Novel Organosilicon Starburst Compounds Based on Ruthenium-Catalyzed Silylative Coupling Reactions of 1,3,5-Tris(dimethylvinylsilyl)benzene

The highly stereo- and regioselective reaction of 1,3,5-tris(dimethylvinylsilyl)benzene (1) with p-substituted styrenes, p-XC 6 H 4 CH=CH 2 , where X = H (2), Cl (3), Br (4), vinyl (5), catalyzed by RuHCl(CO)(PCy 3 ) 2 (I) appeared to be an efficient basis for new starburst compounds involving silylene-vinylene-arylene sequences. Attempts were made to synthesize the first generation of dendrimer (12), based on 1 as a core, via two methods: direct silylative coupling of 1,3,5-tris[dimethyl(4-vinylstyryl)silyl]benzene (5) with 1, which gave a mixture of oligomers containing the SiCH=CHSi structure, and successfully via silylation of 5 with vinylsilyl-3,5-bis(isopropoxysilyl)benzene (10) followed by vinylation with Grignard reagent. Additionally, the double silylation of DVB with 10 followed by vinylation allowed the synthesis of an analogous starburst compound (14), which can be a new core for analogous dendritic compounds.