Enantioselective Synthesis of the G-Ring of Brevetoxin A

An enantioselective synthesis of the eight-membered G-ring of brevetoxin A is described.The synthesis exploits a ring-closing metathesis reaction to construct the eight-membered ether ring.The stereochemistry of the a and a' centers of the ether linkage were established through a Sharpless kinetic resolution and an asymmetric glycolate alkylation reaction.