SmI ₂ /Sm‐Induced Reductive Silacyclization of Alkene/Diene Derivatives Using Dichlorosilanes or 1,2‐Dichlorodisilanes via Reductive Radical‐Polar Crossover

The development of efficient strategies for constructing cyclic organosilicon frameworks is considered of great importance because of their structural diversity and synthetic utility. Herein, we report a SmI 2 /Sm‐mediated silacyclization of unsaturated organic compounds with readily available dichlorosilanes and ‐disilanes, enabling convenient access to 4−7‐membered silacyclic compounds. Mechanistic investigations indicate that the reaction involves silyl radical intermediates and proceeds via a reductive radical‐polar crossover (RRPCO) pathway. The present findings showcase the broad potential of Sm reagents in Si─C bond formation, providing a versatile strategy for constructing diverse silicon‐containing frameworks.