Nuclear magnetic resonance spectroscopy. Carbon-13 chemical shifts of methycyclopentanes, cyclopentanols, and cyclopentyl acetates
作者:John D. Roberts、Manfred Christl、Hans J. Reich
DOI:10.1021/ja00743a028
日期:1971.7
The ^(13)C chemical shifts of the title compounds have been determined by high-resolution nmr spectroscopy with the aid of proton decoupling. Substituent effects have been computed and compared to those obtained for some corresponding cyclohexane compounds, with the hope of providing information about steric interactions and conformations of cyclopentane derivatives. Rather large downfield ɑ (up to
标题化合物的^(13)C化学位移已在质子解偶联的帮助下通过高分辨率核磁共振光谱测定。已经计算了取代基效应,并将其与一些相应的环己烷化合物所获得的效应进行了比较,希望能提供有关环戊烷衍生物的空间相互作用和构象的信息。在环戊醇中溶解高达 0.5 M 铕三(二异丙基甲烷)时观察到相当大的低场 ɑ(高达 ~24 ppm)和 β(高达 ~7 ppm)偏移。顺式和反式 3-甲基环戊醇和 1,3-二甲基环戊醇表现出略有不同的螯合位移,可用于帮助确定这些物质的立体化学构型。比较并合理化了某些脂肪族乙酸酯和醚中由链支化产生的 ^(13)C 化学位移变化。