I₂/K₂S₂O₈ Mediated Direct Oxidative Annulation of Alkylazaarenes with Amidines for the Synthesis of Substituted 1,3,5‐Triazines

Abstract

A direct method for the synthesis of heteroaryl‐substituted 1,3,5‐triazines from readily available methyl‐azaarenes and amidines has been developed. The present method involves iodine mediated cascade aerobic C(sp3)–H oxidative amination and following condensation, cyclization with amidine. Both of methyl quinoline, pyridine and benzothiazole derivatives could be well tolerated to react with various amidines leading to corresponding products in good to excellent yields.

Research Progress in C(sp3)—H Functionalization Reaction via Molecular Iodine-Catalyzed Oxidation

“…作者提出的反应机理: 最初, 氯胺和 碘的相互作用得到活性 N-碘-氯苯磺酰胺 422, 随后激 活吲哚 419a, 得到亚胺中间体 423; 在 2α 位置消除氢原 子转化为烯胺 424, 氯胺对 424 进行 S N 2 取代得到氯胺 425, 然后与碘离子反应生成酰胺化产物 421a; 最后, 得到的氯碘氧化再生碘. 对于 2-甲基-3-取代吲哚类底 物, 中间 2α-胺化吲哚 426 继续与另一分子 422 反应, 该 分子产生最终的亚胺化产物 420a, 同时释放苯磺酰胺 和碘氯.2020 年, 张继东课题组[176] 报道了一种直接合成杂 芳基取代 1,3,5-三嗪衍生物 430 的方法(Scheme 80).…”