Palladium (II)-catalyzed cascade reactions initiated with directed activation of unactivated sp3 C–H bonds

Abstract

Cascade reactions—chemical processes consisting of two or more reactions in one pot—offer considerable advantages in terms of time, cost, atom efficiency, and reduced waste generation, and have thus unsurprisingly attracted considerable attention amongst the chemical community in recent decades. On the other hand, transition metal-catalyzed site-selective carbon-hydrogen (C–H) bond functionalization represents one of the most significant and efficient synthetic approaches in organic chemistry, enabling the conversion of common petroleum chemicals into highly valuable products in a single step. Utilization of this approach in cascades dramatically improves its applicability by allowing for the efficient construction of complex molecules from simple starting materials in a single pot. This perspective summarizes the developments in palladium (II)-catalyzed cascade reactions initiated with directed activation of unactivated aliphatic C–H bonds and our recent efforts in synthesizing bicyclic lactones, followed by current challenges and future opportunities.