Gemoets Hannes P L, Kalvet Indrek, Nyuchev Alexander V, Erdmann Nico, Hessel Volker, Schoenebeck Franziska, Noël Timothy
Department of Chemical Engineering and Chemistry , Micro Flow Chemistry & Process Technology , Eindhoven University of Technology , Den Dolech 2 , 5612 AZ Eindhoven , The Netherlands . Email:
Institute of Organic Chemistry , RWTH Aachen University , Landoltweg 1 , 52074 Aachen , Germany . Email:
Chem Sci. 2017 Feb 1;8(2):1046-1055. doi: 10.1039/c6sc02595a. Epub 2016 Sep 5.
A mild and selective C-H arylation strategy for indoles, benzofurans and benzothiophenes is described. The arylation method engages aryldiazonium salts as arylating reagents in equimolar amounts. The protocol is operationally simple, base free, moisture tolerant and air tolerant. It utilizes low palladium loadings (0.5 to 2.0 mol% Pd), short reaction times, green solvents (EtOAc/2-MeTHF or MeOH) and is carried out at room temperature, providing a broad substrate scope (47 examples) and excellent selectivity (C-2 arylation for indoles and benzofurans, C-3 arylation for benzothiophenes). Mechanistic experiments and DFT calculations support a Heck-Matsuda type coupling mechanism.
本文描述了一种温和且具有选择性的用于吲哚、苯并呋喃和苯并噻吩的C-H芳基化策略。该芳基化方法使用等摩尔量的芳基重氮盐作为芳基化试剂。该方案操作简单，无需碱，耐湿且耐空气。它使用低钯负载量（0.5至2.0 mol% Pd），反应时间短，使用绿色溶剂（乙酸乙酯/2-甲基四氢呋喃或甲醇），并在室温下进行，提供了广泛的底物范围（47个实例）和优异的选择性（吲哚和苯并呋喃的C-2芳基化，苯并噻吩的C-3芳基化）。机理实验和DFT计算支持Heck-Matsuda型偶联机理。
