New strategy for the chemical synthesis of proteins

For the chemical synthesis of proteins, an efficient deprotecting procedure by combination of a hard acid, trimethylsilyl trifluoromethanesulfonate, and a soft nucleophile, such as thioanisole, is described. For disulfide bond formation, two new procedures are presented; the one by oxidation with thallium(III) trifluoroacetate and the other by the acid-catalyzed reaction, involving S-substituted cysteine sulfoxides.