Catalytic system for the stereoselective cationic polymerization of vinyl ethers

Abstract

The application provides a catalytic system for stereoselective cationic polymerization of a vinyl ether. In the presence of a cationic initiator, a chiral hydrogen bond donor (such as a chiral squaramide or a chiral thiourea) is combined with an anion as a catalyst, the donor chirality is transmitted to the anion acceptor through hydrogen bonding, and the anion and the cation are further combined through electrostatic interaction (to form a tight ion pair), so that the cation chain end is provided with an anion stereochemical environment, thereby realizing the stereoselective polymerization of the vinyl ether. The catalyst has high catalytic activity, wide monomer applicability, and can effectively avoid the coloring problem caused by the residual metal catalyst and the complicated purification process, and provides a simple and reliable method for the preparation of a series of polyvinyl ethers with high isotacticity.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer synthesis, and particularly relates to a catalytic system for stereoselective cationic polymerization of vinyl ether. Background Art

[0002] Polymer stereoregularity is a key factor influencing material properties. Atactic polypropylene is a viscoelastic fluid at room temperature, hindering its application. However, stereoregular polypropylene is one of the top ten plastics worldwide and has widespread applications in various fields. Similar to polypropylene, polyvinyl ether (PVE) is an inexpensive and high-performance polymer. However, the lack of effective stereoselective polymerization methods has hindered its development and application, resulting in its typically amorphous state, poor mechanical properties, and viscoelastic properties at room temperature. Isotactic polyvinyl ether (PVE) exhibits significant application potential due to its excellent mechanical properties (comparable to commercial low-density polyethylene), good processability (meltability, moldability, and cooling), broad monomer range, rich functional pendant groups, and potential biodegradability. Furthermore, the abundance of pendant functional groups in PVE makes it a promising material for functional applications. Unfortunately, due to the slow development of relevant stereoselective methods, isotactic PVE has yet to achieve significant industrialization.

[0003] Polyvinyl ethers are typically obtained by cationic polymerization. Stereoselective polymerization of vinyl ethers can be achieved by providing a chiral counterion environment to the cationic active species at the end of the cationic polymerization. For example, in 2019, Leibfarth's team used a catalytic system consisting of chiral phosphoric acid and titanium tetrachloride (Science 2019, 363, 1439–1443) to achieve stereoselective polymerization of various vinyl alkyl ethers, with the resulting polymers having isotacticity up to 94% m. The chiral anions of chiral phosphoric acid and titanium tetrachloride provided a stereochemical microenvironment for the cationic end of the polymerization, thereby achieving stereoselective polymerization of vinyl ethers. Although these titanium metal complexes have made great progress in catalyzing the asymmetric polymerization of vinyl ethers, metal residues in the polymers have potential implications for their applications in biomedicine and optoelectronics. Furthermore, titanium metal complexes can catalyze some side reactions of vinyl ethers, resulting in a narrow range of monomer applications.

[0004] Therefore, the development of a metal-free catalytic system with high catalytic activity, a wide range of monomer applications, and convenient synthesis is of great significance for the advancement of the stereoselective cationic polymerization of vinyl ethers. Prior art, patent publication CN115260350A discloses a method for living cationic polymerization using supramolecular anions combined with catalytic monomers. In the presence of a cationic initiator and a hydrogen bond donor, one or more electron-rich olefin monomers or other cationically polymerizable monomers are polymerized in a controlled manner to form homopolymers or copolymers. However, the hydrogen bond donor employed in this method is achiral, and the resulting polymers have difficulty exceeding 73% m in isotacticity, which limits their application. Summary of the Invention

[0005] Based on the above-mentioned deficiencies and shortcomings in the prior art, the present invention provides a metal-free catalytic system for stereoselective cationic polymerization of vinyl ethers, which has the advantages of simple preparation, easy structural adjustment, and high stereoselectivity.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0007] A catalytic system for stereoselective cationic polymerization of vinyl ether, comprising a hydrogen bond donor and a cationic initiator, wherein the cationic initiator is an initiator capable of generating cationic active species under the action of the hydrogen bond donor, and the hydrogen bond donor is a chiral hydrogen bond donor;

[0008] The chiral hydrogen bond donor acts as a catalyst and combines with the anion of the cationic initiator, transferring the donor chirality to the anion acceptor through hydrogen bonding. With the help of the electrostatic interaction between the anion and the cation, it provides a counterion stereochemical environment for the end of the cationic chain, thereby achieving stereoselective polymerization of vinyl ether.

