A General Copper/Manganese Cocatalyzed C‐H Selenation of Arenes, Heteroarenes, and Alkenes under Air

Despite significant progress, copper‐catalyzed, directed C−H activation to form C‐heteroatom bond is a challenging problem due to strong chelation with the directing group and the incoming nucleophile. Therefore, stoichiometric copper salt was used which is not practical from industrial standpoint. Here we have developed a copper‐manganese dual catalytic system for a general chelation‐assisted C(sp2)‐H selenation of benzamides and acrylamides. Interestingly, the acrylamides provided thermodynamically unfavourable (Z)‐vinyl selenides with complete control of regio‐ and stereoselectivity. In addition, reaction with selenium powder in lieu of diorganyldiselenide provided the cyclic ebselen derivatives via C−Se/N−Se bond formation cascade. Thus, we provide here a practical and user‐friendly protocol for C(sp2)‐H selenation combining inexpensive first row‐transition metal catalysts coupled with aerial oxygen as the terminal oxidant. A general copper‐manganese dual catalytic system for chelation‐assisted C(sp2)‐H selenation of benzamides and acrylamides was developed. The acrylamides provided thermodynamically unfavourable (Z)‐vinyl selenides and reaction with selenium powder afforded benzoisoselenazolones via C−Se/N−Se bond formation cascade.