Chiral recognition of nitriles by 1H NMR spectroscopy in the presence of a chiral dirhodium complex

The H-1 NMR spectra of a variety of chiral racemic nitriles were recorded in CDCl3, in the absence and presence of dirhodium tetra-(R)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetate [Rh-2(MTPA)(4); MTPA = Mosher's acid]. Moderate H-1 signal shifts but clear diastereomeric dispersions due to complexation were observed which allow the determination of the enantiomeric ratio of the nitriles. Tentative statements concerning the complexing mode of the cyano group at the rhodium atom (side-on vs, end-on) are presented. (C) 1998 John Wiley & Sons, Ltd.