Effect of water on the palladium-catalyzed amidation of aryl bromides.

The presence of water was found to have a significant impact on the conversion of some Hartwig-Buchwald reactions between amides with arylbromides. Seven amidation reactions were studied in a series of experiments containing 0-400 mol % water. When cesium carbonate is used as the base both in dioxane and toluene, water can have a beneficial effect. The experiments have also shown that for some reactions, anhydrous conditions are unnecessary and sometimes can hinder the reaction.