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Published March 17, 2023 | public
Journal Article

Computational Exploration of the Nature of Li⁺-Ureide Anion Catalysis on Formation of Highly Reactive Vinyl Carbocations and Subsequent C–C Bond Forming Reactions

Abstract

The mechanisms of the C–H insertion reactions of vinyl carbocations formed by heterolysis of vinyl trifluoromethanesulfonates (triflates) by catalytic lithiated 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea (Li+-ureide) have been studied with ωB97X-D density functional theory. The ionization promoted by the Li⁺-ureide forms a metastable intimate ion pair complex of Li⁺-ureide-triflate anion and vinyl cation. The relative thermodynamic stabilities of isomeric alkyl cations are impacted by ion-pairing with the Li⁺-ureide-triflate anion. We show that the C–H insertion reaction of the vinyl cation intermediate is the rate-determining step and explain the effect of the aryl substituents on the formation of the vinyl cation and its C–H insertion reactivity as well as the regioselectivity of C–H activation by the vinyl cation.

Additional Information

© 2023 American Chemical Society. Financial support of this work was generously provided by the National Science Foundation (CHE-1764328 to K.N.H.). W.L. is grateful for additional funding from the UCLA Graduate Dean's Scholar Award. We thank Stasik Popov and Benjamin Wigman for the discussions of the experimental results. Computations were performed on the UCLA Institute of Digital Research and Education Hoffman2 Cluster. Author Contributions. The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. The authors declare no competing financial interest.

Additional details

Created:
August 22, 2023
Modified:
October 18, 2023