Efficient Continuous-Flow Bromination of Methylsulfones and Methanesulfonates and Continuous Synthesis of Hypobromite

An efficient continuous-flow procedure for the synthesis of tribromomethylsulfones and tribromomethanesulfonates has been developed starting from the corresponding methylsulfones or methanesulfonates and potassium hypobromite using a biphasic reaction. Two different continuous-flow systems were used and compared for the bromination reaction. Different derivatives were synthesized in excellent isolated yields in very short reaction times using a small excess of potassium hypobromite. Hypobromite can be synthesized continuously leading to the continuous production of the brominated derivates. With the optimized flow conditions, a throughput of up to 53 g/day was obtained. The bromination reaction in flow has significant advantages compared to the corresponding batch process.