Rhenium (V) carbine complexes and methods of use and preparation thereof

Abstract

A rhenium (V) carbine-based catalytic system for alkyne metathesis reactions that enables alkyne metathesis, such as homologous metathesis and cross metathesis, ring closing metathesis and ring opening metathesis of alkyne or diyne, at room temperature or mild conditions. The catalyst is stable to air and moisture, has wide tolerance to various functional groups in a substrate, and is easy to prepare on a large scale, so that the catalyst is a practical catalytic system based on rhenium (V) Carbai.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 519,832, filed on August 15, 2023, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to rhenium(V) carbyne-based catalytic systems for alkyne metathesis and methods of using the same. Background Art

[0004] As a very useful chemical transformation in chemical synthesis, transition metal-catalyzed alkyne metathesis has an increasing number of practical applications in organic synthesis, polymer synthesis, and dynamic covalent chemistry. There is great interest in developing catalytic systems that are efficient, readily available, broadly tolerant to functional groups, and easy to use. Early studies focused on heterogeneous mixtures of inorganic oxides such as WO3 and MoO3 with silica, or homogeneous mixtures of Mo(CO)6 and phenol. These in situ catalytic systems with unclear active species can promote alkyne metathesis reactions, but have low efficiency (need to be activated at high temperatures (>150°C)) and very limited compatibility with substrate functional groups.

[0005] Recent catalyst development efforts have focused on high-priced 0 These efforts have resulted in the development of a series of excellent catalysts based on structurally well-defined or in situ generated tungsten (VI) and molybdenum (VI) carbyne complexes. These catalytic systems can efficiently catalyze alkyne metathesis reactions. However, these high-priced 0 Tungsten(VI) and molybdenum(VI) carbyne complexes are generally very sensitive to air and moisture and have limited tolerance to substrate functional groups.

[0006] US Patent US20230059662A1 describes rhenium (V) carbyne complexes that can promote alkyne metathesis reactions. Although the pyridine or phosphine complexes disclosed in the above patent application show certain metathesis activity and unprecedented tolerance to air, moisture and functional groups, they have the following two disadvantages: 1) Compared with the efficient d 0 Compared with molybdenum (VI) and tungsten (VI) carbyne catalysts, these rhenium (V) carbyne complexes have low activity and require more stringent conditions (e.g., 100°C) to catalyze the alkyne metathesis reaction in a reasonable time. 2) Due to technical problems, pyridine coordination complexes are difficult to prepare on a large scale. This has become one of the main obstacles to the commercialization of rhenium (V) alkyne metathesis catalysts.

[0007] To address these issues, an ideal alkyne metathesis catalyst based on a rhenium(V) carbyne complex should have the following characteristics: 1) the catalyst should be stable to air and moisture to facilitate its use and storage; 2) the catalyst should be tolerant to a variety of functional groups; 3) the catalyst should be sufficiently active to catalyze metathesis reactions under mild conditions; and 4) the catalyst can be easily prepared on a large scale from commercially available chemicals. Summary of the invention

[0008] The present disclosure meets the above requirements and provides two catalytic systems based on rhenium (V) carbyne for alkyne metathesis reaction, which are significantly more active than previously reported catalytic systems. Ph PO)2(H2O) can even achieve alkyne metathesis at room temperature. Ph The in situ catalytic system composed of PO)2(PMePh2) and dichlorobis(4-methylisopropylphenyl)ruthenium(II) can promote alkyne metathesis under mild conditions. They can effectively catalyze alkyne homologous metathesis, cross metathesis (ACM), ring-closing alkyne metathesis (RCAM), acyclic diyne metathesis macrocyclization (ADIMAC) and ring-opening alkyne metathesis polymerization (ROAMP) with good functional group tolerance. Both systems are derived from complexes

[0009] Re(≡CCH2Ph)( Ph The complexes are stable in air and can be easily prepared on a large scale from the commercially available phosphine ligand Ph2P(o-C6H4-OH). Therefore, they represent a practical alkyne metathesis catalytic system based on rhenium(V)-carbyne.

[0010] In a first aspect, provided herein is a rhenium (V) carbyne complex of Formula 1:

[0011]

[0012] wherein L is H2O, an ether, a ketone, a furan, a thioether, a thiophene, a tertiary amine, or a salt selected from the group consisting of a metal halide, a metal alkoxide, a metal thiolate, and a metal amide;

[0013] R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group;

[0014] R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and

[0015] R 6In each instance is independently alkyl, alkenyl or aryl.

[0016] In certain embodiments, L is water, tetrahydrofuran, tetrahydropyran, or diethyl ether.

[0017] In certain embodiments, R is CH2Ar 1 , where Ar 1 It is phenyl or o-bromophenyl.

[0018] In certain embodiments, R 4 and R 5 Each is independently alkyl, cycloalkyl or phenyl optionally substituted with one or more substituents selected from alkyl, CH3, OCH3, F and CF3.

[0019] In certain embodiments, R 4 and R 5 Each is cyclohexyl, phenyl, 4-fluorophenyl, 2,4-difluorophenyl, 4-trifluoromethylphenyl, 2,4-bis(trifluoromethyl)phenyl, 2,4-dimethylphenyl or 2,4-dimethoxyphenyl.

[0020] In certain embodiments, R 6 is phenyl optionally substituted by alkyl or trifluoromethyl.

[0021] In certain embodiments, R 6 is part of a group consisting of:

[0022]

[0023] Where * represents the site of covalent bonding to oxygen, and ** represents the site of covalent bonding to phosphorus.

[0024] In certain embodiments, the rhenium(V) carbyne complex is selected from the group consisting of:

[0025]

[0026]

[0027] Where R is alkyl, aryl or 2-thiophene or CH2Ar 1 , where Ar 1 is phenyl or o-bromophenyl; and L is water, tetrahydrofuran, tetrahydropyran or diethyl ether.

[0028] In certain embodiments, R is benzyl.

[0029] In certain embodiments, L is water.

[0030] In certain embodiments, the rhenium(V) carbyne complex has the following structure:

[0031]

[0032] In a second aspect, the present invention provides a method for preparing the rhenium (V) carbyne complex described herein, the method comprising: reacting a catalyst precursor of Formula 2 with a ligand selected from water and an alkyl ether and a phosphine-binding agent selected from cuprous chloride, cuprous iodide and dichlorobis (4-methylisopropylphenyl) ruthenium (II) to form a rhenium (V) carbyne complex:

[0033]

[0034] Where R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group;

[0035] PR'3 is PMePh2 or PMe2Ph;

[0036] R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and

[0037] R 6 In each instance is independently alkyl, alkenyl or aryl.

[0038] In a third aspect, provided herein is a method of performing a metathesis reaction, the method comprising: reacting a rhenium(V) carbyne complex described herein with at least one alkyne substrate to form an alkyne metathesis product.

[0039] In certain embodiments, the at least one alkyne substrate is selected from the group consisting of acyclic alkynes, cycloalkynes, acyclic diynes, and cyclodiynes.

[0040] In a fourth aspect, provided herein is a method for performing a metathesis reaction, the method comprising reacting a catalyst precursor of Formula 2, a phosphine-binding agent, and at least one alkyne substrate to form an alkyne metathesis product, wherein the catalyst precursor of Formula 2 has the following structure:

[0041]

[0042] Where R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group;

[0043] PR'3 is PMePh2 or PMe2Ph;

[0044] R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and

[0045] R6 is independently in each instance alkyl, alkenyl, or aryl; and

[0046] The phosphine-binding agent is selected from dichlorobis(4-methylisopropylphenyl)ruthenium(II), dichlorobis(4-methylisopropylphenyl)osmium(II), (1,5-cyclooctadiene)chlororhodium(I) dimer, (1,5-cyclooctadiene)chloroiridium(I) dimer, (1,5-cyclooctadiene)dichloropalladium, cuprous chloride or cuprous iodide.

[0047] In certain embodiments, R is CH2Ar 1 , where Ar 1 It is phenyl or o-bromophenyl.

[0048] In certain embodiments, R 4 and R 5 Each is cyclohexyl, phenyl, 4-fluorophenyl, 2,4-difluorophenyl, 4-trifluoromethylphenyl, 2,4-bis(trifluoromethyl)phenyl, 2,4-dimethylphenyl or 2,4-dimethoxyphenyl.

[0049] In certain embodiments, R 6 is phenyl optionally substituted by alkyl or trifluoromethyl.

[0050] In certain embodiments, R 6 is part of a group consisting of:

[0051]

[0052] Where * represents the site of covalent bonding to oxygen, and ** represents the site of covalent bonding to phosphorus.

[0053] In certain embodiments, the phosphine-binding agent is dichlorobis(4-methylisopropylphenyl)ruthenium(II), and the catalyst precursor is

[0054]

[0055] In a fifth aspect, provided herein is a rhenium (V) carbyne complex having the following structure:

[0056]

[0057] In certain embodiments, L is a weakly coordinating ligand, such as water, tetrahydrofuran, or diethyl ether.

[0058] In certain embodiments, R is CH2Ar 1 , where Ar 1 It is phenyl or o-bromophenyl.

[0059] In certain embodiments, R 4 and R5 Each is independently alkyl, cycloalkyl or phenyl optionally substituted with one or more substituents selected from alkyl, CH3, OCH3, F and CF3.

[0060] In certain embodiments, R 4 and R 5 Each is cyclohexyl, phenyl, 4-fluorophenyl, 2,4-difluorophenyl, 4-trifluoromethylphenyl, 2,4-bis(trifluoromethyl)phenyl, 2,4-dimethylphenyl or 2,4-dimethoxyphenyl.

