Synthesis of the macrocyclic core of laulimalide.

[figure: see text] A stereoselective synthesis of 3, corresponding to the fully functionalized macrocyclic core of the novel microtubule-stabilizing agent, laulimalide, has been completed. Efficient macrolactonization was achieved by a Mitsunobu reaction, installing the sensitive (Z)-enoate, and macrocyclic stereocontrol was then exploited to introduce the methyl group and trans-epoxide.