WO2024253033A1 - Boron compound, lewis base complex thereof, and methods for producing hydride, polymer, and adduct using these - Google Patents

Abstract

This boron compound is represented by formula (1). In formula (1), X¹ and X² are each independently selected from among electron-withdrawing groups, Y¹ and Y² are each independently selected from among hydrogen and electron-donating groups, with hydrogen not being selected for both simultaneously, R¹ is selected from among C1-24 organic groups, the C1-24 organic group may have a substituent, and n is selected from among the integers from 0 to 2.

Description

Boron compounds, Lewis base complexes thereof, and methods for producing hydrides, polymers, and adducts using the same

The present invention relates to novel boron compounds, their Lewis base complexes, and methods for producing hydrides, polymers, and adducts using them.

Transition metal catalysts that have been used in hydrogenation reactions in the past are poisoned by carbon monoxide, so it has been difficult to use crude hydrogen gas as a hydrogen source in hydrogenation reactions. In recent years, catalysts that create a state called FLP (frustrated Lewis pair), which can heterolytically cleave molecular hydrogen using only organic substances without using metals, have made it possible to proceed with hydrogenation reactions without using transition metal catalysts. Non-Patent Documents 1 and 2 describe boron compounds having phenyl groups partially substituted with fluorine as catalysts for the hydrogenation reaction of imines and quinoline derivatives with substituents introduced at the 2-position and/or 8-position. On the other hand, Non-Patent Document 2 also describes that quinoline itself without a substituent is difficult to generate FLP, and therefore it is difficult to hydrogenate it using an FLP catalyst. Furthermore, catalytic hydrogenation of unsubstituted quinoline under conditions where high concentrations of carbon monoxide and/or carbon dioxide coexist has not been studied, regardless of whether it is a transition metal catalyst or an FLP catalyst.

Patent Document 1 discloses a method for hydrogenating unsaturated compounds using tris(pentafluorophenyl)borane as a catalyst. However, under conditions in which carbon monoxide or carbon dioxide coexists at high concentrations, the activity of existing FLP-type catalysts also drops significantly, making it impossible to complete the reaction. For this reason, there is a demand for a catalyst that can suppress catalyst poisoning in the hydrogenation reaction and complete the reaction even under conditions in which high concentrations of carbon dioxide coexist.

Patent Document 2 discloses a hydrogenation reaction using (2,6-dichlorophenyl)bis(3,5-dichloro-2,6-difluorophenyl)borane (ASB) or tris(3,5-dichloro-2,6-difluorophenyl)borane (MHB) as a catalyst. It has been reported that the use of the boron compound of Patent Document 2 suppresses catalyst poisoning in the hydrogenation reaction even under conditions in which high concentrations of carbon monoxide and/or carbon dioxide coexist, and the compound can be used as a catalyst for smoothly promoting the hydrogenation reaction of 2-methylquinoline. However, the catalytic activity toward unsubstituted quinoline has not been examined.

JP 2017-206474 A Patent No. 7079696

Journal of Organometallic Chemistry, vol. 847, 2017, pp. 258-262 Chemistry－A European Journal, vol. 18, 2012, pp. 574-585.

There are still insufficient types of boron compounds that can be used as catalysts, etc., to suppress catalyst poisoning in hydrogenation reactions and to smoothly proceed with the reaction, preferably even under conditions where high concentrations of carbon monoxide and/or carbon dioxide coexist. It cannot be said that a sufficient understanding is available as to which boron compounds have desirable properties. Boron compounds with desirable properties are of interest from both an academic and industrial perspective.

The present invention aims to provide novel boron compounds and novel catalysts containing them.

As a result of extensive investigations, the present inventors have noticed that the boron compounds disclosed in Patent Documents 1 and 2 have a common feature in that the meta position of the aryl group bonded to boron is substituted with an electron-withdrawing group.
The present inventors then discovered that a novel boron compound in which the meta position of an aryl group bonded to boron is substituted with an electron-donating group can exhibit excellent properties, which led to the completion of the present invention.

［上記式（１）中、Ｘ^１及びＸ^２は、各々独立して、電子求引基から選択され、Ｙ^１及びＹ^２は、各々独立して、水素及び電子供与基から選択されるが、同時に水素は選択されない、Ｒ^１は、炭素数１～２４の有機基から選択され、該炭素数１～２４の有機基は置換基を有していても良く、ｎは、０～２の整数から選択される。］
　２．下記式（２）で表されるホウ素化合物のルイス塩基錯体。

［上記式（２）中、Ｘ^１及びＸ^２は、各々独立して、電子求引基から選択され、Ｙ^１及びＹ^２は、各々独立して、水素及び電子供与基から選択されるが、同時に水素は選択されない、Ｒ^１は、炭素数１～２４の有機基から選択され、該炭素数１～２４の有機基は置換基を有していても良く、ｎは、０～２の整数から選択され、ＬＢは、ルイス塩基から選択される。］
　３．上記１に記載のホウ素化合物又は上記２に記載のルイス塩基錯体を含む化学品組成物。
　４．上記１に記載のホウ素化合物又は上記２に記載のルイス塩基錯体を含む水素化触媒。
　５．上記４に記載の水素化触媒を用いる、水素化物の製造方法。
　６．粗水素ガス存在下で、上記４に記載の水素化触媒を用いることを含む、水素化物の製造方法。
　７．上記１に記載のホウ素化合物又は上記２に記載のルイス塩基錯体を含む重合開始剤。
　８．上記７に記載の重合開始剤を用いることを含む、重合体の製造方法。
　９．上記１に記載のホウ素化合物を含むルイス酸触媒。
　１０．上記９に記載のルイス酸触媒を用いることを含む、付加体の製造方法。 This specification includes the following embodiments.
1. A boron compound represented by the following formula (1):

[In the above formula (1), ^X1 and ^X2 are each independently selected from an electron-withdrawing group, ^Y1 and ^Y2 are each independently selected from hydrogen and an electron-donating group, but are not both hydrogen, ^R1 is selected from an organic group having 1 to 24 carbon atoms, which may have a substituent, and n is selected from an integer of 0 to 2.]
2. A Lewis base complex of a boron compound represented by the following formula (2):

[In the above formula (2), ^X1 and ^X2 are each independently selected from an electron-withdrawing group, ^Y1 and ^Y2 are each independently selected from hydrogen and an electron-donating group, but are not both hydrogen, ^R1 is selected from an organic group having 1 to 24 carbon atoms, which may have a substituent, n is selected from an integer of 0 to 2, and LB is selected from a Lewis base.]
3. A chemical composition comprising the boron compound described in 1 above or the Lewis base complex described in 2 above.
4. A hydrogenation catalyst comprising the boron compound described in 1 above or the Lewis base complex described in 2 above.
5. A method for producing a hydrogenated product using the hydrogenation catalyst described in 4 above.
6. A method for producing a hydrogenated product, comprising using the hydrogenation catalyst described in 4 above in the presence of crude hydrogen gas.
7. A polymerization initiator comprising the boron compound described in 1 above or the Lewis base complex described in 2 above.
8. A method for producing a polymer, comprising using the polymerization initiator described in 7 above.
9. A Lewis acid catalyst comprising the boron compound described in 1 above.
10. A method for producing an adduct, comprising using the Lewis acid catalyst described in 9 above.

In the boron compound according to an embodiment of the present invention, the meta position of the aryl group bonded to boron is substituted with an electron donating group. The novel boron compound and Lewis base complex of the present invention can be suitably used to produce hydrides, polymers, adducts, and the like.

FIG. 1 shows a novel boron compound. FIG. 2 shows Lewis base complexes of novel boron compounds.

［上記式（１）中、Ｘ^１及びＸ^２は、各々独立して電子求引基から選択され、Ｙ^１及びＹ^２は、各々独立して、水素及び電子供与基から選択されるが、同時に水素は選択されない、Ｒ^１は、炭素数１～２４の有機基から選択され、該炭素数１～２４の有機基は置換基を有していても良く、ｎは、０～２の整数から選択される。］ 1. Boron Compound The boron compound according to an embodiment of the present invention is represented by the following formula (1).

[In the above formula (1), ^X1 and ^X2 are each independently selected from an electron-withdrawing group, ^Y1 and ^Y2 are each independently selected from hydrogen and an electron-donating group, but are not both hydrogen, ^R1 is selected from an organic group having 1 to 24 carbon atoms, which may have a substituent, and n is selected from an integer of 0 to 2.]

