We report a hypervalent iodine-mediated C-N cross-coupling between phenols or anilines and azoles. A catalytic variant based on in situ oxidation of an aryl iodide was also developed. The reaction proceeds at room temperature in an HFIP/CH3NO2 solvent system and avoids the use of prefunctionalized aryl halides as coupling partners. Under optimized conditions, triazoles, pyrazoles, and other azoles couple in up to 90% isolated yield with broad functional-group tolerance. The HFIP/CH3NO2 mixture (3:1) suppresses competitive O-N coupling and promotes selective C-N bond formation. A catalytic variant using an aryl iodide (10 mol %) with mCPBA and CF3COOH as the terminal oxidant-acid pair delivers comparable efficiency. This operationally simple protocol complements palladium- or copper-catalyzed methods by eliminating aryl-halide preactivation and transition metals.
Morimoto et al. (Wed,) studied this question.