Palladium-Catalyzed Allylic Amidation with N-Heterocycles via sp3 C-H Oxidation

An atom-economic direct intermolecular allylic amidation of electron-deficient tautomerizable N-heterocycles is reported via allylic C-H activation of terminal olefins with a PdCl2 catalyst. The reaction did not require any activators (base or Lewis acid) or external ligands and proceeded with high chemo- (N vs O), regio- (linear vs branched), and stereoselectivity (E vs Z) for a variety of N-heterocycles and terminal olefins. Mechanistic investigation and stoichiometric studies validate the sulfoxide-ligand-assisted allylic C-H bond cleavage to form a pi-allylpalladium intermediate in the reaction pathway. Excellent selectivity was observed during intermolecular competition demonstrating the differential nucleophilicity of N-heterocycles and differential susceptibility of allyl C-H bond cleavage to form pi-allylpalladium complexes directly from terminal olefins.