Synthesis of β-Keto Sulfones via Coupling of Aryl/Alkyl Halides, Sulfur Dioxide and Silyl Enolates through Metal-Free Photoinduced C-X Bond Dissociation

A photoinduced sulfonylative coupling of aryl/alkyl halides, DABCO center dot(SO2)(2) (1,4-diazabicyclo[2.2.2] octane-sulfur dioxide), and silyl enolates under metal-free conditions has been developed, giving rise to beta-keto sulfones in good yields. This transformation proceeds smoothly at room temperature under ultraviolet irradiation with good tolerance of various functional groups. Aryl iodides/bromides and alkyl halides are all good substrates in the sulfonylative reaction. A plausible mechanism is proposed, which proceeds through a radical process under photoinduced conditions.