The
first total synthesis of (+)-vibsanin A, an 11-membered vibsane diterpenoid,
was achieved, unambiguously establishing its relative and absolute
stereochemistry. Highlights of the synthesis include the stereoselective
formation of an all-carbon quaternary stereocenter by a zinc-mediated
Barbier-type allylation in an aqueous medium, and the efficient construction
of an 11-membered ring skeleton by a combination of an intramolecular
Nozaki–Hiyama–Kishi (NHK) reaction and a Mitsunobu reaction.