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Updated: Jun 25, 2025

Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions
Published on: November 30, 2022
On the mechanism of sp2 C-H borylation using ortho-N-substituted pyridinium cations
Nikita Slesarchuk1, Enlu Ma1, Juan Miranda-Pizarro1
1Department of Chemistry, Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014, Finland. timo.repo@helsinki.fi.
Abstract:
ortho-N-Substituted pyridinium cations with the weakly coordinating anion [B(C6F5)4]- have been studied and crucial structural features in the sp2 C-H borylation catalysis of 3-methylthiophene have been identified. The electron-deficiency of the aromatic core of the cation is essential for activity together with accessible protons. The spectroscopic yield of the borylation of 3-methylthiophene with catecholborane (CatBH) was optimized up to 86% and the method was further applied to other substrates such as N-alkylbenzenes. A mechanistic DFT study revealed the rate-limiting step in the catalysis to be the liberation of molecular H2 (ΔG‡ = 27.5 kcal mol-1), whereas the overall reaction was found to be exergonic by 5.1 kcal mol-1.
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