HBF4·OEt2 as a mild and versatile reagent for the Ritter amidation of olefins: a facile synthesis of secondary amides

A variety of alkenes undergo smooth amidation with nitriles in the presence of HBF4·OEt2 at room temperature under mild conditions to afford the corresponding secondary amides in good to excellent yields. This is a highly efficient method for the preparation of α-aryl ethyl amides especially from vinyl arenes without any side reactions such as olefin polymerization. The use of readily available and easy to handle reagent HBF4·OEt2 makes this method simple, convenient, and practical.