Gold-Catalyzed Cascade Cyclization-Oxidative Alkynylation of Allenoates

A gold(I)-catalyzed cascade-cyclization oxidative cross-coupling process has been applied to prepare beta-alkynyl-y-butenolides directly from allenoates and various terminal alkynes. Following an initial gold-catalyzed C-O bond forming allenoate cyclization, a mechanism based on a Au-I/Au-III redox cycle has been proposed with Selectfluor acting as the external oxidant.