N‐heterocyclic carbene complexes of Rh(I) and electronic effects on catalysts for 1,2‐addition of phenylboronic acid to aldehydes |
| |
Authors: | Hayati Türkmen Bekir Çetinkaya |
| |
Institution: | Department of Chemistry, Ege University, 35100 Bornova‐Izmir, Turkey |
| |
Abstract: | 1,3‐Diarylsubstituted imidazolinium salts, (NHC‐H)Cl, 3, containing hydrogen or alkyl groups at the 4,5‐positions of the imidazolidine ring, served as precursors to rhodium(I) complexes RhCl(NHC)COD], 4, which were converted into cis‐RhCl(NHC)(CO)2] complexes, 5. All compounds prepared were characterized by elemental analyses, 1H NMR and 13C NMR. The relative σ‐donor/π‐acceptor strength of the NHC ligands was determined by means of IR spectroscopy of 5. The ability of NHCs in 4 to enchance activity was explored in the 1,2‐addition of phenylboronic acid to aldehydes. A good correlation was observed between catalytic activity and the electron‐donating power of the NHC ligands. Copyright © 2010 John Wiley & Sons, Ltd. |
| |
Keywords: | arylation diarylmethanol rhodium electronic effects imidazol‐2‐ylidene NHC |
|
|