JPH0465079B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for hydroalumination reaction of olefins. More specifically, the present invention relates to an olefin hydroalumination reaction method using an organic boron compound as a catalyst. The hydroaluminated product of olefin (aluminum dihalide, aluminum monohalide monohydride, aluminum dihydride, etc.) obtained by the hydroalumination reaction method of the present invention yields the corresponding alcohol by the action of an electrophilic agent. [Prior art] In the past, diisobutylaluminum hydride was directly reacted for a long time in the hydroalumination reaction of olefins, but only the terminal olefins reacted (Organometallic Chemistry ACS Monograph).
Organometallic Chemistry ACS Monograph
No.147, p.194~ (1960)). Or biscyclopentadienyl titanium dichloride (Cp ₂ TiCl ₂ )
There is a method using the internal olefin as a catalyst, but the reactivity of internal olefin is low and the yield is also low (E.
Journal of the Organic Chemistry ECAshby, SANoding, J.Org.
Chem.44, 4364, (1979)). [Problems to be solved by the invention] However, both methods are limited to terminal olefins, require severe conditions to react with other olefins, and have low yields that are not industrially satisfactory. It wasn't something I could do. [Means for Solving the Problems] However, the present inventors used various organic boron compounds as catalysts instead of Cp ₂ TiCl ₂ and added an aluminum-containing metal hydrogenating agent or an aluminum-containing metal hydroxidizing agent to the catalyst. By using an electrophilic agent, they found a revolutionary improvement in yield. That is, the present invention uses an organoboron compound (excluding the combination of AlH ₃ and phenylboron dihydroxide (PhB(OH) ₂ )) as a catalyst in a solvent, and reacts an aluminum-containing metal hydrogenating agent with the olefin. In addition to the action of an aluminum-containing metal hydrogenating agent, the present invention is characterized by a hydroalumination reaction of an olefin in which an electrophilic agent acts in addition to the action of an aluminum-containing metal hydrogenating agent, and an electrophilic reaction thereof. [Function] Here, the olefin is a terminal olefin, a cyclic olefin, a di-substituted olefin, and a tri-substituted olefin. Terminal olefin: propylene, 1-butene, 1-
Substrates such as pentene in which one of the four hydrogens of ethylene is replaced with an alkyl group. Cyclic olefins: cyclopentene, cyclohexane, 1-methylcyclohexene, etc.
It is a substrate in which two or three of the hydrogen atoms are substituted with alkyl groups to form a ring. Disubstituted olefin: A substrate in which two of the four hydrogens of ethylene on different carbons are substituted with alkyl groups. Trisubstituted olefin: 3 of the 4 hydrogens of ethylene
A substrate in which two hydrogen atoms are replaced with alkyl groups. Organic boron compounds include phenylboric acid, monoalkylboronic acid, dialkylboronic acid, trialkylboronic acid, dialkylborane, trialkoxyboronic acid, 9-borabicyclo(3,3,1)nonane, and monoalkylboronic acid includes methylboronic acid. acid,
Ethylboric acid, butylboric acid, pentylboric acid,
These include hexylboric acid, heptylboric acid, octylboric acid, cyclopentylboric acid, cyclohexylboric acid, phenylboric acid, tolylboric acid, and naphthylboric acid. Examples of dialkylboric acids include dimethylboric acid,
Examples include diethylboric acid, dibutylboric acid, dihexylboric acid, diphenylboric acid, and ditolylboric acid. Examples of trialkyl boron include trimethyl boron, triethyl boron, tripropyl boron, triisopropyl boron, tributyl boron, tri-sec-butyl boron, triisobutyl boron, tripentyl boron, tricyamyl boron, trihexyl boron, -3-hexylboron, tri-(2-methylpentyl)boron,
Examples include tricyclohexylboron. As the dialkylborane, dimethylborane,
Dipropylborane, diisopropylborane, dibutylborane, di-sec-butylborane, diisobutylborane, dipentylborane, dithiamineborane, dihexylborane, di-3-hexylborane, di-(2-methylpentyl)borane, dicyclohexylborane, 9 -borabicyclo(3,3,
1) Nonane (9-BBN) and the like. Preferred organoboron compounds for the purposes of the present invention are
R ¹ B(OH) ₂ (wherein R ¹ is an alkyl group or phenyl group), R ² ₃ B (however, R ² is an alkyl group) and 9
- At least one selected from borabicyclo(3,3,1)nonane. Examples of aluminum-containing metal hydrogenating agents include dialkylaluminum hydrides such as dichloroaluminum hydride, diisobutylaluminum hydride and diethylaluminum hydride, aluminum trihydride, etc. LiAlH ₄ /
AlCl ₃ , dialkyl aluminum hydride/
A combination of AlCl ₃ or the like may also be used, and the ratio can be changed arbitrarily. The solvent is preferably ether or tetrahydrofuran, or dichloromethane, dichloroethane, pentane, hexane, heptane, benzene, toluene, or xylene, and the reaction is carried out at -78°C to room temperature. [Examples and Effects of the Invention] Next, a detailed explanation will be given while showing examples. Example A FIG. 1 shows the results of reacting 1-dodecene with an aluminum hydrogenating agent (2 equivalents) or various boron compounds (0.05 equivalents) in ether at room temperature. Here, 1 (Comparative example) Diisobutylaluminum hydride only 2 (Comparative example) Cl ₂ AlH only 3 Diisobutylaluminum hydride + PhB
(OH) ₂ 4 AlH ₃ +PhB(OH) ₂ 5 Cl ₂ AlH+PhB(OH) ₂ 6 Cl ₂ AlH+Et ₃ B 7 Cl ₂ AlH+9−BBN 8 Cl ₂ AlH+B(OH) ₃ 9 Cl ₂ AlH+B(OCH ₃ ) ₃ 10 (Comparative example) _{Cl2AlH + Cp2TiCl211Cl2AlH + Et3B} + _H2O . Note: PhB(OH) ₂ ... Phenylboric acid Et ₃ B ... Triethylboron In this way, compared to the reaction with only a metal hydrogenating agent and the combination with conventional biscyclopentadienyl titanium dichloride, It was found that there were significant differences between the combinations of hydrogenating agents and various organoboron compounds. As a metal hydrogenating agent, Cl ₂ AlH was found to be superior to diisobutylaluminum hydride (DIBAL-H), and as a boron compound, it was found to be superior to B(OH) ₃ and B(OCH ₃ ) ₃ . Also organoboron compounds, especially PhB(OH) ₂ ,9-BBN, Et ₃
It was found that B etc. were superior. Also, in ether, 0.05 equivalents of PhB(OH) ₂ ,
Cl ₂ AlH 3 to 4 equivalents of electrophilic agent, for example, in an oxygen atmosphere (dry air or oxygen gas may be used) at room temperature.
Exposure of olefin 1 (2-methyl-1-undecene) for 10 hours sequentially produces the corresponding alcohol 2 in yields of 38-43%. What is even more surprising is that when water is added to this system,
It was found that when 1 equivalent was added, the reaction proceeded further and alcohol 2~ was produced with a good yield of 70-83%. Table 1 shows the results of a similar test performed using different olefins.

