First Comprehensive Bakkane Approach: Stereoselective and Efficient Dichloroketene-Based Total Syntheses of (±)- and (−)-9-Acetoxyfukinanolide, (±)- and (+)-Bakkenolide A, (−)-Bakkenolides III, B, C, H, L, V, and X, (±)- and (−)-Homogynolide A, (±)-Homogynolide B, and (±)-Palmosalide C

Abstract

Cycloaddition of dichloroketene with dimethylcyclohexenes has been used as the key reaction in an efficient, general approach to the bakkanes. New methods and methodologies that have been developed in this work include spiro beta-methylene-gamma-butyrolactonizations, a vicinal dicarboxylation, an angelic ester preparation, a transesterification, an epoxy ketone double reduction, and a retro aldol-aldol approach to low-energy aldol isomers.