A peptide coupling reaction forms an amide bond between the carboxyl group of one amino-acid residue and the amino group of another. In conventional chemical coupling, the carboxylic acid is converted in situ or beforehand into a more electrophilic acyl species, after which nucleophilic attack by the amine, collapse of the tetrahedral intermediate, and loss of the activating group produce the peptide bond [1][2]. Carbodiimides, phosphonium salts, uronium reagents, active esters, acid halides, and mixed anhydrides are common activation classes [1]. The concept requires amide formation between amino-acid-derived partners and is therefore narrower than general amide synthesis, but it is not a transition-metal cross-coupling despite the shared word 'coupling'. Protecting groups or chemoselective activation normally control which amino and carboxyl groups react, while suppression of epimerization preserves residue configuration [2][3]. Peptide coupling is distinguished from native chemical ligation, which proceeds through a chemoselective capture and acyl-transfer sequence, and from ribosomal peptide-bond formation.
- peptide coupling
- amide bond
- acyl activation
- coupling reagent
Catalytic Cross-Coupling Reactions • Organic Chemistry • Chemistry • Physical Sciences
References
- Ayman El-Faham; Fernando Albericio; Peptide Coupling Reagents, More than a Letter Soup. Chem. Rev. 2011, 111, 6557-6602, 10.1021/cr100048w.
- Christian A.G.N. Montalbetti; Virginie Falque; Amide bond formation and peptide coupling. Tetrahedron 2005, 61, 10827-10852, 10.1016/j.tet.2005.08.031.
- Eric Valeur; Mark Bradley; Amide bond formation: beyond the myth of coupling reagents. Chem. Soc. Rev. 2008, 38, 606-631, 10.1039/b701677h.