Process for preparing high purity norbornene silyl ethers

Abstract

A process for preparing high-purity norbornene alkylsilyl ethers is disclosed and claimed. Specifically, a process for preparing high-purity norbornene methylsilyl ethers on an industrial scale is disclosed and claimed. The high-purity monomers prepared according to the process of the present invention are useful in a variety of applications, including, but not limited to, the preparation of high-quality, high-purity polynorbornenes that can be used in a variety of electronic applications, among other applications.

Description

[Technical Field]

[0001] Cross-reference to related applications This application claims the benefit of U.S. Provisional Application No. 63 / 452,364, filed March 15, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] Embodiments of the present invention relate to industrial-scale processes for preparing a variety of norbornene silyl ethers, and more particularly to processes for preparing high-purity norbornene alkyl silyl ethers useful as monomers in a variety of industrial applications, including as starting materials in the manufacture of electronic and optoelectronic polymeric materials. [Background technology]

[0003] Functionalized norbornene monomers are widely used to prepare polymers with a wide range of applications, particularly in the electronics industry. Polynorbornenes, in particular, are utilized in various electronic materials due to their unique film-forming properties combined with desirable electronic material properties. These applications include use as dielectrics, photoresists, and protective layers, among others. However, these applications require very high-purity materials, making it particularly important that the various functionalized norbornene monomers are free of impurities that may make it difficult to form high-molecular-weight polymers. Summary of the Invention [Problem to be solved by the invention]

[0004] U.S. Patent No. 9,382,271 discloses a process for preparing various norbornene alkylsilyl ether monomers. However, the process disclosed in the patent requires a stoichiometric amount of a base such as potassium tert-butoxide, resulting in the generation of a large amount of waste. Therefore, such a process is industrially undesirable and involves significant costs for waste disposal.

[0005] In view of the above, there is a need to develop an environmentally friendly, industrially viable process for preparing high purity norbornene alkyl silyl ether monomers.

[0006] Further objects and scope of application of the present invention will be set forth in the detailed description below. [Means for solving the problem]

[0007] A process for preparing high-purity norbornene alkylsilyl ethers of formula (I) is further described below. Specifically, a process for preparing high-purity norbornene methylsilyl ethers on an industrial scale is disclosed. Surprisingly, a catalytic amount of tris(pentafluorophenyl)borane promotes the reaction of norbornene alkanols of formula (II) with silanes of formula (III) described herein. The high-purity norbornene alkylsilyl ether monomers of formula (I) prepared according to the process of the present invention are useful in a variety of applications, including, but not limited to, the preparation of high-quality, high-purity polynorbornenes that can be used in a variety of electronic applications, among other applications. DETAILED DESCRIPTION OF THE INVENTION

[0008] As used herein, the articles "a," "an," and "the" are deemed to include plural referents unless expressly limited to one referent.

[0009] All numbers, values ​​and / or formulas expressing quantities of ingredients, reaction conditions, and the like described in this specification and the claims appended hereto reflect various uncertainties in the measurements performed to arrive at those numbers, values ​​and / or formulas, and therefore, unless otherwise indicated, are deemed to include the term "about."

[0010] When a range of values ​​is disclosed herein, the range is continuous, including both the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. Furthermore, when multiple ranges are provided to describe a feature or characteristic, such ranges are combinable. Thus, unless otherwise specified, all ranges disclosed herein should be understood to encompass any and all subranges contained therein. For example, a range stated as "1 to 10" should be considered to encompass any and all subranges between the minimum value of 1 and the maximum value of 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, and 5.5 to 10.

[0011] As used herein, the term "alkyl" refers to a straight- or branched-chain saturated hydrocarbon substituent having the specified number of carbon atoms. Particular alkyl groups are methyl, ethyl, n-propyl, isopropyl, tert-butyl, and the like. Derived expressions such as "alkoxy," "thioalkyl," "alkoxyalkyl," "hydroxyalkyl," "alkylcarbonyl," "alkoxycarbonylalkyl," "alkoxycarbonyl," "diphenylalkyl," "phenylalkyl," "phenylcarboxyalkyl," and "phenoxyalkyl" should be construed accordingly.

[0012] As used herein, the term "cycloalkyl" includes all known cyclic groups. Representative examples of "cycloalkyl" include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and the like. Derived expressions such as "cycloalkoxy," "cycloalkylalkyl," "cycloalkylaryl," "cycloalkylcarbonyl," and the like, should be construed accordingly.

