Synthesis of Functionalized (Poly)Siloxanes via Iron‐Catalyzed C–H Bond Alkylation with Polar Olefins †

Comprehensive Summary The synthesis of functionalized linear polysiloxanes has garnered considerable attentions due to their broad applicability. While the selective C−H bond functionalization of dimethylsiloxane monomers or polymers offers a promising and versatile approach, it remains a significant synthetic challenge. In this study, we report a mild and efficient iron‐catalyzed method for the C−H bond alkylation of both dimethylsiloxane monomers and polysiloxane using polar alkenes as coupling partners. This protocol exhibits broad substrate scope, tolerating a wide range of siloxane/silane substrates and polar alkenes. A variety of functional groups, including amide, ester, ketone, and nitrile, can be readily introduced into the siloxane framework. Functionalized polysiloxanes are accessible either through direct C−H bond functionalization or via copolymerization using the modified monomers. Notably, nitrile‐functionalized polysiloxanes display significant photoluminescence properties, offering new opportunities for expanding the application scope of polysiloxane materials. Based on experimental studies, a plausible catalytic mechanism is also proposed.