Stereochemical aspects of proton chemical shifts—IV: The cumulative nature of the geminal proton shift influenced by long chain substituents
Stereochemical aspects of proton chemical shifts—IV: The cumulative nature of the geminal proton shift influenced by long chain substituents
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质子化学位移的立体化学方面——IV：受长链取代基影响的孪生质子位移的累积性质
DOI：
10.1002/mrc.1270081102
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发表时间：
1976
影响因子：
2
通讯作者：
M. Anteunis
中科院分区：
文献类型：
--
作者：
D. Danneels;M. Anteunis
取代基对双质子的位移效应与长链取代基的累积α-、β-和γ-效应一致，即不仅要考虑侧链上的第一个原子，而且要考虑随后的β-和γ-原子。这些位移的贡献依赖于旋转构象，在有必要数据的情况下可以进行计算。因此，必须知道未取代的母体化合物的位移，β和γ基团的个别增量贡献以及旋转分布。相反，如果其他参数是可访问的，这将使其中一个参数的半定量预测成为可能。
Substituent shift effects on geminal protons are consistent with cumulative α-, β- and γ-effects of a long chain substituent, e.g. whereby not only the first, but also the subsequent β- and γ-atoms of the sidechain should be taken into consideration. These shift contributions depend on rotational conformation in a way that lends itself to calculation where the necessary data are available. Therefore the shifts of the unsubstituted parent compound, the individual increment-contributions of the β and γ groupings and the rotameric distribution must be known. This would enable, conversely, a semi-quantitative prediction of one of these parameters if the others are accessible.