Using the Ni-[(benzylprolyl)amino]benzophenone complex in the Glaser reaction for the synthesis of bis α-amino acids

Abstract

New different-structure enantiomerically enriched tailor-made (S)-α-amino acids were obtained through the cross-coupling reactions of Glaser. As the initial complexes, the Schiff base Ni(II) complexes of the chiral auxiliary (S)-BPB (BPB (N-benzyl proline benzophenone) and amino acids were used. The target Ni(II) complexes were disassembled with aqueous HCl and the tailor-made amino acids were isolated with excellent enantioselectivities (>99% ee).