2-Substituted and 2,2-disubstituted adamantane derivatives as models for studying substituent chemical shifts and C–Hax⋯Yax cyclohexane contacts—results from experimental and theoretical NMR spectroscopic chemical shifts and DFT structures
作者:Antonios Kolocouris、Andreas Koch、Erich Kleinpeter、Ioannis Stylianakis
DOI:10.1016/j.tet.2015.01.044
日期:2015.4
The complete 1H and 13C NMR chemical shifts assignment for various 2-substituted and 2,2-disubstituted adamantane derivatives 1–38 in CDCl3 solution was realized on the basis of NMR experiments combined with chemical structure information and DFT-GIAO (B3LYP/6-31+G(d,p)-GIAO) calculations of chemical shifts in solution. Substituent-induced 13C NMR chemical shifts (SCS) are discussed. C–Hax⋯Yax contacts
完整的1 H和13关于各种2-取代和2,2-二取代的金刚烷衍生物C NMR化学位移分配1 - 38在CDCl 3溶液中的NMR实验化学结构信息和DFT-GIAO组合的基础上实现的(B3LYP / 6-31 + G(d,p)-GIAO)计算溶液中的化学位移。讨论了取代基诱导的13 C NMR化学位移(SCS)。C-H斧⋯ÿ斧接触是有机化学中空间位阻的教科书原型。在新的金刚烷衍生物的基础上,将进一步研究这些接触的性质,这些新的金刚烷衍生物在C-2处被取代,以提供1,4-C-H ax ⋯Y ax和1,5-C-H ax的模型⋯Y轴触点。在B3LYP / 6-31 + G(d,p)的计算预测的C-H之间NBO hyperconjugative吸引相互作用的存在斧和Y斧组沿C-H斧⋯ý斧触点。的1层1 H NMR信号分离,Δ δ(γ-CH 2),反映了H-CH键合的强度斧⋯ÿ斧头接触。