Lewis Acid-Catalyzed Direct Conversion of Carboxylic Acids into Primary Amides and Nitriles Using Bis(trimethylsilyl)amine

We report Lewis acid-catalyzed direct conversion of carboxylic acids into primary amides and nitriles using bis(trimethylsilyl)amine as an ammonia surrogate. With 1.1 equiv of bis(trimethylsilyl)amine, ytterbium(III) and hafnium(IV) triflates efficiently catalyzed the reaction, affording various primary amides in high yields with a broad substrate scope. Increasing the amount of bis(trimethylsilyl)amine to more than 2 equiv promoted one-pot dehydration of the primary amides to directly afford the corresponding nitriles. Preliminary mechanistic studies suggest that bis(trimethylsilyl)amine plays a key role in activating the carboxylic acids.