Synthesis of Annulated N-Containing Heterocycles via C-H Activation

Significance

Starting with simple, readily prepared starting materials, a one-step, two-C-C-bond-forming approach to highly substituted six- and seven-membered annulated pyrroles and pyrazoles is described. The efficient palladium-catalyzed synthesis takes advantage of a mechanistically interesting norbornene-mediated sequential aromatic alkylation/aryl-heteroaryl coupling (Catellani-type reaction) and tolerates electron-withdrawing and electron-donating groups at 2-, 3-, and 4-positions of the iodoarenes.