Nuclear magnetic resonance spectroscopy. Conformational equilibration of cycloheptane and cycloheptene derivatives
作者:Edward S. Glazer、Rudolf Knorr、Camille Ganter、John D. Roberts
DOI:10.1021/ja00772a015
日期:1972.8
dependence of the ^(19)F nuclear magnetic resonance (nmr) spectra of 4,4-difluoro-1,1-dimethylcycloheptane has shown that, at low temperatures, this substance exists predominantly in the twist-chair conformation with the methyl groups on the axis carbon atom. 1 ,1-Difluoro-4,5-trans-dibromocycloheptane, at low temperatures, exists predominantly in two different Conformations with the fluorine atoms
对 4,4-二氟-1,1-二甲基环庚烷的 ^(19)F 核磁共振 (nmr) 光谱的温度依赖性的研究表明,在低温下,该物质主要以扭椅构象存在与轴碳原子上的甲基。1,1-二氟-4,5-反式-二溴环庚烷在低温下主要以两种不同的构象存在,氟原子位于轴碳原子上。5,5-二氟环庚烯在低温下以单一构象存在,最好用椅子来表示。已经获得了这些衍生物的构象平衡的活化参数。对于 1,1-二氟环庚烷、1,1,3,3-四氟环庚烷和 4,