Selective C(sp2)-H Halogenation of "Click" 4-Aryl-1,2,3-triazoles.
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.
Department of Organic Chemistry-I, University of the Basque Country (UPV-EHU) , Joxe Mari Korta R&D Center, Av Tolosa 72, 20018 Donostia-San Sebastián, Spain.
Asier
A
Goitia
Department of Organic Chemistry-I, University of the Basque Country (UPV-EHU) , Joxe Mari Korta R&D Center, Av Tolosa 72, 20018 Donostia-San Sebastián, Spain.
Enrique
E
Gómez-Bengoa
Department of Organic Chemistry-I, University of the Basque Country (UPV-EHU) , Joxe Mari Korta R&D Center, Av Tolosa 72, 20018 Donostia-San Sebastián, Spain.
Arkaitz
0000-0002-9004-3842
A
Correa