Simplifying native chemical ligation with an N-acylsulfonamide linker

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Why is it important?

How to make a thioester equivalent by Fmoc chemistry for use in chemical ligation. The sulfonamide linker attached to a solid phase was the first Fmoc method to make peptide thioesters. It was adequate for well-behaved examples but the yields for the final thiolysis were often extremely poor. We discovered that the alkylsulfonamide itself was activated enough to participate in ligation in aqueous buffer so we could miss out the thiolysis reaction. The peptide is simply synthesised off the sulfonamide linker, alkylated and prepped. Very easy and goes in good yield. It works.