The sulfenylation of imidazopyridines with sulfinic acids mediated by DTBP/HCl

A direct sulfenylation reaction of imidazopyridines with sulfinic acid mediated by di- tert -butylperoxide (DTBP) and hydrochloric acid was developed leading to the introduction of C S bonds into the imidazo[1,2- a ]pyridine skeleton. The reaction proceeded under transition-metal-free conditions with good functional group tolerance and moderate to excellent yields. The DTBP/HCl-mediated C-3 sulfenylation of imidazo[1,2- a ]pyridines was developed using readily available and stable sulfinic acids as sulfur source. • t-BuOOBu t /HCl was used to promote the C-3 sulfuration of imidazopyridines. • HCl plays an important role in the formation of Ar-S-O-SO 2 Ar from Ar-SO 2 H. • t-BuOOBu t can efficiently mediate Ar-S-O-SO 2 Ar to generate Ar S radical. • Readily available, odorless and stable RSO 2 H was used as sulfur source. • The method displays broad substrate scope. • Simple operation without metal reagent were used.