Switchable regioselection of C–H thiolation of indoles using different TMS counterions

Abstract

A switchable regioselectivity in C–H thiolation reaction by simply swapping the counteranions of TMS is reported here for the first time. An exclusive C3–H thiolation of indoles with sodium arylsulfinates was achieved in the presence of TMSCl as a promoter. In contrast, with the use of TMSOTf instead of TMSCl under otherwise identical conditions, a regiospecific C2–H thiolation of indoles was realized with the same set of substrates.