Toward the total synthesis of variecolin

Abstract

[reaction: see text] An annulative approach toward the total synthesis of the sesterterpenoid variecolin (1) is presented. Synthesis of the key hemiketal, containing the core ABC ring skeleton, has been achieved on a model system by an expeditious route utilizing samarium(II) iodide. Furthermore, enantioselective syntheses of component fragments for the total synthesis have been developed.