Enantioselective Total Synthesis of Enokipodins A–D, Antimicrobial Sesquiterpenes Produced by the Mushroom, Flammulina velutipes

Abstract

The first enantioselective total synthesis of enokipodins A, B, C and D, highly oxidized α-cuparenone-type sesquiterpenoids possessing antimicrobial activity, was accomplished in 8–28% overall yields from methyl (2,5-dimethoxy-4-methylphenyl)acetate by applying Meyers’ diastereoselective alkylation protocol for the construction of their C7-quaternary asymmetric center. The present synthesis confirmed the absolute configuration of the enokipodins, and also constitutes a formal enantioselective synthesis of (S)-1,4-cuparenediol and (S)-cuparene-1,4-quinone.