Double <i>N</i>-Arylation of Primary Amines: Carbazole Synthesis from 2,2‘-Biphenyldiols
作者:Atsushi Kuwahara、Koji Nakano、Kyoko Nozaki
DOI:10.1021/jo048472+
日期:2005.1.1
The double N-arylation of primary amines with 2,2‘-biphenylylene ditriflates was investigated for the synthesis of multisubstituted carbazoles. Palladium complexes supported by 2-dicyclohexylphosphino-2‘-methylbiphenyl or Xantphos [4,5-bis(diphenylphosphino)-9,9-dimethylxanthene] were found to be efficient catalysts for the reaction. The catalysts allow the use of anilines with an electron-donating
研究了伯胺与2,2'-联亚苯基二三氟甲磺酸酯的双N-芳基化反应,用于合成多取代的咔唑。发现由2-二环己基膦基-2'-甲基联苯或Xantphos [4,5-双(二苯基膦基)-9,9-二甲基x吨]负载的钯配合物是该反应的有效催化剂。该催化剂允许使用具有给电子或吸电子取代基和多取代的2,2'-联亚苯基二三氟甲磺酸酯的苯胺作为底物。氨当量,如ö -叔丁基氨基甲酸酯,也可用作氮源,得到Ñ -保护的咔唑,可以很容易地得到相应的Ñ-脱保护后的未取代咔唑。通过使用这种方法,咔唑生物碱鼠李糖碱以五个步骤的产率合成为40%,效率与最近的先例相当。