J. Technology and Education, Vol.22, No.1, pp.7-10 (2015)

研究論文

メチルアルミニウム触媒を用いるエポキシ化合物の転位を経由するTishchenko反応

 

長原　滋*，梶原 千世，阪　茂明，木村 悦子，水谷 有里，宮崎 由紀

独立行政法人国立高等専門学校機構　鈴鹿工業高等専門学校　生物応用化学科（〒510−0294　三重県鈴鹿市白子町）

*nagahara@chem.suzuka-ct.ac.jp

 

Rearrangement-Tishchenko Reaction of Epoxides Using a Methylaluminum Catalyst

 

Shigeru NAGAHARA,* Chiyo KAJIWARA, Shigeaki SAKA, Etsuko KIMURA,

Yuri MIZUTANI, and Yuki MIYAZAKI

Department of Chemistry and Biochemistry, National Institute of Technology , Suzuka College

 (Shiroko, Suzuka 510-0294, Japan)

 

(Received January 19, 2015; Accepted February 12, 2015 )

 

Abstract

When trans-stilbene oxide and methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) (abbreviated as MAD) (20 mol%) were allowed to react in CH₂Cl₂ solvent, the rearranged aldehyde, diphenylacetaldehyde (6) (3 mol%) and the epoxide rearrangement-Tishchenko reaction product, 2,2-diphenylethyl 2,2-diphenylacetate (7) (90 mol%) were produced.  The reaction using methylaluminum bis(4-bromo-2,6-di-tert-butylphenoxide) (abbreviated as MABR), dimethylaluminum 4-bromo-2,6- di-tert-butylphenoxide (abbreviated as DABR), and dimethylaluminum 2,6-di-tert-butyl-4-methylphenoxide (abbreviated as DAD) as a catalyst also gave aldehyde 6 and carboxylic ester 7 with low selectivity.  The rearrangement-Tishchenko reaction of aromatic epoxides such as styrene oxide derivatives with a MAD catalyst afforded a good yield of the corresponding carboxylic esters, although various aliphatic epoxides were quite unreactive.  A mechanism for this transformation can be proposed as follows.  The first step is a Lewis acid-base complex formation between an epoxide and an organoaluminum catalyst.  The corresponding rearranged aldehydes are then formed by an intramolecular rearrangement of the Lewis acid-base complex, and the subsequent Tishchenko reaction of the aldehyde gives the corresponding carboxylic esters via a six-membered transition state.

Key words: rearrangement, Tishchenko reaction, epoxides, aluminum phenoxides