Intramolecular Pd-Catalyzed Reductive Amination of Enolizable sp-C-H Bonds.

A palladium-catalyzed reductive cyclization of nitroarenes has been designed to construct sp-C-NHAr bonds from sp-C-H bonds by using an enolizable nucleophile to intercept a nitrosoarene intermediate. Exposure of -substituted nitroarenes to 5 mol % of Pd(OAc) and 10 mol % of phenanthroline under 2 atm of CO constructs partially saturated 5-, 6-, or 7-membered -heterocycles using α-pyridyl carboxylates, malonates, 1,3-dimethylbarbituric acid, 1,3-diones, or difurans as the nucleophile.