Efficient Synthesis of Nitrile Compounds through Amide Conversion via N-Boroamide Intermediates

HBpin is used as a boronizing reagent and formal dehydrating agent is reported for the first time. CsF was used as a catalyst to achieve the dehydration and conversion of primary amides, and various nitrile compounds were obtained with good to excellent yields. This method is easy to operate, and the yield of the target product in the gram scale amplification experiment is 96%. The catalytic system exhibits good compatibility with various functional groups, such as halogen, trifluoromethyl, heterocycle, and amino group. These results indicate that this method has good application potential. Mechanism studies have shown that the in-situ generation of N-boroamide intermediates and H-2 is the key to the smooth occurrence of the reaction. And, the formation of thermodynamically stable B-O-B anhydride and nitrile product is the driving force of this transformation.