CONFORMATIONAL ANALYSIS .63. STEREOCHEMICAL STUDIES IN CYCLOBUTANE RING SYSTEM
CONFORMATIONAL ANALYSIS .63. STEREOCHEMICAL STUDIES IN CYCLOBUTANE RING SYSTEM
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DOI：
10.1021/jo01017a057
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发表时间：
1965-01-01
影响因子：
3.6
通讯作者：
TUSHAUS, LA
中科院分区：
文献类型：
--
作者：
ALLINGER, NL;TUSHAUS, LA
用立体定向合成法制备了1，3-二甲基环丁烷的顺式和反式异构体，发现它们的几何归属发生了逆转。顺式异构体被推断为具有较低的焓。通过立体定向反应合成了3-甲基环丁烷甲酸甲酯的顺、反异构体，并进行了平衡。平衡时顺式异构体占优势，反式异构体占优势; Δ Fm为0.3 kcal/摩尔顺式-和Zrons-1，3-环丁烷二羧酸二甲酯已经平衡，并且AFm有利于反式异构体0.1 kcal/mol。摩尔反式异构体的更大稳定性似乎是由于偶极-偶极相互作用。虽然环己烷环的构象方面已被非常详细地研究，但对其他尺寸的环知之甚少。4.本文研究了环丁烷环的某些构象性质。电子衍射5· 6和光谱学及热力学测量7表明，环丁烷是
The cis and trans isomers of 1, 3-dimethylcyclobutane havebeen prepared by stereospecific synthesis and the earlier geometric assignments have been found to be reversed. The cis isomer is inferred to be of lower enthalpy. The cis and trans isomers ofmethyl 3-methylcyclobutanecarboxylate have been prepared by stereospecific reactions and equilibrated. The cis isomer predominates over the trans at equilibrium; AFm is 0.3 kcal./mole. The cis-and Zrons-dimethyl 1, 3-cyclobutanedicarboxylates have been equilibrated and AFm favors the trans isomer by 0.1 kcal./mole. The greater stability of the trans isomer here appears to be due to dipole-dipole interactions.While the conformational aspects of the cyclohexane ring have been studied in great detail, much less is known concerning rings of other sizes. 4 The present paper is concerned with some of the conformational properties of the cyclobutane ring. Cyclobutane has been shown by electron diffraction5· 6 and by spectro-scopic andthermodynamic measurements7 to be