Metal-free, highly regioselective sulfonylation of NH-1,2,3-triazoles with sodium sulfinates and thiosulfonates

A convenient and metal-free protocol for the highly regioselective sulfonylation of NH-1,2,3-triazoles is described. A range of readily accessible NH-1,2,3-triazoles were sulfonylated with various aryl sulfinates in the presence of molecular iodine. The scope was extended to thiosulfonates as an efficient sulfonylating agent and nitrochromene derived triazoles were also explored for selective N-sulfonylation. A variety of synthetically viable N-2-sulfonyl triazoles were obtained in moderate to high yields with excellent regioselectivities via N-S bond construction under mild reaction conditions. (C) 2018 Elsevier Ltd. All rights reserved.