Enantioselective synthesis of the [6,6] spiroketal core of reveromycin A

structure: see text] Reveromycin A (1) belongs to a family of microbial polyketides with unusual structural features and biological activities. The structure of 1 is composed of a 6,6] spiroketal core decorated with highly unsaturated side chains. As a prelude to the synthesis of 1, we present herein a short, efficient, and enantioselective synthesis of the C9-C21 fragment 5 (spiroketal core) of reveromycin A.