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.
1-
对甲苯基-
2-苯基-1-丙醇[(RS⁄SR)-3 和 (RR⁄SS)-3]、1-
对甲苯基-2-苯基
乙醇 (4) 的非对映体构象,和 1-p-
甲苯基-2-苯基-1-
丙酮 (5) 通过核磁共振波谱进行了研究,主要借助
镧系元素引起的位移的计算机模拟。有人建议,在(RS⁄SR)-3、4和5的构象平衡中,
甲苯基靠近苯基的旋转异构体是优选的。对于(RR⁄SS)-3,最稳定旋转异构体(CDCl3)被认为具有与苯基相对的
甲苯基和与甲基相对的
甲苯基。鉴于折叠构象的普遍发生,对结果进行了讨论。