1,5-Asymmetric induction in the boron-mediated aldol reaction of beta-oxygenated methyl ketones

Química Nova

Aguilar, Andrea M.¹  Universidade Estadual de Campinas, Campinas, Brasil¹  Dias, Luiz C.¹  Universidade Federal de São Paulo, Diadema, Brasil¹ 

关键词: 1;    5-anti induction;    boron enolates;    aldol reactions.;   

DOI  :  10.1590/S0100-40422007000800036

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

High levels of substrate-based 1,5-stereoinduction are obtained in the boron-mediated aldol reactions of b-oxygenated methyl ketones with achiral and chiral aldehydes. Remote induction from the boron enolates gives the 1,5-anti adducts, with the enolate p-facial selectivity critically dependent upon the nature of the b-alkoxy protecting group. This 1,5-anti aldol methodology has been strategically employed in the total synthesis of several natural products. At present, the origin of the high level of 1,5-anti induction obtained with the boron enolates is unclear, although a model based on a hydrogen bonding between the alkoxy oxygen and the formyl hydrogen has been recently proposed.

【 授权许可】

Unknown