A Stille cyclisation approach to (–)-periplanone-B: studies in alkene-selective ring-closing metathesis and an improved chromium(II)-mediated synthesis of (E)-alkenylstannanes from aldehydes

Abstract

A synthesis of the dienone 7 via an efficient intramolecular Stille cross-coupling reaction, an improved chromium(II)-mediated synthesis of (E)-alkenylstannanes from aldehydes using Bu₃SnCHI₂ in DMF, and a synthesis of the substituted (–)-dienone 25 via ring-closing alkene metathesis to give dihydropyran 22 are described. The synthesis of (–)-dienone 25 constitutes a formal synthesis of (–)-periplanone-B.