One-Carbon Oxidative Annulations of 1,3-Enynes by Catalytic C-H Functionalization and 1,4-Rhodium(III) Migration.

Rhodium(III)-catalyzed C-H functionalization-oxidative annulations of aromatic substrates with 1,3-enynes that contain allylic hydrogen atoms cis to the alkyne are described. The key step in these reactions is an alkenyl-to-allyl 1,4-rhodium(III) migration to give electrophilic π-allylrhodium(III) species. Nucleophilic trapping of these species gives heterocycles such as benzopyrans, isobenzofuranones, and isoindolinones.