High enantioselection is obtained in α‐amination of acyclic β‐keto esters in the presence of lanthanide triflates and pybox ligands. The Eu3+ complexes proved more active than those with Yb3+ and La3+ and high dependence of ee on the type and steric bulk of the ester group was observed. Excellent results were achieved using a combination of europium triflate with ligand L4 (diphenyl‐pybox). Preparation of ternary complexes (8) [(L4)(β‐keto ester enolate)Ln (OTf)2] was accomplished. Complexes 8 and [(L4)(β‐keto ester)Ln (OTf)2]+, identified by ESI‐MS, are proposed as key intermediates of the α‐amination reaction.

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