[0009] As a preferred embodiment, the chiral hydrogen bond donor contains one or more chiral hydrogen bond modules in the molecule.

[0010] As a preferred embodiment, the chiral hydrogen bond donor includes one or more of chiral urea, chiral thiourea, chiral selenourea, chiral amide, chiral thioamide, chiral selenoamide, chiral square amide, chiral thiosquare amide, chiral selenosquare amide, chiral triangular amide, chiral thiotriangular amide, chiral selenotriangular amide, chiral croconamide, chiral thiocroconamide, chiral selenocroconamide, chiral rhodizonamide, chiral thiorhodizonamide, chiral seleno-rhodizonamide, chiral sulfonamide, chiral guanidine, chiral cyclopropylcarbonium ion, chiral cyclodiphosphine (V) azane diphosphamide, chiral thiocyclodiphosphine (V) azane diphosphamide, and chiral selenocyclodiphosphine (V) azane diphosphamide.

[0011] As a preferred embodiment, the chiral hydrogen bond donor is one or more of the following structural formulas:

[0012]

[0013] Wherein, R* is a chiral or achiral group. In the same molecule, R* may be the same or different, but at least one is a chiral group. Each R* is independently selected from C with or without substituents, containing or not containing O, S, N, Si, or P atoms. 1-30 Alkyl, C 3-30 Cycloalkyl, C 2-30 Alkenyl, C 2-30 Alkynyl, C 6-30 Aromatic group, C 3-30 Heterocyclic and C 5-30 one or more combinations of heteroaromatic groups;

[0014] The substituent is selected from halogen atoms, C 1-10 branched or straight chain hydrocarbon group, C 1-10 branched or straight chain alkoxy, C 3-10 branched or straight chain cycloalkyl, C 6-10 aromatic groups, C 5-20 One or more heteroaromatic groups;

[0015] wherein X is O, S or Se;

[0016] Z is a chiral or achiral group, each Z is independently selected from C with or without substituents, C with or without substituents, C with or without O, S, N, Si, P atoms, halogens, 1-30 Alkyl, C 3-30 Cycloalkyl, C 2-30 Alkenyl, C 2-30 Alkynyl, C 6-30 Aromatic group, C 3-30 Heterocyclic and C 5-30 One or more combinations of heteroaromatic groups; the substituents are selected from halogen atoms, C 1-10 branched or straight chain hydrocarbon group, C 1-10 branched or straight chain alkoxy, C 3-10 branched or straight chain cycloalkyl, C 6-10 aromatic groups, C 5-20 One or more heteroaromatic groups;

[0017] L - Selected from F – 、Cl – Br – , I – 、NO3 – 、CH3COO –, CIO4 – , CF3COO – , ClO4 – , BF4 – , B(C6F5)4 – , BPh4 – , N3 – , PF6 – , SbF6 – , OTf – , p-toluates, p-toluenesulfonates, o-nitrophenoxides, p-nitrophenoxides, m-nitrophenoxides, 2,4-dinitrophenoxides, 3,5-dinitrophenoxides, 2,4,6-trinitrophenoxides, 3,5-dichlorophenoxides, carbonates, bicarbonates, 3,5-difluorophenoxides, 3,5-di-trifluoromethylphenoxides, or pentafluorophenoxides.

[0018] As a preferred solution, the chiral hydrogen bond donor is selected from one of the following structures:

[0019]

[0020]

[0021] As a preferred solution, the cationic initiator is an acid or an adduct thereof.

