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Carboxylate Catalyzed Isomerization of β,γ‐Unsaturated N ‐Acetylcysteamine Thioesters **
Author(s) -
Riuttamäki Saara,
Laczkó Gergely,
Madarász Ádám,
Földes Tamás,
Pápai Imre,
Bannykh Anton,
Pihko Petri M.
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202201030
Subject(s) - isomerization , catalysis , chemistry , carboxylate , medicinal chemistry , stereochemistry , organic chemistry
We demonstrate herein the capacity of simple carboxylate salts – tetrametylammonium and tetramethylguanidinium pivalate – to act as catalysts in the isomerization of β,γ‐unsaturated thioesters to α,β‐unsaturated thioesters. The carboxylate catalysts gave reaction rates comparable to those obtained with DBU, but with fewer side reactions. The reaction exhibits a normal secondary kinetic isotope effect ( k 1H / k 1D =1.065±0.026) with a β,γ‐deuterated substrate. Computational analysis of the mechanism provides a similar value ( k 1H / k 1D =1.05) with a mechanism where γ‐reprotonation of the enolate intermediate is rate determining.