Total Synthesis of (-)-Retigeranic Acid A: A Reductive Skeletal Rearrangement Strategy.

The asymmetric total synthesis of (-)-retigeranic acid A was described, which relies on a crucial reductive skeletal rearrangement cascade for the controllable assembly of diverse angular triquinane subunits. Taken together with an intramolecular Michael/aldol cyclization, an ODI-[5 + 2] cycloaddition/pinacol rearrangement cascade, a Wolff ring contraction and a stereoselective HAT reduction, our synthetic approach has enabled the access to (-)-retigeranic acid A in a concise and practical manner.