[0013] The term "perhaloalkyl" as used herein refers to an alkyl as defined above, wherein all hydrogen atoms of the alkyl group are replaced with halogen atoms selected from fluorine, chlorine, bromine, or iodine. Illustrative examples include, for example, trifluoromethyl, trichloromethyl, tribromomethyl, triiodomethyl, pentafluoroethyl, pentachloroethyl, pentabromoethyl, pentaiodoethyl, as well as linear or branched heptafluoropropyl, heptachloropropyl, heptabromopropyl, nonafluorobutyl, nonachlorobutyl, undecafluoropentyl, undecachloropentyl, tridecafluorohexyl, tridecachlorohexyl, etc. The derived expression "perhaloalkoxy" should be interpreted accordingly. Furthermore, some of the alkyl groups described herein, such as "alkyl," may be partially fluorinated, i.e., only a portion of the hydrogen atoms of the alkyl group are replaced with fluorine atoms, and should be interpreted accordingly.

[0014] The term "acyl" as used herein has the same meaning as "alkanoyl" and may also be structurally represented as "R-CO-," where R is "alkyl" as defined herein having the specified number of carbon atoms. Additionally, "alkylcarbonyl" has the same meaning as "acyl" as defined herein. Specifically, "(C1-C4)acyl" means formyl, acetyl or ethanoyl, propanoyl, n-butanoyl, etc. Derived expressions such as "acyloxy" and "acyloxyalkyl" should be construed accordingly.

[0015] As used herein, the term "aryl" refers to substituted or unsubstituted phenyl or naphthyl. Specific examples of substituted phenyl or naphthyl include, for example, o-, p-, m-tolyl, 1,2-, 1,3-, 1,4-xylyl, 1-methylnaphthyl, 2-methylnaphthyl, and the like. "Substituted phenyl" or "substituted naphthyl" includes any of the possible substituents further defined herein or known in the art.

[0016] As used herein, the term "arylalkyl" refers to an aryl, as defined herein, further bonded to an alkyl, as defined herein. Representative examples include, for example, benzyl, phenylethyl, 2-phenylpropyl, 1-naphthylmethyl, 2-naphthylmethyl, and the like.

[0017] As used herein, the term "alkenyl" refers to an acyclic, straight or branched hydrocarbon chain having the specified number of carbon atoms and containing at least one carbon-carbon double bond, and includes ethenyl, as well as straight-chain or branched propenyl, butenyl, pentenyl, hexenyl, and the like. Derived expressions "arylalkenyl" and 5- or 6-membered "heteroarylalkenyl" should be construed accordingly. Illustrative examples of such derived expressions include furan-2-ethenyl, phenylethenyl, 4-methoxyphenylethenyl, and the like.

[0018] As used herein, the term "heteroaryl" includes all known heteroatom-containing aromatic radicals. Representative 5-membered heteroaryl radicals include furanyl, thienyl, or thiophenyl, pyrrolyl, isopyrrolyl, pyrazolyl, imidazolyl, oxazolyl, thiazolyl, isothiazolyl, and the like. Representative 6-membered heteroaryl radicals include pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, and the like. Representative examples of bicyclic heteroaryl radicals include, for example, benzofuranyl, benzothiophenyl, indolyl, quinolinyl, isoquinolinyl, cinnolyl, benzimidazolyl, indazolyl, pyridofuranyl, pyridothienyl, and the like.

[0019] As used herein, the term "heterocycle" includes all known heteroatoms, including cyclic radicals. Representative five-membered heterocycle radicals include tetrahydrofuranyl, tetrahydrothiophenyl, pyrrolidinyl, 2-thiazolinyl, tetrahydrothiazolyl, tetrahydrooxazolyl, and the like. Representative six-membered heterocycle radicals include piperidinyl, piperazinyl, morpholinyl, thiomorpholinyl, and the like. Other heterocycle radicals include, but are not limited to, aziridinyl, azepanyl, diazepanyl, diazabicyclo[2.2.1]hept-2-yl, triazocanyl, and the like.

[0020] "Halogen" or "halo" means chloro, fluoro, bromo, and iodo.

[0021] In its broadest sense, the term "substituted" is intended to include all permissible substituents of organic compounds. In some of the specific embodiments disclosed herein, the term "substituted" refers to substituted with one or more substituents independently selected from the group consisting of (C-C) alkyl, (C-C) alkenyl, (C-C) perfluoroalkyl, phenyl, hydroxy, -COH, ester, amide, (C-C) alkoxy, (C-C) thioalkyl, and (C-C) perfluoroalkoxy. However, any other suitable substituent known to one of ordinary skill in the art can also be used in these embodiments.

[0022] Any atom in the text, illustrations, examples, and tables of the specification that has unsatisfied valences is presumed to have the appropriate number of hydrogen atoms to satisfy such valences.

