Total Syntheses of Dendrodolides A, B, and E

Convergent total syntheses of dendrodolides A, B, and E comprising 12-membered macrolactones are described. The syntheses of dendrodolides A and B were accomplished in 11 linear steps with 24% and 25% overall yield, respectively, starting from commercially available homoallyl alcohol 19 and enantiomerically pure epoxide 20. Dendrodolide E was subsequently obtained from dendrodolides A or B in 81 % yield by treatment with BCl3. Key steps were Maruoka asymmetric allylation, Corey-Chaykovsky reaction, Yamaguchi esterification, and ring-closing metathesis.