The conversion of C‒H bonds to C‒N bonds offers a sustainable and economical strategy for the synthesis of nitrogen-containing compounds. However, challenges regarding the control of regio- and stereoselectivity currently limit the broad applicability of intermolecular C(sp3)‒H amination reactions. We address these restrictions by directed nitrene-mediated C‒H insertion using a metal-coordinating functional group. We report a highly stereocontrolled, iron-catalysed direct α-amination of abundant carboxylic acid feedstock molecules. The method provides in a single step high-value N-Boc-protected α-monosubstituted and α,α-disubstituted α-amino acids, which can then be immediately used for applications including solution- and solid-phase peptide synthesis. This method fulfils important aspects of sustainability by being highly step efficient and utilizing non-toxic, Earth-abundant iron as the catalytic metal.