Cu(II) homogeneous and heterogeneous catalysts for the asymmetric Henry reaction

New Cu(II) complexes have been prepared and characterised via single crystal X-ray diffraction studies, EPR spectroscopy, elemental analysis and high resolution mass spectrometry. In all cases 1:2 (copper to ligand) stoichiometric complexes were isolated. The homogeneous Cu(II) complexes were tested for the asymmetric Henry reaction. Conversions in excess of 70% were obtained with enantioselectivities in the range 0–78%. Heterogeneous Cu(II) catalysts have been prepared. In these cases high conversions were obtained. However, after prolonged reaction time the main product observed was 1,3-dinitro-2-phenyl propane. The formation of this product can be curtailed by both decreasing the catalyst loading and employing shorter reaction times.

New homogeneous Cu(II) complexes have been prepared, fully characterised and tested for the asymmetric Henry reaction. Heterogeneous Cu(II) catalysts have been synthesised for comparison purposes.Figure optionsDownload high-quality image (115 K)Download as PowerPoint slide