Stereoselective total synthesis of the natural (+)-lasonolide A

Abstract

The natural (+)-lasonolide A (1), an anti-tumor agent, has been synthesized via thermodynamic benzylidene formation at the C-22 quaternary chiral center, use of a disulfone equivalent for elongation of the C-15-C-17 three-carbon chain as well as introduction of the two trans olefins at C-15 and C-17, iodocyclization for the upper THP, Michael addition for the bottom THP, and intramolecular Horner-Emmons olefination for the 20-membered macrolactone.