Palladium-Catalyzed Regiodivergent [4 + 2] Cycloaddition of Benzosilacyclobutenes with Phenylpropiolonitriles

The controlled diversification of reaction pathways from a common substrate through precise modulation of catalyst systems represents a persistent challenge in catalysis and synthetic chemistry. Herein, we report a ligand-controlled Pd-catalyzed regiodivergent (4 + 2) silacyclization between benzosilacyclobutenes and unsymmetrical phenylpropiolonitriles, which selectively affords two distinct classes of dihydrobenzo[c]silane derivatives. Each phosphine ligand steers the reaction along a unique pathway, enabling exceptional control over chemoselectivity. Through steric and electronic modulation of the ligands, both high efficiency and excellent selectivity are achieved. This strategy with divergent catalysis provides a versatile platform for the structurally diverse synthesis of silaheterocycles, with promising implications for atom-economical synthesis and functional materials.