Palladium-Catalyzed Denitrogenative Carbonylation of Benzotriazoles with Cr(CO)6 as the Carbonyl Source

A general palladium and silver co-catalyzed denitrogenative carbonylation of benzotriazoles for the synthesis of benzoxazin-4-ones has been developed. Employing benzotriazoles as easily accessible substrates and Cr(CO)6 as bench-stable solid carbonyl sources, various benzoxazin-4-ones were synthesized through a ring-opening/denitrogenative/carbonylation cascade processes in moderate to good yields. Notably, this protocol avoids the use of toxic CO gas and special equipment and can also be applied to the late-stage functionalization of substrates derived from the uricosuric agent probenecid.