In the boron compound according to the embodiment of the present invention, the following points are important with respect to the (2-X ¹ , 3-Y ¹ , 5-Y ² , 6-X ² ) phenyl group (hereinafter also referred to as a "substituted phenyl group") of the boron compound.
(1) Introduction of electron-withdrawing groups as ortho-substituents (X ¹ , X ² ) in order to sterically protect the boron center and impart electron-withdrawing properties to the substituted phenyl group.
(2) In order to appropriately control the electron affinity of the boron center and the stability of the Lewis base complex, an electron-donating group is introduced into one or both of the substituents (Y ¹ , Y ² ) at the meta positions.

In the above formula (1), X ¹ and X ² are each independently selected from an electron-withdrawing group. Examples of the electron-withdrawing group include a halogeno group, a nitro group, a cyano group, a fluoroalkyl group, a substituted sulfonyl group such as a trifluoromethanesulfonyl group, an alkylsulfonyl group, and an arylsulfonyl group. A fluoroalkyl group, a trifluoromethanesulfonyl group, and a halogeno group are preferred, a halogeno group selected from a bromo group, a chloro group, and a fluoro group is more preferred, and a chloro group and a fluoro group are most preferred. In addition, X ¹ and X ² may be the same or different. For example, X ¹ may be a halogeno group, and X ² may be a group other than a halogeno group (e.g., a substituted sulfonyl group). For example, when X ¹ and X ² are both halogeno groups, X ¹ may be a fluoro group, and X ² may be a chloro group.

In the above formula (1), ^Y1 and ^Y2 are each independently selected from hydrogen and an electron donating group, but are not both hydrogen. Thus, ^X1 and ^X2 may both be selected from an electron donating group, or one may be hydrogen and the other may be selected from an electron donating group, but are not both hydrogen.
In this specification, the electron donating group refers to a group that has the property of donating electrons to the phenyl group when bonded to the phenyl group, and is not particularly limited as long as the boron compound of the present invention can be obtained. Examples of the electron donating group include alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, amino, alkylamide, dialkylamino, silyl, trialkylsilyl, triarylsilyl, and alkylarylsilyl. Examples of the electron donating group include alkyl, alkenyl, alkoxy, alkylamide, dialkylamino, and trialkylsilyl, and alkyl, alkenyl, alkoxy, and trialkylsilyl are preferred.

The alkyl group preferably has 1 to 24 carbon atoms, more preferably has 1 to 18 carbon atoms, further preferably has 1 to 15 carbon atoms, and even more preferably has 1 to 12 carbon atoms.
The alkenyl preferably has 2 to 24 carbon atoms, more preferably has 2 to 18 carbon atoms, further preferably has 2 to 15 carbon atoms, and even more preferably has 2 to 12 carbon atoms.
The alkynyl group preferably has 2 to 24 carbon atoms, more preferably has 2 to 18 carbon atoms, further preferably has 2 to 15 carbon atoms, and even more preferably has 2 to 12 carbon atoms.
The cycloalkyl preferably has 3 to 24 carbon atoms, more preferably has 3 to 18 carbon atoms, even more preferably has 3 to 15 carbon atoms, and even more preferably has 3 to 12 carbon atoms.
The alkoxy preferably has 1 to 24 carbon atoms, more preferably has 1 to 18 carbon atoms, even more preferably has 1 to 15 carbon atoms, and even more preferably has 1 to 12 carbon atoms.
The alkylamide preferably has 3 to 27 carbon atoms, more preferably has 3 to 21 carbon atoms, further preferably has 3 to 18 carbon atoms, and further more preferably has 3 to 12 carbon atoms.
The dialkylamino preferably has 2 to 48 carbon atoms, more preferably has 2 to 36 carbon atoms, further preferably has 2 to 30 carbon atoms, and even more preferably has 2 to 24 carbon atoms.
The trialkylsilyl preferably has 3 to 72 carbon atoms, more preferably 3 to 54 carbon atoms, even more preferably 3 to 45 carbon atoms, and even more preferably 3 to 36 carbon atoms.

Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-hexadecyl group, an n-octadecyl group, and an n-eicosyl group.
Examples of the alkenyl include ethenyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, n-hexenyl, n-dodecenyl, n-tridecenyl, n-tetradecenyl, n-hexadecenyl, n-octadecenyl, and n-eicosenyl.
Examples of the alkynyl group include an ethynyl group, an n-propynyl group, an n-butynyl group, an isobutynyl group, an n-pentynyl group, an n-hexynyl group, an n-dodecynyl group, an n-tridecynyl group, an n-tetradecynyl group, an n-hexadecynyl group, an n-octadecynyl group, and an n-eicosynyl group.
Examples of the cycloalkyl include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group, and an adamantyl group.
Examples of the alkoxy include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a t-butoxy group, a pentoxy group, and a hexoxy group.
Examples of the alkylamide include a methylamide group, an ethylamide group, an n-propylamide group, an isopropylamide group, an n-butylamide group, an isobutylamide group, a t-butylamide group, an n-pentylamide group, an n-hexylamide group, an n-dodecylamide group, an n-tridecylamide group, an n-tetradecylamide group, an n-hexadecylamide group, an n-octadecylamide group, and an n-eicosylamide group.
Examples of the dialkylamino include a dimethylamino group, a diethylamino group, a di-n-propylamino group, a diisopropylamino group, a di-n-butylamino group, a diisobutylamino group, a di-t-butylamino group, a di-n-pentylamino group, a di-n-hexylamino group, a di-n-dodecylamino group, a di-n-tridecylamino group, a di-n-tetradecylamino group, a di-n-hexadecylamino group, a di-n-octadecylamino group, and a di-n-eicosylamino group.
Examples of the trialkylsilyl group include a trimethylsilyl group, a triethylsilyl group, a tri-n-propylsilyl group, a triisopropylsilyl group, a tri-n-butylsilyl group, a triisobutylsilyl group, a tri-t-butylsilyl group, a tri-n-pentylsilyl group, a tri-n-hexylsilyl group, a tri-n-dodecylsilyl group, a tri-n-tridecylsilyl group, a tri-n-tetradecylsilyl group, a tri-n-hexadecylsilyl group, a tri-n-octadecylsilyl group, and a tri-n-eicosylsilyl group.

In the above formula (1), n is an integer of 0 to 2. It is preferable that n is 0 to 1. When n is 0, three (2-X ¹ , 3-Y ¹ , 5-Y ² , 6-X ² )phenyl groups (substituted phenyl groups) are bonded to boron, and when n is 1, two substituted phenyl groups are bonded to boron. When the number of substituted phenyl groups bonded to boron is 2 or 3, this is preferable because the properties as a catalyst and the like are improved.
The boron compound may have one substituted phenyl group, two substituted phenyl groups, or three substituted phenyl groups. When the boron compound has two or more substituted phenyl groups, the substituted phenyl groups may be the same or different from each other.

In the above formula (1), the organic group having 1 to 24 carbon atoms represented by R ¹ is not particularly limited as long as the boron compound targeted by the present invention can be obtained, and examples thereof include an alkyl group having 1 to 24 carbon atoms, a cycloalkyl group having 3 to 24 carbon atoms, an aryl group having 3 to 24 carbon atoms, an alkoxy group having 1 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a linear or cyclic alkoxyalkyl group having 2 to 24 carbon atoms, an arylalkyl group having 7 to 24 carbon atoms, an arylalkoxy group having 7 to 24 carbon atoms, an alkylthio group having 1 to 24 carbon atoms, an arylthio group having 6 to 24 carbon atoms, and an arylalkylthio group having 7 to 24 carbon atoms.

When n is 0, the boron compound does not have R ¹ , when n is 1, the boron compound has one R ¹ , and when n is 2, the boron compound has two R ^1. When n is 2, the two R ^1s in the boron compound may be the same or different.

With respect to R ¹ in the above formula (1), examples of the alkyl group having 1 to 24 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-hexadecyl group, an n-octadecyl group, an n-eicosyl group, etc. An alkyl group having 1 to 18 carbon atoms is preferred, and an alkyl group having 1 to 10 carbon atoms is more preferred.

Cycloalkyl groups having 3 to 24 carbon atoms include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, and adamantyl groups. Of these, cycloalkyl groups having 3 to 18 carbon atoms are preferred, and cycloalkyl groups having 3 to 12 carbon atoms are more preferred.

Examples of the aryl group having 3 to 24 carbon atoms include a phenyl group, a naphthyl group, an indenyl group, a biphenyl group, a phenanthrenyl group, an anthracenyl group, a 4-pyridyl group, a tolyl group, etc. An aryl group having 3 to 18 carbon atoms is preferred, and an aryl group having 3 to 15 carbon atoms is more preferred.
Incidentally, R ¹ does not include the (2-X ¹ , 3-Y ¹ , 5-Y ² , 6-X ² ) phenyl group (also called a "substituted phenyl group") in the above formula (1), and the substituted phenyl group in the above formula (1) is excluded from R ¹ .

