Molybdooxaziridine Catalysis: Synthesis of α‐Hydroxysulfones From Styrenes Through an ATRA Process

Herein, we report the MoO 2 Dipic‐promoted hydroxysulfonation of α‐methyl‐styrenes using N‐Ts‐hydroxylamine as the quantitative source of N. The reaction works with high yields and stereoselectivites for α‐methyl‐styrenes with a wide variety of substitution patterns. An atom‐transfer‐radical‐addition mechanism involving the formation of a molybdooxaziridine complex as the active catalyst, then Ts radical addition, followed by hydroxy radical addition as the rate‐determining step has been proposed. Initial kinetic and mechanistic data indicate initial mono‐functionalization without NO radical addition and provide evidence for the proposed mechanism.