Rh-Catalyzed C–H Activation/Annulation of Enaminones and Cyclic 1,3-Dicarbonyl Compounds: An Access to Isocoumarins

A facile access to isocoumarins has been established via rhodium(III)-catalyzed C–H bond activation and intramolecular C–C cascade annulation of enaminones and cyclic 1,3-dicarbonyl compounds. The synthetic protocol features a wide range of substrates with high functional group tolerance, mild reaction conditions, and the selective cleavage of the enaminone C–C bond. Notably, the cyclic 1,3-dicarbonyl compounds can in situ -generate iodonium ylide as a carbene precursor to prepare polycyclic scaffolds by reacting with PhI(OAc) 2 . The application of this method to prepare useful synthetic precursors and bioactive skeletons is also exemplified.