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

We describe herein a catalyst-free selective C−H sulfenylation of imidazo[1,2-a]pyridines using sulfonothioates as odorless source of thioarylated reagent in an aqueous medium. The method works for a variety of substituted imidazo[1,2-a]pyridines with broad functional group tolerance. The methodology has been extends to selective sulfernylation of indoles and imidazothiazoles. The sulfonothioates are activated exclusively in aqueous medium rather than organic solvent media and the feasibility of the process for scale-up studies have been demonstrated.