An Efficient and Stereoselective Synthesis of Xerulin via Pd-Catalyzed Cross Coupling and Lactonization Featuring (E)-Iodobromoethylene as a Novel Two-Carbon Synthon

Xerulin, an inhibitor of cholesterol biosynthesis, has been synthesized from commercially available (E)-1-bromopropene, acetylene, and propynoic acid in five steps (longest linear sequence) in 30% overall yield and >96% stereoselectivity. The preparation of (E)-iodobromoethylene and its use in the Pd-catalyzed cross coupling are two of the novel aspects of the synthesis reported herein.