Triblock Peptide and Peptide Thioester Synthesis With Reactivity‐Differentiated Sulfonamides and Peptidyl Thioacids

One after the other : Triblock peptide synthesis was achieved at ambient temperature by sequential reaction of sulfonamide‐protected peptidyl thioacids first with highly reactive 2,4‐dinitrobenzenesulfonamides and second with more moderately reactive sulfonamides to produce the oligopeptides in good yields. The method is compatible with C‐terminal thioesters and thus presents a new approach for native chemical ligation strategies.