), and the mixture was then cooled to ambient temperature and passed through a Celite flask. ®The sample was filtered through a short saddle filter and carefully washed with ethyl acetate (20 mL) and dichloromethane (10 mL). The solvent was evaporated, and the residue was purified by silica gel rapid chromatography (pentane / diethyl ether, 10:1–7:3) to yield the title compound as a colorless solid (8 mg, 81%). HRMS (ESI) for C 38 H 65 NO5Si2SNa [M + Na] + Calculated value: 726.40142; Measured value: 726.40156. The spectral data are consistent with those reported in the literature.

[0328] Compound 50

[0329]

[0330] A 50 mL Schlenk flask was loaded with diyne 49 (10 mg, 10 μmol), powdered molecular sieve (250 mg, 5 Å), and toluene (5 mL). The mixture was heated to 50 °C. Adduct 16a (0.5 mg, 0.5 μmol, 5 mol%) was weighed in air and added in one batch. After stirring at 50 °C for 1.5 hours, the reaction was quenched with ethanol (5 mL), and the mixture was then cooled to ambient temperature and passed through a Celite flask. ® The mixture was filtered through a short slab and carefully washed with ethyl acetate (20 mL) and dichloromethane (10 mL). The solvent was evaporated, and the residue was purified by silica gel rapid chromatography (hexane / ethyl acetate, 6:1) to yield the title compound as a colorless oil (6 mg, 65%). Two diastereomers of compound 50 each existed in solution as two rotational isomers. HRMS (ESI) for C 58 H 75 O7NSi2Na [M + Na] + Calculated value: 976.49743; Measured value: 976.49749. The spectral data are consistent with those reported in the literature.

[0331] Compound 52

[0332]

[0333] A 50 mL Schlenk flask was loaded with diyne 51 (10 mg, 17 μmol), powdered molecular sieve (250 mg, 5 Å), and toluene (9 mL). Adduct 16a (2 mg, 2 μmol, 10 mol%) was weighed in air and dissolved in toluene (1 mL). The catalyst solution was added dropwise to the substrate solution at 60 °C, and stirring was continued at this temperature for 1.5 h. The reaction was quenched with ethanol (5 mL), and the mixture was then cooled to ambient temperature and passed through a Celite flask. ® The sample was filtered through a short saddle filter and carefully washed with ethyl acetate (20 mL) and dichloromethane (10 mL). The solvent was evaporated, and the residue was purified by silica gel rapid chromatography (hexane / ethyl acetate, 22:1) to yield the title compound as a colorless solid (9 mg, 94%). HRMS (ESI) for C 28 H 48 O5Si2Na [M + Na] + Calculated value: 543.29325; Measured value: 543.29340. The spectral data are consistent with those reported in the literature.

[0334] Compound 54

[0335]

[0336] Diyne 53 (20 mg, 59 μmol), powdered molecular sieve (500 mg, 5 Å), and toluene (30 mL) were charged into a 50 mL Schlenk flask. Adduct 16a (21 mg, 18 μmol, 30 mol%) was weighed in air and dissolved in toluene (1 mL) in a separate Schlenk flask. The catalyst solution was added dropwise to the substrate solution with stirring at reflux temperature. After 1.5 hours, ethanol (5 mL) was added to quench the reaction, and the mixture was then cooled to ambient temperature and passed through a Celite filter. ® The sample was filtered through a short saddle filter and carefully washed with ethyl acetate (20 mL) and dichloromethane (10 mL). The solvent was evaporated, and the residue was purified by silica gel rapid chromatography (dichloromethane / methanol, 95:5) to yield the title compound as a colorless solid (12 mg, 71%). HRMS (EI) for C 18 H 22 N2O [M] + Calculated value: 282.17266; ​​Measured value: 282.17293. The spectral data are consistent with those reported in the literature.

