Enantioselective β-Protonation of Enals via a Shuttling Strategy

被引：79

作者：

Chen, Jiean ^{[1
]}

Yuan, Pengfei ^{[1
]}

Wang, Leming ^{[1
]}

Huang, Yong ^{[1
]}

机构：

[1] Peking Univ, Shenzhen Grad Sch, Sch Chem Biol & Biotechnol, Key Lab Chem Genom, Shenzhen 518055, Peoples R China

来源：

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | 2017年 / 139卷 / 20期

基金：

中国博士后科学基金; 中国国家自然科学基金;

关键词：

N-HETEROCYCLIC CARBENE; COOPERATIVE CATALYSIS; ASYMMETRIC HYDROGENATION; ALPHA; BETA-UNSATURATED ALDEHYDES; DIRECT ANNULATIONS; GAMMA-LACTAMS; STEREOSELECTIVE-SYNTHESIS; CONJUGATE ADDITION; SPIRO-HETEROCYCLES; EPSILON-LACTONES;

D O I：

10.1021/jacs.7b02889

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Remote asymmetric protonation is a long-standing challenge due to the small size of protons. Reactions involving electron-deficient olefins pose a further difficulty due to the electrophilic nature of these substrates. We report a shuttling system that delivers a proton in a highly enantioselective manner to the beta-carbon of enals using a chiral N-heterocyclic carbene (NHC) catalyst. Choices of a Bronsted base shuttle and a Bronsted acid cocatalyst are critical for highly stereoselective beta-protonation of the homoenolate intermediate and regeneration of the NHC catalyst results in functionalization of the carbonyl group. Thioesters with a beta-chiral center were prepared in a redox-neutral transformation with an excellent yield and ee.

引用

页码：7045 / 7051

页数：7

共 78 条

[1] Asymmetric conjugate reduction of α,β-unsaturated esters using a chiral phosphine-copper catalyst [J].