Examples of alkoxy groups having 1 to 24 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, isobutoxy, t-butoxy, pentoxy, and hexoxy. Alkoxy groups having 1 to 18 carbon atoms are preferred, alkoxy groups having 1 to 15 carbon atoms are more preferred, and alkoxy groups having 1 to 10 carbon atoms are even more preferred.

Examples of aryloxy groups having 6 to 24 carbon atoms include phenoxy groups, 1-naphthyloxy groups, p-ethylphenoxy groups, 3,5-diphenylphenoxy groups, 3,5-bis(3',4'-bis(trifluoromethyl)phenyl)phenoxy groups, and 4-n-octylphenoxy groups. Aryloxy groups having 6 to 18 carbon atoms are preferred, and aryloxy groups having 6 to 15 carbon atoms are more preferred.

Examples of linear or cyclic alkoxyalkyl groups having 2 to 24 carbon atoms include methoxyethyl, ethoxyethyl, methoxyethoxymethyl, methoxyethoxymethyl, and ethoxyethoxyethyl groups. Of these, alkoxyalkyl groups having 2 to 18 carbon atoms are preferred, and alkoxyalkyl groups having 2 to 15 carbon atoms are more preferred.

Examples of arylalkyl groups having 7 to 24 carbon atoms include benzyl, 2-phenylethyl, and 1-methyl-1-phenylethyl groups. Arylalkyl groups having 7 to 18 carbon atoms are preferred, and arylalkyl groups having 7 to 15 carbon atoms are more preferred.

Examples of arylalkoxy groups having 7 to 24 carbon atoms include benzyloxy groups, chlorobenzyloxy groups, α-methylbenzyloxy groups, α,α-dimethylbenzyloxy groups, and phenylethyloxy groups. Arylalkoxy groups having 7 to 18 carbon atoms are preferred, and arylalkoxy groups having 7 to 15 carbon atoms are more preferred.

Examples of alkylthio groups having 1 to 24 carbon atoms include methylthio, ethylthio, propylthio, n-butylthio, s-butylthio, t-butylthio, and i-propylthio. Alkylthio groups having 1 to 18 carbon atoms are preferred, and alkylthio groups having 1 to 15 carbon atoms are more preferred.

Examples of arylthio groups having 6 to 24 carbon atoms include phenylthio groups, phenylmethanethio groups, o-, m-, or p-tolylthio groups, and groups derived from thiosalicylic acid and its esters. Arylthio groups having 6 to 18 carbon atoms are preferred, and arylthio groups having 6 to 15 carbon atoms are more preferred.

Examples of arylalkylthio groups having 7 to 24 carbon atoms include methylthiophenyl, ethylthiophenyl, propylthiophenyl, n-butylthiophenyl, s-butylthiophenyl, t-butylthiophenyl, and i-propylthiophenyl groups. Arylalkylthio groups having 7 to 18 carbon atoms are preferred, and arylalkylthio groups having 7 to 15 carbon atoms are more preferred.

Examples of the substituents that the organic group having 1 to 24 carbon atoms may have include halogen atoms, electron-withdrawing groups such as nitro and cyano groups, hydroxyl groups, alkoxy groups, aryloxy groups, carboxyl groups and salts thereof, alkoxycarbonyl groups, acyloxy groups, aroyloxy groups, amino groups, aminocarbonyl groups, cyano groups, sulfone groups and salts thereof, alkylsulfonyl groups, alkylsulfanyl groups, alkylsulfinyl groups, alkylsulfenyl groups, arylsulfonyl groups, arylsulfanyl groups, arylsulfinyl groups, arylsulfenyl groups, chain-like or cyclic alkyl groups, chain-like or cyclic alkenyl groups, aryl groups, heteroaryl groups, chain-like or cyclic dialkylamino groups, chain-like or cyclic dialkylaminocarbonyl groups, chain-like or cyclic alkoxyalkyl groups, and the like. These substituents may further have a substituent. In addition, "may have a substituent" means that one or more hydrogen atoms of the organic group are substituted with a substituent, and for example, an alkyl group having a substituent refers to an alkyl group having a structure in which one or more hydrogen atoms of the alkyl group are substituted with a substituent.
The organic group having 1 to 24 carbon atoms which may have a substituent and is represented by ^R1 above preferably has 2 or more carbon atoms, more preferably 4 or more carbon atoms, and even more preferably 6 or more carbon atoms, and preferably has 22 or less carbon atoms, and more preferably has 20 or less carbon atoms.

The organic group having 1 to 24 carbon atoms represented by R ¹ preferably has an electron-withdrawing substituent. This is because it is believed that the Lewis acidity of the Lewis acid compound portion in the boron compound according to the embodiment of the present invention can be further improved, and the performance as a catalyst can be further enhanced. As the electron-withdrawing group, a group consisting of a halogen atom is preferable among the above-mentioned nitro group, cyano group, and halogen atom. As the group consisting of a halogen atom, a fluoro group, a chloro group, a bromo group, and an iodo group can be mentioned, and among them, a fluoro group and/or a chloro group is particularly preferable.
The organic group having 1 to 24 carbon atoms represented by R ¹ is preferably an alkyl group or an aryl group, and more preferably an aryl group which may have a substituent.

The organic group having 1 to 24 carbon atoms represented by R ¹ is preferably an aryl group or a heteroaryl group, specifically, a 4-pyridyl group, a 2,5-difluoro-4-pyridyl group, a 2,6-difluoro-4-pyridyl group, a 2,3,6-trifluoro-4-pyridyl group, a 2,3,5,6-tetrafluoro-4-pyridyl group, a 2-fluorophenyl group, a 2,3-difluorophenyl group, a 2,4-difluorophenyl group, a 2,5-difluorophenyl group, a 2,6-difluorophenyl group, a 3,5-difluorophenyl group, a 2,3,6-trifluorophenyl group, a 2,4,6-trifluorophenyl group, a a 2,3,5,6-tetrafluorophenyl group, a 2-chlorophenyl group, a 2,3-dichlorophenyl group, a 2,4-dichlorophenyl group, a 2,5-dichlorophenyl group, a 2,6-dichlorophenyl group, a 3,5-dichlorophenyl group, a 2,3,6-trichlorophenyl group, a 2,4,6-trichlorophenyl group, a 2,3,5,6-tetrachlorophenyl group, a 3,5-bis(trifluoromethyl)phenyl group, a 2,6-difluoro-4-chlorophenyl group, a 2,6-difluoro-4-trifluoromethylphenyl group, a 2,6-difluoro-3-chlorophenyl group, More preferably, it is a 2,6-difluorophenyl group, a 2,6-dichlorophenyl group, a 2,6-difluoro-3-chlorophenyl group, or a 2,6-difluoro-3,5-dichlorophenyl group, and particularly preferably a 2,6-dichlorophenyl group or a 2,6-difluoro-3,5-dichlorophenyl group.

［上記式（２）中、Ｘ^１及びＸ^２は、各々独立して、ハロゲノ基から選択され、Ｙ^１及びＹ^２は、各々独立して、水素及び電子供与基から選択されるが、同時に水素は選択されない、Ｒ^１は、炭素数１～２４の有機基から選択され、該炭素数１～２４の有機基は置換基を有していても良く、ｎは、０～２の整数から選択され、ＬＢは、ルイス塩基から選択される。］ 2. Lewis Base Complex of Boron Compound The Lewis base complex of the boron compound according to the embodiment of the present invention is represented by the following formula (2).

[In the above formula (2), ^X1 and ^X2 are each independently selected from a halogeno group, ^Y1 and ^Y2 are each independently selected from hydrogen and an electron-donating group, but are not both hydrogen, ^R1 is selected from an organic group having 1 to 24 carbon atoms, which may have a substituent, n is selected from an integer of 0 to 2, and LB is selected from a Lewis base.]

In this specification, the Lewis base is generally called a Lewis base, includes at least one selected from the group consisting of Group 14, Group 15 and Group 16 atoms having at least one electron pair (lone electron pair) that is not used in a covalent bond, can donate its electron pair to boron to form a coordinate bond, and is not particularly limited as long as it can form the boron compound-Lewis base complex that is the object of the present invention.
Examples of Lewis bases include H ₂ O, CO, chain ethers such as diethyl ether, cyclic ethers such as tetrahydrofuran (THF), phosphines such as triphenylphosphine (PPh ₃ ), phosphine oxides such as triethylphosphine oxide (Et ₃ P═O), nitriles such as acetonitrile, amines such as triethylamine, and heterocyclic compounds containing nitrogen or oxygen. Preferred Lewis bases are nitriles such as acetonitrile, chain and cyclic ethers, phosphines, amines, and heterocyclic compounds.

