Biogenetic Model Reactions of Epoxygermacrones

Abstract

From a biogenetic point of view, acid- or base-catalyzed cyclizations of epoxygermacrones (2, 23, and 33) were carried out. In most cases, the stereospecific cyclizations of these epoxygermacrones took place to give many compounds with an 11-oxabicyclo[5.3.1]undecane system, cadinane-type, selinane-type or guaiane-type compounds depending on the kinds of reagents and solvents. The formation process of each cyclization product will be discussed in detail.