Efficient Synthesis of γ-Lactones via Gold-Catalyzed Tandem Cycloisomerization/Oxidation

A novel Au-catalyzed tandem cycloisomerization/oxidation of homopropargyl alcohols was developed. Various gamma-lactones can be accessed readily by utilizing this strategy. Notably, the mechanism of this reaction is distinctively different from the related Ru-catalyzed reactions where the ruthenium vinylidene intermediate was proposed.