Organoboron Acids and Their Derivatives as Catalysts for Organic Synthesis

An Overview of the applications of boronic and borinic acids, in catalysis is presented. Taking advantage of the Lewis acidity of trivalent boron and the reversible covalent interactions of organoboron acids with OH groups, diverse modes of catalytic reactivity have been achieved. Interactions with carbonyl compounds enable acceleration of addition, and cycloaddition processes, whereas binding of their enol tautomers can lead to organoboron-catalyzed aldol and related reactions. Binding of organoboron acids to hydroxyl and carboxyl OH groups has been employed as a mode of electrophilic activation for catalysis of substitution, cycloaddition, rearrangement, and elimination reactions. By altering the nature of the interaction with the organoboron acid catalyst, activation of OH groups as pronucleophiles is also possible, restating in catalyst-controlled Methods for regioselective functionalization of diols and carbohydrate derivatives. Applications of organoboron acids in bifunctional and assisted catalysis are also discussed,: