biostudies-literatureRiuttamaki SAcademy of FinlandNKFIH Hungarye202201030https://www.ebi.ac.uk/biostudies/studies/S-EPMC9541288biostudies-literatureUnknown28(45)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.Chemistry (Weinheim an der Bergstrasse, Germany)Carboxylate Catalyzed Isomerization of β,γ-Unsaturated N-Acetylcysteamine Thioesters.PMC9541288K-112028297874322899307624Papai IFoldes TPihko PMMadarasz ALaczko GBannykh ARiuttamaki SfalseCarboxylate Catalyzed Isomerization of β,γ-Unsaturated N-Acetylcysteamine Thioesters.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.2022-01-01T00:00:00Z2022 Aug2024-11-07T03:11:29.051Z2024-11-07T03:11:29.051ZS-EPMC95412883560420010.1002/chem.202201030