We report a new synthesis of phenanthridines based on palladium-catalyzed picolinamide-directed sequential C–H functionalization reactions starting from readily available benzylamine and aryl iodide precursors. Under the catalysis of Pd(OAc)2, the ortho-C–H bond of benzylpicolinamides is first arylated with an aryl iodide. The resulting biaryl compound is then subjected to palladium-catalyzed picolinamide-directed intramolecular dehydrogenative C–H amination with PhI(OAc)2 oxidant to form the corresponding cyclized dihydrophenanthridines. The benzylic position of these dihydrophenanthridines could be further oxidized with Cu(OAc)2, removing the picolinamide group and providing phenathridine products. The cyclization and oxidation could be carried out in a single step and afford phenathridines in moderate to good yields.
我们报告了一种基于
钯催化的
吡啶酰胺导向的顺序C-H官能团化反应的新合成方法,该反应以易得的
苄胺和芳基
碘化物为起始物。在Pd(OAc)
2的催化下,首先用芳基
碘化物芳基化
苄基吡啶酰胺的ortho-C-H键。然后,所得的双芳基化合物经过
钯催化的
吡啶酰胺导向的分子内脱氢C-H
氨化反应,使用PhI(OAc)
2氧化剂形成相应的环化二氢苯并啶。这些二氢苯并啶的苄位可进一步被Cu(OAc)
2氧化,去除
吡啶酰胺基团并提供苯并啶产物。环化和氧化可以在单个步骤中进行,并以中等到良好的收率得到苯并啶。