The above formula (2) shows a structure in which the boron compound of the above formula (1) and a Lewis base form a complex.
^X1 and ^X2 , ^Y1 and ^Y2 , and n in the above formula (2) respectively correspond to ^X1 and ^X2 , ^Y1 and ^Y2 , and n in the above formula (1).
The descriptions (explanations) of ^X1 and ^X2 , ^Y1 and ^Y2 , and n in the above formula (2) are the same as the descriptions (explanations) of ^X1 and ^X2 , ^Y1 and ^Y2 , and n in the above formula (1), and reference may be made to the descriptions (explanations ⁾ of ^X1 and X2, ^Y1 and ^Y2 , and n in the above formula (1).

3. Chemical Composition The chemical composition according to an embodiment of the present invention comprises the boron compound and/or Lewis base complex of the boron compound according to the embodiment of the present invention.
Examples of the chemical composition according to the embodiment of the present invention include a chemical composition before the reaction in the production of a hydride, which will be described later, a composition containing the hydride after the reaction, a monomer composition before the reaction in the production of a polymer, a composition containing the polymer (resin) after the reaction, a chemical composition before the reaction in the production of an adduct, and a composition containing the adduct after the reaction.

4. Method for Producing a Hydride In the method for producing a hydride according to the embodiment of the present invention, the boron compound and/or Lewis base complex of the boron compound according to the embodiment of the present invention is used as a hydrogenation catalyst. The method for producing a hydride according to the embodiment of the present invention preferably includes a step of adding a hydrogen atom to at least one unsaturated bond of an unsaturated compound using hydrogen gas or crude hydrogen gas as a hydrogen source in the presence of the above-mentioned hydrogenation catalyst (also referred to as a "hydrogenation step"). The above "hydride" refers to a compound in which a hydrogen atom is added to at least one unsaturated bond of an unsaturated compound, and may also be referred to as a "hydrogenated compound".
When the unsaturated compound contains two or more unsaturated bonds, a hydrogen atom may be added to only one of the unsaturated bonds, or a hydrogen atom may be added to two or more of the unsaturated bonds. Therefore, the hydride in the method for producing a hydride according to the embodiment of the present invention may be an unsaturated compound or a saturated compound.

The above-mentioned "crude hydrogen gas" refers to a mixed gas containing hydrogen produced from hydrocarbons such as natural gas, naphtha, heavy oil, coal, petroleum exhaust gas, and shale oil, alcohols such as methanol and ethanol, and organic waste such as biomass and industrial waste plastics, and contains carbon monoxide and/or carbon dioxide. The crude hydrogen gas may be produced in a large chemical plant, or may be supplied from a small household reformer. The hydrogen content of the crude hydrogen gas is not particularly limited, as it can be selected arbitrarily depending on the raw materials and equipment used, but from the viewpoint of smoothly proceeding with the hydrogenation reaction, the preferred hydrogen content is 20 mol% or more and less than 99.9 mol%, more preferably 50 mol% or more and less than 99.9 mol%, and even more preferably 70 mol% or more and less than 99.9 mol%, based on 100 mol% of the total of hydrogen, carbon monoxide, and carbon dioxide.

In the method for producing a hydrogenated product according to an embodiment of the present invention, the unsaturated compound used in the hydrogenation reaction is an imine, a nitrogen-containing heterocyclic compound, an aldehyde, a ketone, an alkene, an alkyne, an oligomer or polymer having an unsaturated bond, etc., and one or more types can be used. Examples of nitrogen-containing unsaturated heterocyclic compounds include pyridines, pyrazines, quinolines, acridines, 1,10-phenanthrolines, indoles, etc. In addition, oligomers and polymers having an unsaturated bond may have one or more unsaturated bonds in the same molecule.

Examples of hydrogenated compounds obtainable by the method for producing hydrogenated products according to an embodiment of the present invention include nitrogen-containing heterocyclic compounds such as amines, piperidines, piperazines, tetrahydroquinolines, tetrahydrophenanthrolines, and indolines; alcohols, alkanes, and alkenes.

In the method for producing a hydrogenated product of the present invention, a solvent can be used. The solvent that can be used is preferably one that does not react with the boron compound and/or Lewis base complex of the boron compound of the present invention as a hydrogenation catalyst, or does not inhibit the hydrogenation reaction of the unsaturated compound in the subsequent step, and can adequately dissolve the boron compound and/or Lewis base complex of the boron compound of the present invention and the unsaturated compound. For example, aromatic hydrocarbon solvents such as toluene; aliphatic hydrocarbon solvents such as n-hexane; ketone solvents such as acetone; alcohol solvents such as methanol; ether solvents such as tetrahydrofuran; ester solvents such as ethyl acetate; nitrile solvents such as acetonitrile; halogenated hydrocarbon solvents such as dichloromethane; amide solvents such as dimethylformamide; sulfoxide solvents such as dimethyl sulfoxide; lactone solvents such as γ-butyrolactone; carbonate ester solvents such as ethylene carbonate. More preferably, aromatic hydrocarbon solvents such as toluene; aliphatic hydrocarbon solvents such as n-hexane; ether solvents such as tetrahydrofuran; halogenated hydrocarbon solvents such as dichloromethane. A mixed solvent of two or more of the above solvents can also be used. In addition, when the boron compound and/or Lewis base complex of the boron compound, unsaturated compound, etc. of the embodiment of the present invention are dissolved in a solvent in advance, the solvents of these solutions may be the same or different. Also, the process may be carried out without using a solvent.

In the method for producing a hydride according to an embodiment of the present invention, it is preferable to carry out hydrogenation by dissolving the boron compound and/or Lewis base complex of the boron compound, or unsaturated compound according to an embodiment of the present invention in a solvent and mixing with a hydrogen source such as hydrogen gas or crude hydrogen gas. The hydrogenation reaction according to the present invention can also be carried out while adding a hydrogen source. Another feature of the embodiment of the present invention is that the hydrogenation reaction can be carried out near normal pressure or under slightly pressurized conditions. The pressure may be normal pressure, but carrying out the hydrogenation reaction under pressurized conditions allows the hydrogenation reaction to be carried out efficiently. When carrying out under pressurized conditions, if the pressure is too high, the energy required for pressurization is large and may become inefficient, so a pressure of 500 atmospheres or less is preferable, 100 atmospheres or less is more preferable, and 50 atmospheres or less is particularly preferable.

The method for producing a hydrogenated product according to an embodiment of the present invention includes the hydrogenation step as an essential feature, but may also include other steps. Examples of such steps include a purification step, a catalyst deactivation step, a dilution step, a concentration step, an extraction step, a recovery step of unreacted raw materials, a filtration step, and a catalyst recovery step.

For example, if the hydrogenated compound is insoluble or crystallized and precipitates, a step of filtering out the precipitate may be provided. If the hydrogenated compound is solid, a step of washing with a poor solvent such as n-hexane may be provided. If the hydrogenated compound is solid, a drying step may be provided. The drying step may be performed under reduced pressure. If the hydrogenated compound is liquid, a step of purifying it by distillation or the like may be provided.

If the catalyst is to be reused, it can be insolubilized or crystallized to precipitate, recovered through a filtration process, and reused in the next reaction.

5. Polymer Production Method In the polymer production method of the embodiment of the present invention, the boron compound and/or Lewis base complex of the boron compound of the embodiment of the present invention is used as an initiator. In the polymer production method of the embodiment of the present invention, for example, a compound having a cationic polymerizable group such as an oxirane group (oxirane ring), an oxetane group (oxetane ring), an ethylene sulfide group, a dioxolane group, a trioxolane group, a vinyl ether group, or a styryl group can be polymerized using the boron compound and/or Lewis base complex of the boron compound of the embodiment of the present invention as an initiator. Known conditions can be applied as polymerization conditions, and the reaction can be accelerated by applying heat.

The method for producing a polymer according to an embodiment of the present invention includes the above-mentioned polymerization step as an essential feature, but may also include other steps. Examples of such steps include a purification step, a catalyst deactivation step, a dilution step, a concentration step, an extraction step, a step of recovering unreacted raw materials, a filtration step, and a catalyst recovery step.

For example, if the polymerized compound is insoluble or crystallized and precipitates, a step of filtering out the precipitate may be provided. If the polymerized compound is solid, a step of washing with a poor solvent such as n-hexane may be provided. If the polymerized compound is solid, a drying step may be provided. The drying step may be performed under reduced pressure. If the polymerized compound is liquid, a step of purifying it by distillation or the like may be provided. In the case of a compound that polymerizes to form a three-dimensional cross-linked structure, the polymerization reaction may be continued without removing the initiator, and the polymerization product may be used as is.

