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Visible‐light photoredox‐catalyzed desulfurization of thiol‐ and disulfide‐containing amino acids and small peptides
Author(s) -
Lee Myungmo,
Neukirchen Saskia,
Cabrele Chiara,
Reiser Oliver
Publication year - 2017
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.3016
Subject(s) - chemistry , cysteine , catalysis , cystine , sulfoxide , flue gas desulfurization , combinatorial chemistry , thiol , glutathione , visible spectrum , sulfur , methionine sulfoxide , organic chemistry , amino acid , methionine , biochemistry , enzyme , physics , optoelectronics
A scalable protocol for the desulfurization of cysteine by using visible light, the photocatalyst Ir(dF(CF 3 )ppy) 2 (dtb‐bpy)PF 6 and triethylphosphite under biphasic reaction conditions has been developed. The loading of the catalyst can be as low as 0.01 mol%, which can be efficiently removed during the workup (≤0.3 ppm), giving rise to the corresponding desulfurized product in high yields. This method has been applied also to cystine, penicillamine, and reduced and oxidized glutathione. The desulfurization has been found to be pH sensitive, with an optimal pH value of 6.5 and 7.0 for the cysteine derivatives and glutathione, respectively. In addition, during the desulfurization of a decapeptide containing cysteine and methionine, concurrent oxidation of the two sulfur‐containing residues to disulfide and sulfoxide has been observed. Therefore, whereas the presented protocol allows a straightforward visible light‐mediated desulfurization of simple thiols by using very low catalyst loading and a cost‐effective trialkylphosphite as thiyl radical trapping agent, its application to complex substrates needs to be carefully validated. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.