Cobalt Carbonyl as a Solid CO(g) Source for the Synthesis of Novel Coumarin Derivatives and Biaryl Ketones by Palladium‐Catalyzed Carbonylative Suzuki–Miyaura Reaction

We herein report an atom‐economical, facile, and efficient approach developed for synthesizing a variety of C‐7 carbonylated coumarin derivatives and biaryl ketones in good‐to‐excellent yields. The use of aryl fluorosulfates as an atom‐economical electrophilic coupling partner and the employment of cobalt carbonyl as a solid source of gaseous CO in the palladium‐catalyzed carbonylative Suzuki–Miyaura reaction are the key for success of this developed protocol. The excellent reactivity of coumarin fluorosulfate as a leaving group for the carbonylative Suzuki reaction has been realized by doing a comparative study with other pseudohalide leaving groups in the later stage. The practical utility of the developed methodology has been demonstrated by performing a gram‐scale synthesis of phenstatin derivative of 4‐methyl coumarin.