SUBSTITUTION-REACTIONS WHICH PROCEED VIA RADICAL-ANION INTERMEDIATES
SUBSTITUTION-REACTIONS WHICH PROCEED VIA RADICAL-ANION INTERMEDIATES
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DOI：
10.1002/anie.197507341
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发表时间：
1975-01-01
期刊：
影响因子：
--
通讯作者：
KORNBLUM, N
中科院分区：
文献类型：
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作者：
KORNBLUM, N
描述了一种新型的饱和碳原子取代过程。这些反应是通过以自由基和自由基为中间体的链序列进行的，值得注意的是提供了新的和强大的合成手段：它们在温和的条件下很容易发生，它们提供了很好的纯产品产率，并且与SN2取代相比，它们对空间位阻相当不敏感。因此，自由基阴离子过程对于制备高度支化的结构特别有价值。许多无机和有机阴离子很容易进入这些置换，实际上，胺也是有效的。通过这种电子转移机制进行取代的体系包括苄基、异丙基、严格脂肪族和杂环分子。有趣的是，许多在SN2置换中不表现为离开基团的基团在室温下很容易从饱和的碳原子中通过自由基阴离子自由基途径置换，例如硝基、叠氮、砜和乙醚基团。
A new type of substition process at a saturated carbon atom is described. These reactions, which proceedviaa chain sequence in which radical anions and free radicals are intermediates, are noteworthy for providing novel and powerful means of synthesis: they occur readily under mild conditions, they give excellent yields of pure products, and, in contrast to SN2 displacements, they are rather insensitive to steric hindrance. As a consequence, radical anion processes are especially valuable for the preparation of highly branched structures. Many inorganic and organic anions readily enter into these displacements and, indeed, amines are also effective. Systems which undergo substitutionsviathis electron transfer mechanism include benzylic, cumylic, strictly aliphatic, and heterocyclic molecules. It is of interest that a number of groups which do not behave as leaving groups in SN2 displacements are readily displaced at room temperature from a satureted carbon atomviathe radical anion‐free radical pathway,e.g., nitro, azide, sulfone, and ether groups.