Chelating alkoxy NHC-Rh(I) complexes and their applications in the arylation of aldehydes

In this study, new rhodium(I) complexes (5 and 6) have been prepared by the reaction of [RhCI(COD)](2) with a series of imidazolium salts (3 and 4), which were obtained from a chiral amino alcohol. The catalytic activities of these complexes were tested in the arylation of aldehydes. It was found that the synthesized rhodium complexes were highly effective catalysts for the arylation of aldehydes in short reaction times (5 mm, TOF = 1193 h(-1)). However, the obtained ee values (up to 32% ee) remained low. We have proposed a mechanism for the arylation reaction of aldehydes, which is confirmed via F-19 NMR spectroscopy. (C) 2014 Elsevier Ltd. All rights reserved.