If the initiator is to be reused, it can be insolubilized or crystallized to precipitate, recovered through a filtration process, and reused in the next reaction.

6. Method for Producing Adducts In the method for producing an adduct according to an embodiment of the present invention, the boron compound according to the embodiment of the present invention is used as a Lewis acid catalyst. The method for producing an adduct according to the present invention is not particularly limited, as long as it is a reaction promoted by activating an oxygen functional group or a nitrogen functional group in a Lewis acid manner, and therefore the reaction promotion effect is expected. For example, the addition reaction of a carbon nucleophile represented by an enol derivative, an allyl silicon compound, or an allyl boron compound to a carbonyl compound such as an aldehyde or ketone, the addition reaction of a carbon nucleophile represented by an enol derivative, an allyl silicon compound, or an allyl boron compound to an alkene or an α,β-unsaturated carbonyl compound, the addition reaction of a heteroatom nucleophile represented by an enol derivative, an allyl silicon compound, or an allyl boron compound to a heteroatom nucleophile represented by an alcohol, a phenol, a carboxylic acid, an amide, an amine, a thiol, or a phosphine, the Diels-Alder reaction, etc. can be carried out in good yield by using the boron compound according to an embodiment of the present invention as a Lewis acid catalyst.

The method for producing an adduct of the present invention essentially includes the addition reaction step described above, but may include other steps. Examples include a purification step, a catalyst deactivation step, a dilution step, a concentration step, an extraction step, a recovery step of unreacted raw materials, a filtration step, a catalyst recovery step, etc.

For example, if the adduct becomes insoluble or crystallizes and precipitates, a step of filtering out the precipitate may be provided. If the adduct is solid, a step of washing with a poor solvent such as n-hexane may be provided. If the adduct is solid, a drying step may be provided. The drying step may be performed under reduced pressure. If the adduct is liquid, a step of purifying it by distillation or the like may be provided.

If the catalyst is to be reused, it can be insolubilized or crystallized to precipitate, recovered through a filtration process, and reused in the next reaction.

7. Hydrogenation catalyst for unsaturated compounds using crude hydrogen gas as a hydrogen source In the hydrogenation reaction of unsaturated compounds using crude hydrogen gas as a hydrogen source, the boron compound and/or Lewis base complex of the boron compound of the present invention is used as a hydrogenation catalyst. According to the hydrogenation catalyst for unsaturated compounds using crude hydrogen gas as a hydrogen source according to an embodiment of the present invention, even under conditions in which high concentrations of carbon monoxide and/or carbon dioxide coexist, catalyst poisoning in the hydrogenation reaction is suppressed, the hydrogenation reaction proceeds smoothly, and the target product can be obtained in a high yield. Here, the term "crude hydrogen gas" is as defined above.

The present invention will be specifically and in detail explained below with reference to examples and comparative examples. However, these examples are merely one embodiment of the present invention, and the present invention is not limited to these examples in any way.
In the description of the examples, unless otherwise specified, parts by weight and percentages by weight are based on the parts not taking into account the solvent.

　１，５－ジブロモ－２，４－ジフルオロベンゼン（２１．８ｇ、８０．０ｍｍｏｌ、１．３MのＴＨＦ溶液）に、０℃にて、^ｉＰｒＭｇＣｌ（９６．０ｍＬ、９６．０ｍｍｏｌ、１．０Ｍのジエチルエーテル溶液）を滴下した後、３０℃にて３時間攪拌した。反応溶液をトリメチルシリルトリフルオロメタンスルホン酸（２７．３ｍＬ、１５１．３ｍｍｏｌ）とＡｇＯＡｃ（１．３ｇ、８．０ｍｍｏｌ）のＴＨＦ（２８０ｍＬ）溶液に、０℃にて加えた後、３０℃にて１８時間攪拌した。反応溶液にＮＨ_４Ｃｌ（２０ｍＬ）を加えた後、溶媒を減圧留去した。有機層をヘキサン（１００ｍＬ×３）で抽出し、水（２０ｍＬ×３）および飽和食塩水（２０ｍＬ×３）を用いて洗浄した後、Ｎａ_２ＳＯ_４を用いて乾燥させ、ろ過した。溶媒を減圧留去することで（５－ブロモ－２，４－ジフルオロフェニル）トリメチルシランを黄濁した液体として得た（１８．６ｇ、７０．２ｍｍｏｌ、８８％）。得られた液体を４Åモレキュラーシーブで乾燥させ、さらなる精製をせずに次の実験に用いた。 Example 1. Synthesis of tris(2,6-difluoro-3,5-bis(trimethylsilyl)phenyl)borane (1a) (i) Synthesis of (5-bromo-2,4-difluorophenyl)trimethylsilane

^iPrMgCl (96.0mL, 96.0mmol, 1.0M diethyl ether solution) was added dropwise to 1,5-dibromo-2,4-difluorobenzene (21.8g, 80.0mmol, 1.3M THF solution) at 0°C, and the mixture was stirred at 30°C for 3 hours. The reaction solution was added to a solution of trimethylsilyltrifluoromethanesulfonic acid (27.3mL, 151.3mmol) and AgOAc (1.3g, 8.0mmol) in THF (280mL) at 0°C, and the mixture was stirred at 30°C for 18 hours. NH ₄ Cl (20mL) was added to the reaction solution, and the solvent was distilled off under reduced pressure. The organic layer was extracted with hexane (100mL x 3), washed with water (20mL x 3) and saturated saline (20mL x 3), dried with Na ₂ SO ₄ , and filtered. The solvent was removed under reduced pressure to give (5-bromo-2,4-difluorophenyl)trimethylsilane as a hazy yellow liquid (18.6 g, 70.2 mmol, 88%), which was dried over 4 Å molecular sieves and used in the next experiment without further purification.

¹ H NMR (400 MHz, CDCl ₃ ): δ 7.49 (dd, ⁴ J _H,F = 8.4 Hz, 5.6 Hz, 1H, Ar-H), 6.82 (t, ³ J _H,F = 8.4 Hz, 1H, Ar-H), 0.31 (d, J = 0.8 Hz, 18H, Si(CH ₃ ) ₃ ). ¹⁹ F NMR (376 MHz, CDCl ₃ ): δ -101.8 (m, 1F), -105.2 (q, J = 8.8 Hz, 1F).

　（５－ブロモ－２，４－ジフルオロフェニル）トリメチルシラン（１０．６ｇ、４０．０ｍｍｏｌ、１．３MのＴＨＦ溶液）に、０℃にて、^ｉＰｒＭｇＣｌ（６０．０ｍＬ、６０．０ｍｍｏｌ、１．０Ｍのジエチルエーテル溶液）を滴下後、３０℃にて、１．５時間攪拌した。反応溶液をトリメチルシリルトリフルオロメタンスルホン酸（１９．０ｍＬ、１０５．２ｍｍｏｌ）とＡｇＯＡｃ（０．７ｇ、４．０ｍｍｏｌ）のＴＨＦ（１５０ｍＬ）溶液に、０℃にて加えた後、３０℃にて７時間攪拌した。反応溶液にＮＨ_４Ｃｌ（１０ｍＬ）を加えた後、溶媒を減圧留去した。有機層をヘキサン（１００ｍＬ×３）で抽出し、水（２０ｍＬ×３）および飽和食塩水（２０ｍＬ×３）を用いて洗浄した後、Ｎａ_２ＳＯ_４を用いて乾燥させ、ろ過した。溶媒を減圧留去し、シリカゲルカラムクロマトグラフィー（展開溶媒：ヘキサン）を用いて精製することで（４，６－ジフルオロ－１，３－フェニレン）ビス（トリメチルシラン）を無色の液体として得た（７．４ｇ、２８．８ｍｍｏｌ，７２％）。得られた液体を４Åモレキュラーシーブで乾燥させ、さらなる精製をせずに次の実験に用いた。 (ii) Synthesis of (4,6-difluoro-1,3-phenylene)bis(trimethylsilane)

^iPrMgCl (60.0mL, 60.0mmol, 1.0M diethyl ether solution) was added dropwise to (5-bromo-2,4-difluorophenyl)trimethylsilane (10.6g, 40.0mmol, 1.3M THF solution) at 0°C, and the mixture was stirred at 30°C for 1.5 hours. The reaction solution was added to a THF (150mL) solution of trimethylsilyltrifluoromethanesulfonic acid (19.0mL, 105.2mmol) and AgOAc (0.7g, 4.0mmol) at 0°C, and the mixture was stirred at 30°C for 7 hours. NH ₄ Cl (10mL) was added to the reaction solution, and the solvent was distilled off under reduced pressure. The organic layer was extracted with hexane (100mL x 3), washed with water (20mL x 3) and saturated saline (20mL x 3), dried with Na ₂ SO ₄ , and filtered. The solvent was removed under reduced pressure, and the residue was purified using silica gel column chromatography (eluent: hexane) to give (4,6-difluoro-1,3-phenylene)bis(trimethylsilane) as a colorless liquid (7.4 g, 28.8 mmol, 72%). The liquid was dried over 4 Å molecular sieves and used in the next experiment without further purification.

