5-exo Atom transfer cyclisation onto alkynes mediated by copper(I) complexes

Multidentate amine derived copper(I) halide complexes mediate the atom transfer radical cyclisation of 1-halo-N-propargylacetamides. While cyclisation of trichloro- and dichloroacetamide derivatives leads to α,β-unsaturated γ-lactams containing the gem-dihalide functional group, monohaloacetamides give rise to either cyclised atom transfer or reduction products depending upon the solvent and catalyst used.