Regioselective formation, using orthogonal cysteine protection, of an alpha-conotoxin dimer peptide containing four disulfide bonds.

[structure: see text] The combination of the cysteine thiol protecting groups Trt, Acm, tBu, and MeBzl were used for the regioselective formation of an alpha-conotoxin dimer peptide containing four disulfide bridges. Additionally, a protocol is described whereby two one-pot oxidations were employed in order to improve the efficiency of the folding process. The target compound was produced in good yield.