Pd-Catalyzed Regioselective Si–C Bond Cleavage: Maximizing Chemo-Divergence in (4 + 2) Silacyclization Reactions of Alkynals
Xing‐Ben Wang, Jia‐Wei Si, Mengqiong Pu, Junjie Guo, Zheng Xu, Li Li, Zhuangzhi Shi, Fuk Yee Kwong, Li‐Wen Xu
Abstract
Precise control of catalyst systems to achieve chemodivergent synthesis from identical starting materials remains a fundamental challenge in catalysis and synthetic chemistry. Herein, we report a ligand-driven Pd-catalyzed regio- and chemodivergent (4 + 2) silacyclization reactions of benzosilacyclobutenes with unsymmetric alkynals, enabling the synthesis of all four dihydrobenzo[c]siline derivatives with remarkable selectivity. Each phosphine ligand uniquely dictates the reaction pathway, demonstrating unparalleled chemo-control and addressing long-standing challenges, including uncontrollable Si–C( sp 2 ) or Si–C( sp 3 ) bond cleavage and selective α-site or β-site addition to unsymmetrical alkynes. By leveraging steric and electronic properties of ligands, we achieve high yields and good selectivities, supported by mechanistic insights from DFT calculations. This strategy establishes a versatile platform for silacycle synthesis, with broad potential for atom-economics, chemistry, and materials science.