Pharmaceutical Research Institute, Wuhan Institute of Technology, Wuhan 430205, China.
School of Chemical Engineering & Pharmacy, Wuhan Institute of Technology, Wuhan 430205, China.
Chem Commun (Camb). 2022 May 30;58(44):6429-6432. doi: 10.1039/d2cc01404a.
Selective alkylation of indazoles is still a highly challenging topic in chemistry and the synthesis of important molecules. Herein, a novel highly selective -alkylation of indazoles with diazo compounds is described in the presence of TfOH. Unlike the traditional metal- and base-catalysed version, this protocol highlights the regioselectivity of alkylation of indazoles and a metal-free catalysis system, affording -alkylated products in good to excellent yields with high regioselectivity (/ up to 100/0) and excellent functional group tolerance. Furthermore, a gram scale synthesis was conducted successfully to give rise to the corresponding products. Mechanistic studies through control experiments provide plausible mechanistic proposals.
吲哚的选择性烷基化在化学和重要分子的合成中仍然是一个极具挑战性的课题。在此，我们描述了一种在 TfOH 存在下用重氮化合物对吲哚进行新型高区域选择性烷基化的方法。与传统的金属和碱催化版本不同，该方案突出了吲哚烷基化的区域选择性和无金属催化体系，以良好至优秀的收率和高区域选择性（/高达 100/0）以及优异的官能团耐受性提供 -烷基化产物。此外，还成功地进行了克级规模的合成，得到了相应的产物。通过控制实验进行的机理研究提供了合理的机理建议。
