The present disclosure describes operationally simple methods for the low temperature, catalytic activation of carboxylic acids for organic reactions, in particular for direct amidation reactions with amines. The methods involve the use of orthosubstituted arylboromc acids of the formula (I), wherein the groups R1 to R5 are as defined herein. In preferred embodiments R1 is halogen. The arylboromc acids catalyze nucleophilic 1,2-addition reactions, conjugate 1,4-addition reactions, and cycloaddition reactions, including Diels-Alder reactions involving α,β-unsaturated carboxylic acids.