[0061] In certain embodiments, R 6 is alkyl, alkenyl or phenyl optionally substituted by alkyl or trifluoromethyl.

[0062] In certain embodiments, R 6 is part of a group consisting of:

[0063]

[0064] Where * represents the site of covalent bonding to oxygen, and ** represents the site of covalent bonding to phosphorus.

[0065] In certain embodiments, the rhenium(V) carbyne complex has the following structure:

[0066]

[0067] Compared to the rhenium (V) carbyne catalyst described in US Pat. No. 20230059662A1, the water complex disclosed herein has the following advantages: 1) The water complex is easier to synthesize and can be prepared on a large scale (at least 1 gram scale). 2) Compared to the pyridine complex, the water complex is significantly more active in catalyzing alkyne metathesis reactions. Figure 1 As shown, in In the presence of molecular sieves (MS), the metathesis of 1-methoxy-4-(1-propyn-1-yl)benzene (15) catalyzed by the hydrate complex 14 at 100 °C was completed within 5 min. In contrast, the reactions using the phosphine complex 11 and the pyridine complex 8b obtained conversions of less than 5% and about 50%, respectively, even after 2 h. 3) The hydrate complex is able to catalyze the metathesis of alkynes at room temperature. Figure 2 As shown in entry 3, the conversion rate of the model reaction at room temperature (25°C) for 16 h also reached 92%. In contrast, the pyridine complex 8b described in US Pat. No. US20230059662A1 could not catalyze the model reaction under the same conditions. Figure 2 shown.

[0068] In a sixth aspect, the present invention provides a method for preparing the rhenium (V) carbyne complex described herein, the method comprising: contacting a catalyst precursor of Formula 2 with a phosphine-binding agent and a weakly coordinating ligand compound such as water, tetrahydrofuran or diethyl ether to form a rhenium (V) carbyne complex:

[0069]

[0070] Where R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group;

[0071] PR'3 is PMePh2 or PMe2Ph;

[0072] R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and

[0073] R 6 is independently in each instance alkyl, alkenyl or aryl;

[0074] The phosphine-binding agent is selected from late transition metal complexes, including but not limited to dichlorobis(4-methylisopropylphenyl)ruthenium(II), dichlorobis(4-methylisopropylphenyl)osmium(II), (1,5-cyclooctadiene)chlororhodium(I) dimer, (1,5-cyclooctadiene)chloroiridium(I) dimer, and (1,5-cyclooctadiene)dichloropalladium.

[0075] In a seventh aspect, provided herein is a method of using a catalyst precursor, the method comprising: reacting a catalyst precursor of Formula 2 and a phosphine-binding agent, wherein the catalyst precursor of Formula 2 is represented by the following chemical structure:

[0076]

[0077] Where R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group;

[0078] PR'3 is PMePh2 or PMe2Ph;

[0079] R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and

[0080] R 6 is independently in each instance alkyl, alkenyl, or aryl; and

[0081] The phosphine-binding agent is selected from a late transition metal complex, such as dichlorobis(4-methylisopropylphenyl)ruthenium(II), dichlorobis(4-methylisopropylphenyl)osmium(II), (1,5-cyclooctadiene)chlororhodium(I) dimer, (1,5-cyclooctadiene)chloroiridium(I) dimer, (1,5-cyclooctadiene)dichloropalladium. In certain embodiments, the catalyst precursor and the phosphine-binding agent are reacted in a molar ratio of 1:0.5, respectively. In certain embodiments, the catalyst precursor of Formula 2 and the phosphine-binding agent are contacted in the presence of at least one alkyne substrate. In certain embodiments, the catalyst precursor of Formula 2 and the phosphine-binding agent are contacted in the absence of any ligand (such as pyridine).

[0082] Compared to the pyridine complex described in US Pat. No. 20230059662A1, the novel method disclosed herein using a 1:0.5 in situ mixture of rhenium (V) carbyne of Formula 6 and a phosphine-binding agent has the following advantages: 1) This is a more convenient method for using rhenium (V) carbyne complexes for alkyne metathesis reactions. By using this method, there is no need to prepare difficult-to-prepare pyridine complexes. 2) Compared to pyridine complexes or PMePh2 complexes, the in situ mixture is significantly more active in catalyzing alkyne metathesis reactions. Figure 1 As shown, in In the presence of molecular sieves (MS), the homologous metathesis of 1-methoxy-4-(1-propyn-1-yl)benzene (15) catalyzed by a 1:0.5 mixture of complex 11 / dichlorobis(4-methylisopropylphenyl)ruthenium(II) at 100°C was completed within 30 min. In contrast, the reactions using phosphine complex 11 and pyridine complex 8b obtained conversions of less than 5% and about 50%, respectively, even after 2 h. 3) The in situ mixture is able to catalyze the metathesis of alkynes under mild conditions. Figure 2 As shown, the model reaction catalyzed by a mixture of 11 and dichlorobis(4-methylisopropylphenyl)ruthenium(II) achieved complete conversion within 12 h at 60 °C.

[0083] In an eighth aspect, provided herein is a method of performing a metathesis reaction, the method comprising contacting the rhenium(V) carbyne complex of the first aspect or the fifth aspect with at least one alkyne substrate to form an alkyne metathesis product.

[0084] In certain embodiments, the metathesis reaction is an alkyne homometathesis reaction, an alkyne cross-metathesis, a ring-closing alkyne metathesis, a ring-opening alkyne metathesis polymerization, or an acyclic diyne metathesis macrocyclization.

[0085] In certain embodiments, the at least one alkyne substrate is selected from the group consisting of acyclic alkynes, cycloalkynes, acyclic diynes, and cyclodiynes. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] The above and other objects and features of the present disclosure will become apparent from the following description of the present disclosure in conjunction with the accompanying drawings.

[0087] Figure 1 Depicted are graphs showing catalyst test data, of which 11 is

[0088] Re(≡CCH2Ph)( Ph PO)2(PMePh2), 8b is Re(≡CCH2Ph)( Ph PO)2(py), 14 is Re(≡CCH2Ph)( Ph PO)2(H2O). Conditions: substrate (1-methoxy-4-(1-propyn-1-yl)benzene (0.3 mmol), catalyst (5 mol%), MS (450 mg), anhydrous toluene (3 mL), 100 ° C. Using CH2Ph2 as an internal standard, 1 H NMR, to determine the yield.

[0089] Figure 2 Depicted is a graph showing catalyst test data under mild conditions, where 11 is Re(≡CCH2Ph)( Ph PO)2(PMePh2), 14 is Re(≡CCH2Ph)( Ph PO)2(H2O), 8b is Re(≡CCH2Ph)( Ph PO)2(py). Standard conditions: 1-methoxy-4-(1-propynyl)benzene (15, 0.3 mmol), catalyst (5 mol%), MS (450 mg), anhydrous toluene (3 mL). All reagents and catalysts were weighed in air. CH2Ph2 was used as an internal standard. 1 Yield determined by H NMR. [a] 0.5 mol% catalyst loading.

[0090] Figure 3 The complex Re(≡CCH2Ph)( Ph Single crystal X-ray diffraction structure of PO)2(H2O) (ORTEP). DETAILED DESCRIPTION

[0091] definition

[0092] The following terms are used to describe the present invention. If no specific definition is given herein, the terms used to describe the present invention shall have the ordinary meaning understood by those of ordinary skill in the art.

[0093] Throughout this disclosure, unless the context requires otherwise, variations such as the word "comprise" or "include" should be understood to mean including the stated integer or group of integers, but not excluding any other integer or group of integers. It should also be noted that in this disclosure, especially in the claims and / or the specification, terms such as "comprise" or "include" may have the meanings assigned to them by the Chinese Patent Law; and terms such as "essentially consisting of..." allow for elements not explicitly stated, but do not include elements found in the prior art or that affect the basic features or novel features of the present invention.

[0094] Unless otherwise specifically stated, the use of the singular in this document includes the plural (and vice versa). In addition, if the term "about" is used before a quantitative value, the present teachings also include the specific quantitative value itself unless otherwise specifically stated. Unless otherwise stated or inferred, the term "about" as used herein refers to a change of ±10%, ±7%, ±5%, ±3%, ±1% or ±0% compared to the nominal value.

[0095] As used herein, unless otherwise indicated, the term "halo" or "halide" includes fluorine, chlorine, bromine or iodine.

[0096] As used herein, the term "alkyl" refers to a straight or branched saturated hydrocarbon group. Examples of alkyl groups include methyl, ethyl, propyl (e.g., n-propyl and isopropyl), butyl (e.g., n-butyl, isobutyl, sec-butyl, tert-butyl), pentyl (e.g., 1-methylbutyl, 2-methylbutyl, isopentyl, tert-pentyl, 1,2-dimethylpropyl, neopentyl, and 1-ethylpropyl), hexyl, etc. In various embodiments, the alkyl group may have 1-40 carbon atoms (i.e., C1-40 alkyl), such as 1-30 carbon atoms (i.e., C1-30 alkyl). In certain embodiments, the alkyl group may have 1-6 carbon atoms, which may be referred to as "low alkyl". Examples of low alkyl groups include methyl, ethyl, propyl (e.g., n-propyl and isopropyl) and butyl (e.g., n-butyl, isobutyl, sec-butyl, tert-butyl). In certain embodiments, the alkyl group may be optionally substituted as described herein. The alkyl group is generally not substituted by another alkyl group, alkenyl, or alkynyl.

