Nature Chemistry, Published online: 15 June 2026; doi:10.1038/s41557-026-02178-7 The selective functionalization of unprotected amines with alkenes remains a challenge in contemporary synthesis. Now a strategy has been developed for an alkyl swap of N-methylamines, enabling late-stage bioconjugation and peptide modification. The resulting retrosynthetic disconnection also streamlines the preparation of several pharmaceuticals and medicinally relevant compounds.