作者:Rudolph A. Abramovitch、Xiaocong Ye、William T. Pennington、George Schimek、Dariuz Bogdal
DOI:10.1021/jo991139z
日期:2000.1.1
NMR. In the solid state, 1 and 2 exist in the staggered, linear conformation, stacked head-to-tail, with the plane of the nitro group being tilted above the plane of the benzene ring. It appears that the crystal lattice forces overcome the weak edge-to-face intramolecular aromatic interactions that dominate in the gas phase and in solution. The corresponding azides were treated with trifluoromethanesulfonic
合成了1-(4-硝基苯基)-7-苯基硫庚烷(1)和-9-苯基硫壬烷(2),并在溶液和固态下研究了它们的构象。MMX计算表明,全局能量最小结构在气相中弯曲,这可能是由于富电子和贫电子末端芳基之间的边对面分子内吸引力相互作用所致。使用2D NOESY NMR在溶液中确认了这些构象。在固态下,1和2以交错的线性构象存在,头尾相叠,硝基的平面倾斜于苯环的平面上方。看来晶格力克服了在气相和溶液中占主导地位的弱的面对面分子间芳族相互作用。相应的叠氮化物用三氟甲磺酸处理以生成nitr离子,该nitr离子经过分子内闭环反应以适度收率得到相应的17和19元环噻唑大环。这些结果支持这样的建议,即在适当的模型化合物上进行MMX计算可能有助于预测哪些前体会导致大环,而哪些不会。