Arylsilane

Arylsilane is an organosilicon compound in which at least one aryl group is directly bonded to silicon. Silicon can carry up to four substituents, so arylsilanes range from monosubstituted species such as Ar–SiR3 to tetra-substituted Ar4Si. Common examples include phenylsilane (PhSiH3), diphenylsilane (Ph2SiH2), triphenylsilane (Ph3SiH), and tetraphenylsilane (Ph4Si).

The Ar–Si bond is relatively robust, but arylsilane substrates can undergo selective C–Si bond activation under fluoride-promoted or metal-catalyzed conditions, enabling cross-coupling and other transformations. Physical properties vary with substitution; many arylsilanes are colorless liquids or solids with moderate volatility, and higher aryl content tends to increase thermal stability and reduce reactivity.

Arylsilane preparation typically involves forming a carbon–silicon bond by reacting an aryl nucleophile, such as an aryl Grignard reagent, with a chlorosilane (R3SiCl) to yield Ar–SiR3 after workup. Alternative routes include hydrosilylation of arenes or alkynes and C–H silylation of arenes followed by functionalization to install the silane moiety. In practice, arylsilane building blocks are widely used as starting materials in cross-coupling and as protecting-group precursors.

Applications of arylsilanes are prominent in Hiyama cross-coupling, where an arylsilane participates in carbon–carbon bond formation with organohalides under fluoride activation and a metal catalyst. They also serve as intermediates in organic synthesis and as scaffolds in materials chemistry, including silsesquioxane-based polymers and surface-modification reagents. Safety and handling depend on the specific compound.