DETERMINATION OF Z-CONFIGURATION AND E-CONFIGURATION IN TRIFLUOROMETHYLATED VINYL COMPOUNDS - 3J(CF) COUPLING-CONSTANTS AS A CRITERION FOR CONFIGURATIONAL ASSIGNMENTS

被引：44

作者：

BEGUE, JP ^{[1
]}

BONNETDELPON, D ^{[1
]}

MESUREUR, D ^{[1
]}

OUREVITCH, M ^{[1
]}

机构：

[1] CNRS,CERCOA,2 RUE H DUNANT,F-94320 THIAIS,FRANCE

来源：

MAGNETIC RESONANCE IN CHEMISTRY | 1991年 / 29卷 / 07期

关键词：

H-1; NMR; C-13; F-19; T1 AND NOE MEASUREMENTS; TRIFLUOROMETHYLATED VINYL COMPOUNDS;

D O I：

10.1002/mrc.1260290707

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

NOE and T1 proton measurements were carried out in order to determine unambiguously the Z and E configurations of some CF3-trisubstituted vinylic compounds (HCR = CR'CF3). The beta-ethylenic carbon in olefins, enol ethers and enamines is always more strongly coupled to CF3 in the cis compound (CF3 and the vinylic proton cis to each other): \ 3J(CF) \cis > \ 3J(CF) \trans. This observation, in addition to the already known higher shielding of F-19 NMR signal in the cis isomer, allows the safe assignments of Z and E isomers even when only one is obtained, regardless of the nature of R and R'.

引用

页码：675 / 678

页数：4

共 30 条

[1]

AHMED G, 1977, J CHEM SOC P2, P838

[2] NEW GEOMETRIC ISOMERS OF VITAMIN-A AND CAROTENOIDS .11. 19,19,19-TRIFLUORORETINAL AND 20,20,20-TRIFLUORORETINAL [J].