Asymmetric synthesis of S-(+)-argentilactone and S-(-)-goniothalamin

The asymmetric synthesis of an alpha,beta -unsaturated delta -lactone equiv alent 8 as a key intermediate towards the total synthesis of a variety of n atural products bearing such structural motifs is reported. An enzymatic ap proach was applied to provide both enantiomers of compound 8 using recl-BAD H (ee > 99%) and baker's yeast (ee = 94%), respectively. The utility of the intermediate was demonstrated by the total synthesis of the non-natural en antiomers of argentilactone [(S)-1] and goniothalamin [(S')-2].