Synthesis of C 1-symmetric primary-secondary diamines and their application in the enantioselective Henry reaction

Abstract

Two new C1-symmetric primary-secondary diamines were synthesized via the reaction of (S,S)-1,2-diphenyl ethylene diamine with 3,5-ditert-butyl salicylaldehyde and salicylaldehyde, respectively, followed by reduction with NaBH4. The combination of the ligand from 3,5-ditert-butyl salicylaldehyde with CuBr could effciently catalyze the Henry reaction to afford β-nitroalkanols in moderate to good yields (up to 87%) and high enantioselectivities (up to 88% ee). A possible mechanism of the reaction was proposed.