Scheme 22. a: Peptides macrocyclized through their Trp-C2 and a iodophenyl residue from Phe or Tyr; X = H, Ac; Y = OH, NH₂; R = H, OH; PEPTIDE₁ = 0–1 amino acids: PEPTIDE₂ = 0–3 amino acids; PEPTIDE₃ = 0–1 amino acids; b: a typical substrate for a macrocyclization between a sp²-CH₂ group and a phenyl iodide; n = 1, 2; PEPTIDE = 2, 3, 4 or 6 amino acids; c: oxidative cross-coupling between an alkenyl ester and a phenyl group to obtain macrocyclic peptides; n = 0, 2; PEPTIDE = 1–4 amino acids.