The Elaboration of a General Approach to the Asymmetric Synthesis of 1,4-Substituted 1,2,3-Triazole Containing Amino Acids via Ni(II) Complexes

Herein we report a general method of the asymmetric synthesis of 1,4-substituted 1,2,3-triazole containing amino acids via copper(I) iodide catalyzed “click reaction” between azides and chiral Ni(II) complexes of Schiff bases of (S)- or (R)-BPB with alkyne side chain derivatised amino acids. The final Ni(II) complexes were decomposed with aqueous HCl and the 1,4-substituted 1,2,3-triazole containing amino acids isolated with excellent enantioselectivities (>99% ee). The chiral auxiliary ligand (BPB=N-benzyl proline benzophenone) can be recycled and reused for the synthesis of starting Ni(II) complexes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim