Asymmetric synthesis of alpha,beta-dialkyl-alpha-phenylalanines via direct alkylation of a chiral alanine derivative with racemic alpha-alkylbenzyl bromides. A case of high enantiomer differentiation at room temperature.

[figure: see text] This study demonstrates that the direct alkylation of a Ni(II)-complex of the chiral Schiff base of alanine with (S)-o-[N-(N-benzylprolyl)amino]- benzophenone, with racemic alpha-alkylbenzyl bromides, is a synthetically feasible and methodologically advantageous approach to the target alpha,beta-dialkylphenylalanines over previously reported methods. For the first time we report and rationalize a case of a high enantiomer differentiation process at room temperature.