General method for generating functionalized arylsilyllithium species.

Although silyllithium species are valuable reagents in organosilicon chemistry due to their versatile reactivity and utility, especially in Si-Si bond-forming reactions, access to functionalized variants remains limited. In particular, while dimethylphenylsilyllithium is widely used, functionalized arylsilyllithium species remain extremely rare because classical lithium-mediated reduction of chlorosilanes is largely restricted to simple substrates. Here, we report a general method for accessing silyllithium species bearing functionalized aryl groups, enabled by the activation of silylboranes with organolithium reagents. By tuning the activator to match the electronic properties of the substrate, both electron-rich and electron-poor dialkylarylsilyl systems are converted into the corresponding silyllithium species. In situ 11B{1H} and 29Si{1H} NMR studies support a boron-metal exchange pathway involving borate intermediates. Notably, these species are inaccessible via conventional lithium-mediated reduction of chlorosilanes. Furthermore, their reactions with chlorosilanes afford disilanes and oligosilanes in moderate to good yields, broadening the scope of silicon-based transformations and enabling access to electronically diverse organosilicon compounds.