[0097] As used herein, the term "alkenyl" refers to a straight or branched alkyl group with one or more carbon-carbon double bonds. Examples of alkenyl groups include vinyl, propenyl, butenyl, pentenyl, hexenyl, butadienyl, pentadienyl, hexadienyl, etc. One or more carbon-carbon double bonds can be inside (e.g., 2-butene) or at the end (e.g., 1-butene). In various embodiments, alkenyl groups can have 2-40 carbon atoms (i.e., C2-40 alkenyl), such as 2-20 carbon atoms (i.e., C2-20 alkenyl). In certain embodiments, alkenyl groups can be substituted as described herein. Alkenyl groups are usually not substituted by another alkenyl, alkyl, or alkynyl.

[0098] As used herein, the term "cycloalkyl" by itself or as part of another substituent, unless otherwise indicated, refers to a monocyclic hydrocarbon having 3-12 carbon atoms in the ring system, including hydrogen, straight chain, branched and / or cyclic substituents. Exemplary cycloalkyls include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like.

[0099] As used herein, the term "heteroatom" refers to an atom of any element other than carbon or hydrogen, including, for example, nitrogen, oxygen, silicon, sulfur, phosphorus, and selenium.

[0100] As used herein, the term "heterocycloalkyl" includes reference to a saturated heterocyclic moiety having 3, 4, 5, 6, or 7 ring carbon atoms and 1, 2, 3, 4, or 5 ring heteroatoms selected from nitrogen, oxygen, phosphorus, and sulfur. The group can be a polycyclic ring system, but more commonly a monocyclic ring. The term includes reference to groups such as azetidinyl, pyrrolidinyl, tetrahydrofuranyl, piperidinyl, oxiranyl, pyrazolidinyl, imidazolyl, indolalkyl, piperazinyl, thiazolidinyl, morpholinyl, thiomorpholinyl, quinolizinyl, etc.

[0101] As used herein, the term "aryl" refers to an aromatic monocyclic hydrocarbon ring system or an aromatic polycyclic ring system in which two or more aromatic hydrocarbon rings are fused together (i.e., sharing a bond) or at least one aromatic monocyclic hydrocarbon ring is fused to one or more cycloalkyl and / or heterocycloalkyl rings. The ring system of the aryl can have 6-24 carbon atoms (e.g., C6-24 aryl), and the ring system can include multiple fused rings. In certain embodiments, polycyclic aryl can have 8-24 carbon atoms. Any suitable ring position of the aryl can be covalently linked to the defined chemical structure. Examples of aryl groups having only aromatic carbocyclic rings include phenyl, 1-naphthyl (bicyclic), 2-naphthyl (bicyclic), anthracenyl (tricyclic), phenanthrenyl (tricyclic), pentaenyl (pentacyclic) and similar groups. Examples of polycyclic ring systems in which at least one aromatic carbocyclic ring is fused to one or more cycloalkyl and / or heterocycloalkyl rings include, inter alia, benzo derivatives of cyclopentane (i.e., indanyl, which is a 5,6-bicyclic cycloalkyl / aromatic ring system), benzo derivatives of cyclohexane (i.e., tetrahydronaphthyl, which is a 6,6-bicyclic cycloalkyl / aromatic ring system), derivatives of imidazoline (i.e., benzimidazolinyl, which is a 5,6-bicyclic heterocycloalkyl / aromatic ring system), and benzo derivatives of pyran (i.e., chromenyl, which is a 6,6-bicyclic heterocycloalkyl / aromatic ring system). Other examples of aryl groups include benzodioxanyl, benzodioxolanyl, chromanyl, indolinyl, and the like. In certain embodiments, aryl groups may be optionally substituted.

[0102] The term "aralkyl" refers to an alkyl group substituted with an aryl group.

[0103] The term "optionally substituted" refers to chemical groups such as alkyl, cycloalkylaryl, etc., in which one or more hydrogens may be replaced by substituents as described herein, such as halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxy, alkoxy, amino, nitro, sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, sulfonamido, ketone, aldehyde, ester, heterocyclyl, aromatic or heteroaromatic moiety, -CF3, -CN or the like.

[0104] The term "nitro" is art-recognized and refers to -NO2; the term "halo" is art-recognized and refers to -F, -Cl, -Br or -I; the term "thiol" is art-recognized and refers to -SH; the term "hydroxyl" refers to -OH; the terms "sulfonyl" and "sulfone" are art-recognized and refer to -SO2-. "Halide" refers to the corresponding anion of the halogen.

[0105] As used herein, the term "substantially pure" in relation to a sample of a compound described herein means that the sample contains at least 60% of the compound by weight. In certain embodiments, the sample contains at least 70% of the compound, at least 75% of the compound, at least 80% of the compound, at least 85% of the compound, at least 90% of the compound, at least 95% of the compound, or at least 98% of the compound by weight.

[0106] Symbols in chemical structures Represents the position where a specified chemical structure is bonded to another chemical structure.

[0107] The present disclosure provides a rhenium (V) carbyne complex having a chemical formula 1:

[0108]

[0109] wherein L is water, ether, ketone, furan, thioether, thiophene, tertiary amine or a metal salt selected from metal halides, metal alkoxides, metal thiolates and metal amides;

[0110] R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group;

[0111] R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and

[0112] R 6 In each instance is independently alkyl, alkenyl or aryl.

[0113] For clarity, the rhenium (V) carbyne complexes described herein are shown as single isomers. However, the present disclosure contemplates all isomeric forms of the rhenium (V) carbyne complexes, including structural isomers, geometric isomers, and stereoisomers. The rhenium (V) carbyne complexes described herein may be present in enantiomerically pure form (e.g., enantiomeric excess 50-100%, 50-99.9%, 60-99.9%, 70-99.9%, 80-99.9%, 90-99.9%, 95-99.9%, 97-99.9%, or 99-99.9%) or in the form of a racemic mixture.

[0114] In certain embodiments, the rhenium(V) carbyne complex is substantially pure.

[0115] In certain embodiments, L is water, a 2-alkyl substituted furan (e.g., 2-methylfuran, 2-ethylfuran, 2-propylfuran, or 2-isopropylfuran), a 2-alkyl substituted thiophene (e.g., 2-methylthiophene, 2-ethylthiophene, 2-propylthiophene, or 2-isopropylthiophene), a ketone (e.g., acetone, 2-butanone, or methyl isopropyl ketone), a halide (e.g., chloride, bromide, or iodide), a thiolate (e.g., -S-C1-C6 alkyl, -S-C1-C5 alkyl, -S-C1-C4 alkyl, -S-C1-C3 alkyl, or -S-C1-C2 alkyl), a tertiary amine (e.g., N(R 7 )3, where R 7 In each instance, R is independently selected from C1-C6 alkyl, C1-C5 alkyl, C1-C4 alkyl, C1-C3 alkyl and C1-C2 alkyl; or 7 Two examples of alkylamides are -N(R) and -N(R) 7 )2, where R 7 In each instance, R is independently selected from C1-C6 alkyl, C1-C5 alkyl, C1-C4 alkyl, C1-C3 alkyl and C1-C2 alkyl, or 7 Together with the nitrogen to which they are covalently bonded, they form a 3-6, 3-5, 3-4 or 4-6 membered cycloalkylamine, or R 7 Y 7 A dialkyl ether or dialkyl sulfide (wherein Y is O or S, R 7 is independently selected in each instance from C1-C6 alkyl, C1-C5 alkyl, C1-C4 alkyl, C1-C3 alkyl and C1-C2 alkyl, or R 7Two examples of L together with their covalently bonded oxygen form 3-6, 3-5, 3-4 or 4-6 membered cycloalkyl ethers. Exemplary alkyl ethers include, but are not limited to, dimethyl ether, diethyl ether, diisopropyl ether, tert-butyl methyl ether, 2-methyltetrahydrofuran, 2-ethyltetrahydrofuran, tetrahydropyran, and the like. In certain embodiments, L is water, diethyl ether, tetrahydrofuran or tetrahydropyran.

[0116] In the case where L is a metal salt or metal complex, L may be bonded (e.g., via a coordination bond) to a bridging halide, alkoxide, thiolate, or amide, the latter being bonded to one or more metal cations, as shown in the exemplary embodiments below, where L is MgCl2, ZnCl2, RuCl2(C6H6), PdCl2(COD):

[0117]

[0118] Among them, R 4 , R 5 and R 6 Each is independently as described herein. In certain embodiments, the metal salt is of formula (A t+ )U(B u- ) T In other words, A represents a metal cation selected from elements of Groups 1 to 14, and B represents a metal cation selected from halides, R 7 O - , R 7 S - and (R 7 )2N - anion, where R 7 In each instance, R is independently selected from C1-C6 alkyl, C1-C5 alkyl, C1-C4 alkyl, C1-C3 alkyl and C1-C2 alkyl, or 7 Two examples of are formed with their covalently bonded nitrogen to form 3-6, 3-5, 3-4 or 4-6 membered cyclic amides, u represents the anionic charge, U is equal to the absolute value of the anionic charge, and T is equal to the absolute value of the metal cation charge. Exemplary metal cations include, but are not limited to, Li, Na, K, Rb Cs, Mg, Ca, Sr, Ba, Zr, Ti, Cr, Mn, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Hg, Al, Ga, In, Sn and Pb.

[0119] In certain embodiments, R is phenyl, 2-thiophene, or CH2Ar 1 , where Ar 1 It is phenyl and o-bromophenyl.

