Structure elucidation and synthesis of (4S,5S,6Z,8E)-5-hydroxydeca-6,8-dien-4-olide [(S,S)-sapinofuranone B] - a novel gamma-lactone metabolite of Acremonium strictum

The structure of (4S,5S,6Z,8E)-5-hydroxydeca-6,8-dien-4-olide, a novel meta bolite of Acremonium strictum, has been established by spectroscopic studie s and chemical correlation with the known L-factor. The structure has been confirmed by a total synthesis in which the asymmetric centres at C-4 and C -5 were elaborated from dimethyl L-tartrate and the 6,8-diene moiety was in troduced via Stille coupling of (E)-prop-1-enyltributyltin with a (Z)-vinyl ic iodide. The absolute configurations of sapinofuranones A and B, recently isolated metabolites of Sphaeropsis sapinae, are shown to be the correspon ding (4R,5S) and (4R,5R) diastereomers of the A. strictum metabolite.