Hydrogen bond catalyzed direct reductive amination of ketones.

[reaction: see text] A novel, biomimetic concept for the direct reductive amination of ketones is described that relies on selective imine activation by hydrogen bond formation. The mild, acid- and metal-free process requires only catalytic amounts of thiourea as hydrogen bond donor and utilizes the Hantzsch ester for transfer hydrogenation. The method allows the efficient synthesis of structurally diverse amines.