[0120] In certain embodiments, R 4 and R 5Each independently is a cyclohexyl or phenyl group optionally substituted with one or more substituents selected from alkyl, CH3, OCH3, F and CF3. Each phenyl group may be independently substituted with 0, 1 or 2 substituents. In certain embodiments, R 4 and R 5 Each is independently a moiety selected from phenyl, 4-fluorophenyl, 2,4-difluorophenyl, 4-trifluoromethylphenyl, 2,4-bis(trifluoromethyl)phenyl, 2,4-dimethylphenyl and 2,4-dimethoxyphenyl.

[0121] In certain embodiments, R 6 is phenyl optionally substituted with alkyl or trifluoromethyl. 6 It is selected from the following parts:

[0122]

[0123] Where * represents the site of covalent bonding to oxygen, and ** represents the site of covalent bonding to phosphorus.

[0124] In certain embodiments, the rhenium(V) carbyne complex has Formula 3:

[0125]

[0126] Where R 8 is an alkyl group; R 9 is an alkyl group or a heteroatom-containing group selected from F, CF3 and OMe; L is water, tetrahydrofuran, tetrahydropyran or diethyl ether; and R is benzyl.

[0127] In certain embodiments, the rhenium(V) carbyne complex is selected from:

[0128]

[0129] as well as

[0130] Where R is alkyl, aryl, 2-thiophene or CH2Ar 1 , where Ar 1 is phenyl or o-bromophenyl; and L is water.

[0131] In certain embodiments, the rhenium(V) carbyne ligand has the structure:

[0132]

[0133] The rhenium (V) carbyne complex of Formula 1 herein can be synthesized by methods well known to those skilled in the art. In certain embodiments, the rhenium (V) carbyne complex of Formula 1 is prepared by a ligand substitution reaction of the rhenium (V) carbyne complex with a phosphine phenol or a phosphine alcohol. In certain embodiments, as shown in Scheme 1, the rhenium (V) carbyne complex described herein is prepared:

[0134]

[0135] Solution 1

[0136] R 4 , R 5 and R 6 Each as defined in any embodiment described herein; X 3 is Cl; PR'3 is PMePh2 or PMe2Ph; and R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 The rhenium (V) carbyne complex of formula 2 can be prepared according to the method described in the following literature: W. Bai et al., Organometallics 2016, 35, 3808-3815, Organometallics 2018, 37, 559-569 or G. He et al., New J. Chem. 2013, 37, 1823-1832.

[0137] Generally, the synthesis reaction can be carried out at 100°C in toluene under inert gas. Adding an excess (2-5 equivalents) of an organic base, such as triethylamine, can accelerate the conversion. The reaction is generally completed within a few hours. After the reaction, insoluble salts can be removed by filtration, and PR'3 can be removed by washing with hexane, ether, methanol or a mixture thereof.

[0138] The rhenium (V) carbyne complex described herein can be synthesized by a ligand exchange reaction of an existing rhenium (V) carbyne complex with a neutral electron donor ligand. For example, the reaction formula can be shown in Scheme 2:

[0139]

[0140] Solution 2

[0141] Among them, L, R, R', R 4 , R 5 and R 6Each independently as defined in any embodiment described herein; the phosphine-binding agent is selected from dichlorobis(4-methylisopropylphenyl)ruthenium(II), dichlorobis(4-methylisopropylphenyl)osmium(II), (1,5-cyclooctadiene)chlororhodium(I) dimer, (1,5-cyclooctadiene)chloroiridium(I) dimer, (1,5-cyclooctadiene)dichloropalladium, cuprous chloride and cuprous iodide.

[0142] In general, the synthesis reaction can be carried out at 80-140°C or 100-140°C in toluene under an inert atmosphere. The amount of the phosphine-binding agent added can be 1 equivalent. The reaction can be completed in a few hours. Advantageously, the product is stable to air and moisture in solution. After the reaction, the by-product phosphine complex can be easily removed by washing with hexane, ether, methanol or a mixture thereof. In particular, only when the product is well soluble in diethyl ether can it be purified by diethyl ether extraction and then recrystallization from diethyl ether.

[0143] The present disclosure provides a method for preparing a rhenium (V) carbyne complex of Formula 1, the method comprising: reacting a catalyst precursor of Formula 2 with a ligand selected from water and an alkyl ether and a phosphine-binding agent to form a rhenium (V) carbyne complex of Formula 1,

[0144]

[0145] Where R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group;

[0146] PR'3 is PMePh2 or PMe2Ph;

[0147] R 4 and R 5 are each independently aryl, alkyl or cycloalkyl; and

[0148] R 6 is independently in each instance alkyl, alkenyl or aryl;

[0149] The phosphine-binding agent is selected from dichlorobis(4-methylisopropylphenyl)ruthenium(II), dichlorobis(4-methylisopropylphenyl)osmium(II), (1,5-cyclooctadiene)chlororhodium(I) dimer, (1,5-cyclooctadiene)chloroiridium(I) dimer, (1,5-cyclooctadiene)dichloropalladium, cuprous chloride or cuprous iodide.

[0150] In certain embodiments, R is CH2Ar 1 , where Ar 1 It is phenyl or o-bromophenyl.

[0151] In certain embodiments, R 4 and R5 Each independently is a cyclohexyl group, a phenyl group, optionally substituted by one or more substituents selected from alkyl, CH3, OCH3, F and CF3. Each phenyl group can be independently substituted by 0, 1 or 2 substituents. In certain embodiments, R 4 and R 5 Each is independently a moiety selected from phenyl, 4-fluorophenyl, 2,4-difluorophenyl, 4-trifluoromethylphenyl, 2,4-bis(trifluoromethyl)phenyl, 2,4-dimethylphenyl and 2,4-dimethoxyphenyl.

[0152] In certain embodiments, R 6 is phenyl optionally substituted by alkyl or trifluoromethyl. 6 It is selected from the following parts:

[0153]

[0154] Where * represents the site of covalent bonding to oxygen, and ** represents the site of covalent bonding to phosphorus.

[0155] The method for preparing the rhenium (V) carbyne complex of Formula 1 may further include the step of contacting a compound of Formula 4 with a compound of Formula 5 to form a catalyst precursor of Formula 2:

[0156]

[0157] Where X 3 is Cl; PR'3 is PMePh2 or PMe2Ph; R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group;

[0158]

[0159] Where R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and R 6 is an alkyl, alkenyl or aryl group.

[0160] Also provided herein is a method of performing a metathesis reaction, the method comprising contacting a rhenium (V) carbyne complex described herein with at least one alkyne substrate, thereby forming an alkyne metathesis product.

[0161] Rhenium (V) carbyne complexes have a high degree of functional group compatibility. Therefore, the type of alkyne substrates that can be used for the methods described herein is not particularly limited. In certain embodiments, the alkyne substrate is selected from acyclic alkynes, cycloalkynes, acyclic diynes and cyclodiynes. In certain embodiments, the alkyne substrate comprises one or more functional groups selected from the following: alkyl, aralkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, perhaloalkyl, nitro, nitrile, halide (e.g., F, Cl, Br or I), hydroxyl, ether, thioether, tertiary amine, aldehyde, ketone, ester, amide, carbonate, phosphite, phosphonate, phosphate, carbamate, urea and sulfonamide.

[0162] The rhenium (V) carbyne complex can be present in a catalytic amount, a stoichiometric amount, or an excess relative to the alkyl substrate in the metathesis reaction. In certain embodiments, the rhenium (V) carbyne complex is present at 0.1-10 mol%, 0.5-10 mol%, 1-10 mol%, 3-7 mol%, 4-6 mol%, or 1-5 mol% relative to the alkyne substrate. In certain embodiments, the rhenium (V) carbyne complex is present at 5 mol% relative to the alkyne substrate.

[0163] Metathesis reactions catalyzed by the rhenium (V) carbyne complexes described herein can be carried out in non-polar organic solvents, polar organic solvents, or mixtures thereof. In certain embodiments, the solvent is an aromatic solvent, such as benzene, toluene, xylene, or mixtures thereof.

[0164] The rhenium (V) carbyne complexes described herein are highly active metathesis catalysts. Therefore, metathesis reactions catalyzed by the rhenium (V) carbyne complexes described herein can be carried out at any temperature. For example, the metathesis reaction can be carried out at a temperature of -40°C to 200°C, -40°C to 180°C, -40°C to 160°C, -40°C to 140°C, -40°C to 120°C, -40°C to 100°C, -20°C to 100°C, 0°C to 100°C, 10°C to 100°C, 20°C to 100°C, 20°C to 90°C, 20°C to 80°C, 30°C to 80°C, 40°C to 80°C, 50°C to 70°C, 55°C to 65°C, 20°C to 70°C, 20°C to 60°C, 20°C to 50°C, 20°C to 40°C, 20°C to 30°C, 25°C to 30°C, or 20°C to 25°C. In certain embodiments, the metathesis reaction catalyzed by the rhenium (V) carbyne complex described herein is carried out at about 25°C or about 60°C.

[0165] The metathesis reaction using the rhenium (V) carbyne complex described herein can be carried out for any length of time. Selecting an appropriate reaction time is entirely within the skill range of those of ordinary skill in the field. In certain embodiments, the metathesis reaction using the rhenium (V) carbyne complex described herein is carried out for 1-20 hours, 5-20 hours, 10-20 hours, 15-20 hours, 1-15 hours, 1-10 hours, 1-5 hours or 2-4 hours. In certain embodiments, the metathesis reaction using the rhenium (V) carbyne complex described herein is carried out for about 1 hour, about 3 hours or about 16 hours.