[Table] Example B A catalyst was prepared by reacting 0.05 equivalents of PhB(OH) ₂ with 0.05 equivalents of Cl ₂ AlH2 (prepared from LiAlH ₄ and AlCl ₃ in ether). In case of ketone synthesis, the catalyst Et ₃
Prepared from 0.05 equivalents of B and 2 equivalents of Cl ₂ AlH (prepared from Et ₂ AlH and AlCl ₃ in 1,2-dichloroethane).

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a chart showing the relationship between the yield of dodecane and time (hours) in Example A of the present invention.

Claims (1)

[Claims] 1. R ¹ B as a catalyst in a solvent to an olefin.
(OH) ₂ (wherein R ¹ is an alkyl group or phenyl group), R ² ₃ B (however, R ² is an alkyl group), and an organic boron compound selected from 9-borabicyclo(3,3,1)nonane. and producing a hydroaluminated product of olefin which gives the corresponding alcohol by the action of an electrophilic agent, characterized in that it is treated with an aluminum-containing metal hydrogenating agent (excluding the combination of AlH ₃ and phenylboric acid). Method. 2. The method according to claim 1, wherein the aluminum-containing metal hydrogenating agent is dichloroaluminum hydride, dialkyl aluminum hydride, or aluminum trihydride. 3 Olefins are propylene, 1-butene, 1-
Terminal olefins such as pentene, cyclopentene,
The method according to claim 1 or 2, which is a cyclic olefin such as cyclohexene or 1-methylcyclohexene, a disubstituted olefin such as 1,2-dialkyl substituted ethylene, or a trisubstituted olefin such as trialkyl substituted ethylene. . 4 Ether, tetrahydrofuran, as a solvent
Any one of claims 1 to 3 in which dichloromethane, dichloroethane, pentane, hexane, heptane, benzene, toluene, and xylene are used and the reaction is carried out at -78°C to room temperature.
The method described in section.