The Conformational Analysis of 1-p-Tolyl-2-phenyl-1-propanols, 1-p-Tolyl-2-phenylethanol, and 1-p-Tolyl-2-phenyl-1-propanone by Means of NMR Spectroscopy

The conformations of the diastereomers of 1-p-tolyl-2-phenyl-1-propanols[(RS⁄SR)-3 and (RR⁄SS)-3], 1-p-tolyl-2-phenylethanol (4), and 1-p-tolyl-2-phenyl-1-propanone (5) were studied by means of NMR spectroscopy, mostly with the aid of the computer-simulation of the lanthanoid-induced shifts. It has been suggested that the rotamers in which the tolyl group lies close to the phenyl group are preferred in the conformational equilibria of (RS⁄SR)-3, 4, and 5. For(RR⁄SS)-3, the most stable rotamer (in CDCl3) has been suggested to have the tolyl group anti to the phenyl group and gauche to the methyl group. The results have been discussed in view of the general occurrence of the folded conformation.