[0166] Figure 1 Results are shown for homologous metathesis reactions of model alkynes using the rhenium(V) carbyne complexes described herein. The results show that the rhenium(V) carbyne complexes described herein are more active than pyridine and phosphine substituted analogs.

[0167] Figure 2 Shown is a table demonstrating the results of homologous metathesis reactions of model alkynes using the rhenium(V) carbyne complexes described herein. Advantageously, the rhenium(V) carbyne complexes described herein produce the desired alkyne metathesis products in high yields at 25-80°C.

[0168] The present disclosure also provides a method for performing a metathesis reaction, the method comprising: contacting a catalyst precursor of Formula 2, a phosphine-binding agent, and at least one alkyne substrate to form an alkyne metathesis product, wherein the catalyst precursor of Formula 2 has the following structure:

[0169]

[0170] Where R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group;

[0171] PR'3 is PMePh2 or PMe2Ph;

[0172] R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and

[0173] R 6 is independently in each instance alkyl, alkenyl, or aryl; and

[0174] The phosphine-binding agent is selected from dichlorobis(4-methylisopropylphenyl)ruthenium(II), dichlorobis(4-methylisopropylphenyl)osmium(II), (1,5-cyclooctadiene)chlororhodium(I) dimer, (1,5-cyclooctadiene)chloroiridium(I) dimer, (1,5-cyclooctadiene)dichloropalladium, cuprous chloride or cuprous iodide.

[0175] In certain embodiments of the catalyst precursor of Formula 2, R is phenyl, 2-thiophene or CH2Ar 1 , where Ar 1 It is phenyl and o-bromophenyl.

[0176] In certain embodiments of the catalyst precursor of Formula 2, R 4 and R 5 Each independently is a cyclohexyl or phenyl group optionally substituted with one or more substituents selected from alkyl, CH3, OCH3, F and CF3. Each phenyl group can be independently substituted with 0, 1 or 2 substituents. In certain embodiments, R 4 and R 5 Each is independently a moiety selected from phenyl, 4-fluorophenyl, 2,4-difluorophenyl, 4-trifluoromethylphenyl, 2,4-bis(trifluoromethyl)phenyl, 2,4-dimethylphenyl and 2,4-dimethoxyphenyl.

[0177] In certain embodiments of the catalyst precursor of Formula 2, R 6 is phenyl optionally substituted with alkyl or trifluoromethyl. 6 It is selected from the following parts:

[0178]

[0179] Where * represents the site of covalent bonding to oxygen, and ** represents the site of covalent bonding to phosphorus.

[0180] In certain embodiments, the catalyst precursor has Formula 6:

[0181]

[0182] Where R 8 is an alkyl group; R 9 is an alkyl group or a heteroatom-containing group selected from F, CF3 and OMe; PR'3 is PMePh2 or PMe2Ph; and R is benzyl.

[0183] In certain embodiments, the catalyst precursor is selected from:

[0184]

[0185]

[0186] Where R is alkyl, aryl or 2-thiophene or CH2Ar 1 , where Ar 1 is phenyl or o-bromophenyl; and PR'3 is PMePh2 or PMe2Ph.

[0187] In certain embodiments, the carbyne catalyst precursor has the following structure:

[0188]

[0189] The metathesis catalyst system comprising a catalyst precursor of Formula 2 and a phosphine-binding agent has a high degree of functional group compatibility. Therefore, the type of alkyne substrate that can be used for the method described herein is not particularly limited. In certain embodiments, the alkyne substrate is selected from acyclic alkynes, cycloalkynes, acyclic diynes and cyclodiynes. In certain embodiments, the alkyne substrate comprises one or more functional groups selected from the following: alkyl, aralkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, perhaloalkyl, nitro, nitrile, halide (e.g., F, Cl, Br or I), hydroxyl, ether, thioether, tertiary amine, aldehyde, ketone, ester, amide, carbonate, phosphite, phosphonate, phosphate, carbamate, urea and sulfonamide.

[0190] The metathesis reaction catalyzed by the metathesis catalyst system comprising the catalyst precursor of Formula 2 described herein and a phosphine-binding agent can be carried out in a non-polar organic solvent, a polar organic solvent, or a mixture thereof. In certain embodiments, the solvent is an aromatic solvent, such as benzene, toluene, xylene, or a mixture thereof.

[0191] The catalyst precursor of Formula 2 and the phosphine-binding agent may be present in any molar ratio. In certain embodiments, the catalyst precursor of Formula 2 and the phosphine-binding agent are present in a molar ratio of 1:1 to 1:2, 1:1 to 1:1.5, 1:1 to 1:1.25, 1:1 to 1:1.1, 1:1 to 1:1.05, 1:0.1 to 1:0.9, 1:0.2 to 1:0.8, 1:0.3 to 1:0.7, 1:0.4 to 1:0.6, or 1:0.45 to 1:0.55, respectively. In certain embodiments, the catalyst precursor of Formula 2 and the phosphine-binding agent are present in a molar ratio of about 1 to about 1 or about 1 to about 0.5, respectively.

[0192] The metathesis catalyst system comprising the catalyst precursor of Formula 2 described herein can be present in the metathesis reaction in a catalytic amount, a stoichiometric amount, or in excess relative to the excess alkyne substrate. In certain embodiments, the catalyst precursor of Formula 2 is present at 0.1-10 mol%, 0.5-10 mol%, 1-10 mol%, 3-7 mol%, 4-6 mol%, or 1-5 mol% relative to the alkyne substrate. In certain embodiments, the rhenium (V) carbyne complex is present at about 5 mol% relative to the alkyne substrate.

[0193] The metathesis catalyst system comprising a catalyst precursor of Formula 2 as described herein and a phosphine-binding agent is a highly active metathesis catalyst system. Therefore, the metathesis reaction catalyzed by the catalyst system comprising a catalyst precursor of Formula 2 as described herein and a phosphine-binding agent can be carried out at any temperature. For example, the metathesis reaction can be carried out at a temperature of 25°C-200°C, 40°C-150°C, 40°C-150°C, 40°C-100°C, 50°C-90°C, 60°C-80°C, 70°C-80°C, 60°C-70°C, 40°C-80°C, 50°C-70°C, 55°C-65°C, 60°C-100°C, 70°C-90°C, or 75°C-85°C. In certain embodiments, the metathesis reaction catalyzed by the catalyst system comprising a catalyst precursor of Formula 2 as described herein and a phosphine-binding agent is carried out at about 60°C or about 80°C.

[0194] The metathesis reaction of the catalyst system using the catalyst precursor of Formula 2 as described herein and the phosphine-binding agent can be carried out for any time length. Selecting appropriate reaction time is completely within the skill range of those of ordinary skill in the art. In certain embodiments, the metathesis reaction of the catalyst system using the catalyst precursor comprising Formula 2 as described herein and the phosphine-binding agent is carried out for 1-20 hours, 5-20 hours, 10-20 hours, 15-20 hours, 1-15 hours, 1-10 hours, 1-5 hours or 2-4 hours. In certain embodiments, the metathesis reaction using the rhenium (V) carbyne complex as described herein is carried out for about 1 hour, about 3 hours or about 16 hours.

[0195] Example

[0196] General considerations. Unless otherwise noted, all manipulations were performed under nitrogen atmosphere using standard Schlenk techniques. Solvents were freshly distilled from sodium benzophenone (hexane, diethyl ether, tetrahydrofuran, toluene) or CaH2 (dichloromethane) under nitrogen. Methanol and ethanol were sparged with nitrogen for approximately 20 min before use. Deuterated solvents were dried with CaH2 (d-dichloromethane, deuterated chloroform) or sodium benzophenone (d-benzene), distilled under nitrogen or vacuum transferred, degassed by three freeze-pump-thaw cycles, and stored in a refrigerator with In a sealed tube with molecular sieve. Powder Molecular sieve( MS) was purchased from Sigma-Aldrich and activated before use by heating at 150°C under vacuum for about 24 hours or by heating with a heat gun (at 450°C) under vacuum for about 5 minutes. 1 H. 13 C{ 1 H} and 31 P{ 1H} NMR spectra were collected by a Bruker-400 spectrometer. 1 H and 13 C{ 1 H} NMR shifts are reported in ppm relative to the solvent signal ( 1 H NMR, CDCl3 is 7.26 ppm, CD2Cl2 is 5.32 ppm, C6D6 is 7.16 ppm; 13 C{ 1 H} NMR, CDCl3 is 77.16ppm, CD2Cl2 is 53.84ppm, C6D6 is 128.06ppm). 31 P{ 1 H} chemical shifts are relative to 85% H3PO4. FT-IR spectra were recorded on a Bruker ALPHA spectrometer with an ATR accessory and the selected peaks are expressed in cm -1 HRMS were recorded using chemical ionization (CI) or electrospray ionization (ESI) mass spectrometers. Elemental analysis was performed by MEDA L Ltd (Egham, UK).

