Purposeful regioselectivity control of the Birch reductive alkylation of biphenyl-4-carbonitrile
作者:Pavel A. Fedyushin、Roman Yu. Peshkov、Elena V. Panteleeva、Evgeny V. Tretyakov、Irina V. Beregovaya、Yuri V. Gatilov、Vitalij D. Shteingarts
DOI:10.1016/j.tet.2017.12.046
日期:2018.2
Birch's reductive alkylation of biphenyl-4-carbonitrile (1) provides alkylated 1,4-dihydroderivatives of various structural types: 4-alkyl-4-phenylcyclohexa-2,5-dienone, 1,4-dialkyl-4-phenylcyclohexa-2,5-dienecarbonitrile (with the same or different alkyl fragments), and 4-(1-alkylcyclohexa-2,5-dienyl)benzonitrile. Each of these products become dominant depending on the nature of long-living anionic
桦木对联苯-4-腈(1)的还原烷基化可提供各种结构类型的烷基化1,4-二氢衍生物:4-烷基-4-苯基环己-2,5-二烯酮,1,4-二烷基-4-苯基环己-2, 5-二烯腈(具有相同或不同的烷基片段)和4-(1-烷基环六-2,5-二烯基)苄腈。这些产物各自取决于1生成的长寿命阴离子形式的性质,即两电子还原的稳定产物–二价阴离子(1 2-); 1-烷基-4-氰基-1-苯基环己-2,5-二烯-4-基阴离子(1-Alk 1 –),是由于二价阴离子1 2−的烷基化而产生的在联苯部分的1位; 或1-(4-氰基苯基)环己-2,5-二烯-1-基阴离子(1-H 4' - ),作为二价阴离子的产物1 2-第4位的质子化'由质子化试剂(MeOH或NH 4 Cl)。烷基片段并入联苯-4-腈支架的取向与所研究的阴离子物质的计算电子结构一致。它们对烷基卤化物反应性的主导类型被证明是亲核(小号Ñ 2机构)。