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Spontaneous head-to-tail cyclization of unprotected linear peptides with the KAHA ligation.

ABSTRACT: The ?-ketoacid-hydroxylamine (KAHA) ligation with 5-oxaproline enables the direct cyclization of peptides upon cleavage from a solid support, without coupling reagents, protecting groups, or purification of the linear precursors. This Fmoc SPPS-based method was applied to the synthesis of a library of 24 homoserine-containing cyclic peptides and was compared side-by-side with the synthesis of the same products using a standard method for cyclizing side-chain protected substrates. A detailed mechanistic study including 2H and 18O labeling experiments and the characterization of reaction intermediates by NMR and mass spectrometry is reported.

SUBMITTER: Rohrbacher F

PROVIDER: S-EPMC5664356 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature

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Spontaneous head-to-tail cyclization of unprotected linear peptides with the KAHA ligation.

Rohrbacher Florian F Deniau Gildas G Luther Anatol A Bode Jeffrey W JW

Chemical science 20150610 8

The α-ketoacid-hydroxylamine (KAHA) ligation with 5-oxaproline enables the direct cyclization of peptides upon cleavage from a solid support, without coupling reagents, protecting groups, or purification of the linear precursors. This Fmoc SPPS-based method was applied to the synthesis of a library of 24 homoserine-containing cyclic peptides and was compared side-by-side with the synthesis of the same products using a standard method for cyclizing side-chain protected substrates. A detailed mech ...[more]

PMID: 29142720

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