Total synthesis of amphidinolide Y by formation of trisubstituted (E)-double bond via ring-closing metathesis of densely functionalized alkenes.

Amphidinolide Y, a 17-membered cytotoxic macrolide isolated from marine dinoflagellates, has been synthesized via ring-closing metathesis to assemble the congested trisubstituted (E)-double bond. The seco precursor was prepared from readily available chiral synthons with the tetrahydrofuran ring formed via 5-endo epoxide ring-opening cyclization. It was found that the C6-keto seco substrate showed higher reactivity toward Grubbs' second generation catalyst while Schrock's Mo catalyst was completely inactive for formation of the macrocycle.