Preparation of a-substituted allylboronates by chemoselective iridium-catalyzed asymmetric allylic alkylation of 1-propenylboronates

被引：46

作者：

Peng, Feng ^{[1
]}

Hall, Dennis G. ^{[1
]}

机构：

[1] Univ Alberta, Dept Chem, Edmonton, AB T6G 2G2, Canada

来源：

TETRAHEDRON LETTERS | 2007年 / 48卷 / 18期

基金：

加拿大自然科学与工程研究理事会;

关键词：

D O I：

10.1016/j.tetlet.2007.02.124

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Chiral alpha-substituted allylic boronates are attractive reagents that add to aldehydes with very high stereoselectivity. This study examined the feasibility of an improved method of preparation based on the catalytic asymmetric allylic alkylation of simple 3-hydroxy-1-propenylboronate derivatives with malonate anions. Whereas palladium catalysis failed in promoting the desired process, iridium catalysis led to a regioselective formation of the desired, branched allylboronates with up to 84% ee using a chiral monophosphoramidite ligand. This allylation reagent adds to aldehydes with high chirality transfer. A diastereoselective alkoxycyclization on the resulting homoallylic alcohols allows a separation of the epimeric E/Z isomers. (c) 2007 Elsevier Ltd. All rights reserved.

引用

页码：3305 / 3309

页数：5

共 31 条

[1] Very efficient phosphoramidite ligand for asymmetric iridium-catalyzed allylic alkylation [J].