Synthesis of mono- and polyfunctional organosilicon derivatives of polyhedral carboranes for the preparation of hybrid polymer materials

A series of mono- and polyfunctional carborane organosilicon derivatives were prepared with good yields based on the hydrosilylation reactions of allylcarboranes with hydride-containing organosilicon compounds such as tetramethyldisiloxane, decamethylpentasiloxane and triethoxysilane in the presence of Karstedt's catalyst. The functionalization of the double bonds in the allylcarboranes proceeded regioselectively in accordance with the Farmer's rule, providing efficient access to carborane silicon compounds. It was found for 9-o- and 9-m-allylcarboranes that an excess of Karstedt's catalyst could promote the migration of a double bond in allylcarboranes to form boron-substituted propenyl derivatives; the structure of the ortho-isomer was supported by X-ray diffraction analysis.