Electrochemical sulfonylation of imidazoheterocycles under batch and continuous flow conditions.

An efficient and versatile protocol for the C-H sulfonylation of imidazoheterocycles via electrochemical activation was established under batch and flow conditions. The selective C-H bond functionalization proceeded under catalyst- and oxidant-free conditions and tolerated a wide range of functional groups. Various sodium sulfinates as well as imidazo[1,2-a]-pyridines, -pyrimidine, -quinolines, and -isoquinolines, imidazo[1,2-b]pyridazine, imidazo[2,1-b]thiazoles and benzo[d]imidazo[1,2-b]thiazoles reacted successfully. Interestingly, significant acceleration and higher yields were obtained under microfluidic conditions.