Total synthesis of (+)-cephalosporolide E and (-)-cephalosporolide F en route to bassianolone

Abstract

A stereoselective synthesis of (+)-cephalosporolide E and (-)-cephalosporolide F en route to bassianolone is described. The key steps involve cross metathesis to get the desired β ,γ-unsaturated ester, asymmetric dihydroxylation to install the β-hydroxy-γ-lactone moiety and spiroketalization. Although attempts to get free bassianolone failed, the first total synthesis of natural cephalosporolides E and F has been achieved in nine steps and 6.3% and 3.5% overall yields, respectively. © Georg Thieme Verlag Stuttgart.