The effect of carbonyl substitution on the strain energy of small ring compounds and their six-member ring reference compounds
The effect of carbonyl substitution on the strain energy of small ring compounds and their six-member ring reference compounds
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DOI：
10.1021/ja055086g
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发表时间：
2006-04-12
影响因子：
15
通讯作者：
Dmitrenko, O
中科院分区：
文献类型：
--
作者：
Bach, RD;Dmitrenko, O
用高水平从头计算方法估算了一系列三元环和六元环化合物的环应变能。在CBS-APNO理论水平上，环己烷的SE估计为2.2 kcal/mol。环丙烷的SE经环己烷SE的一半校正后，增加到28.6千卡/摩尔。在CBS-Q水平上，通过与环丙烷结合生成六元环参比化合物，估算了一系列含羰基三元环化合物的SE。环丙酮（5）、最简单的α-内酯（6）[环氧乙烷酮]和a.内酰胺（7）[氮丙啶酮]在校正相应六元环参比化合物的SE后，预测分别为49、47和55 kcal/mol。环己酮、δ-戊内酯和δ-戊内酰胺的SE估计分别为4.3、11.3和5.1 kcal/mol。已建立了硅环丙烷和硅环氧乙烷的SE的显著增加，而观察到含磷、硫、二氧杂和二氮杂的三元环化合物的SE的显著降低。环的应变能的碳氢化合物（但不杂环）表现出很强的相关性，其C-H键的离解能。
High level ab initio calculations have been applied to the estimation of ring strain energies (SE) of a series of three- and six-member ring compounds. The SE of cyclohexane has been estimated to be 2.2 kcal/mol at the CBS-APNO level of theory. The SE of cyclopropane has been increased to 28.6 kcal/mol after correction for the one-half of the SE of cyclohexane. The SEs of a series of carbonyl-containing three-member ring compounds have been estimated at the CBS-Q level by their combination with cyclopropane to produce a six-member ring reference compound. The SEs of cyclopropanone (5), the simplest a-lactone (6) [oxiranone], and a.-lactam (7) [aziridinone] have been predicted to be 49, 47, and 55 kcal/mol, respectively, after correction for the SE of the corresponding six-member ring reference compound. The SEs of cyclohexanone, delta-valerolactone, and delta-valerolactam have been estimated to be 4.3, 11.3, and 5.1 kcal/mol, respectively. Marked increases in the SE of silacyclopropane and silaclioxirane have been established, while significant decreases in the SEs of phosphorus, sulfur, dioxa- and diaza-containing three-member ring compounds were observed. The ring strain energies of the hydrocarbons (but not heterocycles) exhibit a strong correlation with their C-H bond dissociation energies.