Cobalt-Catalyzed Cross-Coupling Reactions

Transition-metal-catalyzed cross-coupling reactions have been an essential strategy for the construction of C-C bonds, including in the syntheses of pharmaceuticals and natural products, since the pioneering work of Heck, Negishi, and Suzuki, among others. Of the widely applied catalysts based on group 8-10 metals, economical cobalt salts have been shown to be advantageous as an alternative to other commonly used expensive and/or toxic catalysts. In this review, cobalt-catalyzed cross-coupling reactions of organometallic reagents, such as organomagnesium or organozinc derivatives, to achieve the formation of C-C bonds, are summarized. Furthermore, various methods for the cobalt-catalyzed reductive cross coupling of C-X/C-O electrophiles have also been reported for selective C-C bond formation, and these are also discussed.