作者:Charles F. Wilcox、David A. Blain
DOI:10.1016/s0040-4020(01)88099-6
日期:1986.1
3H-Cyclonona[def] biphenylene, 6, was deprotonated with n-butyllithium to form the mono-trans anion 7. This anion was fully delocalized and aromatic, with the interior proton having a 1H NMR absorption at -2.79 ppm. This downfield shift was attributed to the proton being in the middle of a ring with a large diamagnetic ring current, calculated to be +0.96 (relative to +1.00 for benzene). Molecular
将3H-Cyclonona [def]联苯6用正丁基锂去质子化,形成单反阴离子7。该阴离子被完全离域并且是芳族的,内部质子在-1.79 ppm处具有1 H NMR吸收。该场下偏移归因于质子位于具有大反磁性环电流的环中间,计算得出为+0.96(相对于苯为+1.00)。分子力学计算预测,其中7个不是平面的,内部碳和附着的质子脱离平面以缓解严重的范德华相互作用。负离子7将其用多种亲电试剂淬灭,以得到亲电试剂处于外位的产物。由于空间和电子方面的原因,尝试生成的阴离子3-roethyl-3H-cyclonona [def]-联亚苯基10的稳定性较阴离子7差,但未成功。取而代之的是,将正丁基锂添加到π系统中,得到稳定的苄基阴离子13,将其用甲醇-d淬灭,得到化合物14。