DEHYDROGENATION MECHANISMS . ON MECHANISM OF DEHYDROGENATION OF ACENAPHTHENE BY QUINONES
DEHYDROGENATION MECHANISMS . ON MECHANISM OF DEHYDROGENATION OF ACENAPHTHENE BY QUINONES
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DOI：
10.1021/ja00984a017
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发表时间：
1967-01-01
影响因子：
15
通讯作者：
TROST, BM
中科院分区：
文献类型：
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作者：
TROST, BM
研究了醌类化合物脱氢苊的反应机理。用2，3-二氯-5，6-二氰基苯醌和四氯邻苯醌脱氢，顺式-1，2-二氘代苊的顺式消除率分别为77.7%和62.9%。这些数据要求对现有的脱氢机理进行修正。大的同位素效应，缺乏1，2位移，和消除的立体化学支持经典的碳正离子的中间性。初始离子对的形成和部分崩溃的离子对解离前的产品占所观察到的净顺式消除。随着溶剂极性的增加，净顺式消除的量减少，这一观察结果支持离子对假说。
The mechanism of the dehydrogenation of acenaphthene by quiñones has been investigated. De-hydrogenation of cz's-l, 2-dideuterioacenaphthene utilizing 2, 3-dichloro-5, 6-dicyanobenzoquinone proceeded with 77.7% cis elimination and employing tetrachloro-o-benzoquinonewith 62.9% cis elimination. These data re-quire modification of the existing mechanism of dehydrogenation. The large isotope effect, the lack of 1, 2 shifts, and the stereochemistry of elimination support the intermediacy of classical carbonium ions. Initial ion-pair formation and partial collapse of the ion pair to product before dissociation accounts for the observed net cis elimination. The amount of net cis elimination decreases as solvent polarity increases, an observation in support of the ion-pair hypothesis.