Cobalt‐Catalyzed C(sp 3 )−H Functionalization Reactions

C−H functionalization reactions hold great potential for the streamlined synthesis of complex molecules and are currently a “hot” topic in organic synthesis. Among the various transition metals that have been used, cobalt has recently attracted increased attention as a catalyst for C−H functionalization reactions, owing to its ready availability and high reactivity. Although a number of cobalt‐catalyzed C(sp 2 )−H functionalization reactions have been reported to date, C(sp 3 )−H functionalization reactions remain challenging. This Focus Review summarizes recent progress in cobalt‐catalyzed C(sp 3 )−H functionalization reactions that involve C−H activation to form organometallic intermediates.