[0022] As a preferred solution, the catalytic system, when catalyzing the stereoselective cationic polymerization of a vinyl ether monomer, has a monomer with the following general structure:

[0023]

[0024] wherein R 1 is a substituent or a non-substituted, C1-C 30 alkyl, C3-C 30 cycloalkyl, C2-C 30 alkenyl, C2-C 30 alkynyl, C6-C 30 aromatic, C3-C 30 heterocyclic, and C5-C 30 heteroaromatic group, in one or more combinations;

[0025] said substituent is selected from one or more of a halogen atom, a C 1-20 branched or linear alkyl group, a C 1-20 branched or linear alkoxy group, a C 3-10 branched or linear cycloalkyl group, a C 6-10 aromatic group, a C 5-20 heteroaromatic group.

[0026] As a preferred embodiment, the vinyl ether monomer is one or more of the following structures:

[0027]

[0028] As a preferred embodiment, the molar ratio of the cationic initiator to the chiral hydrogen bond donor is 1: (0.01-100); the molar ratio of the cationic initiator to the vinyl ether monomer is 1: (10-10 6 ).

[0029] As a preferred embodiment, the reaction temperature of cationic polymerization is -80°C to 180°C, and the reaction time is 10 minutes to 1000 hours;

[0030] Cationic polymerization is carried out in bulk or in a solvent selected from C1-C 12 Alkanes or cycloalkanes, C1-C 12 Aromatic hydrocarbons, C1-C 12 Halogenated alkanes, C1-C 12 One or more nitro compounds of alkanes, cycloalkanes or aromatic hydrocarbons.

[0031] As a preferred embodiment, the catalytic system for stereoselective cationic polymerization of vinyl ethers can also be used for stereoselective cationic polymerization of the following structural monomers:

[0032]

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention discloses a catalytic system for stereoselective cationic polymerization of vinyl ethers. In the presence of a cationic initiator, a chiral hydrogen bond donor acts as a catalyst and combines with an anion. The chirality of the donor is transferred to an anion acceptor through hydrogen bonding. Furthermore, the electrostatic interaction between the anion and the cation (forming a tight ion pair) provides a counterion stereochemical environment for the end of the cationic chain, thereby achieving stereoselective polymerization of the vinyl ether. Furthermore, the catalytic system has the advantages of simple preparation, easy structural adjustment, and high stereoselectivity. It effectively avoids the coloring problem of metal catalyst residues and the cumbersome purification process, providing a simple and reliable method for the preparation of a series of highly isotactic polyethylene ethers. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further explained below through specific embodiments.

[0036] The present invention innovatively designs a metal-free catalytic system for stereoselective cationic polymerization of vinyl ethers. In the presence of a cationic initiator, a chiral hydrogen bond donor acts as a catalyst and combines with anions, transferring the chirality of the donor to an anion receptor through hydrogen bonding. Furthermore, with the help of the electrostatic interaction between the anion and the cation (forming a tight ion pair), a counterion stereochemical environment is provided for the end of the cationic chain, thereby achieving stereoselective polymerization of vinyl ethers.

[0037] Among them, the molecular structure of the chiral hydrogen bond donor contains one or more chiral hydrogen bond modules, including chiral urea, chiral thiourea, chiral selenourea, chiral amide, chiral thioamide, chiral selenoamide, chiral deltamide, chiral thiodeltamide, chiral selenodeltamide, chiral croconamide, chiral thiocroconamide, chiral selenocroconamide, chiral rhodizonamide, chiral thiorhodizonamide, chiral seleno-rhodizonamide, chiral sulfonamide, chiral guanidine, chiral cyclopropylcarbonium ion, chiral cyclodiphosphine (V) azane diphosphamide, chiral thiocyclodiphosphine (V) azane diphosphamide, chiral selenocyclodiphosphine (V) azane diphosphamide modules. The specific type can be selected according to actual application requirements.

