Application of Ru(II)-Catalyzed Enyne Cyclization in the Synthesis of Brefeldin A.

The approach to brefeldin A described herein hinges on Ru(II)-catalyzed cycloisomerization of an enyne obtained by the reaction of an alkynylzinc reagent with an α-chloro sulfide. Other key steps include Mislow-Evans rearrangement, cross-metathesis, and macrocyclization using a Roush-Masamune protocol.