Cobalt(III)‐Catalyzed Construction of Benzofurans, Benzofuranones and One‐Pot Orthogonal C−H Functionalizations to Access Polysubstituted Benzofurans

Benzofuran and benzofuranone derivatives have been synthesized through exclusive 5‐ exo ‐ dig intramolecular hydroarylation using the amide‐directed, cost‐effective, high‐valent Cp*Co III ‐catalytic system. Challenging one‐pot, orthogonal C−H functionalizations using two different electrophiles are also reported to afford polysubstituted benzofurans. Several valuable functional group interconversions along with removal of the amide directing group provide a route to access several diversely functionalized benzofurans. The mechanistic study suggests a reversible cobaltation step is operative here.