Metal‐Free TBN‐Mediated Regioselective Azolation of Phenols

ABSTRACT A metal‐free, ortho‐selective C–H amination of phenols with azoles using TBN as the sole mediator is reported. The reaction provides direct access to N‐arylazoles, key scaffolds in pharmaceuticals and agrochemicals, under mild conditions (room temperature, inert atmosphere) without transition‐metal catalysts, prefunctionalized arenes, or external oxidants. A wide range of phenols and azoles (pyrazoles, imidazoles, triazoles, and tetrazoles) are compatible, affording ortho‐aminated products in good to excellent yields (up to 94%) with exceptional regiocontrol. Gram‐scale synthesis (2.08 g, 77% yield) and subsequent derivatizations demonstrate synthetic utility. Mechanistic studies support a radical pathway involving TBN‐generated nitrogen‐centered radicals.