Synthesis of (2S,3S)-β-(trifluoromethyl)-α,β-diamino acid by Mannich addition of glycine Schiff base Ni(II) complexes to N-tert-butylsulfinyl-3,3,3-trifluoroacetaldimine

•A chiral CF3-bearing sulfinimine is a suitable Mannich acceptor upon reaction with Ni(II) complexes of glycine Schiff bases.•The Mannich reaction proceeds with very high diastereoselectivity starting from an achiral Ni(II) complex.•The optically pure free diamino acid is released from the Ni(II) complex with recovery of the chiral ligand.

A convenient access to (2S,3S)-β-(trifluoromethyl)-α,β-diamino acid is reported by using highly diastereoselective Mannich addition reactions of either chiral or achiral Ni(II) complexes derived from glycine Schiff bases to a chiral sulfinimine, N-tert-butylsulfinyl-3,3,3-trifluoroacetaldimine. Disassembly of the resultant Ni(II) complexes affords the target amino acid which was, for the first time, isolated in enantiomerically pure form and fully characterized.

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