Electrostatic Effects on the Population of Atropisomers of Charged and Dipolar Derivatives of 1,8-Di(2‘-pyridyl)naphthalene
作者:John A. Zoltewicz、Nobert M. Maier、Walter M. F. Fabian
DOI:10.1021/jo962232f
日期:1997.5.1
6'-dipyridone (7) derivatives of 1,8-di(2'-pyridyl)naphthalene were prepared. Proton NMR failed to reveal the presence of individual anti-syn atropisomers over a wide range of temperatures. By contrast, the 1',1"-dimethyl derivative of 1-(2'-pyridyl)-8-(3"-pyridyl)naphthalene (8), a positional isomer of 6a, existed in DMSO-d(6) as a 2:1 mixture of anti to syn atropisomers at ambient temperatures. Electrostatic
1,8-二(2'-吡啶基)萘的双阳离子1',1'-二甲基(6a),偶极1',1'-二氧化物(6b)和6',6'-联吡啶酮(7)衍生物是准备好了。质子NMR无法揭示在宽温度范围内单个抗同位阻转异构体的存在。相反,1-(2'-吡啶基)-8-(3“-吡啶基)萘(8)的1',1”-二甲基衍生物(6a的位置异构体)在DMSO-d(6)中以在室温下为抗阻转异构体的2:1混合物。静电排斥被认为使抗阻转异构体受到青睐,特别是在6a中,由于环的张开排列,带电区域比在8a中更靠近在一起,因此尤其如此。AM1和PM3的计算证实了6a,6b和7的抗同构异构体比同构异构体更受青睐。