Chemistry of zamoranic acid. Part V Homochiral semisyntheses of active drimanes: Pereniporin B, polygodial and warburganal

Abstract Methyl 14,15-di nor -13-oxo-7-labden-15-oate was obtained from acid zamoranic acid methyl ester. The former by photochemical cleavage yielded methyl 7,9(11)-drimadien-12-oate, whose chemoselective epoxidation afforded methyl 9α,11-epoxy-7-drimen-12-oate, which is the key synthetic precursor for pereniporin B, polygodial and warbuganal.