[0023] Thus, in accordance with the practice of the present invention, there is provided a process for preparing compounds of formula (I). [ka] Here, n is an integer of 1 to 10, inclusive, where one or more CH2 are (C1-C 10 ) alkyl or (C1-C 10 ) optionally substituted with perfluoroalkyl; m is an integer between 0 and 2, R1, R2, and R3 may be the same or different and independently represent hydrogen, halogen, methyl, ethyl, straight or branched chain (C3-C 12 ) alkyl, (C3-C 12 ) cycloalkyl, (C6-C 12 )bicycloalkyl, (C7-C 14 )tricycloalkyl, (C6-C 10 ) aryl, (C6-C 10 )aryl(C1-C3)alkyl, (C5-C 10 ) heteroaryl, (C5-C 10 )heteroaryl(C1-C3)alkyl, (C1-C 12 ) alkoxy, (C3-C 12 ) cycloalkoxy, (C6-C 12 ) bicycloalkoxy, (C7-C 14 )tricycloalkoxy, (C6-C 10 )aryloxy(C1-C3)alkyl, (C5-C 10 )heteroaryloxy(C1-C3)alkyl, (C6-C 10 )aryloxy, (C5-C 10 )heteroaryloxy, and (C1-C6)acyloxy; R4, R5, and R6 may be the same or different and independently represent methyl, ethyl, straight-chain or branched (C3-C 12 ) alkyl, and substituted or unsubstituted (C6-C 14 ) aryl;

[0024] The process is introducing a solution of tris(pentafluorophenyl)borane into a suitable reactor under an inert atmosphere; To the above solution, a compound of formula (II) [ka] and a silane of formula (III) R4R5R6SiH (III) simultaneously at a temperature of about 40°C to about 90°C over a period of about 10 minutes to about 120 minutes; allowing the reaction mixture to further react for a period of at least about 15 minutes; cooling the reaction mixture to room temperature and treating it with an aqueous solution of a base selected from the group consisting of lithium carbonate, lithium bicarbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium hydroxide, tetramethylammonium hydroxide, and pyridine; and distilling the reaction mixture under reduced pressure at a temperature of about 130°C to about 170°C to obtain the compound of formula (I).

[0025] Surprisingly, it has been found that by metering a mixture containing substantially equimolar amounts of a compound of formula (II) and a compound of formula (III) to a solution containing a catalytic amount of tris(pentafluorophenyl)borane, the compound of formula (I) can be obtained in quantitative yield and high purity, as summarized in Scheme I.

[0026] [ka]

[0027] It should be noted that various other Lewis acid catalysts having properties similar to those of tris(pentafluorophenyl)borane can also be used as catalysts in the process of the present invention. As used herein, a "Lewis acid" is any substance that accepts electron pairs to form covalent bonds; i.e., an electron pair acceptor. Exemplary Lewis acids include, but are not limited to, tris(2,4,6-trifluorophenyl)borane, tris(2,6-difluorophenyl)borane, tris(4-fluorophenyl)borane, and tris(4-trifluoromethylphenyl)borane.

[0028] Generally, it is advantageous to use a Lewis acid that is also soluble in a solvent that is compatible with the compounds of formula (II) and (III) to effect the desired reaction as shown in Scheme I. Thus, Lewis acids of formula (IV) are preferred Lewis acids applicable in the process of the present invention.

[0029] M(R7) x X y (IV)

[0030] wherein M is selected from the group consisting of boron, aluminum, gallium, indium, and thallium; R7 may be the same or different from each other and are independently substituted monovalent (C6-C 14 ) aryl, where the aryl is substituted with at least one electron-withdrawing group selected from the group consisting of -CF3, -NO2, -CN, and halogen; X is a halogen; x is an integer between 1 and 3; and y is an integer between 0 and 3, inclusive, with the proviso that x + y = 3. In some embodiments, R7 is substituted with at least two halogens. In some other embodiments, a Lewis acid suitable for the process of the present invention is represented by formula (V):

[0031] B(R8) x X y (V)

[0032] wherein each R8 is independently the same or different from each other and is a substituted monovalent (C6-C 14 ) aryl, wherein the aryl is substituted with at least one electron-withdrawing group selected from the group consisting of —CF, —NO, —CN, and halogen; X is a halogen; x is an integer between 1 and 3, inclusive; and y is an integer between 0 and 3, inclusive, with the proviso that x+y=3. In some embodiments, R is substituted with at least two halogens.

