Copper-Catalyzed Radical [2+2+1] Annulation of Benzene-Linked 1,n-Enynes with Azide: Fused Pyrroline Compounds

A novel selective copper-catalyzed radical [2 + 2 + 1] annulation of benzene-linked 1,n-enynes with azido-benziodoxolone to access fused pyrroline compounds, including 3H-pyrrolo[3,4-c]quinolin-4(3aH)-ones, chromeno[3,4-c]pyrrol-4(9bH)-one, and indeno[1,2-c]pyrroline, has been developed, which proceeds via the addition of the azide radical to the alkene, annualtion, and azidation cascade.