对映选择合成
化学
烷基化
醛
手性(物理)
非对映体
烷基
试剂
有机化学
组合化学
手性助剂
催化作用
有机合成
醇盐
羟醛反应
物理
量子力学
手征对称破缺
Nambu–Jona Lasinio模型
夸克
作者
Ryoji Noyori,Masato Kitamura
标识
DOI:10.1002/anie.199100491
摘要
Abstract Nucleophilic addition of organometallic reagents to carbonyl substrates constitutes one of the most fundamental operations in organic synthesis. Modification of the organometallic compounds by chiral, nonracemic auxiliaries offers a general opportunity to create optically active alcohols, and the catalytic version in particular provides maximum synthetic efficiency. The use of organozinc chemistry, unlike conventional organolithium or ‐magnesium chemistry, has realized an ideal catalytic enantioselective alkylation of aldehydes leading to a diverse array of secondary alcohols of high optical purity. A combination of dialkylzinc compounds and certain sterically constrained β‐dialkylamino alcohols, such as (–)‐3‐ exo ‐dimethylaminoiso‐ borneol [(–)‐DAIB], as chiral inducers affords the best result (up to 99% ee ). The alkyl transfer reaction occurs via a dinuclear Zn complex containing a chiral amino alkoxide, an aldehyde ligand, and three alkyl groups. The chiral multiplication method exhibits enormous chiral amplification: a high level of enantioselection (up to 98%) is attainable by use of DAIB in 14% ee . This unusual nonlinear effect is a result of a marked difference in chemical properties of the diastereomeric (homochiral and heterochiral) dinuclear complexes formed from the dialkylzinc and the DAIB auxiliary. This phenomenon may be the beginning of a new generation of enantioselective organic reactions.
科研通智能强力驱动
Strongly Powered by AbleSci AI