Three‐Component Castagnoli‐Cushman Reaction of 3‐Arylglutaconic Acid Anhydrides, Carbonyl Compounds, and Ammonium Acetate: a Quick and Flexible Way to Assemble Polysubstituted NH ‐δ‐lactams

Cover Feature: Three‐Component Castagnoli‐Cushman Reaction of 3‐Arylglutaconic Acid Anhydrides, Carbonyl Compounds, and Ammonium Acetate: a Quick and Flexible Way to Assemble Polysubstituted NH ‐δ‐lactams (Eur. J. Org. Chem. 11/2021)

Carboxylate 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. peerReviewed

CCDC 2034845: Experimental Crystal Structure Determination

Related Article: Anatoly Peshkov, Olga Bakulina, Dmitry Dar'in, Grigory Kantin, Anton Bannykh, Vsevolod Peshkov, Mikhail Krasavin|2021|Eur.J.Org.Chem.|2021|1726|doi:10.1002/ejoc.202001617