A Continuous Flow Bromodimethylsulfonium Bromide Generator: Application to the Synthesis of 2-Arylaziridines from Styrenes

A continuous flow procedure for the synthesis of aziridines from alkenes based on the in situ generation and utilization of bromodimethylsulfonium bromide (BDMS) is presented. In this process, BDMS was generated from hydrogen bromide and dimethylsulfoxide in the presence of the olefin, ensuing the corresponding 1,2-bromodimethylsulfonium bromide addition product. The solution containing this intermediate was mixed with a primary amine in flow, resulting in a rapid aziridination in a fast 3-step telescoped process. Notably, the exothermic formation of BDMS could be readily controlled in flow mode at room temperature, rendering a safe and reliable process. The complete sequence only required 7 min of total residence time, and provided a variety of 2-aryl aziridines in synthetically useful yields.