A rapid access to the core skeleton of atypical tricyclic polyprenylated acylphloroglucinols

Abstract

A synthesis of (4S*,6S*)-2,4,6-triallyl- 3,3-dimethylcyclohexanones, and the treatment of their TMS enol ethers with malonyl dichloride in the presence of BF3•lEt2O, are reported. Formation of a ketoacid, resulting from acylation without cyclization, and of a tricyclic phloroglucinol derivative, involving Effenberger annulation with concomitant O-cyclization, were obtained. The tricyclic compound has the core skeleton of the hyperibones H and I, atypical natural polycyclic polyprenylated acylphloroglucinols. Mechanistic and stereochemical aspects are discussed. © ARKAT USA, Inc.