TMEDA-enabled regioselective sulfenylation of unprotected N-heterocycles via electrochemical sulfinyl radical generation

Abstract

An electrochemical sulfenylation of unprotected N-heterocycles with a wide range of commercially available arylsulfonyl chlorides was developed. This protocol features the use of inexpensive N,N,N′,N’-tetramethylethylenediamine (TMEDA) serving as both a promoter and a base to tune the sulfenylation process, thus affording sulfenylated products in good yields with high regioselectivity. Importantly, TMEDA significantly lowers the oxidation potential of indole, thus avoiding the over-oxidation of indole.