Borates were purchased from commercial suppliers or synthesized from the respective alcohols and BH3.SMe2 or BCl3, as described in the SI. Initial screening (Table ) was performed using the reaction of benzoic acid with benzylamine under Dean-Stark dehydration conditions in tert-amyl methyl ether (TAME) as previously employed in our initial work with B(OCH2CF3)3. This reaction was chosen as although it will go to completion with B(OCH2CF3)3, it is relatively slow, enabling differences in catalyst reactivity to be readily identified. After 18 hours, B(OCH2CF3)3 gives a 58% yield of amide, with boric acid and trimethyl borate giving significantly lower yields as expected. and.