The influence of ortho-substituents on the properties of phenylboronic acids

The review discusses the structures, properties and applications of ortho-substituted phenylboronic acids. The compounds were compared with meta- and para-isomers, indicating differences resulting from the presence of a substituent in close proximity to the boron group. The effect of an individual substituent on the electron density on boron atom and, as a result, on the acidity constant of these compounds were discussed. Geometric parameters for compounds with known crystal structures were collected and their relationships with the possibility of forming intramolecular hydrogen bonds were evaluated. The most important groups of ortho-substituted boronic acids were evaluated from the point of view of their use in synthesis, analytical chemistry as well as their biological activity. (C) 2020 Elsevier B.V. All rights reserved.