Easy Access to α,β-Diamino-Substituted Cyclopentenaminones through Copper-Catalyzed Double Amination of Unactivated Cyclic Ketones.

Here, we report a copper-catalyzed double amination of unactivated cyclic ketones with commercially available secondary arylamines for the synthesis of α,β-diamino-substituted cyclopentenaminones. The direct intermolecular C-N bond formation reaction offers the advantages of using an inexpensive copper catalyst, high atom and step economy, mild reaction conditions, and convenient operation. Mechanistic experiments indicate that this α,β-difunctionalization reaction proceeds through oxidative α-enamination/desaturation of the cyclic ketone with one secondary arylamine molecule to form an α-enaminone intermediate, followed by intermolecular amination of the α-enaminone with another secondary arylamine molecule.