C3 Sulfenylation of N‐Heteroarenes in Water under Catalyst‐Free Conditions

A method for the catalyst‐free C–H sulfenylation of imidazo[1,2‐ a ]pyridines by using sulfonothioates as an odorless thioarylated reagent in aqueous medium was developed. This protocol was used for a variety of substituted imidazo[1,2‐ a ]pyridines with broad functional‐group tolerance and was extended to the sulfenylation of indoles and imidazothiazoles. The sulfonothioates were activated exclusively in aqueous medium rather than in an organic solvent, and the feasibility of the process for scale‐up studies was demonstrated.