[0038] The structure of the hydrogen bonding functional group in the chiral hydrogen bonding module is shown below ( represents a covalent bond):

[0039]

[0040] The chiral hydrogen bond donor of the present invention is selected from one or more of the following structures:

[0041]

[0042] Wherein, R* is defined as a chiral or achiral group. In the same molecule, R* may be the same or different, but at least one is a chiral group. Each R* is independently selected from C with or without substituents, containing or not containing O, S, N, Si, or P atoms. 1-30 Alkyl, C 3-30 Cycloalkyl, C 2-30 Alkenyl, C 2-30 Alkynyl, C 6-30 Aromatic group, C 3-30 Heterocyclic and C 5-30 One or more combinations of heteroaromatic groups; the substituents are selected from halogen atoms, C 1-10 branched or straight chain hydrocarbon group, C 1-10 branched or straight chain alkoxy, C 3-10branched or straight chain cycloalkyl, C 6-10 aromatic groups, C 5-20 One or more heteroaromatic groups;

[0043] In each molecule, X is one or more of O, S and Se;

[0044] Z is a chiral or achiral group, each Z is independently selected from C with or without substituents, C with or without substituents, C with or without O, S, N, Si, P atoms, halogens, 1-30 Alkyl, C 3-30 Cycloalkyl, C 2-30 Alkenyl, C 2-30 Alkynyl, C 6-30 Aromatic group, C 3-30 Heterocyclic and C 5-30 One or more combinations of heteroaromatic groups; the substituents are selected from halogen atoms, C 1-10 branched or straight chain hydrocarbon group, C 1-10 branched or straight chain alkoxy, C 3-10 branched or straight chain cycloalkyl, C 6-10 aromatic groups, C 5-20 One or more heteroaromatic groups;

[0045] L - Selected from F – 、Cl – Br – , I – 、NO3 – 、CH3COO – 、CCl3COO – CF3COO – 、ClO4 – 、BF4 – 、B(C6F5)4 – , BPh4 – 、N3 – PF6 – 、SbF6 – 、OTf – , p-toluenesulfonate, p-toluenesulfonate, o-nitrophenoloxy, p-nitrophenoloxy, m-nitrophenoloxy, 2,4-dinitrophenoloxy, 3,5-dinitrophenoloxy, 2,4,6-trinitrophenoloxy, 3,5-dichlorophenoloxy, carbonate, bicarbonate, 3,5-difluorophenoloxy, 3,5-di-trifluoromethylphenoloxy or pentafluorophenoloxy anion.

[0046] More specifically, the chiral hydrogen bond donor of the present invention is selected from one or more of the following structures:

[0047]

[0048]

[0049]

[0050] The cationic initiator used in the present invention is Acid or its adduct. Specifically, The general structural formula of the acid is: HY;

[0051] wherein the anion Y is selected from Cl, Br, I, ClO4, BrO4, IO4, CN, N3, (C6F5)4B, SCN, NO2, PF6, BF4, SbF6, R'COO, R'SO3, OP(=O)(OR')2, SC(=S)NR', ​​OR', SR' or N(SO2R')2;

[0052] Each R' is independently selected from hydrogen, halogen atoms, CN, SCN, NO2, C6F5, C1-C5, which is unsubstituted or substituted, and contains or does not contain O, S, N, Si, P, B, or Se atoms. 30 Alkyl, C3-C 30 Cycloalkyl, C2-C 30 Alkenyl, C2-C 30 Alkynyl, C6-C 30 Aromatic, C3-C 30 Heterocyclic and C5-C 30 One or more combinations of heteroaromatic groups; wherein the substituents are selected from halogen atoms, C 1-20 branched or straight chain hydrocarbon group, C 1-20 branched or straight chain alkoxy, C 3-10 branched or straight chain cycloalkyl, C 6-10 aromatic groups, C 5-20 One or more heteroaromatic groups.

[0053] The present invention The acid is selected from one of the following structures:

[0054]

[0055] Among them, Ph represents phenyl, tolyl represents tolyl, and Ar represents substituted or unsubstituted C6-C 12 When an aromatic group has a substituent, the substituent is a C1-C6 alkyl group or a halogenated or non-halogenated aromatic group;

[0056] The above-mentioned adducts are one or more of the following structural formulas:

[0057]

[0058] wherein Y is Cl, Br, I, ClO4, BrO4, IO4, CN, N3, (C6F5)4B, SCN, NO2, PF6, BF4, SbF6, R'COO, R'SO3, OP(=O)(OR)2, SC(=S)NR', ​​OR', SR', or N(SO2R')2;

[0059] Each R" is independently selected from hydrogen, C 1-30 Alkyl, C 1-30 Substituted or unsubstituted alicyclic hydrocarbon group, C 6-30 Aromatic group, C 2-30 Alkenyl, C 2-30 Alkynyl, C 3-30 Heterocyclic group, or C 5-30 Heteroaromatic group.