[0033] Advantageously, tris(pentafluorophenyl)borane has been found to provide good catalytic activity in the preparation of compounds of Formula (I). As mentioned above, the amount of tris(pentafluorophenyl)borane used is catalytic, thereby minimizing the effort required to purify the final product. The amount of tris(pentafluorophenyl)borane that can be used generally depends on the type of compound of Formula (I) being prepared. Generally, the amount of tris(pentafluorophenyl)borane used is 0.1 mol% or less relative to the moles of compound of Formula (II) used. That is, the molar ratio of Formula (II) to tris(pentafluorophenyl)borane is generally 2000:≦2. In some other embodiments, the molar ratio of compound of Formula (II) to tris(pentafluorophenyl)borane is generally about 2000:1. That is, the molar % of tris(pentafluorophenyl)borane is about 0.05 mol% relative to the moles of compound of Formula (II) used. Thus, in some embodiments, less than 0.1 mol% tris(pentafluorophenyl)borane, such as 0.05 mol%, 0.001 mol%, or even less, can be used to obtain a compound of Formula (I) with higher purity. Similarly, in some other embodiments, greater than 0.2 mol% tris(pentafluorophenyl)borane can be used, depending on the type of compound of Formula (I) being prepared. All such variations in the catalytic amount of tris(pentafluorophenyl)borane used are included within the scope of the process of the present invention.

[0034] By implementing the process conditions of the present invention, it is possible to prepare a compound of formula (I) with high purity. As used herein, "high purity" means a product that is independent of other impurities. Thus, in some embodiments, the compound of formula (I) prepared according to the present invention is at least 99% pure. In some other embodiments, the compound of formula (I) is at least 99.5% pure. In still other embodiments, the compound of formula (I) is at least 99.8% pure.

[0035] By suitably using various silanes of formula (III), various norbornene alkanols of formula (II) can be used to form the corresponding silyl ethers of formula (I). In some embodiments, the compound of formula (II) used is one in which n is 1, R, R, and R are each hydrogen, R is methyl, and R and R are each phenyl.

[0036] Generally, the process of the present invention is carried out under an inert atmosphere. Any known inert atmosphere may be used herein. In some embodiments, the inert atmosphere used is nitrogen. Other inert atmospheres that may be used include helium or argon.

[0037] It has surprisingly been found that adding an equimolar mixture of a compound of formula (II) and a compound of formula (III) to a solution of tris(pentafluorophenyl)borane at a moderately low temperature results in the formation of a compound of formula (I). Tris(pentafluorophenyl)borane can be dissolved in any inert solvent. Suitable solvents include hydrocarbon solvents such as hexane, heptane, petroleum ether, benzene, toluene, and xylene, and halohydrocarbon solvents such as dichloromethane, 1,1-dichloroethane, chloroform, and carbon tetrachloride, including mixtures of any combination thereof. In some embodiments, the solvent used is toluene.

[0038] As mentioned above, the compound of formula (II) and the compound of formula (III) are generally used in an equimolar ratio. However, various other molar ratios that can result in a high yield of the compound of formula (I) can also be used, as will be well understood by those skilled in the art. Thus, in some embodiments, the compound of formula (III) is used in slight excess. For example, using the compound of formula (III) in a 5-10% molar excess appears to result in a higher yield of the compound of formula (I).

[0039] As shown in Scheme I, according to the process of the present invention, a substantially equimolar mixture of a compound of Formula (II) and a compound of Formula (III) is slowly added to a stirred solution of tris(pentafluorophenyl)borane under an inert atmosphere to form a compound of Formula (I) with concomitant evolution of hydrogen. The reaction is suitably carried out at temperatures moderately elevated above room temperature. For example, such reactions can be carried out in a suitable reactor system at a temperature range of about 40°C to about 90°C. In some embodiments, the reaction can be carried out at a temperature range of about 50°C to about 80°C, in some other embodiments at a temperature range of about 60°C to about 70°C, and in some other embodiments at a temperature of about 65°C. In some other embodiments, the reaction can be carried out at temperatures greater than about 90°C.

[0040] Generally, the reaction between the compound of Formula (II) and the compound of Formula (III) is exothermic in the presence of tris(pentafluorophenyl)borane, and therefore the addition of the reactants is carried out in a predetermined order. The mixture is generally added slowly over a period of at least one hour. In some embodiments, the addition of the mixture is carried out over a period of about 10 to 120 minutes. In some other embodiments, the addition of the mixture can be carried out for more than 120 minutes, as will be apparent to those skilled in the art. After the addition of the mixture, it is generally advantageous to carry out the reaction for an additional period of about 10 minutes, or 20 minutes or more. Suitable reactor systems include, but are not limited to, vented glass reactors, suitable glass vessels and / or reactors, and glass-lined metal vessels.

