AN INTERPRETATION OF THE CHEMICAL BEHAVIOR OF 5-MEMBERED AND 6-MEMBERED RING COMPOUNDS
AN INTERPRETATION OF THE CHEMICAL BEHAVIOR OF 5-MEMBERED AND 6-MEMBERED RING COMPOUNDS
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DOI：
10.1021/ja01631a041
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发表时间：
1954-01-01
影响因子：
15
通讯作者：
SHECHTER, H
中科院分区：
文献类型：
--
作者：
BROWN, HC;BREWSTER, JH;SHECHTER, H
环状化合物，从小到大，都表现出许多不同寻常的化学特性。在以前的文章中指出，许多与环原子上的反应有关的化学反应可以用环原子的配位数变化所引起的内部应变的变化（i -应变）来系统化。4.5对于小环（3到4个环成员），内部应变主要来自法向键角的扭曲。在5-和6-及更大的环中，应变主要归因于由不利构象引起的排斥项。在本文中，我们希望提出一个简单的概括，它可以把五元或六元环的许多不寻常的化学特性联系起来。这种概括包括各种物质，如环酮、内酯和内酯、环亚胺、糖醛和酸、外端和内端互变异构体和异构体以及萜烯烃。一个经验的方法将被用于发展的推广。在对其适用性和实用性进行调查后，将表明它与现有的热化学数据一致。最后，探讨本文的理论意义。目前已有大量的资料证实，环戊烷中一个环原子的配位数从4变为3的反应进行得很快，而环己烷衍生物的反应进行得很慢。叔卤化物在水溶液（80%）乙醇中的溶解法是一个典型的例子。6（仅表示速率决定阶段。）RC1+ H20 fíRH Cl-
Ring compounds, from small2 3to large, 8 exhibit numerous unusual chemical characteristics. In previous papers it was pointed out that a great deal of the chemistry dealing with reaction at one of the ring atoms can be systematized in terms of the change in internal strain accompanying the change in coordination number of the ring atom participating in the reaction (I-strain). 4· 5 For small rings (3 to 4 ring members) the internal strain arises primarily from the distortions of the normal bond angles. 6 In 5-and 6-and larger rings the strain is attributed primarily to repulsion terms arising from unfavorable conformations. 7 In the present paper we wish to suggest a simple generalization which serves to correlatemany of the unusual chemical characteristics of rings of five or six members. The generalization includes such diverse substances as the cyclic ketones, lactones and lactals, cyclic imides, the sugar aldehydes and acids, exo and endo tautomers and isomers, and the terpene hydrocarbons. An empirical approach will be utilized in de-veloping the generalization. Following a survey of its applicability and utility, it will be shown to be consistent with available thermochemical data. Finally the theoretical implications will be explored. The GeneralizationConsiderable data now exist to establish that reactions involving a change in coordination num-ber of a ring atom from four to three proceed rapidly in cyclopentane and slowly in cyclohexane deriva-tives. 4 A typical example is furnished by the sol-volysis of tertiary halides in aqueous (80%) ethanol. 6 (Only the rate-determining stage is indicated.) RC1+ H20 fíRH Cl-