[0060] More specifically, the adduct is one or more of the following structures:

[0061]

[0062] The preparation method of the chiral hydrogen bond donor of the present invention is relatively mature. 1-30 Alkyl, C 1-30 Substituted or unsubstituted alicyclic hydrocarbon group, C 6-30 Aromatic group, C 2-30 Alkenyl, C 2-30 Alkynyl, C 3-30 Heterocyclic group, or C 5-30 Heteroaromatic group.

[0063] Chiral urea, chiral thiourea, and chiral selenourea can be prepared by reacting cyanate esters with primary amines, as shown in the following formula, which is reported in detail in the literature Chem. Commun. 2013, 49, 4289.

[0064]

[0065] Chiral diamides, chiral thiodiamides, and chiral selenodiamides can be prepared by reacting cyanate esters with diamines, as shown in the following formula, which is reported in detail in the literature Tetrahedron: Asymmetry 2004, 23 5589–5592.

[0066]

[0067] Chiral squaramides, chiral thiosquaramides, and chiral selenosquaramides can be prepared by reacting esters with primary amines. See the following formula (see ACS Catal. 2017, 7, 3532–3539).

[0068]

[0069] The preparation methods of chiral deltamide, chiral thiodeltamide, and chiral selenodeltamide are shown in the following formula, and reference can be made to Chem. Eur. J. 2018, 24, 1140–1150.

[0070]

[0071] The preparation methods of chiral croconamide, chiral thiocroconamide, and chiral selenocroconamide are shown in the following formula, and reference can be made to Chem. Eur. J. 2018, 24, 1140–1150.

[0072]

[0073] The preparation methods of chiral rhodizonamide, chiral thiorhodizonamide, and chiral seleno-rhodizonamide are shown in the following formula, and reference can be made to Chem. Eur. J. 2018, 24, 1140–1150.

[0074]

[0075] The preparation method of chiral sulfonyl diamide is shown in the following formula, and reference may be made to Chem. Commun. 2009, 44, 833–835.

[0076]

[0077] The preparation method of the chiral guanidine catalyst is shown in the following formula, and reference may be made to J. Am. Chem. Soc. 2006, 128, 16044.

[0078]

[0079] The preparation method of chiral cyclopropylcarbonium ion is shown in the following formula, and reference can be made to Chem. Eur. J. 2018, 24, 1140–1150.

[0080]

[0081] The preparation of chiral cyclodiphosphine(V) azane diphosphamide, chiral thiocyclodiphosphine(V) azane diphosphamide, and chiral selenocyclodiphosphine(V) azane diphosphamide catalysts can be seen in the following formula: first, a four-membered heterocyclic ring is formed from a dichloride and a primary amine, which is then reacted with a primary amine and subsequently oxidized with a peroxide or sulfide. See J. Org. Chem. 2018, 83, 13973–13980.

[0082]

[0083] When the catalyst system of the present invention catalyzes stereoselective cationic polymerization of vinyl ether monomers,

[0084] The monomer has the following general structural formula:

[0085]

[0086] Among them, R 1 C1-C2 is substituted or unsubstituted, containing or not containing O, S, N, Si, P, B, Se atoms 30 Alkyl, C3-C 30 Cycloalkyl, C2-C 30 Alkenyl, C2-C 30 Alkynyl, C6-C 30 Aromatic, C3-C 30 Heterocyclic and C5-C 30 One or more combinations of heteroaromatic groups; wherein the substituents are selected from halogen atoms, C 1-20 branched or straight chain hydrocarbon group, C 1-20 branched or straight chain alkoxy, C 3-10 branched or straight chain cycloalkyl, C 6-10 aromatic groups, C 5-20 One or more heteroaromatic groups.