[0041] After the reaction is complete, it is very important to remove any residual tris(pentafluorophenyl)borane catalyst from the reaction mixture. It has been found that, advantageously, substantially all of the residual tris(pentafluorophenyl)borane can be removed by treating the reaction mixture with a suitable base. Suitable bases include, but are not limited to, alkali metal bases such as hydroxides, alkoxides, carbonates, or bicarbonates of lithium, sodium, potassium, or cesium, and alkaline earth metal bases such as hydroxides, alkoxides, carbonates, or bicarbonates of calcium or magnesium. Suitable inorganic or organic bases include, but are not limited to, ammonia, trialkylamines, imidazole, pyridine, and the like. Specific alkali groups include lithium hydroxide, lithium methoxide, lithium ethoxide, lithium tert-butoxide, lithium carbonate, lithium bicarbonate, sodium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium methoxide, potassium ethoxide, potassium tert-butoxide, potassium carbonate, potassium bicarbonate, cesium hydroxide, cesium methoxide, cesium ethoxide, cesium tert-butoxide, cesium carbonate, cesium bicarbonate, calcium hydroxide, calcium methoxide, calcium ethoxide, calcium tert-butoxide, calcium carbonate, calcium bicarbonate, magnesium hydroxide, magnesium methoxide, magnesium ethoxide, magnesium tert-butoxide, magnesium carbonate, magnesium bicarbonate, ammonia, trimethylamine, triethylamine, imidazole, and any combination of mixtures thereof. In some embodiments, the base used to remove tris(pentafluorophenyl)borane is sodium carbonate in the form of an aqueous solution.

[0042] Generally, the progress of the reaction can be monitored by withdrawing samples from the reactor and analyzing them by a suitable method, such as thin layer chromatography (TLC), gas chromatography (GC), liquid chromatography (LC) or high performance liquid chromatography (HPLC), or a combination of GC / mass spectrometry (MS), LC / MS, or other known techniques.

[0043] The various norbornene alkanols of formula (II) described herein are known and can be readily prepared by known methods. For example, U.S. Patent No. 9,382,271 describes a process for preparing high-purity norbornene alkanols, the relevant portions of which are incorporated herein by reference.

[0044] After the aqueous sodium carbonate treatment, the reaction mixture is isolated and distilled. It has been found advantageous to remove volatile organics, such as solvents (e.g., toluene), present in the resulting product mixture at relatively low temperatures and under reduced pressure. Thus, in some embodiments, the resulting product mixture is distilled at a temperature of about 130°C to 160°C and a pressure of 100 to 200 Torr. The product is then distilled at a temperature of about 160°C to 170°C and a reduced pressure of 1 to 2 Torr to obtain a compound of Formula (I) in very high purity, as described herein.

[0045] Surprisingly, the process of the present invention still allows the preparation of compounds of Formula (I) that are substantially free of boron remaining from the catalyst used. Thus, in some embodiments, the amount of boron present in compounds of Formula (I) is less than 5 ppm, less than 4 ppm, less than 3 ppm, less than 2 ppm, or less than 1 ppm. In some other embodiments, the amount of boron present in compounds of Formula (I) is about 1 ppm to 2 ppm. It is crucial that compounds of Formula (I) are not only highly pure, but also boron-free. This is because the compounds are used as monomers in the preparation of high-quality polymers, as demonstrated in the specific examples below.

[0046] In another embodiment of the present invention, there is further provided a process for preparing the compounds of formula (I) described herein, comprising: introducing a toluene solution of tris(pentafluorophenyl)borane into a suitable reactor under a nitrogen atmosphere; adding to the solution equimolar amounts of a compound of formula (II) described herein and a silane of formula (III) described herein at a temperature of about 60° C. to about 70° C. over a period of about 120 minutes; allowing the reaction mixture to react completely for an additional period of about 15 to 30 minutes; cooling the reaction mixture to room temperature and treating with sodium carbonate; removing toluene by vacuum distillation at a temperature of about 130°C and 100-200 Torr; and vacuum distilling at a temperature of about 160°C to 170°C and less than 1 Torr to obtain a compound of formula (I) having a purity of at least 99% and less than about 5 ppm of residual boron.

[0047] In another embodiment of the present invention, there is also provided a process for preparing (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane of formula (IB). [ka]

[0048] The process is introducing a toluene solution of tris(pentafluorophenyl)borane into a suitable reactor under a nitrogen atmosphere; adding equimolar amounts of norbornenemethanol (IIB) and methyldiphenylsilane (IIIB) to the solution over a period of about 100 minutes to about 120 minutes; [ka] (C6H5)2(CH3)SiH (IIIB) allowing the reaction mixture to react for an additional period of about 20 minutes; cooling the reaction mixture to room temperature and treating with sodium carbonate; removing the toluene by evaporation; and vacuum distilling to obtain (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane of formula (IB) having a purity of at least 99% and less than about 2 ppm residual boron. In another embodiment of the process of the present invention, the (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane is at least 99.8% pure and has less than about 1 ppm residual boron.

[0049] The present invention is further described by the following examples, which are provided for illustrative purposes and are not intended to limit the scope of the invention.

[0050] (General) Example

[0051] The following abbreviations have been used herein to describe some of the compounds, devices, and / or methods employed to describe certain embodiments of the present invention.

