The Scope of the Direct Proline‐Catalyzed Asymmetric Addition of Ketones to Imines

A full account of catalytic direct asymmetric Mannich‐type reactions is presented describing the scope of amino acid‐catalyzed additions of unmodified ketones to a large variety of imines. These reactions are performed under very mild, operationally simple, and environmentally friendly and benign conditions employing a one‐pot, three‐component protocol as well as preformed imines. Typically, products were obtained with high regio‐ and diastereoselectivities and excellent enantioselectivities. The methodology developed was applied as a powerful approach toward the synthesis of enantiomerically pure functionalized α‐amino acids, γ‐lactones, oxime‐functionalized amino acids as well as pharmacologically important targets such as (R)‐cyclohexylglycine.