Daher Ahmad, Abidi Oumaima, Hierso Jean-Cyrille, Roger Julien
Institut de Chimie Moléculaire de l'Université de Bourgogne (UMR-CNRS 6302), Université Bourgogne Franche-Comté (UBFC) 9 Avenue Alain Savary 21078 Dijon France
RSC Adv. 2022 Oct 26;12(47):30691-30695. doi: 10.1039/d2ra06169d. eCollection 2022 Oct 24.
A general palladium-catalysed selective C-H halogenation reaction is reported, which was successfully achieved for a large variety of functionalized aromatic rings incorporating diverse N-directing groups. By using simple alkali halides of MX type as the nucleophilic reagent source (M = Li, Na, K, Cs and X = I, Br and Cl), and phenyliodanediacetate oxidant, clean C-H-iodination, bromination and chlorination reactions were performed. This general protocol of selective -monohalogenation, which complements but contrasts with the classical methods using electrophilic reagents, is achievable in a short time (30 min) with microwave irradiation assistance. The reaction was extended to substrates bearing N-directing pyridine, pyrimidine, pyrazole, oxazoline, naphtho[1,2-]thiazole, and azobenzene groups. Notably, the topical and selectivity-challenging -tetrazine, as a nitrogen-rich heteroaromatic, was successfully halogenated by this protocol.
报道了一种通用的钯催化选择性C-H卤化反应，该反应成功应用于多种含有不同N-导向基团的功能化芳香环。通过使用MX型简单碱金属卤化物作为亲核试剂源（M = Li、Na、K、Cs，X = I、Br、Cl）和苯基二乙酸碘氧化剂，实现了清洁的C-H碘化、溴化和氯化反应。这种选择性单卤化的通用方法与使用亲电试剂的经典方法互补但形成对比，在微波辐射辅助下可在短时间（30分钟）内完成。该反应扩展到带有N-导向吡啶、嘧啶、吡唑、恶唑啉、萘并[1,2-b]噻唑和偶氮苯基团的底物。值得注意的是，具有挑战性的局部和选择性的四嗪作为一种富含氮的杂芳烃，通过该方法成功实现了卤化。
