Photocatalytic Ring-Closing Metathesis/Amination of 1,6-Enynes and 1,7-Enynes: Synthesis of α,β-Unsaturated γ-Lactams and Quinolin-2-ones

A photocatalyzed ring-closing metathesis/amination of 1,6-enynes and 1,7-enynes using alkyl oxime esters as both an alkene deconstruction auxiliary and amination source is present for the synthesis of α,β-unsaturated γ-lactams and quinolin-2-ones. Preliminary mechanistic studies suggest that intramolecular 1,5-hydrogen atom transfer is the key to the generation of the unstabilized alkyl radicals, which subsequently promote homolytic Cα-Cβ cleavage under the driving force of formation of more stable captodative radicals.