Iridium-Catalyzed Enantioselective Allylic Substitutions of Aliphatic Esters via Silyl Ketene Acetals

摘要

Enantioselective allylic substitutions with enolates derived from aliphatic esters under mild conditions remain challenging. Herein we report iridium-catalyzed enantioselective allylations of silyl ketene acetals, the silicon enolates of esters, to form products containing a quaternary carbon at the nucleophile moiety and a tertiary carbon at the electrophile moiety. Under relatively neutral conditions, the allylated aliphatic esters were obtained with excellent regioselectivity and enantioselectivity. These products were readily converted to primary alcohols, carboxylic acids, amides, isocyanates, and carbamates, as well as tetrahydrofuran (THF) and γ-butyrolactone derivatives, without erosion of enantiomeric purity.