Organic azides are easily reduced to the corresponding amines by reaction with dichloroindium hydride under very mild conditions and in a highly chemoselective fashion. gamma-Azidonitriles give rise to outstanding five-membered cyclizations affording pyrrolidin-2-imines. A rationalization of the overall experimental data cannot exclude the occurrence of competitive radical and nonradical pathways, but certain results are, however, soundly consistent with the intermediacy of indium-bound nitrogen-centered radicals.
Cyclizations of <i>N-</i>Stannylaminyl Radicals onto Nitriles
[reaction: see text] Stannylaminyl radicals derived from radical reactions of Bu(3)SnH with azidoalkylmalononitriles exhibit highly efficient 5- and 6-exo cyclizationonto either nitrile group to give aminoiminyl radicals that in turn are reduced to amidines or undergo successive 5-exo cyclizationonto an internal alkene.