| Abstract |
The imidazolium salts, 1-(2,4,6-trimethylphenyl)-3-[(1R,2S,5R)-(-)-menthoxymethyl] imidazolium chloride (Mes-NHC-CH(2)OMent center dot HCl) (1a) and 1-(2,6-diisopropylphenyl)-3-[(1R, 2S, 5R)-(-)-menthoxymethyl] imidazolium chloride (iPr(2)Ph-NHC-CH(2)OMent center dot HCl) (1b), are readily accessible from inexpensive (1R,2S,5R)-(-)-menthol. They react with nickelocene to give two new chiral nickel-N-heterocyclic carbene (NHC) complexes, [Ni(Mes-NHC-CH(2)OMent)ClCp] (2a) and [Ni(iPr(2)Ph-NHC-CH(2)OMent)ClCp] (2b), in good yields. The new complexes were fully characterized by standard spectroscopic techniques and by a single crystal X-ray diffraction study on complex 2b. Complex 2b crystallizes in the chiral spacegroup P1, with two independent molecules in the unit cell, which are slightly different from each other. Preliminary studies show that these complexes are effective catalysts for the hydrosilylation of ketones. However no chiral induction was observed. (C) 2016 Elsevier B.V. All rights reserved. |