[0197] Example 1—Re(≡CCH2Ph)( Ph Large-Scale Synthesis of PO)2(PMePh2)(Complex 11)

[0198]

[0199] mer-ReCl3(PMePh2)3. (NH4)ReO4 (6.50 g, 24.2 mmol), concentrated hydrochloric acid (aqueous solution, 18.4 mL) and 100 mL of degassed ethanol were added to a 250 mL three-necked flask equipped with a gas inlet, a condenser and a magnet. The mixture was stirred for 30 min until the solid was completely dissolved, and then PMePh2 (25.00 g, 125.0 mmol) was added thereto. Under vigorous stirring, the mixture was refluxed for 1 hour until a yellow suspension was obtained. Note: Typically, the powdered product precipitates suddenly, accompanied by the formation of oily phosphine oxide. Vigorous stirring is key to avoid the formation of dark green lumps that prevent the reaction from being completed. The mixture was cooled to room temperature, and the air-stable yellow powder was collected by filtration, washed with ethanol (30 ml×3), and dried in vacuo. Yield: 20.07 g, 91%. 1 H NMR (400MHz, CDCl3) δ13.90(d,J=7.7Hz,8H),9.83(d,J=7.6Hz,4H),9.42(t,J=7.5Hz,2H),8. 86(t,J=7.5Hz,4H), 8.58(t,J=7.6Hz,8H), 7.89(t,J=7.5Hz,4H), -0.69(s,6H), -2.12(s,3H).

[0200] Re(≡CCH2Ph)Cl2(PMePh2)3. ReCl3(PMePh2)3 (9.5 g, 10.6 mmol), NaBH4 (5.25 g, 140 mmol) and 130 mL of degassed ethanol were added to a 250 mL three-necked flask equipped with a gas inlet, a condenser and a magnet. The mixture was vigorously stirred at room temperature for 20 min and then heated to reflux for about 1 hour until gas generation stopped. After cooling to room temperature, the solvent was completely evaporated under vacuum to obtain a light red solid. The red ReH5(PMePh2)3 was extracted from the mixture with toluene (45 mL×3), filtered and the white inorganic salt was discarded. The combined filtrate was collected in a 250 mL Schlenk flask equipped with a magnet and phenylacetylene (2.94 g, 28.7 mmol, about 3.15 mL) was added thereto. At room temperature, 28.7 mL of 1 M hydrochloric acid in ether solution was added dropwise to the stirred solution over 1 hour. During the addition, the color of the solution gradually changed from red to brown, followed by slight gas generation. After addition, the reaction mixture was further stirred at room temperature for 6-7 hours until a large amount of yellow precipitate was formed. Note: Long reaction time may lead to an increase in the phenyl byproduct Re(≡CPh)Cl2(PMePh2)3, which is generated by the alkyne metathesis of Re(≡CCH2Ph)Cl2(PMePh2)3 with excess phenylacetylene. The volume of the solution was reduced to one-half under vacuum, and then 120mL of hexane was added to the solution to precipitate more solids. The solid was collected by cannula filtration, washed with hexane (60mL×2), diethyl ether (60mL×3) and methanol (16mL×3) in sequence, and dried in vacuum to obtain the desired product Re(≡CCH2Ph)Cl2(PMePh2)3 as a yellow solid. Yield of two-step synthesis of ReCl3(PMePh2)3: 7.42g, 74%.

[0201] The small amount of byproduct Re(≡CPh)Cl2(PMePh2)3 can be isolated and purified by the following procedure: Combine the toluene / hexane filtrate and the Et2O extract, evaporate to dryness to give an oily residue, and wash the residue with methanol (15 mL×3). Extract the resulting orange solid with toluene (10 mL×3). Filter the extract into a long Schlenk tube by cannula filtration and layer it with hexane. After 2 weeks, red crystals (benzyl) as well as orange crystals (benzylcarbyne) are deposited on the walls of the Schlenk tube. Pick up the red crystals manually with a spatula. Repeat this procedure twice to obtain pure red crystals.

[0202] Re(≡CPh)Cl2(PMePh2)3. Yield: 705 mg (7% for two steps).

[0203] Characterization data of Re(≡CCH2Ph)Cl2(PMePh2)3:1 H NMR (400MHz, CDCl3) δ7.54–7.45(m,4H),7.40–7.31(m,4H),7.31–7.10(m,15H),7.1 0–6.94(m,12H),2.68(q,J=3.6Hz,2H),2.14(t,J=4.0Hz,6H),1.80(d,J=8.8Hz,3H). 31 P{ 1 H} NMR (162MHz, CDCl3) δ -7.19 (t, J = 11.4Hz, 1P), -9.59 (d, J = 11.5Hz, 2P).

[0204] Characterization data of Re(≡CPh)Cl2(PMePh2)3: 1 H NMR (400MHz, CDCl3)δ

[0205] 7.45–6.85(m,35H),2.20(t,J=4.0Hz,6H),1.81(d,J=8.6Hz,3H).

[0206] 31 P{ 1 H} NMR (162MHz, CDCl3) δ -3.41 (t, J = 10.9Hz, 1P), -11.18 (d, J = 11.6Hz, 2P).

[0207] Re(≡CCH2Ph)( Ph PO)2(PMePh2). To a 250 mL Schlenk flask equipped with a magnet, Re(≡CCH2Ph)Cl2(PMePh2)3 (7.42 g, 7.7 mmol), (2-hydroxyphenyl)diphenylphosphine (4.50 g, 16.2 mmol), 80 mL of toluene and triethylamine (2.34 g, about 3.2 mL, 23.2 mmol) were added. The mixture was stirred at 100°C for 3 hours. After cooling to room temperature, the precipitate (triethylamine hydrochloride) was filtered and discarded. The filtrate was evaporated under vacuum to obtain an orange residue, which was washed with hexane (50 mL×2) and methanol (20 mL×3) and dried in vacuo to obtain the desired product as a yellow solid. Yield: 6.66 g, 83%. 1H NMR (400.1MHz, CDCl3): δ7.36-7.23(m,5H),7.21-7.10(m,15H),7.05-6.90(m,14H),6.84-6.76(m,5H) ,6.59-6.42(m,4H),2.80(dq,J=19.8,3.2Hz,1H),2.56(dq,J=19.6,2.8Hz,1H),1.31(d,J=8.5Hz,3H). 1 H NMR (400MHz, C6D6) δ7.81–7.71(m,2H),7.65–7.50(m,4H),7.47–7.33(m,3H),7.28–7.18(m,2H),7.15–6.68(m,3 0H), 6.60–6.45 (m, 2H), 2.79 (dq, J=19.7, 3.5Hz, 1H), 2.55 (dq, J=19.9, 3.6Hz, 1H), 1.27 (dd, J=8.5, 1.0Hz, 3H). 31 P{ 1 H} NMR (162.0MHz, CDCl3): δ37.28 (br s, 1P), 27.00 (br d, J = 225.3Hz, 1P), 3.39 (brd, J = 224.0Hz, 1P). 31 P{ 1 H} NMR (162MHz, C6D6) δ38.92 (br s, 1P), 25.88 (dd, J = 222.9, 5.6Hz, 1P), 4.99 (d, J = 223.9, 1P).

[0208] Example 2 - Hydrated Complex Re(≡CCH 2 Ph)( Ph PO) 2(H2 Synthesis of O)

[0209]

[0210] Add Re(≡CCH2Ph)( PhPO)2(PMePh2) (1g, 0.958mmol), dichlorobis(4-methylisopropylphenyl)ruthenium(II) (391mg, 1.28mmol), 28mL anhydrous toluene. The resulting mixture was vigorously stirred at 100°C for 1h. The hot solution was filtered into another Schlenk flask to remove trace black impurities from dichlorobis(4-methylisopropylphenyl)ruthenium(II). 140μL of distilled water (7.78mmol) was added to the filtrate, and the mixture was stirred at 100°C for another 1h. After the reaction was completed, the mixture was cooled to 0°C to obtain a yellow crystalline solid, which was collected by filtration, washed with toluene (15mL×4), and dried in vacuo. Yield: 744mg, 90%. 1 H NMR (400MHz, CD2Cl2) δ8.25 (dd, J=9.7,8.0

[0211] Hz,2H),7.84(s,2H,H2O),7.55–6.66(m,26H),6.34(dd,J=5.7,3.3Hz,2H),6.14(dd,J =11.5,7.4Hz,2H),5.28–5.21(m,1H),2.65(dt,J=19.1,3.3Hz,1H),1.37–1.27(m,1H). 31 P{ 1 H}NMR (162MHz, CD2Cl2) δ38.18(s),23.40(s). Elemental analysis, C 44 H 37 Calculated values ​​for O3P2Re: C, 61.31; H, 4.33. Found values: C, 61.08; H, 4.32.

[0212] Example 3: Alkyne metathesis reaction

[0213] General Metathesis Procedure A . Re(≡CCH2Ph)( Ph PO)2(H2O)-catalyzed alkyne metathesis. A hot air gun (450°C) was used to heat the The Schlenk tube of molecular sieve (MS) was heated under vacuum for more than 5 min (to activate MS). After cooling to room temperature, the Schlenk tube was evacuated and filled with nitrogen three times. One or more substrates, Re (≡CCH2Ph) ( Ph PO)2(H2O) (14) and distilled toluene. The mixture is stirred at a specified temperature for a specified time. After the reaction is completed, the mixture is filtered through Celite and washed thoroughly with dichloromethane. The volatiles are evaporated on a rotary evaporator to obtain a residue, which is purified by column chromatography to obtain the desired product.

