Comparison of Carbon−Silicon Hyperconjugation at the 2- and 4-Positions of the <i>N</i>-Methylpyridinium Cation
作者:Kathryn Hassall、Sofia Lobachevsky、Jonathan M. White
DOI:10.1021/jo048384p
日期:2005.3.1
pyridinium cations 6a−c and 4-trialkylsilylmethylpyridinium cations 5a−c were prepared and investigated using 29Si and 13C NMR and single-crystal X-ray crystallography. Systematic differences in the 29Si chemical shifts and 29Si−13C one-bond coupling constants for these cations suggested that the Si−CH2 bond interacts more strongly at the 2-position of the electron-deficientpyridinium ring than at
制备了N-甲基-2-三烷基甲硅烷基甲基吡啶阳离子6a - c和4-三烷基甲硅烷基甲基吡啶阳离子5a - c并使用29 Si和13 C NMR和单晶X射线晶体学进行了研究。这些阳离子在29 Si化学位移和29 Si - 13 C单键耦合常数上的系统差异表明,Si-CH 2键在缺电子吡啶鎓环的2位上比在4位上的相互作用更强。位置。吡啶鎓阳离子5b和6b的X射线结构证明了这一结果。