¹ H NMR (400 MHz, CDCl ₃ ): δ 7.38 (t, ⁴ J _H,F = 7.2 Hz, 1H, Ar-H), 6.66 (t, ³ J _H,F = 9.0 Hz, 1H, Ar-H ), 0.31 (s, 18H, Si(CH ₃ ) ₃ ). ¹³ C{ ¹ H} NMR (101 MHz, CDCl ₃ ): δ 169.2 (dd, ¹ J _C,F = 246.4 Hz, ³ J _C,F = 12.1 Hz), 141.5 (t, ³ J _C,F = 13.1 Hz), 121.4 (m) , 102.6 (dt, J = 5.1 Hz, J = 28.8 Hz), -0.89. ¹⁹ F NMR (376 MHz, CDCl ₃ ): δ -99.8 (t, J _H,F = 7.5 Hz, 2F). HRMS (EI ⁺ ): m/z Calcd for C ₁₂ H ₂₀ F ₂ Si ₂ 258.1072, found 258.1075 .

　ジイソプロピルアミン（４．５ｍＬ、３２．０ｍｍｏｌ，０．３ＭのＴＨＦ溶液）に、ｎＢｕＬｉ（２６．７ｍＬ、３２．０ｍｍｏｌ、１．２Ｍのヘキサン溶液）を、－６０℃にて、ゆっくり加えた。反応溶液を－６０℃にて、１時間攪拌した後、（４，６－ジフルオロ－１，３－フェニレン）ビス（トリメチルシラン）（５．５ｇ、２１．３ｍｍｏｌ、０．２ＭのＴＨＦ溶液）に、－７８℃にて加えた。反応溶液を－７８℃にて１時間攪拌した後、Ｉ_２（１０．８ｇ、４２．６ｍｍｏｌ、１．１ＭのＴＨＦ溶液）を加え、室温にて１４時間攪拌した。Ｎａ_２Ｓ_２Ｏ_３水溶液（５０ｍＬ）を加えた後、ヘキサン（２００ｍＬ×２）とジエチルエーテル（１００ｍＬ×１）を用いて抽出し、飽和食塩水（５０ｍＬ×３）を用いて洗浄し、Ｎａ_２ＳＯ_４を用いて乾燥し、ろ過した。溶媒を減圧留去し、シリカゲルカラムクロマトグラフィー（展開溶媒：ヘキサン）を用いて精製した。溶媒を減圧留去し、得られた固体をエタノールを用いて洗浄することで（４，６－ジフルオロ－５－ヨード－１，３－フェニレン）ビス（トリメチルシラン）を無色の結晶として得た（６．４ｇ、１６．６ｍｍｏｌ，７８％）。得られた結晶を減圧下（約０．２ｍｍＨｇ）、１００℃にて昇華精製した後、次の反応に用いた。 (iii) Synthesis of (4,6-difluoro-5-iodo-1,3-phenylene)bis(trimethylsilane)

To diisopropylamine (4.5 mL, 32.0 mmol, 0.3 M THF solution), nBuLi (26.7 mL, 32.0 mmol, 1.2 M hexane solution) was slowly added at −60° C. After the reaction solution was stirred at −60° C. for 1 hour, (4,6-difluoro-1,3-phenylene)bis(trimethylsilane) (5.5 g, 21.3 mmol, 0.2 M THF solution) was added at −78° C. After the reaction solution was stirred at −78° C. for 1 hour, I ₂ (10.8 g, 42.6 mmol, 1.1 M THF solution) was added, and the mixture was stirred at room temperature for 14 hours. After adding Na ₂ S ₂ O ₃ aqueous solution (50 mL), the mixture was extracted with hexane (200 mL x 2) and diethyl ether (100 mL x 1), washed with saturated saline (50 mL x 3), dried with Na ₂ SO ₄ , and filtered. The solvent was distilled off under reduced pressure, and the mixture was purified using silica gel column chromatography (developing solvent: hexane). The solvent was distilled off under reduced pressure, and the obtained solid was washed with ethanol to obtain (4,6-difluoro-5-iodo-1,3-phenylene)bis(trimethylsilane) as colorless crystals (6.4 g, 16.6 mmol, 78%). The obtained crystals were purified by sublimation at 100°C under reduced pressure (about 0.2 mmHg), and then used in the next reaction.

¹ H NMR (400 MHz, C ₆ D ₆ ): δ 7.36 (t, ⁴ J _H,F = 6.8 Hz, ¹ H, Ar-H), 0.22 (s, 18H, Si(CH ₃ ) ₃ ). ¹³ C{ ¹ H} NMR (101 MHz, C ₆ D ₆ ): δ 168.4 (dd, ¹ J _{19 F} ^{NMR (} _​ ^​ 376 MHz, C ₆ D ₆ ): δ -81.7 (d, ⁴ J _H,F = 7.5 Hz, 2F). HRMS (EI ⁺ ): m/z Calcd for C ₁₂ H ₁₉ F ₂ Si ₂ I ₁ 384.0038, found 384.0043.

　（４，６－ジフルオロ－５－ヨード－１，３－フェニレン）ビス（トリメチルシラン）（３．２ｇ、８．３ｍｍｏｌ、０．２MのＴＨＦ溶液）に、０℃にて、^ｉＰｒＭｇＣｌ（５．１ｍＬ、８．３ｍｍｏｌ、２．０ＭのＴＨＦ溶液）をゆっくり加えた。反応溶液を０℃にて１．５時間攪拌後、ＢＦ_３・ＯＥｔ_２（０．３ｍＬ、２．６ｍｍｏｌ）を、－１０℃にてすばやく加えた。室温にて終夜攪拌後、溶媒を減圧留去した。得られた固体を、ヘキサンを用いて抽出し、セライトろ過した。溶媒を減圧留去した後固体を温ヘキサンにて溶解させ、１５～２０℃にて静置することで無色結晶として、純度９５―９８％のトリス（２，６－ジフルオロ－３，５－ビス（トリメチルシリル）フェニル）ボランを、収率３５％（７１７．８ｍｇ、０．９２ｍｍｏｌ）で得た。 (iv) Synthesis of tris(2,6-difluoro-3,5-bis(trimethylsilyl)phenyl)borane (1a)

To (4,6-difluoro-5-iodo-1,3-phenylene)bis(trimethylsilane) (3.2 g, 8.3 mmol, 0.2 M THF solution) was slowly added ⁱ PrMgCl (5.1 mL, 8.3 mmol, 2.0 M THF solution) at 0° C. After stirring the reaction solution at 0° C. for 1.5 hours, BF ₃ ·OEt ₂ (0.3 mL, 2.6 mmol) was quickly added at −10° C. After stirring overnight at room temperature, the solvent was distilled off under reduced pressure. The obtained solid was extracted with hexane and filtered through Celite. After the solvent was distilled off under reduced pressure, the solid was dissolved in warm hexane and allowed to stand at 15 to 20°C to obtain tris(2,6-difluoro-3,5-bis(trimethylsilyl)phenyl)borane with a purity of 95-98% as colorless crystals in a yield of 35% (717.8 mg, 0.92 mmol).

¹ H NMR (400 MHz, C ₆ D ₆ ): δ 7.78 (t, ⁴ J _H,F = 7.0 Hz, 3H, Ar-H), 0.26 (s, 54H, Si(CH ₃ ) ₃ ). ¹¹ B NMR (128 MHz, C ₆ D ₆ ): Not observed. ¹³ C{ ¹ H} NMR (101 MHz, C ₆ D ₆ ): δ 172.2 (dd, ¹ J _C,F = 248.5 Hz, ³ J _C,F = 12.1 Hz), 146.6 (dt, J = 15.2 Hz, J = 3.0 Hz), 121.3 (m ), 118.7 (t, J = 28.3 Hz), -1.0. ¹⁹ F NMR (376 MHz, C ₆ D ₆ ): δ -86.7 (d, ⁴ J _H,F = 7.5 Hz, 6F).

