Cascade reactions in organic chemistry refer to a series of consecutive reactions that occur in a single reaction vessel, leading to the formation of complex molecules from simpler starting materials. These reactions often involve the use of multiple catalytic steps, with each step triggering the next reaction in a sequential manner. Cascade reactions are highly efficient and can provide significant advantages in terms of time, cost, and waste reduction compared to traditional step-by-step synthesis processes. They are widely used in the synthesis of natural products, pharmaceuticals, and other complex organic molecules.