[0052] NBMeOH: norbornene methanol; DPMS: diphenylmethylsilane; FAB: tris(pentafluorophenyl)borane; Pd-1206: (acetonitrile)bis(triisopropylphosphine)palladium(acetate)tetrakis(pentafluorophenyl)borate; DANFABA: dimethylanilinium tetrakis(pentafluorophenyl)borate; EA: ethyl acetate; GC-FID: Gas chromatography-flame ionization detector; GPC: gel permeation chromatography; M W :Weight average molecular weight; PDI: Dispersity Index

[0053] Example 1

[0054] NBMeOSiPh2Me: (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane

[0055] A solution of FAB (0.98 g) in toluene (2930 mL) was placed in an appropriately sized stirred reactor. The reactor was then sealed, filled with nitrogen, and pressure tested. The reactor was operated in vent mode with a high flow rate of nitrogen through the vent system. The reactor was heated to 65 °C. After reaching temperature, a mixture of NBMeOH (584 g) and DPMS (971 g) was quantitatively added (over 100 minutes) to the reactor to generate hydrogen and the compound of the present invention. Upon completion of the quantitative addition, the reaction mixture was held at this temperature for 20 minutes before being cooled to room temperature (approximately 25 °C). A solution of sodium carbonate (4100 g, 2.5 wt%) was added to the cooled reaction mixture and stirred for 30 minutes. The layers were allowed to settle for approximately 30-45 minutes, after which the lower aqueous layer was decanted and discarded. The process was repeated twice with 4100 g of deionized water. Volatile organics (mainly toluene) were then removed under reduced pressure (approximately 100 Torr and 160° C.).

[0056] The resulting compound of the present invention was then purified by vacuum distillation using a short-path wiped film evaporator. The first distillation pass at 130°C and approximately 1 Torr removed minor impurities (approximately 5% by weight). The second distillation pass at 164°C and approximately 1 Torr afforded the compound of the present invention (approximately 85% recovery). The purity of the compound of the present invention was >99% as determined by GC FID and yield. Residual boron (from FAB) was approximately 1 ppm.

[0057] Polymerization of the compounds of the present invention resulted in high quality polymers as shown below.

[0058] Copolymerization of the Compounds of the Invention in Example 1

[0059] A 40 mL vial was charged with toluene (15 mL), hexylnorbornene (0.8 g), the compound of the present invention from Example 1 (1.5 g), and 1-hexene (0.2 g) and heated to 80°C. A catalyst solution of Pd-1206 (0.00044 g) and DANFABA (0.00029 g) in 0.1 mL of anhydrous EA was then added to the reaction mixture to initiate polymerization. After 35 minutes, an additional 0.2 g of hexylnorbornene dissolved in 0.4 mL of toluene was added. After 3.5 hours, the conversion of the resulting polymer was 82%. The molecular weight of the polymer was determined by GPC, and M W :156,000 and PDI:3.1.

[0060] Comparative Example 1

[0061] NBMeOSiPh2Me: (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane

[0062] A solution of FAB (0.98 g) in toluene (2900 mL) was placed in an appropriately sized stirred reactor. The reactor was then sealed, filled with nitrogen, and pressure tested. The reactor was then operated in vent mode with a high flow rate of nitrogen through the vent system. The reactor was then heated to 65°C. A mixture of NBMeOH (584 g) and DPMS (971 g) was quantitatively charged to the reactor (over 100 minutes) to produce hydrogen and compounds of the present invention. Upon completion of the metered addition, the mixture was allowed to react for an additional 20 minutes, maintaining the reaction temperature at 65°C. Pyridine (26 g) was then added via sealed transfer to quench the FAB, and the contents were cooled and vented via sealed transfer. Volatile organics (mainly toluene) were then removed by vacuum stripping (approximately 100 Torr and 160°C).

[0063] The resulting crude compound of the present invention was then purified by vacuum distillation using a short-path wiped-film evaporator. A first distillation pass at 130°C and approximately 1 Torr further removed minor residual impurities (approximately 5 wt%). A second distillation pass at 164°C and approximately 1 Torr afforded the compound of the present invention (approximately 85% recovery). The purity of the compound of the present invention was >99% as determined by GC FID. Residual boron (from FAB) was approximately 12 ppm.

[0064] The following examples show that the compound of the present invention prepared in Comparative Example 1 produces copolymers of poor quality at low conversions.

[0065] Copolymerization of the Compound of the Present Invention in Comparative Example 1

[0066] A 40 mL vial was charged with toluene (15 mL), hexylnorbornene (0.8 g), NBMeOSiPh2Me (1.5 g) from Comparative Example 1, and 1-hexene (0.2 g) and heated to 80 °C. A catalyst solution of Pd-1206 (0.00044 g) and DANFABA (0.00029 g) in 0.1 mL of anhydrous EA was then charged to the reaction mixture to initiate polymerization. After 35 minutes, an additional 0.2 g of hexylnorbornene dissolved in 0.4 mL of toluene was added. After 3.5 hours, the conversion of the resulting polymer was 36%. The molecular weight of the polymer was determined by GPC, and M W :245,000 and PDI:2.1.

