A Remarkable Substituent Effect on the Enantioselectivity of Tandem Asymmetric Epoxidation and Enantiospecific Ring Expansion of Cyclopropylidene Alcohols: A New Enantiocontrolled Synthesis of (-)-Debromoaplysin and (-)-Aplysin

Article abstract of DOI:10.1021/jo00080a014

A remarkable substituent effect by the tert-butyldimethylsiloxy group on the enantioselectivity of the tandem asymmetric epoxidation and enantiospecific ring expansion of 2-<2-(tert-butyldimethylsiloxy)-4-methylphenyl>-2-cyclopropylideneethanol (18), affording (S)-(-)-2-<2-(tert-butyldimethylsiloxy)-4-methylphenyl>-2-hydroxymethylcyclobutanone (21) in high yield and high enantiomeric excess, was observed.This enabled us to accomplish a concise and highly enantioselective total synthesis of (-)-debromoaplysin (2) and (-)-aplysin (1), providing a new and general strategy for the enantioselective synthesis of biologically important substances having the dihydrobenzofuran framework.