　１，５－ジブロモ－２，４－ジフルオロベンゼン（８．２ｇ、３０．０ｍｍｏｌ、０．３ＭのＴＨＦ溶液）に、０℃にて、^ｉＰｒＭｇＣｌ（２２．５ｍＬ、４５．０ｍｍｏｌ、２．０ＭのＴＨＦ溶液）を滴下した。反応溶液を室温にて１．５時間攪拌後、アリルブロミド（５．１ｍＬ、６０．３ｍｍｏｌ）を０℃にて加えた。室温にて２０時間攪拌後、^ｉＰｒＭｇＣｌ（２２．５ｍＬ、４５．０ｍｍｏｌ、２．０ＭのＴＨＦ溶液）を滴下し、２時間攪拌した。アリルブロミド（３．６ｍＬ、４２．６ｍｍｏｌ）を０℃にて加えた後、室温にて１９時間攪拌した。ＮＨ_４Ｃｌ水溶液（１５ｍＬ）を加えた後、溶媒を減圧留去した。有機層を、ヘキサン（１００ｍＬ×３）を用いて抽出し、水（２０ｍＬ×３）と飽和食塩水（２０ｍＬ×３）を用いて洗浄した後、Ｎａ_２ＳＯ_４を用いて乾燥し、ろ過した。溶媒を減圧留去することで１，５－ジアリル－２，４－ジフルオロベンゼンを無色の液体として得た（５．６ｇ、２８．８ｍｍｏｌ、９６％）。得られた液体は、さらなる精製をせずに次の実験に用いた。NMR測定用の単離サンプルは、減圧下（約０．２ｍｍＨｇ）、７０℃にて蒸留することで得た。 Example 2. Synthesis of tris(2,6-difluoro-3,5-diallylphenyl)borane (1b) (i) Synthesis of 1,5-diallyl-2,4-difluorobenzene

To 1,5-dibromo-2,4-difluorobenzene (8.2 g, 30.0 mmol, 0.3 M THF solution), ⁱ PrMgCl (22.5 mL, 45.0 mmol, 2.0 M THF solution) was added dropwise at 0° C. The reaction solution was stirred at room temperature for 1.5 hours, and then allyl bromide (5.1 mL, 60.3 mmol) was added at 0° C. After stirring at room temperature for 20 hours, ⁱ PrMgCl (22.5 mL, 45.0 mmol, 2.0 M THF solution) was added dropwise, and the mixture was stirred for 2 hours. Allyl bromide (3.6 mL, 42.6 mmol) was added at 0° C., and the mixture was stirred at room temperature for 19 hours. An aqueous NH ₄ Cl solution (15 mL) was added, and then the solvent was distilled off under reduced pressure. The organic layer was extracted with hexane (100 mL x 3), washed with water (20 mL x 3) and saturated saline (20 mL x 3), dried with Na ₂ SO ₄ , and filtered. The solvent was distilled off under reduced pressure to obtain 1,5-diallyl-2,4-difluorobenzene as a colorless liquid (5.6 g, 28.8 mmol, 96%). The obtained liquid was used in the next experiment without further purification. An isolated sample for NMR measurement was obtained by distillation at 70°C under reduced pressure (about 0.2 mmHg).

¹ H NMR (400 MHz, CDCl ₃ ): δ 6.98 (t, ⁴ J _H,F = 8.6 Hz, 1H, Ar-H), 6.75 (t, ³ J _H,F = 9.6 Hz, 1H, Ar-H ), 5.92 (m, 2H, CH ₂ CH=CH ₂ ), 5.06 (m, 4H, CH ₂ CH=CH ₂ ), 3.34 (d, J = 6.4 Hz, 4H, CH ₂ CH=CH ₂ ). ¹³ C{ ¹ H} NMR (101 MHz, C ₆ D ₆ ): δ 159.7 (dd, ¹ J _C,F = 247.5 Hz, J = 12.1 Hz), 135.9, 132.1 (q, J = 5.7 Hz), 122.8 (m), 116.2 (m), 103.6 (m), 32.7. ¹⁹ F NMR (376 MHz, CDCl ₃ ): δ -121.1 (t, J = 9.4 Hz, 2F). HRMS (EI ⁺ ): m/ z Calcd for C ₁₂ H ₁₂ F ₂ 194.0907, found 194.0902.

　ジイソプロピルアミン（６．１ｍＬ、４３．５ｍｍｏｌ、０．４ＭのＴＨＦ溶液）に、^ｎＢｕＬｉ（２７．２ｍＬ、４３．５ｍｍｏｌ、１．６Ｍのヘキサン溶液）を、－７８℃にて、ゆっくり加えた。反応溶液を－７８℃にて１時間攪拌後、１，５－ジアリル－２，４－ジフルオロベンゼン（５．６ｇ，２９．０ｍｍｏｌ，０．２ＭのＴＨＦ溶液）に、－７８℃にてゆっくり加えた。反応溶液を－７８℃にて１時間攪拌後、Ｉ_２（１４．６ｇ，５８．０ｍｍｏｌ，０．４ＭのＴＨＦ溶液）を加え、室温にて１２時間攪拌した。Ｎａ_２Ｓ_２Ｏ_３水溶液（５０ｍＬ）を加えた後、ヘキサン（1００ｍＬ×２）とジエチルエーテル（１００ｍＬ×１）を用いて抽出し、飽和食塩水（５０ｍＬ×３）を用いて洗浄し、Ｎａ_２ＳＯ_４を用いて乾燥し、ろ過した。溶媒を減圧留去した後、減圧下（約０．２ｍｍＨｇ）、９５℃にて揮発物を留去し、さらに減圧下（約０．２ｍｍＨｇ）、１７０℃にて蒸留することで、１，５－ジアリル－２，４－ジフルオロ－３－ヨードベンゼンを無色の液体として得た（７．１ｇ、２２．２ｍｍｏｌ，７７％）。 (ii) Synthesis of 1,5-diallyl-2,4-difluoro-3-iodobenzene

To diisopropylamine (6.1 mL, 43.5 mmol, 0.4 M THF solution), ⁿ BuLi (27.2 mL, 43.5 mmol, 1.6 M hexane solution) was slowly added at −78° C. After stirring the reaction solution at −78° C. for 1 hour, 1,5-diallyl-2,4-difluorobenzene (5.6 g, 29.0 mmol, 0.2 M THF solution) was slowly added at −78° C. After stirring the reaction solution at −78° C. for 1 hour, I ₂ (14.6 g, 58.0 mmol, 0.4 M THF solution) was added, and the mixture was stirred at room temperature for 12 hours. After adding an aqueous solution of Na ₂ S ₂ O ₃ (50 mL), the mixture was extracted with hexane (100 mL × 2) and diethyl ether (100 mL × 1), washed with saturated saline (50 mL × 3), dried with Na ₂ SO ₄ , and filtered. After the solvent was distilled off under reduced pressure, the volatiles were distilled off at 95°C under reduced pressure (about 0.2 mmHg), and further distilled at 170°C under reduced pressure (about 0.2 mmHg), to obtain 1,5-diallyl-2,4-difluoro-3-iodobenzene as a colorless liquid (7.1 g, 22.2 mmol, 77%).

¹ H NMR (400 MHz, C ₆ D ₆ ): δ 6.59 (t, ⁴ J _H,F = 8.2 Hz, 1H, Ar-H), 5.65 (m, 2H, CH ₂ CH=CH ₂ ), 4.89 ( m, 4H, CH ₂ CH=CH ₂ ), 3.03 (d, J = 6.4 Hz, 4H, CH ₂ CH=CH ₂ ). ¹³ C{ ¹ H} NMR (101 MHz, C ₆ D ₆ ): δ 159.3 (dd, ¹ J _C,F = 245.4 Hz, ³ J _C,F = 5.1 Hz) , 135.4, 131.9 (q, ³ J _C,F = 5.4 Hz), 123.5 (m), 116.6 (m), 71.6 (t, J = 30.3 Hz), 33.1 (t, ³ J _C,F = 4.0 Hz). ¹⁹ F NMR (376 MHz, C ₆ D ₆ ): δ -102.0 (d, ⁴ J _H,F = 7.5 Hz, 2F).
HRMS (EI ⁺ ): m/z Calcd for C ₁₂ H ₁₁ F ₂ I 319.9874, found 319.9883.

