tBu4P6, a Novel Bicyclic Organophosphane†‡
tBu4P6, a Novel Bicyclic Organophosphane†‡
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tBu4P6，一种新型双环有机膦†‡
DOI：
10.1002/anie.198109672
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发表时间：
1981
影响因子：
--
通讯作者：
T. Heinlein
中科院分区：
文献类型：
--
作者：
M. Baudler;Y. Aktalay;K. Tebbe;T. Heinlein
选择具有相似极性但空间效应显着不同的烷基作为烯烃的取代基 R' 和 R' (6)。表 1 中的数据表明，空间影响明显取决于烯烃 (6) 上屏蔽基团的位置。乙烯基 C 原子上的取代基受到攻击后，从 R’= H 通过 CH3 到 iC3H7 的速率分别降低了 90 倍和 670 倍（a 效应）。相比之下，未受到攻击的 C 原子的相同变化仅分别产生 1.4 和 2.3 的因子（p 效应）。根据与空间取代基参数的相关性，叔丁基的不可测量效应可估计为 3000，而其 B 效应仅为 4（表 1）。
Alkyl groups having similar polarity but substantially different steric effects were selected as substituents R’and R’for the alkenes (6). The data in Table 1 show that steric influences depend markedly on the position of the shielding group on the alkene (6). A substituent at the vinylic C atom undergoing attack reduces the rate from R’= H via CH3 to iC3H7 by factors of 90 and 670, respectively (a-effect). In contrast, the same variation at the C atom not undergoing attack only produces factors of 1.4 and 2.3, respectively (p-effect). From the correlation with steric substituent parametersl’l the nonmeasurable effect of a tert-butyl group can be estimated as 3000, whilst its B-effect is only 4 (Table 1).