Asymmetric Addition of Cyanide to β-Nitroalkenes Catalysed by Chiral Salen Complexes of Titanium(IV) and Vanadium(V)
Article first published online: 28 MAY 2013
© 2013 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Volume 5, Issue 8, pages 2405–2409, August 2013
How to Cite
North, M. and Watson, J. M. (2013), Asymmetric Addition of Cyanide to β-Nitroalkenes Catalysed by Chiral Salen Complexes of Titanium(IV) and Vanadium(V). ChemCatChem, 5: 2405–2409. doi: 10.1002/cctc.201300215
- Issue published online: 25 JUL 2013
- Article first published online: 28 MAY 2013
- Manuscript Received: 22 MAR 2013
- Funded Access
- asymmetric catalysis;
- Michael addition;
- N,O ligands;
Structurally well-defined bimetallic titanium(IV) (salen) and monometallic vanadium(V) (salen) complexes have been used as catalysts for the asymmetric addition of trimethylsilyl cyanide to β-nitroalkenes to produce chiral nitronitriles with ee values in the range of 79–89 % and conversions up to 100 % at 0 °C. The reaction conditions (solvent, temperature, time and vanadium complex counter-ion) were optimised, and it was shown that the catalyst loading could be significantly reduced (20 to 2 mol %) and the reaction temperature increased (−40 to 0 °C) compared to previous studies that used an in situ prepared catalyst. The results are compared and contrasted with previous results obtained by using the same catalysts for the asymmetric addition of trimethylsilyl cyanide to aldehydes, and a transition-state structure for the asymmetric addition of trimethylsilyl cyanide to nitroalkenes is proposed to account for the observed stereochemistry.