Cobalt-Catalyzed Allylic Alkylation at sp-Carbon Centers.

The rising demand and financial costs of noble transition metal catalysts have emphasized the need for sustainable catalytic approaches. Over the past few years, base-metal catalysts have emerged as ideal candidates to replace their noble-metal counterparts because of their abundance and easiness of handling. Despite the significant advancements achieved with precious transition metals, earth-abundant cobalt catalysts have emerged as efficient alternatives for allylic substitution reactions. In this review, allylic alkylations at sp-carbon centers mediated by cobalt will be discussed, with a special focus on the mechanistic features, scope, and limitations.