TFA-promoted direct C-H sulfenylation at the C2 position of non-protected indolesElectronic supplementary information (ESI) available: Experimental procedures, characterization, 1H and 13C NMR spectra of isolated compounds. See DOI: 10.1039/c5cc05421d

A simple, efficient and practical metal-free C-H sulfenylation process at the C2 position of non-protected indoles has been developed. 2-Thioindoles were obtained in moderate to high yields using stable and readily available N -(thio)succinimides at room temperature in the presence of TFA. An efficient metal-free C-H sulfenylation process at the C2 position of non-protected indoles has been developed.