Vitamin B12: An efficient cobalt catalyst for sustainable generation of radical species

Vitamins are organic molecules that are essential for the proper functioning of mammalian cells. Among them, there is only one organometallic molecule: vitamin B-12, a natural cobalt complex that is involved in DNA synthesis and regulation, the functioning of the nervous system, the formation of red blood cells, etc. Being a co- factor for enzymes dependent on adenosylcobalamin and methylcobalamin, vitamin B-12 plays a crucial role in isomerization, methyl transfer, and dehalogenation reactions. Its activity, however, is not limited to the reactions taking place under physiological settings. It has been widely explored as a preferable catalyst for sustainable organic synthesis, and an abundance of B-12-catalyzed strategies has already been developed. In this perspective, we highlight the underlying principles and catalytic propensity of vitamin B-12 in the generation of C-centered radicals from various precursors and their use in the synthesis of important molecular scaffolds. We also discuss challenges for future discoveries.