Not-So-Innocent Anions Determine the Mechanism of Cationic Alkylators.

Autor: Taimoory SM; Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Ave., ON, N9B 3P4, Windsor, Canada.; Department of Chemistry, University of Michigan, 930 N University Ave., Ann Arbor, MI, 48109, USA., Cataldo VA; Colloid Chemistry Department, Max Planck Institute for Colloids and Interfaces, Am Mühlenberg 1 OT Golm, 14476, Potsdam, Germany., Schäfer A; Institut für Chemie und Biochemie-Organische Chemie, Freie Universität Berlin, Takustr. 3, 14195, Berlin, Germany., Trant JF; Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Ave., ON, N9B 3P4, Windsor, Canada., Guterman R; Colloid Chemistry Department, Max Planck Institute for Colloids and Interfaces, Am Mühlenberg 1 OT Golm, 14476, Potsdam, Germany.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2021 Feb 15; Vol. 27 (10), pp. 3440-3448. Date of Electronic Publication: 2021 Jan 18.
DOI: 10.1002/chem.202004208
Abstrakt: Alkylating reagents based on thioimidazolium ionic liquids were synthesized and the influence of the anion on the alkylation reaction mechanism explored in detail using both experimental and computational methods. Thioimidazolium cations transfer alkyl substituents to nucleophiles, however the reaction rate was highly dependent on anion identity, demonstrating that the anion is not innocent in the mechanism. Detailed analysis of the computationally-derived potential energy surfaces associated with possible mechanisms indicated that this dependence arises from a combination of anion induced electronic, steric and coordinating effects, with highly nucleophilic anions catalyzing a 2-step process while highly non-nucleophilic, delocalized anions favor a 1-step reaction. This work also confirms the presence of ion-pairs and aggregates in solution thus supporting anion-induced control over the reaction rate and mechanism. These findings provide new insight into an old reaction allowing for better design of cationic alkylators in synthesis, gene expression, polymer science, and protein chemistry applications.
(© 2020 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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