Discovery of competing anaerobic and aerobic pathways in umpolung amide synthesis allows for site-selective amide ^sup 18^O-labeling

The mechanism of umpolung amide synthesis was probed by interrogating potential sources for the oxygen of the product amide carbonyl that emanates from the α-bromo nitroalkane substrate. Using a series of ...-labeled substrates and reagents, evidence is gathered to advance two pathways from the puta...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2012-01, Vol.109 (1), p.44
Main Authors: Shackleford, Jessica P, Shen, Bo, Johnston, Jeffrey N
Format: Article
Language:English
Subjects:
Bacteria
Oxygen
Peptides
Protein synthesis
Online Access:Get full text
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Summary:The mechanism of umpolung amide synthesis was probed by interrogating potential sources for the oxygen of the product amide carbonyl that emanates from the α-bromo nitroalkane substrate. Using a series of ...-labeled substrates and reagents, evidence is gathered to advance two pathways from the putative tetrahedral intermediate. Under anaerobic conditions, a nitro-nitrite isomerization delivers the amide oxygen from nitro oxygen. The same homolytic nitro-carbon fragmentation can be diverted by capture of the carbon radical intermediate with oxygen gas (...) to deliver the amide oxygen from ... This understanding was used to develop a straightforward protocol for the preparation of ...-labeled amides in peptides by simply performing the umpolung amide synthesis reaction under an atmosphere of ... (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0027-8424
1091-6490