Studies for the total synthesis of amphidinolide P.

A convergent, enantiocontrolled total synthesis of the 15-membered macrolide, amphidinolide P, is described. The synthesis utilizes three nonracemic components for an efficient assembly of the macrolactone in 12 steps via the longest linear pathway. Key developments include studies of the Hosomi-Sakurai reaction for the formation of the C6-C7 bond, a "ligandless" palladium-mediated Stille cross-coupling of the vinylic stannane 4 and the alkenyl bromide 5 to produce a highly functionalized dienol, and a thermally induced, intramolecular lactonization via the late-stage formation of an intermediate α-acylketene.