School of Chemical Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar , HBNI, P.O. Bhimpur-Padanpur, Via Jatni, Khurda 752050, Odisha, India.
Org Lett. 2017 May 5;19(9):2454-2457. doi: 10.1021/acs.orglett.7b01117. Epub 2017 Apr 21.
An intermolecular dehydrogenative annulation (IDA) for carbazole synthesis via sequential C-C/C-N bond formation with a selective alkyl group migration is reported. Using the hypervalent iodine(III) reagent PhI(OAc) (PIDA), in a one-pot operation, up to five C(sp2)-H bonds, one N(sp3)-H bond functionalization, and one alkyl (Me, Et) group migration could all be achieved from non-prefunctionalized 1,3,5-trialkylbenzenes and anilides under ambient laboratory conditions. Mechanistically, it is shown that PIDA reacts with anilides to generate a nitrenium ion or an equivalent carbenium ion which influences the second aromatic ring to be activated for C-C/C-N bond formation. Strategically, regioselective fusion of arenes to anilides is described.
报道了一种通过顺序 C-C/C-N 键形成和选择性烷基迁移的分子间脱氢环化（IDA）来合成咔唑的方法。使用高价碘(III)试剂 PhI(OAc)（PIDA），在一锅操作中，可以在环境实验室条件下，从未预官能化的 1,3,5-三烷基苯和酰胺中实现多达五个 C(sp2)-H 键、一个 N(sp3)-H 键功能化和一个烷基（Me，Et）基团迁移。从机理上表明，PIDA 与酰胺反应生成氮宾离子或等价的碳正离子，这影响第二个芳环被激活以进行 C-C/C-N 键形成。从策略上讲，描述了芳基与酰胺的区域选择性融合。
