Binuclear Cu(II) chiral complexes: synthesis, characterization and application in enantioselective nitroaldol (Henry) reaction

Abstract

Enantiopure macrocyclic ligands were synthesized from (1 R ,2 R )‐(+)‐ and (1 S ,2 S )‐(−)‐diphenylethylenediamine with 3,3'‐methylenebis(5‐( tert ‐butyl)‐2‐hydroxybenzaldehyde) and characterized. The chirality transfer and chiral inversion from ligand to copper(II) metal centre were studied using circular dichroism spectroscopy. The enantiopure binuclear copper(II) complexes (ΔΔ and ΛΛ) were used as catalysts for asymmetric nitroaldol reaction to generate β‐nitroalcohol with 88% yield and 67% enantioselectivity. Copyright © 2015 John Wiley & Sons, Ltd.