Cyclizations of N-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 cyclization onto either nitrile group to give aminoiminyl radicals that in turn are reduced to amidines or undergo successive 5-exo cyclization onto an internal alkene.