Studies toward the total synthesis of sorangiolides and their analogues. A convergent stereoselective synthesis of the macrocyclic lactone precursors.

ABSTRACT

Stereoselective synthesis of the fully protected 18-membered macrocyclic lactones as the immediate precursors of the natural products, sorangiolides A and B, is described. The key steps used in the synthesis include the sp3-hybridized carbon-carbon Fu cross coupling, the stereoselective Evans' aldol reaction with 1,5-anti induction, the 1,3-diastereoselective syn reduction of a beta-hydroxyketone intermediate, and Mukaiyama macrolactonization reactions.