Direct C(sp2)‐H Bond Alkylation of Maleimide via Fe(III)‐Catalyzed Hydrogen Atom Transfer Strategy

Comprehensive Summary The direct C(sp 2 )‐H bond alkylation of maleimides using iminophosphorane‐induced Fe(III)‐catalyzed HAT (hydrogen atom transfer) strategy was achieved, and a series of novel alkyl maleimide derivatives were synthesized. The reaction has the characteristics of mild conditions, widespread functional group compatibility and substrates adaptability. The mechanism study shows that it mainly involves MHAT (metal‐catalyzed hydrogen atom transfer), radical conjugate addition, SET (single electron transfer) processes, and theoretical calculations reveal that the critical step is that phosphorus radical intermediate G is converted to phosphorus cationic intermediate I . The research provides a new insight into the direct functionalization of C(sp 2 )‐H to form C(sp 2 )‐C(sp 3 ) bonds via the HAT strategy.