Formal Synthesis of the Bryostatin Northern Hemisphere: Asymmetric Synthesis of the B Ring and C1-C9 Fragment

Abstract

A formal synthesis of the top half fragment of bryostatin 11 has been developed. Stereoselective construction of the B ring was achieved by using a ring-closing metathesis reaction in conjunction with asymmetric glycolate alkylation. Furthermore, the C1-C9 fragment was synthesized by Brown allylation, chelation-controlled aldol condensation, and Saksena-Evans reduction to construct all stereogenic centers.