Carbanionic Friedel−Crafts Equivalents. Regioselective Directed <i>Ortho</i> and Remote Metalation−C−N Cross Coupling Routes to Acridones and Dibenzo[<i>b</i>,<i>f</i>]azepinones
作者:Stephen L. MacNeil、Matthew Gray、Dmitry G. Gusev、Laura E. Briggs、Victor Snieckus
DOI:10.1021/jo801856n
日期:2008.12.19
respectively, in good to excellent yields with regioselectivity which depends upon the presence or absence of directed metalation groups (DMGs). Brief investigations as follows are described: the synthesis of desmethyl acridone 15 (Scheme 4), an attempt to effect a double-directed remote metalation sequence which leads only to a monocyclization product 13 (Scheme 3), and an analogous but nonregioselective
描述了通过碳负离子介导的对cri啶酮4(表2)和二苯并[b,f]氮杂环庚酮20(表4)的一般区域选择性途径。邻卤代苯甲酰胺1与苯胺2或16的Buchwald-Hartwig CN交叉偶联,然后简单的N-甲基化,可靠地提供了N-甲基二芳基胺3(表1)和18(表3)。用LDA处理后,3和18分别以良好或优异的产率转化为a烯4和二苯并[b,f]氮杂环庚酮20,其区域选择性取决于存在或不存在定向金属化基团(DMG)。描述了以下简要研究:合成去甲基a啶酮15(方案4),尝试实现双向远程金属化序列(仅导致单环化产物13)(方案3)以及类似但非区域选择性的途径黄酮22和二苯并[b,f]氧哌啶酮24(方案5)。DFT计算显示出化合物18b和23的低能构象,这说明了产物的形成,并表明环化反应处于动力学控制之下。