While 1 H NMR analysis of 8a confirmed that the allylic protons were not present (indicating successful cyclisation), further analysis was sought to fully characterise the macrocycle for peptide 8a. A TOCSY NMR experiment was carried out on this model and a complete assignment of the macrocycle was achieved (Figure ). Proton environments in the hydrocarbon linker were found to couple to H signals on residues at each end of the macrocycle, indicating successful cyclisation. Moreover, the H signal from what was initially the Cys residue prior to cyclisation coupled to the H of the first Ala residue, which could only occur as a result of macrocycle formation. A significant chemical shift dispersion suggests an ordered structure. Furthermore, the phenylalanine (Phe) H resonances show an NOE interaction to the H of the allyl glycine position, suggesting that the macrocycle is strained.