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The introduction of a triphenylborate group at the 4‐position of 2,6‐dimesitylpyridine afforded a sterically demanding anionic pyridine. The charge introduced through the borate group drastically increases its basicity and measurement of its pKa value (18.46) revealed a significantly higher value than that of 4‐dimethylaminopyridine (17.95). THF ring‐opening was observed upon treating its lithium salt with TMSCl, which demonstrates its high nucleophilicity. The mesityl groups at the 2,6‐positions are oriented orthogonal to the pyridine ring and do not block the nitrogen atom of the pyridine. The reaction of the protonated pyridine with Li[BH4] yielded the corresponding Lewis acid/base adduct, which shows that the title compound can be used as a monodentate ligand in coordination chemistry. The crystal structures of all the compounds presented in this work are reported. Sterically demanding and negatively charged! The introduction of a triphenylborate group at the 4‐position of 2,6‐dimesitylpyridine affords a sterically demanding anionic pyridine (see scheme). The negatively charged triphenylborate substituent acts as a strong electron‐donating substituent, making the title compound one of the most basic pyridines known. Reactions demonstrating its nucleophilicity and Lewis basicity are presented. [ABSTRACT FROM AUTHOR]

The introduction of a triphenylborate group at the 4-position of 2,6-dimesitylpyridine afforded a sterically demanding anionic pyridine. The charge introduced through the borate group drastically increases its basicity and measurement of its pK a value (18.46) revealed a significantly higher value than that of 4-dimethylaminopyridine (17.95). THF ring-opening was observed upon treating its lithium salt with TMSCl, which demonstrates its high nucleophilicity. The mesityl groups at the 2,6-positions are oriented orthogonal to the pyridine ring and do not block the nitrogen atom of the pyridine. The reaction of the protonated pyridine with Li[BH 4 ] yielded the corresponding Lewis acid/base adduct, which shows that the title compound can be used as a monodentate ligand in coordination chemistry. The crystal structures of all the compounds presented in this work are reported., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)