[0087] The vinyl ether monomers of the present invention are one or more of the following structures:

[0088]

[0089] In addition, the catalytic system of the present invention can also be used for the stereoselective cationic polymerization of the following monomers, whose structures are:

[0090]

[0091] When the catalyst system of the present invention catalyzes stereoselective cationic polymerization of vinyl ether, the molar ratio of the cationic initiator to the hydrogen bond donor can be determined in the range of 1:0.01 to 1:100 according to actual application requirements; the molar ratio of the cationic initiator to the monomer can be determined in the range of 1:10 to 1:10. 6 The range is determined according to actual application requirements. The catalytic system catalyzes stereoselective cationic polymerization of vinyl ether at a reaction temperature selected from -80°C to 180°C and a reaction time selected from 10 minutes to 1000 hours, which are determined according to actual application requirements.

[0092] In addition, the catalyst system catalyzes stereoselective cationic polymerization of vinyl ether, which can be carried out in bulk or in a solvent selected from C1-C 12 Alkanes or cycloalkanes, C1-C12 Aromatic hydrocarbons, C1-C 12 Halogenated alkanes, C1-C 12 One or more nitro compounds of alkanes, cycloalkanes or aromatic hydrocarbons.

[0093] The following is an example of practical application of the catalytic system of the present invention. The chiral hydrogen bond donors used and their numbers are as follows:

[0094]

[0095] The cationic initiators used and their numbers are as follows:

[0096]

[0097] The monomers used and their numbers are as follows:

[0098]

[0099] Examples 1 to 40:

[0100] In a sealed container (such as a glass reaction bottle, Schlenk polymerization tube, etc.) or in an autoclave, a predetermined amount of pre-cooled initiator and catalyst is sequentially added to the monomer solution via a dry syringe to initiate the polymerization reaction. Rapid stirring is performed at an appropriate temperature. After a predetermined time interval, the reaction is terminated and the product is precipitated in a solvent. The resulting product is separated by centrifugation and dried under vacuum. The specific ratios of the raw materials and the properties of the resulting products are shown in the table below.

[0101] When the following Examples 1-40 are carried out at a lower temperature and in a more dilute solution, products with higher isotacticity can be obtained. As the temperature and monomer concentration increase, the isotacticity decreases slightly, but the catalyst still has good activity, as shown in Table 1.

[0102] Table 1 Reaction materials, conditions and product performance indicators of Examples 1-40

[0103]

[0104]

[0105] a pass 1 The monomer conversion was determined by H NMR spectroscopy; b Determination of polymer molecular weight by GPC; c pass 13 C NMR was used to determine the polymer isotacticity.

[0106] Comparative Examples 41-42:

[0107] Comparative Examples 41-42 differ from Example 8 in that Comparative Example 41 does not employ a chiral hydrogen bond donor and Comparative Example 42 employs a non-chiral hydrogen bond donor as follows; otherwise the process is the same as Example 8.

[0108] The non-chiral hydrogen bond donor structures used are as follows:

[0109]

[0110]

[0111] The foregoing merely illustrates the principles of the application and application of its principles. For a better understanding of the application, reference should be made to the drawings and embodiments, in which: the scope of the application should be determined, not with the illustrated embodiments, but rather by the broadest interpretation of the principles thereof.

