Enantioselective nitromethane addition to brominated and fluorinated benzaldehydes (Henry reaction) catalyzed by chiral bisoxazoline–copper(II) complexes
The successful enantioselective Henry reaction of nitromethane to brominated and fluorinated benzaldehydes was achieved using a chiral bisoxazoline (unbridged)-Cu(II) complex as a catalyst. Nitroalcohols were obtained in excellent yields (up to 99%) and with enantioselectivities up to >99%. Theoretical calculations support the idea that the unbridged bisoxazoline-Cu(II) complex behaves similarly to the privileged bisoxazolines as catalysts in the Henry reaction. (C) 2016 Elsevier Ltd. All rights reserved.
Design of chiral sulfoxide–Schiff base hybrids and their application in Cu-catalyzed asymmetric Henry reactions
A new class of chiral sulfoxideâSchiff base ligands has been developed by the rational combination of two privileged chiral backbones. These sulfoxideâSchiff base ligands were found to be highly efficient for Cu-catalyzed asymmetric Henry reactions (up to 98% yield and 96% ee).