Native chemical ligation with Nα acyl transfer auxiliaries

Shifting Native Chemical Ligation into Reverse through N→S Acyl Transfer

Peptide thioester synthesis by N→S acyl transfer is being intensively explored by many research groups the world over. Reasons for this likely include the often straightforward method of precursor assembly using Fmoc-based chemistry and the fundamentally interesting acyl migration process. In this review we introduce recent advances in this exciting area and discuss, in more detail, our own efforts towards the synthesis of peptide thioesters through N→S acyl transfer in native peptide sequences. We have found that several peptide thioesters can be readily prepared and, what's more, there appears to be ample opportunity for further development and discovery.

Direct Fmoc-chemistry-based solid-phase synthesis of peptidyl thioesters

Attachment of a growing peptide chain to a glycylaminomethyl resin via a thioglycinamide bond is compatible with Fmoc-chemistry solid-phase peptide synthesis. Subsequent S-alkylation of the thioamide gives a thioimide that, on treatment with aqueous trifluoroacetic acid, releases the peptide from the resin in the form of a C-terminal thioester.