Claims

1. A catalytic system for stereoselective cationic polymerization of vinyl ether, comprising a hydrogen bond donor and a cationic initiator, wherein the cationic initiator is an initiator capable of generating cationic active species under the action of the hydrogen bond donor, characterized in that: The hydrogen bond donor is a chiral hydrogen bond donor; The chiral hydrogen bond donor acts as a catalyst and combines with the anion of the cationic initiator, transferring the donor chirality to the anion acceptor through hydrogen bonding. With the help of the electrostatic interaction between the anion and the cation, it provides a counterion stereochemical environment for the end of the cationic chain, thereby achieving stereoselective polymerization of vinyl ether. The chiral hydrogen bond donor is one or more of the following structural formulas: ； in, Has chiral or achiral groups, in the same molecule may be the same or different, but at least one of them is a chiral group. independently selected from unsubstituted or substituted C with or without O, S, N, Si, P atoms 6-30 Aromatic group, C 3-30 Heterocyclic and C 5-30 one or more combinations of heteroaromatic groups; The substituent is selected from halogen atoms, C 1-10 branched or straight chain hydrocarbon group, C 1-10 branched or straight chain alkoxy, C 3-10 branched or straight chain cycloalkyl, C 6-10 aromatic groups, C 5-20 One or more heteroaromatic groups; wherein X is O, S or Se; Z is a chiral or achiral group, each Z is independently selected from C with or without substituents, C with or without substituents, C with or without O, S, N, Si, P atoms, halogens, 1-30 Alkyl, C 3-30 Cycloalkyl, C 2-30 Alkenyl, C 2-30 Alkynyl, C 6-30 Aromatic group, C 3-30 Heterocyclic and C 5-30 One or more combinations of heteroaromatic groups; the substituents are selected from halogen atoms, C 1-10 branched or straight chain hydrocarbon group, C 1-10 branched or straight chain alkoxy, C 3-10 branched or straight chain cycloalkyl, C 6-10 aromatic groups, C 5-20 One or more heteroaromatic groups; L - Selected from F – 、Cl – Br – , I – 、NO3 – 、CH3COO – 、CCl3COO – CF3COO – 、ClO4 – 、BF4 – 、B(C6F5)4 – , BPh4 – 、N3 – PF6 – 、SbF6 – ,OTf – , p-toluate, p-toluenesulfonate, o-nitrophenoloxy, p-nitrophenoloxy, m-nitrophenoloxy, 2,4-dinitrophenoloxy, 3,5-dinitrophenoloxy, 2,4,6-trinitrophenoloxy, 3,5-dichlorophenoloxy, carbonate, bicarbonate, 3,5-difluorophenoloxy, 3,5-di-trifluoromethylphenoloxy or pentafluorophenoloxy anion; The cationic initiator is a Brønsted acid or an adduct thereof.

2. The catalytic system for stereoselective cationic polymerization of vinyl ether according to claim 1, characterized in that The chiral hydrogen bond donor is selected from one of the following structures: ； ； 。 3. The catalytic system for stereoselective cationic polymerization of vinyl ether according to claim 1, characterized in that When the catalytic system catalyzes stereoselective cationic polymerization of vinyl ether monomers, the monomers have the following general structural formula: ； Among them, R 1 C1-C2 is a substituted or unsubstituted C1-C2 containing or not containing O, S, N, Si, P, B, Se atoms. 30 Alkyl, C3-C 30 Cycloalkyl, C2-C 30 Alkenyl, C2-C 30 Alkynyl, C6-C 30 Aromatic, C3-C 30 Heterocyclic and C5-C 30 one or more combinations of heteroaromatic groups; The substituent is selected from halogen atoms, C 1-20 branched or straight chain hydrocarbon group, C 1-20 branched or straight chain alkoxy, C 3-10 branched or straight chain cycloalkyl, C 6-10 aromatic groups, C 5-20 One or more heteroaromatic groups.

4. The catalytic system for stereoselective cationic polymerization of vinyl ether according to claim 3, characterized in that The vinyl ether monomer is one or more of the following structures: 。 5. The catalytic system for stereoselective cationic polymerization of vinyl ether according to claim 3, characterized in that: The molar ratio of the cationic initiator to the chiral hydrogen bond donor is 1: (0.01-100); the molar ratio of the cationic initiator to the vinyl ether monomer is 1: (10-10 6 ).

6. The catalytic system for stereoselective cationic polymerization of vinyl ether according to claim 1, characterized in that The reaction temperature of cationic polymerization is -80℃~180℃, and the reaction time is 10min~1000h; Cationic polymerization is carried out in bulk or in a solvent selected from C1-C 12 Alkanes or cycloalkanes, C1-C 12 Aromatic hydrocarbons, C1-C 12 Halogenated alkanes, C1-C 12 One or more nitro compounds of alkanes, cycloalkanes or aromatic hydrocarbons.

7. The catalytic system for stereoselective cationic polymerization of vinyl ether according to claim 1, characterized in that Used for stereoselective cationic polymerization of the following structural monomers: 。

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