Lewis-Acid-Catalyzed Asymmetric Alkynylation of Alkynyl 1,2-Diketones: Controllable Formation of 3(2H)-Furanones and α-Hydroxy Ketones

We report the highly regio- and enantioselective alkynylation of alkynyl 1,2-diketones under Lewis acid catalysis, leading to the formation of a series of biologically important 3(2H)-furanones with high to excellent ee values. Moreover, a slight change of the reaction conditions produces a range of highly functionalized alpha-hydroxy ketones with a high level of enantioselectivity. A variety of further transformations can be easily achieved, demonstrating the synthetic potential of this protocol.