[0337] Compound 56

[0338]

[0339] Diyne 55 (10 mg, 8.7 μmol), powdered molecular sieve (400 mg, 5 Å), and toluene (5 mL) were added to a 25 mL Schlenk flask. Adduct 16a (3 mg, 2.6 μmol, 30 mol%) was weighed in air and dissolved in toluene (1 mL). The catalyst solution was added dropwise to the substrate solution under stirring at reflux temperature. After stirring for 2 hours, the reaction was quenched with ethanol (5 mL), and the mixture was then cooled to ambient temperature and passed through a Celite flask. ® The sample was filtered through a short saddle filter and carefully washed with ethyl acetate (20 mL) and dichloromethane (10 mL). The solvent was evaporated, and the residue was purified by silica gel rapid chromatography (hexane / ethyl acetate, 4:1, using 5% trimethylamine) to yield the title compound as a light brown oil (8 mg, 81%). HRMS (ESI) for C 50 H 67 O3N4Br4 [M + H] + The calculated value is 1087.19412; the measured value is 1087.19569. The spectral data are consistent with the data reported in the literature.

[0340] Compound 58

[0341]

[0342] Compound 57 (34.0 mg, 0.037 mmol) was dissolved in toluene (12 mL), and powdered molecular sieve (200 mg, 5 Å) was added. The resulting suspension was heated to 90 °C. Catalyst 16a (4.2 mg, 3.7 μmol, 10 mol%) was dissolved in toluene (3 mL) to produce a pink solution, which was added to the reaction once the temperature stabilized at 90 °C. The resulting pink catalyst solution turned pale orange upon addition to the hot reaction mixture. Stirring was continued at 90 °C for 2 hours, followed by the addition of ethanol (2 mL), and the suspension was cooled to ambient temperature. The reaction mixture was filtered through a Celite® stopper to produce a colorless solution, which was concentrated under reduced pressure. The crude residue was purified by rapid column chromatography, eluting with tert-butyl methyl ether (MTBE) / hexane (0–10 v / v MTBE) to yield the title compound (27.2 mg, 0.031 mmol, 84% yield) as a colorless oil. HRMS (ESI) for C 48 H 82 O8Si3Na [M+Na] + Calculated value: 893.52097; Measured value: 893.52090.

[0343]

[0344] Compound 60

[0345] Powdered molecular sieve (100 mg, 5 Å) was added to a solution of diyne 59 (3.7 mg, 5 μmol) in toluene (3 mL), and the resulting suspension was heated to 110 °C. The mixture was stirred for 30 min. Then, a solution of catalyst 17b (1.3 mg, 1.5 μmol, 30 mol%) in toluene (0.5 mL) was added to the boiling mixture. After stirring for 3 hours, ethanol (1 mL) was added to quench the reaction mixture. After cooling to ambient temperature, the mixture was filtered through a Celite® short pad. The solvent was evaporated, and the resulting residue was purified by rapid column chromatography (hexane / ethyl acetate 100:2.5) to yield the title compound as a colorless film (1.6 mg, 47%).

[0346]

[0347] Compound 62

[0348] A molecular sieve (1.2 g, 5 Å) was added to a solution of enone 61 (50.3 mg, 83.4 μmol) in toluene (20 mL), and the mixture was stirred at ambient temperature for 30 min. Subsequently, the mixture was heated to 110 °C, and a solution of 17a (13.3 mg, 16.6 μmol, 20 mol%) in toluene (2 mL) was added dropwise over one minute. Stirring was continued at the same temperature for 2 h. The reaction was then quenched with ethanol (10 mL), cooled to ambient temperature, and filtered through a Celite® short-pad filter, washed with ethyl acetate. Celite® was added to evaporate all volatiles, and the crude product was purified by silica gel rapid column chromatography (hexane / ethyl acetate 50:1 to 20:1-10:1), which provided the title compound as a colorless solid (26.7 mg, 48.6 μmol, 58%).

