Total synthesis of (+)-bourgeanic acid utilizing desymmetrization strategy

Abstract

A highly stereoselective total synthesis of an aliphatic depside (+)-bourgeanic acid via (-)-hemibourgeanic acid and bourgeanic lactone is described. The key steps involved in this synthesis are desymmetrization of bicyclic olefin with Brown's asymmetric hydroboration, Gillman's reaction, TEMPO-BAIB mediated selective oxidation of 1,3-diol, Yamaguchi macro-lactonization and LiOH-mediated partial hydrolysis of unusually stable eight-membered cyclic dilactone