Enantioselective α,α-Chlorofluorination of Sulfoxonium Ylides

The first examples of enantioselective α,α-chlorofluorination of α-carbonylsulfoxonium ylides are described. Herein, two modes of reaction are explored, using chiral aminosulfoxonium ylides and a chiral fluorinating reagent, prepared in situ from commercially available cinchona alkaloids. Using these approaches, 25 examples of gem-dihalogenated compounds (including bromochlorination) were obtained in good yields (up to 90%) and enantioselectivity (up to 96:4 er).