　１，５－ジアリル－２，４－ジフルオロ－３－ヨードベンゼン（２．０ｇ、６．３ｍｍｏｌ、０．２ＭのＴＨＦ溶液）に、室温にて、^ｉＰｒＭｇＣｌ（３．２ｍＬ、６．３ｍｍｏｌ、２．０ＭのＴＨＦ溶液）を加えた。反応溶液を室温にて１時間攪拌した後、ＢＦ_３・ＯＥｔ_２（０．３ｍＬ、２．０ｍｍｏｌ）を加え、室温にて一晩攪拌した。揮発成分を減圧留去した後、ヘキサンを加え、セライトろ過し、再度、揮発成分を全て減圧下にて留去した。得られた粗生成物へ十分な量のアセトニトリルを加え、室温にて攪拌した後、溶媒を減圧留去した。次に、ペンタンを加えて激しく攪拌すると白色固体が析出した。生じた白色固体を濾過により回収した。さらに、母液のペンタン溶液を－３０度にて放置することで、白色結晶が生じた。これらの固体と結晶を合わせて回収することで、トリス（２，６－ジフルオロ－３，５－ジアリルフェニル）ボランのＣＨ_３ＣＮ錯体（２ｂ）が収率２６％（３２０．８ｍｇ、０．５ｍｍｏｌ）にて得られた。得られたＣＨ_３ＣＮ錯体をトルエンに溶解させ、減圧乾燥させることで、トリス（２，６－ジフルオロ－３，５－ジアリルフェニル）ボラン（１ｂ）を収率２３％（２６５．１ｍｇ、０．４ｍｍｏｌ）にて得た。 (iii) Synthesis of tris(2,6-difluoro-3,5-diallylphenyl)borane (1b)

To 1,5-diallyl-2,4-difluoro-3-iodobenzene (2.0 g, 6.3 mmol, 0.2 M THF solution), ^iPrMgCl (3.2 mL, 6.3 mmol, 2.0 M THF solution) was added at room temperature. After stirring the reaction solution at room temperature for 1 hour, BF ₃ ·OEt ₂ (0.3 mL, 2.0 mmol) was added and stirred at room temperature overnight. After evaporating the volatile components under reduced pressure, hexane was added, filtered through Celite, and all the volatile components were again distilled under reduced pressure. A sufficient amount of acetonitrile was added to the obtained crude product, stirred at room temperature, and the solvent was distilled under reduced pressure. Next, pentane was added and stirred vigorously to precipitate a white solid. The resulting white solid was collected by filtration. Furthermore, white crystals were generated by leaving the pentane solution of the mother liquor at -30 degrees. The solid and the crystals were collected together to give tris(2,6-difluoro-3,5-diallylphenyl)borane CH ₃ CN complex (2b) in a yield of 26% (320.8 mg, 0.5 mmol). The obtained CH ₃ CN complex was dissolved in toluene and dried under reduced pressure to give tris(2,6-difluoro-3,5-diallylphenyl)borane (1b) in a yield of 23% (265.1 mg, 0.4 mmol).

NMR of _CH3CN complex
¹ H NMR (400 MHz, CD ₃ CN): δ 6.89 (t, ⁴ J _H,F = 8.2 Hz, 3H, Ar-H), 5.92 (m, 6H, CH ₂ CH=CH ₂ ), 4.98 (m, 12H, CH ₂ CH=CH ₂ ), 3.24 (d, J = 6.0 Hz, 12H, CH ₂ CH=CH ₂ ), 1.96 (s, CH ₃ CN). ¹¹ B NMR (128 MHz, CD ₃ CN): -9.6. ¹³ C{ ¹ H} NMR (101 MHz, CD ₃ CN): δ 162.8 (dd, J = ¹ J _C,F = 243.4 Hz, 15.2 Hz), 137.7, 130.5 (m), 122.2 (m), 115.9, 33.7. Resonances of the C _ipso with respect to the boron atom were not observed. ¹⁹ F NMR (376 MHz, CD ₃ CN): δ -113.9 (d, ⁴ J _H,F = 7.5 Hz, 6F).
NMR of tris(2,6-difluoro-3,5-diallylphenyl)borane
¹ H NMR (400 MHz, C ₆ D ₆ ): δ 6.93 (t, ⁴ J _H,F = 8.2 Hz, 3H, Ar-H), 5.75 (m, 6H, CH ₂ CH=CH ₂ ), 4.94 (m, 12H, CH ₂ CH=CH ₂ ), 3.13 (d, J = 6.4 Hz, 12H, CH ₂ CH=CH ₂ ). ¹¹ B NMR (128 MHz, C ₆ D ₆ ): Not observed. ¹³ C{ ¹ H} NMR (101 MHz, C ₆ D ₆ ): δ 161.6 (dd, ¹ J _C,F = 249.5 Hz, J = 11.1 Hz), 136.3, 135.9, 122.7 (m), 116.3, 32.9. Resonances of the C _ipso with respect to the boron atom were not observed. ¹⁹ F NMR (376 MHz, C ₆ D ₆ ): δ -110.0 (d, ⁴ J _H,F = 7.5 Hz, 6F).

Examples 3-4 and Comparative Examples 1-2. Hydrogenation of quinoline using hydrogen gas Hydrogenation of quinoline (Qin) was carried out in the presence of various boron compounds. The procedure is as follows.
Quinoline (2.0 mmol), boron compounds (1a), (1b), (1'c), and (1'd) (0.1 mmol; 5 mol%), tetradecane (internal standard), and toluene were added to a 30 mL autoclave. After sealing, H ₂ (10 atm) was added and the mixture was stirred at 100° C. for 8 hours. After cooling to room temperature and degassing, the yield of hydrogenated quinoline (H4-Qin) was calculated using GC.
The results are shown in the table below.

Examples 5 and 6. Hydrogenation reaction of quinoline using a mixed gas containing hydrogen. In the presence of a boron compound or its acetonitrile complex, a hydrogenation reaction of quinoline was carried out using a mixed gas of H ₂ /CO/CO ₂ = 1/1/1 (molar ratio).

Example 5.
Quinoline (263.2 mg, 2.0 mmol), tris(2,6-difluoro-3,5-diallylphenyl)borane (1b) (59.8 mg, 0.1 mmol; 5 mol%), tetradecane (142.5 mg; internal standard), and toluene (1.3 mL) were added to a 30 mL autoclave. After sealing, H ₂ /CO/CO ₂ (each 20 atm) was added and the mixture was stirred at 100° C. for 8 hours. After cooling to room temperature and degassing, hydrogenated quinoline (H4-Qin) was obtained with a GC yield of >99%.

Example 6.
Tris(2,6-difluoro-3,5-diallylphenyl)borane CH ₃ CN complex (2b) (63.2 mg, 0.1 mmol; 5 mol%) was weighed in a 10 mL eggplant flask, 2-3 mL of toluene was added, and the volatile components were distilled off under reduced pressure. Toluene (1.3 mL) and tetradecane (141.5 mg; internal standard) were added again, and the mixture was transferred to a 30 mL autoclave. Quinoline (253.0 mg, 2.0 mmol) was further added, and the flask was sealed, after which H ₂ /CO/CO ₂ (each 20 atm) was applied, and the mixture was stirred at 100°C for 8 hours. After cooling to room temperature and degassing, hydrogenated quinoline was obtained with a GC yield of 77%.

In the boron compound according to the embodiment of the present invention, the meta position of the aryl group bonded to boron is substituted with an electron donating group. The novel boron compound and Lewis base complex of the present invention can be suitably used for producing hydrides, polymers, adducts, and the like.
[Related Applications]
This application claims priority under Article 4 of the Paris Convention or Article 41 of the Japanese Patent Act, based on Japanese Patent Application No. 2023-095773 filed on June 9, 2023. The contents of this basic application are incorporated herein by reference.

Claims (10)

A boron compound represented by the following formula (1):

[In the above formula (1), ^X1 and ^X2 are each independently selected from an electron-withdrawing group, ^Y1 and ^Y2 are each independently selected from hydrogen and an electron-donating group, but are not both hydrogen, ^R1 is selected from an organic group having 1 to 24 carbon atoms, which may have a substituent, and n is selected from an integer of 0 to 2.] A Lewis base complex of a boron compound represented by the following formula (2):

[In the above formula (2), ^X1 and ^X2 are each independently selected from an electron-withdrawing group, ^Y1 and ^Y2 are each independently selected from hydrogen and an electron-donating group, but are not both hydrogen, ^R1 is selected from an organic group having 1 to 24 carbon atoms, which may have a substituent, n is selected from an integer of 0 to 2, and LB is selected from a Lewis base.] A chemical composition comprising the boron compound of claim 1 or the Lewis base complex of claim 2. A hydrogenation catalyst comprising the boron compound according to claim 1 or the Lewis base complex according to claim 2. A method for producing a hydride using the hydrogenation catalyst described in claim 4. A method for producing a hydrogenated product, comprising using the hydrogenation catalyst described in claim 4 in the presence of crude hydrogen gas. A polymerization initiator comprising the boron compound according to claim 1 or the Lewis base complex according to claim 2. A method for producing a polymer, comprising using the polymerization initiator according to claim 7. A Lewis acid catalyst containing the boron compound according to claim 1. A method for producing an adduct, comprising using the Lewis acid catalyst described in claim 9.

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