Alkali-Metal-Catalyzed Deprotonative Addition of Toluenes with Styrenes

A LiN(SiMe3)2/CsF-catalyzed benzylic C-H bond addition of toluene to styrene is reported, which enables the functionalization of weakly acidic C-H bonds (pKa ≈ 43) with high efficiency and a broad substrate scope. This method overcomes the limitations of traditional strong base systems by utilizing a bimetallic catalyst that reversibly deprotonates benzylic positions, achieving yields of 62-89% across 34 examples. Key advantages include excellent functional group tolerance, scalability, and operational simplicity. Mechanistic studies, supported by kinetic isotope effects, confirm that benzylic deprotonation is the turnover-limiting step.