Recent progress in applications of cobalt catalysts in organic reactions

In recent decades, cobalt catalyst has represented a powerful strategy for developing common organic reactions. This review includes the most recent efforts of Co catalysts applications in selective organic reactions such as C–H & C—X activation, hydrogenation & dehydrogenation, and cycloaddition. The contribution of cobalt salt or earth-abundant cobalt complexes usually accomplishes these reactions. It mainly involves different fundamental reaction paths, such as the concerted metalation-deprotonation (CMD) path associated with non-oxidative C–H activation and the intermolecular single-electron transfer (SET) path. Here, we summarize the advances of Co catalyst applications in three main sections: (i) C–H & C—X activation, (ii) hydrogenation-dehydrogenation, and (iii) cycloaddition. The characteristics of each catalyst are discussed according to parameters such as efficiency, recyclability, catalyst life, lack of catalyst nanoparticles agglomeration, and required time of catalyst effects on the reactions.