Selenium-Catalyzed Electrophilic Cascade Reactions of Vinylarenes with N-Fluorobenzenesulfonimide: A Novel Strategy for the Synthesis of β-Keto Sulfones

A selenium-catalyzed electrophilic cascade reaction of vinylarenes with N-fluorobenzenesulfonimide for the efficient synthesis of important beta-keto sulfones via a single operation is developed. The reactions of vinylarenes bearing electron-withdrawing groups and electron-donating groups proceeded smoothly in the air and gave products in up to 94 % yield. Mechanistic studies suggest that vinyl amines generated by oxidative amination of vinylarenes are the intermediates, the cleavage of N-S bond and the recombination of sulfonyl radical lead to 1,3-migration of sulfonyl, and hydrolysis affords the products beta-keto sulfones.