HYDROHALOGENATION OF PERPHENYLCYCLOSILANES

Anhydrous hydrogen halides have been found to react with octaphenylcyclotetrasilane to give the corresponding 1-halo-1,1,2,2,3,3,4,4-octaphenyltetrasilane in good yields. The order of reactivity observed with these reagents under similar conditions is HI>HBr>HCl. Several halogenated hydrocarbons also bring about cleavage and hydrohalogenation of octaphenylcyclotetrasilane. Some of the halogenated hydrocarbons cause a secondary cleavage of the silicon hydride formed to provide the 1,4-dihalo-1,1,2,2,3,3,4,4-octaphenyltetrasilane derivative. This may provide a route for mixed dihalo derivatives. Decaphenylcyclopentasilane reacts only to a small extent with the same reagents and then to give non-isolable products. © 1968.