One-pot Synthesis of Substituted Pyridines from Alkyl Ketones and Enamines by the Nickel-catalyzed Dehydrogenation of Alkyl Ketones

The one-pot synthesis of substituted pyridines from alkyl ketones, Stork enamines, and ammonia is reported. This reaction involves the nickel-catalyzed dehydrogenation of the alkyl ketone and conjugate addition of the enamine, followed by condensation with an ammonium salt to yield the corresponding pyridine. Furthermore, the a-alkylation of 8-amino-y,8-unsatu-rated ketone intermediates leads to the synthesis of tetrasub-stituted pyridine in excellent yields by means of a three-step one-pot reaction.