A novel and efficient palladium‐catalyzed cyclization amination of propargylamines and 1,3‐dienes is reported for the first time, yielding a series of chloromethylene pyrrolidines with high efficiency and excellent selectivity. This method was successfully applied to the late‐stage modification of natural products and drug molecules, providing molecular backbones with potential applications. The reaction was shown to achieve regioselective modulation of the product molecules through the resonance between the solvent and allylpalladium. Additionally, the E‐form products were found to be thermodynamically stable.