Stereoselective Total Synthesis of Bioactive Styryllactones (+)-Goniofufurone, (+)7-<i>epi</i>-Goniofufurone, (+)-Goniopypyrone, (+)-Goniotriol, (+)-Altholactone, and (−)-Etharvensin^†

Abstract

Stereoselective total synthesis of biologically active styryllactones 7-epi-goniofufurone, goniofufurone, goniopypyrone, goniotriol, altholactone, and etharvensin was achieved in high overall yields from a common intermediate derived from d-(−)-tartaric acid. It is based on the utility of a masked tetrol, comprising an alkene tether and four contiguous hydroxy groups. The pivotal reaction sequence involves hydroxy-directed lactonization via the oxidation of alkene, and subsequent elaboration to styryllactones. The masked tetrol was prepared by the extension of γ-phenyl-γ-hydroxy butyramide, readily obtained from the bis-dimethylamide of tartaric acid, employing a combination of selective Grignard additions and a stereoselective reduction