is the most stable. A simple model for the assignment of the absolute configuration from NMR data is presented and its reliability corroborated with alcohols (8−20) of known configuration. Nevertheless, cyclic alcohols 21−23 have much higher ΔEag values (2.2−3.1 kcal/mol) due to their different conformational composition, and their absolute configuration cannot be reliably predicted by this method
讨论了从其与 (R)- 和 (S)-9-
蒽基
甲氧基乙酸 (9-AMA, 3) 的酯的 1H NMR 光谱预测 β-手性伯醇的绝对构型。低温 NMR 实验、MM、半经验、从头算和芳族屏蔽效应计算允许识别主要构象异构体,并表明,在所有醇中,计算出的 ΔEag (CVff) 在 0.7-1.5 kcal/ mol,构象异构体 a/a 是最稳定的。提出了从 NMR 数据分配绝对构型的简单模型,其可靠性与已知构型的醇 (8-20) 相一致。然而,由于构象组成不同,
环醇 21-23 具有更高的 ΔEag 值(2.2-3.1 kcal/mol),