[0067] Comparative Example 2

[0068] NBMeOSiPh2Me: (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane

[0069] This Comparative Example 2 demonstrates that adding reactants in an order other than that described in the process of the present invention reduces conversion and reduces the purity of the compounds of the present invention.

[0070] A suitably sized four-neck round-bottom flask equipped with a thermometer insert, stir bar, N2 inlet via a septum, gas outlet, oil bubbler, and reflux condenser was charged with norbornene methanol (NBMeOH) (10 g) and toluene (100 mL), followed by the addition of FAB (0.82 g) as a 10 wt% solution in toluene (9 mL) under high N2 flow. To this stirred solution, a solution of diphenylmethylsilane (15.9 g) in toluene (80 mL) was added dropwise slowly to control gas evolution and exotherm (keep the temperature below 50 °C). After the addition was complete (approximately 1 h), the reaction mixture was stirred for 18 h.

[0071] The reaction mixture was then filtered through a silica gel plug (10 cm diameter × 2.5 cm height). The silica gel plug was washed with toluene (100 mL × 2). The residual washing solvent from the silica gel cake was checked by TLC to confirm that the desired product had already eluted from the plug. The resulting solution was concentrated to a small volume, and 8.9 g (34% yield) of the desired product was isolated as a colorless liquid without further purification.

[0072] Although the present invention has been described with reference to the above examples, it is not limited to the examples, but generally encompasses the general scope set forth hereinabove. Various modifications and embodiments may be made without departing from the spirit and scope thereof.

Claims

1. A process for preparing a compound of formula (I), comprising: 【Chemistry 1】 In formula (I), n is an integer of 1 to 10, ２ However, (C １ -C １０ ) alkyl or (C １ -C １０ ) optionally substituted with perfluoroalkyl; m is an integer of 0 to 2, R １ , R ２ , and R ３ may be the same or different and independently represent hydrogen, halogen, methyl, ethyl, straight-chain or branched (C ３ -C １２ ) alkyl, (C ３ -C １２ ) cycloalkyl, (C ６ -C １２ ) bicycloalkyl, (C ７ -C １４ ) tricycloalkyl, (C ６ -C １０ ) aryl, (C ６ -C １０ ) aryl (C １ -C ３ ) alkyl, (C ５ -C １０ ) heteroaryl, (C ５ -C １０ ) heteroaryl (C １ -C ３ ) alkyl, (C １ -C １２ ) alkoxy, (C ３ -C １２ ) cycloalkoxy, (C ６ -C １２ ) bicycloalkoxy, (C ７ -C １４ ) tricycloalkoxy, (C ６ -C １０ ) aryloxy(C １ -C ３ ) alkyl, (C ５ -C １０ ) heteroaryloxy (C １ -C ３ ) alkyl, (C ６ -C １０ ) aryloxy, (C ５ -C １０ ) heteroaryloxy, and (C １ -C ６ ) acyloxy; R ４ , R ５ , and R ６ may be the same or different and are each independently methyl, ethyl, straight-chain or branched (C ３ -C １２ ) alkyl, and substituted or unsubstituted (C ６ -C １４ ) aryl; The process comprises: introducing a solution of tris(pentafluorophenyl)borane into a suitable reactor under an inert atmosphere; adding to the solution a mixture of a compound of formula (II) and a silane of formula (III) at a temperature of about 25° C. to about 80° C. over a period of about 10 minutes to about 120 minutes; 【Chemistry 2】 10 ４ 10 ５ 10 ６ THIS IS NOT allowing the reaction mixture to react for an additional period of about 15 minutes to about 120 minutes; cooling the reaction mixture to room temperature and treating with a suitable base selected from the group consisting of lithium carbonate, lithium bicarbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium hydroxide, tetramethylammonium hydroxide, and pyridine; distilling the reaction mixture under reduced pressure at a temperature of about 130°C to about 170°C to obtain the compound of formula (I).

2. 10. The process of claim 1, wherein the compound of formula (I) is of high purity.

3. 10. The process of claim 1, wherein the compound of formula (I) is at least 99% pure.

4. 10. The process of claim 1, wherein the compound of formula (I) is at least 99.5% pure.

5. 10. The process of claim 1, wherein the compound of formula (I) is at least 99.8% pure.

6. n is 1 and R １ , R ２ , and R ３ are each hydrogen, and R ４ is methyl, and R ５ and R ６ 10. The process of claim 1, wherein each is phenyl.

7. 10. The process of claim 1, wherein tris(pentafluorophenyl)borane is present in a catalytic amount.

