The Buchwald–Hartwig amination forms aryl–amine bonds by coupling aryl halides with amines under palladium catalysis. The reaction proceeds through a Pd(0)/Pd(II) cycle involving oxidative addition, amine coordination and deprotonation, and reductive elimination. Early studies by Buchwald and Hartwig established the basic catalytic framework, and subsequent work from many groups broadened the reaction’s scope and reliability. Today it is one of the most versatile C–N bond-forming methods in synt