Selective C(sp2)–H Halogenation of “Click” 4-Aryl-1,2,3-triazoles

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• 作者：Asier Goitia ; Enrique Gómez-Bengoa ; Arkaitz Correa
• 刊名：Organic Letters
• 出版年：2017
• 出版时间：February 17, 2017
• 年：2017
• 卷：19
• 期：4
• 页码：962-965
• 全文大小：401K
• ISSN：1523-7052

文摘

Selective bromination reactions of “click compounds” are described. Electron-neutral and electron-deficient arenes selectively undergo unprecedented Pd-catalyzed C–H ortho-halogenations assisted by simple triazoles as modular directing groups, whereas electron-rich arenes are regioselectively halogenated following an electrophilic aromatic substitution reaction pathway. These C–H halogenation procedures exhibit a wide group tolerance, complement existing bromination procedures, and represent versatile synthetic tools of utmost importance for the late-stage diversification of “click compounds”. The characterization of a triazole-containing palladacycle and density functional theory studies supported the mechanism proposal.