[0349] in conclusion

[0350] This invention describes a new generation of molybdenum-alkyl carbamates used as catalysts for various alkyne metathesis reactions. Specifically, the type 16 derived pyridine adducts are readily manufactured on a large scale, can be routinely weighed and handled in air, and can be stored for extended periods outside a glove box in a desiccator or in screw-cap vials in a refrigerator. When dissolved in toluene, the spontaneous dissociation of the stable pyridine ligands releases the active material: its performance is excellent, and its functional group tolerance is outstanding. In fact, the new catalysts meet high standards in terms of reactivity and selectivity, and are comparable to the best alkyne metathesis catalysts known to date. Their functional group tolerance is remarkable because they contain many polar and nonpolar groups, diverse proton sites, and many basic functional groups.

Claims

1. Organometallic compounds of general formula (I), in: X represents N, CR X SiR X , where R X Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl or 5-10 heteroaryl, wherein the alkyl, cycloalkyl, aromatic or heteroaromatic ring structure may be substituted with one or more heteroatoms; R 1 R 2 and R 3 They may be the same as or different from each other, and are independently selected from H, C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, di-C1-C4 alkylamino, halogen, nitro, cyano, trifluoromethyl or -COOR 8 , where R 8 Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl, or (R on the same benzene ring) 1 and R 2 ) or (R 2 and R 3 This forms an aromatic or heteroaromatic ring structure, which is conjugated with the benzene ring and has a total of 10-18 carbon atoms in the ring structure, of which 1-3 ring carbon atoms can be replaced by nitrogen. This aromatic or heteroaromatic ring structure can be replaced by one or more heteroatoms. R 4 Selected from H, methyl or ethyl, R 5 and R 6 They may be the same as or different from each other, and are independently selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, and di-C1-C4 alkylamino. The alkyl, cycloalkyl, aromatic, or heteroaromatic ring structure may be substituted with one or more substituents selected from C1-C6 alkyl, 6-14 aryl, or heteroatoms. R 7 It is selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl or 5-10 heteroaryl, and the alkyl, cycloalkyl, aromatic or heteroaryl ring structure can be substituted by one or more substituents selected from C1-C6 alkyl, 6-14 aryl or heteroatom.

2. The organometallic compound of formula (I) according to claim 1, in: X represents N, CR X SiR X , where R X Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl. R 1 R 2 and R 3 They may be the same as or different from each other, and are independently selected from H, C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, di-C1-C4 alkylamino, halogen, nitro, cyano, trifluoromethyl or -COOR 8 , where R 8 Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl. R 4 Selected from H, methyl or ethyl, R 5 and R 6 They may be the same as or different from each other, and are independently selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, di-C1-C4 alkylamino, 6-18 aryl, or 5-10 heteroaryl. The alkyl, cycloalkyl, aromatic, or heteroaromatic ring structure may be substituted with one or more substituents selected from C1-C6 alkyl, 6-14 aryl, or heteroatoms. R 7 It is selected from C1-C12 alkyl, C3-C12 cycloalkyl or 6-18 aryl, and the alkyl, cycloalkyl or aromatic ring structure can be substituted by one or more substituents selected from C1-C6 alkyl, 6-14 aryl or heteroatom.

3. The organometallic compound of formula (I) according to claim 1, in X is N, R 1 R 2 and R 3 They may be the same as or different from each other, and are independently selected from H, C1-C12 alkyl, or C3-C12 cycloalkyl. R 4 Selected from H, methyl or ethyl, R 5 and R 6 They may be the same as or different from each other, and are independently selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl groups. The alkyl, cycloalkyl, aromatic, or heteroaromatic ring structure may be substituted with one or more substituents selected from C1-C6 alkyl, 6-14 aryl, or heteroatoms. R 7 It is selected from C1-C12 alkyl or 6-18 aryl groups, and the alkyl or aromatic ring structure can be substituted by one or more substituents selected from C1-C6 alkyl, 6-14 aryl or heteroatoms.