[0214] General Metathesis ProcedureB. Re(≡CCH2Ph)( Ph Metathesis of alkynes catalyzed by a 1:0.5 mixture of 1HPO)2(PMePh2) and dichlorobis(4-methylisopropylphenyl)ruthenium(II). A hot air gun (450°C) was used to heat the The Schlenk tube of molecular sieve (MS) was heated under vacuum for more than 5 min (to activate MS). After cooling to room temperature, the Schlenk tube was evacuated and filled with nitrogen three times. One or more substrates, Re (≡CCH2Ph) ( Ph PO)2(PMePh2)(11), dichlorobis(4-methylisopropylphenyl)ruthenium(II) and distilled toluene. The mixture is stirred at a specified temperature for a specified time. After the reaction is completed, the mixture is filtered through Celite and washed thoroughly with dichloromethane. The volatiles are evaporated on a rotary evaporator to obtain a residue, which is purified by column chromatography to obtain the desired product.

[0215] Example 3A: Alkyne Homometathesis

[0216] 9-Octadecyne-1,18-diol

[0217]

[0218] Synthesized according to general procedure A. 9-Undecyne-1-ol (50.5 mg, 57 μL, 0.30 mmol), Re (≡CCH2Ph) ( Ph PO)2(H2O)(12.9mg,0.015mmol,5mol%), Molecular sieves (450 mg) and toluene (3 mL). 60°C, 2 h. Purification by column chromatography (hexane:EA=1:1). White solid. Yield: 38.4 mg, 89%.

[0219] Synthesized according to general procedure B. 9-Undecyne-1-ol (50.5 mg, 57 μL, 0.30 mmol), Re (≡CCH2Ph) ( Ph PO)2(PMePh2)(15.7mg, 0.015mmol, 5mol%), dichlorobis(4-methylisopropylphenyl)ruthenium(II)(4.6mg, 0.0075mmol, 2.5mol%), molecular sieves (450 mg) and toluene (3 mL). 80°C, 4 h. Using CH2Ph2 as an internal standard (75.6 mg, 75 μL, 0.45 mmol), 1 Yield determined by H NMR: 97%. NMR data are identical to those reported

[0220] 4,4'-(Ethylene-1,2-diyl)benzaldehyde

[0221]

[0222] Synthesized according to general procedure A. 4-(1-propyn-1-yl)benzaldehyde (43.2 mg, 0.30 mmol), Re (≡CCH2Ph) ( Ph PO)2(H2O)(12.9mg,0.015mmol,5mol%), molecular sieves (450 mg) and toluene (3 mL). 60°C, 4 h. Using CH2Ph2 as an internal standard (75.6 mg, 75 μL, 0.45 mmol), 1 Yield determined by H NMR: 80%.

[0223] Synthesized according to general procedure B. 4-(1-Propyn-1-yl)benzaldehyde (43.2 mg, 0.30 mmol), Re (≡CCH2Ph) ( Ph PO)2(PMePh2)(15.7mg, 0.015mmol, 5mol%), dichlorobis(4-methylisopropylphenyl)ruthenium(II)(4.6mg, 0.0075mmol, 2.5mol%), Molecular sieves (450 mg) and toluene (3 mL). 80°C, 4 h. Purified by column chromatography (hexane: DCM = 10: 1). Pale yellow solid. Yield: 27.7 mg, 79%. NMR data are identical to those reported.

[0224] Example 3B: Alkyne Cross-Metathesis Reaction

[0225] 9-Tetradecyn-1-ol

[0226]

[0227] Synthesized according to general procedure A. 9-Undecyne-1-ol (84.2 mg, 0.5 mmol), 5-octyne (172.9 mg, 1.25 mmol), Re (≡CCH2Ph) ( Ph PO)2(H2O) (21.6 mg, 5 mol%), Molecular sieves (750 mg) and distilled toluene (5 mL). 60°C, 3 h. Purified by column chromatography (hexane:EA=5:1). Light yellow oil. Yield: 78.0 mg, 74%.

[0228] Synthesized according to general procedure B. 9-Undecyne-1-ol (84.2 mg, 0.5 mmol), 5-octyne (172.9 mg, 1.25 mmol), Re (≡CCH2Ph) (Ph PO)2(PMePh2)(26.1mg, 0.025mmol, 5mol%), dichlorobis(4-methylisopropylphenyl)ruthenium(II)(7.7mg, 0.0125mmol, 2.5mol%), Molecular sieves (750 mg) and toluene (5 mL). 80°C, 5 h. Purification by column chromatography gave the desired product as a light yellow oil. Yield: 78.9 mg, 75%. 1 H NMR (400MHz, CDCl3) δ3.58(t,J=6.7Hz,2H),2.19–2.00(m,4H),1.89(br,1H),1.59–1.48(m,2H),1.48–1.14(m,14H),0.87(t,J=7.2Hz,3H). 13 C{ 1 H}

[0229] NMR (101MHz, CDCl3) δ80.27,80.21,62.97,32.81,31.33,29.40,29.19(2C),28.84,25.78,21.99,18.80,18.50,13.70. IR(ATR,cm -1 ):3331,2929,2857,1464,1434,1056. [C 14 H 26 O] + [M] + HRMS (CI) calcd: 210.1984; found: 210.1990.

[0230] (4-((4-methoxyphenyl)ethynyl)phenyl)(piperidin-1-yl)methanone

[0231]

[0232] Synthesized according to General Procedure A. Piperidin-1-yl(4-(1-propyn-1-yl)phenyl)methanone (68.2 mg, 0.3 mmol), 1-methoxy-4-(1-propyn-1-yl)benzene (131.6 mg, 0.9 mmol), Re(≡CCH2Ph)( Ph PO)2(H2O)(12.9mg,0.015mmol,5mol%), Molecular sieves (1.80 g) and toluene (5 mL). 60° C., 4.5 h. Purification by column chromatography (hexane:EA=10:1 to 3:1). Light brown crystals. Yield: 66.0 mg, 69%.

[0233] Synthesized according to general procedure B. Piperidin-1-yl(4-(1-propyn-1-yl)phenyl)methanone (68.2 mg, 0.3 mmol), 1-methoxy-4-(1-propyn-1-yl)benzene (131.6 mg, 0.9 mmol), Re(≡CCH2Ph)( Ph PO)2(PMePh2)(15.7mg, 0.015mmol, 5mol%), dichlorobis(4-

[0234] methylisopropylphenyl)ruthenium(II) (4.6 mg, 0.0075 mmol), Molecular sieves (1.80 g) and toluene (6 mL). 80° C., 6 h. Purification by column chromatography (hexane:EA=10:1 to 3:1) afforded the desired product. Yield: 63.2 mg, 66%. 1 H NMR (400MHz, CDCl3) δ7.52(d,J=8.1Hz,2H),7.46(d,J=8.7Hz,2H),7.36(d,J=8.1Hz,2H),6 .87(d,J=8.7Hz,2H),3.82(s,3H),3.69(br,2H),3.33(br,2H),1.67(br,4H),1.51(br,2H). 13 C{ 1 H}NMR (101MHz, CDCl3) δ169.83,159.89,135.76,133.23,131.48,127.04,124.92,115. 06,114.13,90.82,87.57,55.41,48.83(br),43.35(br),26.64(br),25.68(br),24.65. IR(ATR,cm -1 ):2999,2934,2854,2214,1624,1600,1568,1515,1434,1279,1247,1174,1137,1106,1026,1000,832. [C 21 H 21 NNaO2] + [M+Na] + HRMS (ESI) calcd.: 342.1465; found: 342.1468.

[0235] 4-(10-Bromo-1-decyn-1-yl)benzaldehyde

[0236]

[0237] Synthesized according to general procedure B. 4-(1-propyn-1-yl)benzaldehyde (43.3 mg, 0.3 mmol), 11-bromo-2-undecyne (208.1 mg, 0.9 mmol), Re (≡CCH2Ph) ( Ph PO)2(PMePh2)(15.7mg, 0.015mmol), dichlorobis(4-methylisopropylphenyl)ruthenium(II)(4.6mg, 0.0075mmol), Molecular sieves (1.80 g) and toluene (6 mL). 80° C., 5 h. Purification by column chromatography (hexane:EA=100:1). Colorless oil. Yield: 59.2 mg, 61%. 1 H NMR (400MHz, CDCl3) δ9.98 (s, 1H), 7.79 (d, J = 7.9Hz, 2H), 7.52 (d, J = 8.0Hz, 2H), 3.40 (t, J = 6.8Hz,2H),2.44(t,J=7.0Hz,2H),1.95–1.77(m,2H),1.68–1.56(m,2H),1.54–1.28(m,8H). 13 C{ 1 H}NMR (101MHz, CDCl3) δ191.64,135.07,132.21,130.69,129.63,95.32,80.31,34.12,32.89,29.05,28.91,28.75,28.56,28.23,19.67. IR(ATR,cm -1 ):2928,2854,2729,2226,1699,1600,1561,1206,1164,828. [C 17 H 22 BrO] + [M+H] + HRMS (CI) calcd: 321.0849; found: 321.0858.

[0238] Example 3C - Ring Closing Alkyne Metathesis

[0239] 1,8-Diepoxytetradec-11-yne-2,7-dione

[0240]

[0241] Synthesized according to general procedure A. Di(3-pentyn-1-yl)adipate (83.5 mg, 0.30 mmol), Re(≡CCH2Ph)( Ph PO)2(H2O)(12.9mg,0.015mmol), Molecular sieves (1.0 g) and toluene (60 mL). 80°C, 8 h. Purification by column chromatography (hexane:EA=5:1). White needle-shaped crystals. Yield: 62.0 mg, 92%.

