Rhodium(III)-Catalyzed C–H Activation: Annulation of Petrochemical Feedstocks for the Construction of Isoquinolone Scaffolds

We describe a simple and robust procedure for the Rh(III)-catalyzed [4+2] cycloaddition of feedstock gases enabled through C–H activation. A diverse set of 3,4-dihydroisoquinolones and 3-methylisoquinolones have been prepared in good to excellent yields. The effects of using ethylene and propyne as coupling partners on C–H site selectivity have also been explored with a representative set of substrates and are discussed herein.