Synthesis of the monomeric counterpart of marinomycin A.

An efficient and highly convergent synthesis of the monomeric counterpart of the antitumor-antibiotic marine natural product marinomycin A was achieved by using optically active titanium complexes to control the configuration of the stereogenic centers, a highly stereo- and regioselective cross-metathesis to generate the (E)-configured C20-C21 double bond, and a Horner-Wadsworth-Emmons olefination followed by a Pd-catalyzed Stille cross-coupling to construct the tetraene moiety.