钯催化 2-卤代苄基卤化物与芳肼之间的反应直接形成 2-取代 2-吲哚。
Direct Formation of 2-Substituted 2-Indazoles by a Pd-Catalyzed Reaction between 2-Halobenzyl Halides and Arylhydrazines.
机构信息
Department of Chemistry, Faculty of Science, The Hashemite University, P.O. Box 330127, Zarqa 13133, Jordan.
Bioorganische Chemie, Institut für Chemie, Universität Hohenheim, Garbenstraße 30, Stuttgart D-70599, Germany.
出版信息
J Org Chem. 2021 Jan 15;86(2):1408-1418. doi: 10.1021/acs.joc.0c01923. Epub 2020 Dec 11.
A direct and operationally simple method for the regioselective synthesis of 2-aryl-substituted 2-indazoles is reported. The Pd-catalyzed reaction between easily available 2-bromobenzyl bromides and arylhydrazines employing CsCO as the base and -BuPHBF as the ligand in DMSO at 120 °C in a sealed tube delivers the 2-substituted-2-indazoles in a single synthetic step with yields up to 79%. The new method is based on a regioselective intermolecular -benzylation followed by intramolecular -arylation and oxidation.
本文报道了一种直接且操作简单的 2-芳基取代 2-吲哚合成方法。在密封管中，DMSO 作为溶剂，碳酸铯作为碱，-BuPHBF 作为配体，在 120°C 下，用 Pd 催化易于获得的 2-溴苯甲溴和芳基肼进行反应，可一步合成 2-取代-2-吲哚，产率高达 79%。该新方法基于区域选择性的分子间苄基化，随后是分子内芳基化和氧化。
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