8. 10. The process of claim 1, wherein the amount of tris(pentafluorophenyl)borane used is less than about 0.2 mole percent based on the moles of compound of formula (II) used.

9. 2. The process of claim 1, wherein the amount of tris(pentafluorophenyl)borane used is from about 0.1 mol % to about 0.2 mol % based on the moles of compound of formula (II) used.

10. 10. The process of claim 1, wherein the inert atmosphere is nitrogen.

11. 10. The process of claim 1, wherein the tris(pentafluorophenyl)borane is dissolved in toluene.

12. A process for preparing a compound of formula (I), comprising: 【Transformation 3】 In formula (I), n is an integer of 1 to 10, ２ However, (C １ -C １０ ) alkyl or (C １ -C １０ ) optionally substituted with perfluoroalkyl; m is an integer of 0 to 2, R １ , R ２ , and R ３ may be the same or different and independently represent hydrogen, halogen, methyl, ethyl, straight-chain or branched (C ３ -C １２ ) alkyl, (C ３ -C １２ ) cycloalkyl, (C ６ -C １２ ) bicycloalkyl, (C ７ -C １４ ) tricycloalkyl, (C ６ -C １０ ) aryl, (C ６ -C １０ ) aryl (C １ -C ３ ) alkyl, (C ５ -C １０ ) heteroaryl, (C ５ -C １０ ) heteroaryl (C １ -C ３ ) alkyl, (C １ -C １２ ) alkoxy, (C ３ -C １２ ) cycloalkoxy, (C ６ -C １２ ) bicycloalkoxy, (C ７ -C １４ ) tricycloalkoxy, (C ６ -C １０ ) aryloxy(C １ -C ３ ) alkyl, (C ５ -C １０ ) heteroaryloxy (C １ -C ３ ) alkyl, (C ６ -C １０ ) aryloxy, (C ５ -C １０ ) heteroaryloxy, and (C １ -C ６ ) acyloxy; R ４ , R ５ , and R ６ may be the same or different and are each independently methyl, ethyl, straight-chain or branched (C ３ -C １２ ) alkyl, and substituted or unsubstituted (C ６ -C １４ ) aryl; The process comprises: introducing a toluene solution of tris(pentafluorophenyl)borane into a suitable reactor under a nitrogen atmosphere; adding to the solution a mixture of a compound of formula (II) and a silane of formula (III) at a temperature of about 60° C. to about 70° C. over a period of about 120 minutes; 【Chemistry 4】 10 ４ 10 ５ 10 ６ THIS IS NOT allowing the reaction mixture to react completely for an additional period of about 15 minutes to about 30 minutes; cooling the reaction mixture to room temperature and treating with sodium carbonate; removing the toluene by vacuum distillation at a temperature of about 130° C. and 100-200 Torr; and vacuum distillation at a temperature of about 160°C to 170°C and less than 1 Torr to obtain said compound of formula (I) having a purity of at least 99% and less than about 5 ppm residual boron.

13. 13. The process of claim 12, wherein the compound of formula (I) is at least 99.5% pure and has less than about 2 ppm residual boron.

14. n is 1 and R １ , R ２ , and R ３ are each hydrogen, and R ４ is methyl, and R ５ and R ６ 13. The process of claim 12, wherein each is phenyl.

15. 13. The process of claim 12, wherein tris(pentafluorophenyl)borane is present in a catalytic amount.

16. 13. The process of claim 12, wherein the amount of tris(pentafluorophenyl)borane used is less than about 0.2 mole percent based on the moles of compound of formula (II) used.

17. 13. The process of claim 12, wherein the amount of tris(pentafluorophenyl)borane used is from about 0.1 mol % to about 0.2 mol % based on the moles of compound of formula (II) used.

18. 13. The process of claim 12 for preparing (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane with a purity of at least 99.8%.

19. 1. A process for preparing (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane of formula (IB), comprising: 【Transformation 5】 introducing a toluene solution of tris(pentafluorophenyl)borane into a suitable reactor under a nitrogen atmosphere; adding to the solution equimolar amounts of norbornenemethanol (IIB) and methyldiphenylsilane (IIIB) over a period of about 100 minutes to about 120 minutes; 【Transformation 6】 (C ６ H ５ ) ２ (CH) ３ )SiH (IIIB) allowing the reaction mixture to react for an additional period of about 20 minutes; cooling the reaction mixture to room temperature and treating with sodium carbonate; removing the toluene by evaporation; and distilling under reduced pressure to obtain (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane of formula (IB) having a purity of at least 99% and less than about 2 ppm residual boron.

20. 20. The process of claim 19, wherein the purity of (bicyclo[2.2.1]hept-5-en-2-ylmethoxy)(methyl)diphenylsilane is at least 99.8% and has less than about 1 ppm residual boron.

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