4. The organometallic compound of formula (I) according to claim 1, in X is N, R 1 R 2 and R 3 Independently selected from H or C1-C6 alkyl groups, R 4 It's H. R 5 and R 6 They may be the same as or different from each other, and represent C1-C12 alkyl or 6-18 aryl groups. R 7 It represents a C1-C12 alkyl or a 6-18 aryl group, which can be substituted with one or more substituents selected from C1-C6 alkyl, 6-14 aryl or heteroatoms.

5. An adduct of the organometallic compound of formula (I) according to any one of claims 1-4 with an adduct-forming compound selected from: Nitrogen-containing 5-10-membered heteroaryl compounds, wherein the heteroaryl group is optionally substituted with one or more C1-C6 alkyl, halogen, -CN, -CF3, -N(C1-C6 alkyl)2 or -NO2 substituents, or PR P 3, where R P It is independently selected from C1-C6 alkyl or 6-18 aryl groups, which are optionally substituted with one or more C1-C3-alkyl, halogen, -CN, -CF3, -N(C1-C3alkyl)2 or -NO2 substituents.

6. An adduct of the organometallic compound of formula (I) according to claim 5, wherein the adduct-forming compound is pyridine, optionally substituted with one or more C1-C6 alkyl, halogen, -CN, -CF3, -N(C1-C6 alkyl)2 or -NO2 substituents, provided that at least one of the pyridine substituents at the 2 and 6 positions is H, the adduct being shown by formula (II): Where R 1 -R 7 It has the meaning as defined in any one of claims 1-4.

7. A method for preparing organometallic compounds of general formula (I), in: X represents N, CR X SiR X , where R X Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl or 5-10 heteroaryl, wherein the alkyl, cycloalkyl, aromatic or heteroaromatic ring structure may be substituted with one or more heteroatoms; R 1 R 2 and R 3 They may be the same as or different from each other, and are independently selected from H, C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, di-C1-C4 alkylamino, halogen, nitro, cyano, trifluoromethyl or -COOR 8 , where R 8 Selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, or 5-10 heteroaryl, or (R on the same benzene ring) 1 and R 2 ) or (R 2 and R 3 It can form an aromatic or heteroaromatic ring structure, which is conjugated with the benzene ring and has a total of 10-18 carbon atoms in the ring structure, of which 1-3 ring carbon atoms can be replaced by nitrogen. The aromatic or heteroaromatic ring structure can be replaced by one or more heteroatoms. R 4 Selected from H, methyl or ethyl, R 5 and R 6 They may be the same as or different from each other, and are independently selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl, 5-10 heteroaryl, C1-C12 alkoxy, C3-C12 cycloalkoxy, C6-C20 aryloxy, and di-C1-C4 alkylamino, wherein the alkyl, cycloalkyl, aromatic, or heteroaromatic ring structure may be substituted with one or more heteroatoms. R 7 It is selected from C1-C12 alkyl, C3-C12 cycloalkyl, 6-18 aryl or 5-10 heteroaryl, and the alkyl, cycloalkyl, aromatic or heteroaryl ring structure can be substituted by one or more substituents selected from C1-C6 alkyl, 6-14 aryl or heteroatom; The method includes the step of reacting a molybdenum complex of formula (III) with a compound of formula (IV) to produce a compound of formula (I): Where Z represents C1-C6 alkyl, -O-C1-C6 alkyl, -N(C1-C6 alkyl)2, -N(6-18 aryl)2, or –N[(C1-C6 alkyl)(6-18 aryl)], and where X and R 1 -R 7 It has the meaning as defined in any one of claims 1-4.

8. Use of the organometallic compound of formula (I) according to any one of claims 1-4 as a catalyst for alkyne metathesis reaction.

9. Use of the adduct of the organometallic compound of formula (I) according to any one of claims 5-6 as a catalyst for alkyne metathesis reactions.

Images