作者:D.J. Loomes、M.J.T. Robinson
DOI:10.1016/0040-4020(77)80406-7
日期:——
of derivatives of cyclohexane, piperidine, and thian in chair and twist eonformers, and of model compounds, lead to estimates of deshielding (Δδ = 3.6 ± 0.2 ppm) for axial CMe3 on a cyclohexane ring and shielding (Δδ = −0.2 to −0.6 ppm) for ψe-CMe3 in twist conformers, relative to equatorial CMe3. Ring carbon atoms are considerably shielded in twist conformers relative to chair eonformers. The value
椅子和扭曲形成物中环己烷,哌啶和硫杂的衍生物以及模型化合物的13 C NMR光谱导致对环己烷环上轴向CMe 3的去屏蔽作用(Δδ= 3.6±0.2 ppm)和屏蔽作用(Δδ= -0.2至-0.6 ppm的)为方位角Ψe-CME 3在捻构象,相对于赤道CME 3。相对于椅子构形者,环碳原子在扭曲构象异构体中被显着屏蔽。在椅子扭扭平衡研究中13 C化学位移的值通过对化合物的非对映异构体对(11和13;38和50)进行可变温度测量来举例说明。