Convenient sulfonylation of benzotriazoles with the in situ–generated sulfonyl bromides

A convenient procedure is developed for the preparation of N-sulfonylbenzotriazoles from sodium sulfinates, benzotriazoles, and sodium bromide in the present of m-chloroperbenzoic acid as oxidant. This radical sulfonylation proceeds efficiently at room temperature under neutral conditions, affording the corresponding N-sulfonylbenzotriazoles in moderate to good yields in a short time.