Organosilicon

Organosilicon compounds are chemical species that contain at least one carbon–silicon (C–Si) bond. They form a large and diverse class that includes small molecules, protecting groups, and polymers. The Si–C bond is relatively strong and polarizable, enabling substantial stability while allowing a range of transformations at silicon through Si–H, Si–O, and Si–X substituents. Because silicon can bear multiple organic groups, organosilicon chemistry covers structures from simple alkyl and aryl silanes to vinylsilanes, alkynylsilanes, and silicone polymers.

Major subgroups include organosilanes (R3Si–H, R2SiR'–), and silyl-protecting groups such as tert-butyldimethylsilyl (TBDMS, TBS) and tert-butyldiphenylsilyl (TBDPS) ethers. Siloxanes and polysiloxanes (silicones) feature Si–O–Si backbones with organic substituents on silicon. Organosilicon reagents are also employed in cross-coupling, notably the Hiyama coupling that uses organosilanes with fluoride activation to form C–C bonds.

Principal reactions include hydrosilylation of alkenes and alkynes, where Si–H adds across C=C or C≡C bonds under metal catalysis, and various methods to form Si–C bonds. Oxidative and functionalization strategies, such as the Tamao–Fleming oxidation, convert Si–C bonds into hydroxyl-bearing products, expanding the utility of organosilicon frameworks.

Applications span silicones (polysiloxanes) used in coatings, lubricants, and medical devices; silyl-protecting groups in organic synthesis; and silicon-containing materials in electronics and specialty polymers. Organosilicon chemistry is valued for combining stable carbon–silicon linkages with versatile reactivity at silicon and wide material applications.