[0242] Synthesized according to general procedure B. Di(3-pentyn-1-yl)adipate (83.5 mg, 0.30 mmol), Re(≡CCH2Ph)( Ph PO)2(PMePh2)(15.7mg, 0.015mmol), dichlorobis(4-methylisopropylphenyl)ruthenium(II)(4.6mg, 0.0075mmol), Molecular sieves (1.0 g) and toluene (60 mL). 80° C., 8 h. Purification by column chromatography (hexane:EA=5:1) gave the desired product. Yield: 62.8 mg, 93%. 1 H NMR (400MHz, CDCl3) δ4.13 (t, J = 5.4Hz, 4H), 2.57–2.46 (m, 4H), 2.43–2.32 (m, 4H), 1.77–1.72 (m, 4H). 13 C{ 1 H}NMR (101MHz, CDCl3) δ173.28,78.03,62.67,35.08,25.12,19.24. [C 12 H 16 NaO4] + [M+Na] + HRMS (ESI) calcd.: 247.0941; found: 247.0947.

[0243] Azacyclopenta ...

[0244]

[0245] Synthesized according to general procedure B. N-(9-Undecyn-1-yl)-9-undecynamide (66.3 mg, 0.20 mmol), Re (≡CCH2Ph) ( Ph PO)2(PMePh2)(20.9mg, 0.02mmol), dichlorobis(4-methylisopropylphenyl)ruthenium(II)(6.1mg, 0.01mmol), Molecular sieves (0.60 g) and toluene (40 mL). 100°C, 12 h. Purification by column chromatography (hexane:EA=2:1). White crystals. Yield: 38.0 mg, 68%. 1H NMR(400MHz, CDCl3)δ5.56(br,1H),3.30(td,J=5.8,5.7Hz,2H),2.25–2.06(m,6 H),1.71–1.57(m,2H),1.55–1.46(m,2H),1.46–1.36(m,8H),1.38–1.27(m,10H).

[0246] Example 3D: Acyclic Diyne Metathesis Macrocyclization (ADIMAC)

[0247] Big Ring 32

[0248]

[0249] Synthesized according to general procedure A. 3,6-di(1-propyn-1-yl)-9-tetradecylcarbazole (83.5 mg, 0.30 mmol), Re (≡CCH2Ph) ( Ph PO)2(H2O)(8.6mg,0.01mmol), Molecular sieves (0.60 g) and toluene (10 mL). 60°C, 14 h. Purification by column chromatography (hexane:chloroform=1:1). White solid. Yield: 38.2 mg, 99%.

[0250] Synthesized according to general procedure B. 3,6-Di(1-propyn-1-yl)-9-tetradecylcarbazole (44.0 mg, 0.10 mmol), Re(≡CCH2Ph)( Ph PO)2(PMePh2)(10.4mg, 0.01mmol), dichlorobis(4-methylisopropylphenyl)ruthenium(II)(3.1mg, 0.005mmol), Molecular sieves (0.60 g) and toluene (10 mL). 80°C, 20 h. Purification by column chromatography (hexane: chloroform = 1:1) gave the desired product. Yield: 38.0 mg, 98%. 1 H NMR (400MHz, CDCl3) δ8.37(d,J=1.0Hz,2H),7.71(dd,J=8.4,1.4Hz,2H),7.36(d,J=8.5Hz ,2H),4.27(t,J=7.0Hz,2H),1.95–1.80(m,2H),1.46–1.13(m,22H),0.88(t,J=6.8Hz,3H).

[0251] 13 C{ 1H}NMR(101MHz,CDCl3)δ140.24,129.38,124.06,122.77,114.55,109.00,89.23,43 .45,32.08,29.85,29.81,29.78,29.73,29.68,29.53,29.15,27.46,22.85,14.29.

[0252] Example 3E - Ring-Opening Alkyne Metathesis Polymerization

[0253]

[0254] Re(≡CCH2Ph)( Ph A mixture of 1,4-dihydro-2-nitropropene (2,4-dihydro-2-nitropropene) (4,4-dihydro-2-nitropropene) (4,4-dihydro-2-nitropropene) (5,4-dihydro-2-nitropropene) (6,4-dihydro-2-nitropropene) (7,4-dihydro-2-nitropropene) (8,6-dihydro-2-nitropropene) (6,4-dihydro-2-nitropropene) (7,4 ... 1 H NMR (400MHz, CDCl3) δ2.13(br,4H),1.47(br,4H),1.37(br,4H). 13 C{ 1 H}NMR (101MHz, CDCl3) δ80.29, 29.19, 28.53, 18.86.

Claims

1. Rhenium (V) carbyne complex of formula 1: wherein L is water, ether, ketone, furan, thioether, thiophene, tertiary amine or a metal salt selected from the group consisting of metal halides, metal alkoxides, metal thiolates and metal amides, R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group; R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and R 6 In each instance is independently alkyl, alkenyl or aryl.

2. The rhenium (V) carbyne complex according to claim 1, characterized in that L is water, tetrahydrofuran, tetrahydropyran or diethyl ether.

3. The rhenium (V) carbyne complex according to claim 1, characterized in that R is CH2Ar 1 , where Ar 1 It is phenyl or o-bromophenyl.

4. The rhenium (V) carbyne complex according to claim 1, characterized in that R 4 and R 5 Each is independently alkyl, cycloalkyl or phenyl optionally substituted with one or more substituents selected from alkyl, CH3, OCH3, F and CF3.

5. The rhenium (V) carbyne complex according to claim 1, characterized in that R 4 and R 5 Each is cyclohexyl, phenyl, 4-fluorophenyl, 2,4-difluorophenyl, 4-trifluoromethylphenyl, 2,4-bis(trifluoromethyl)phenyl, 2,4-dimethylphenyl or 2,4-dimethoxyphenyl.

6. The rhenium (V) carbyne complex according to claim 1, characterized in that R 6 is phenyl optionally substituted by alkyl or trifluoromethyl.

7. The rhenium (V) carbyne complex according to claim 1, characterized in that R 6 is part of a group consisting of: Where * represents the site of covalent bonding to oxygen, and ** represents the site of covalent bonding to phosphorus.

8. The rhenium (V) carbyne complex according to claim 1, characterized in that The rhenium (V) carbyne complex is selected from the group consisting of: Where R is alkyl, aryl, 2-thiophene or CH2Ar 1 , characterized in that Ar 1 is phenyl or o-bromophenyl; and L is water, tetrahydrofuran, tetrahydropyran or diethyl ether.

9. The rhenium (V) carbyne complex according to claim 8, characterized in that R is benzyl.

10. The rhenium (V) carbyne complex according to claim 9, characterized in that L is water.

11. The rhenium (V) carbyne complex according to claim 1, characterized in that The rhenium (V) carbyne complex has the following structure:

12. A method for preparing the rhenium (V) carbyne complex according to claim 1, the method comprising: reacting the catalyst precursor of Formula 2 with a ligand and a phosphine-binding agent to form the rhenium (V) carbyne complex, Where R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group; PR'3 is PMePh2 or PMe2Ph; R 4 and R 5 are each independently alkyl, cycloalkyl or aryl; and R 6 is independently in each instance alkyl, alkenyl or aryl; The ligand is selected from the group consisting of water and alkyl ethers; The phosphine-binding agent is selected from cuprous chloride, cuprous iodide or dichlorobis(4-methylisopropylphenyl)ruthenium(II).

13. A method for performing a metathesis reaction, the method comprising: The rhenium (V) carbyne complex of any one of claims 1 to 11 is contacted with at least one alkyne substrate to form an alkyne metathesis product.

14. The method according to claim 13, characterized in that The at least one alkyne substrate is selected from the group consisting of acyclic alkynes, cycloalkynes, acyclic diynes, and cyclodiynes.

15. A method for performing a metathesis reaction, the method comprising: A catalyst precursor of Formula 2, a phosphine-binding agent, and at least one alkyne substrate are contacted to form an alkyne metathesis product, wherein the catalyst precursor of Formula 2 has the following structure: Where R is alkyl, aryl, thiophene or CH2Ar 1 , where Ar 1 is an aromatic group; PR'3 is PMePh2 or PMe2Ph; R 4 and R 5 are each independently alkyl, cycloalkyl or aryl, and R 6 is independently in each instance alkyl, alkenyl, or aryl; and The phosphine-binding agent is selected from dichlorobis(4-methylisopropylphenyl)ruthenium(II), dichlorobis(4-methylisopropylphenyl)osmium(II), (1,5-cyclooctadiene)chlororhodium(I) dimer, (1,5-cyclooctadiene)chloroiridium(I) dimer, (1,5-cyclooctadiene)dichloropalladium, cuprous chloride and cuprous iodide.

16. The method according to claim 15, characterized in that R is CH2Ar 1 , where Ar 1 It is phenyl or o-bromophenyl.

17. The method according to claim 15, characterized in that R 4 and R 5 Each is cyclohexyl, phenyl, 4-fluorophenyl, 2,4-difluorophenyl, 4-trifluoromethylphenyl, 2,4-bis(trifluoromethyl)phenyl, 2,4-dimethylphenyl or 2,4-dimethoxyphenyl.

18. The method according to claim 15, characterized in that R 6 is phenyl optionally substituted by alkyl or trifluoromethyl.

19. The method according to claim 15, characterized in that R 6 is part of a group consisting of: Where * represents the site of covalent bonding to oxygen, and ** represents the site of covalent bonding to phosphorus.

20. The method according to claim 15, characterized in that The phosphine-binding agent is dichlorobis(4-methylisopropylphenyl)ruthenium(II), and the catalyst precursor is:

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