Bu3SnH mediated oxidative radical cyclisation onto imidazoles and pyrroles

Article abstract of DOI:10.1016/S0040-4020(99)00419-6

A new protocol using radical cyclisation has been developed for the synthesis of [1,2-c]-fused imidazoles and [1,2-a]-fused pyrroles. The intermediate nucleophilic N-alkyl radicals, generated using Bu₃SnH from N- (ω-bromoalkyl) or N-[ω-(phenylselanyl)alkyl] imidazoles and pyrroles, undergo regio-selective radical cyclisalion onto the azole rings followed by oxidative re-aromatisation.