Visible-Light Induced and Iron Peroxo-Promoted Radical Difunctionalization of Alkene for the Synthesis of β-Ketosulfone and α-Chloroketone.

In this work, a switchable synthesis of β-ketosulfone and α-chloroketone through a radical difunctionalization of alkenes is reported. The transformation works well under iron peroxo species/photoredox dual catalysis and an open-flask atmosphere, and the reaction is highlighted with good yields and a broad reaction scope. Mechanism studies show that the reaction is initiated by a formal [4 + 2] cyclization of the sulfonyl radical in a regioselective manner.