An effective selective silylative coupling functionalization of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane with olefins catalyzed by ruthenium-hydride complex [RuHCl(CO)(PCy3)(2)] has been described. We have obtained numerous unsaturated derivatives of cyclosiloxane possessing a SiCH=CHX fragments (where X = alkyl, aryl, silyl, alkoxy, amine and amide groups). One of the products synthesized (1,3,5,7tetramethyl-1,3,5,7-tetra-(E)-4-bromostyrylcyclotetrasiloxane) has been efficiently coupled with aryl iodides in the presence of palladium(O) catalyst to yield substituted 4-bromostilbenes. (c) 2006 Elsevier B.V. All rights reserved.