Silylative Coupling versus Metathesis—Efficient Methods for the Synthesis of Difunctionalized Double‐Decker Silsesquioxane Derivatives

Abstract

A series of functionalized dialkenylsilsesquioxanes were obtained by efficient and highly stereoselective silylative coupling and cross-metathesis of divinylsubstituted double-decker silsesquioxanes (DDSQ-2SiVi) with substituted styrenes and other olefins. Both reactions proceed highly stereoselectively and lead to nearly quantitative formation of E isomers. The optimized reaction conditions for styrene were adopted for successful silylative coupling polycondensation of DDSQ-2SiVi with 1,4-divinylbenzene yielding stereoregular cooligomer containing double-decker (silsesquioxyl-silylene)-vinylene-phenylene units.

A new class of stereoregular vinylene-arylene copolymers with double-decker silsesquioxane in the main chain

“…The overview of this process is presented in Scheme . As expected, the DDSQ‐2SiVi containing a methyl group located at Si‐9 and Si‐19 atoms ( 1A ) was confirmed to be inactive in metathetic transformations. For this reason, ADMET copolymerization of the DDSQ‐2SiVi with phenyl group at Si‐9 and Si‐19 atoms ( 1B ) was chosen.…”

“…The SC and CM reaction optimization for a variety of olefins performed and presented in our previous paper enabled efficient synthesis of a series of new, functionalized double‐decker‐based silsesquioxanes . The positive results from the preliminary test of the SCC of DDSQ‐2SiVi ( 1A ) with DVB prompted us to extend this procedure not only to new diolefins, but also to the utilization of a complementary catalytic reaction, that is, ADMET copolymerization.…”

“…For this reason, ADMET copolymerization of the DDSQ‐2SiVi with phenyl group at Si‐9 and Si‐19 atoms ( 1B ) was chosen. The reactions were optimized in terms of the catalyst amount, presence of a co‐catalyst, type of solvent, temperature, and reagent stoichiometry based on the results of the reaction conditions for the synthesis of styryl‐substituted DDSQ compounds in our previous article . The presented procedures ensure the efficiency of both reactions and also allow the undesirable polyarenes to be avoided without the need for any inhibitor addition.…”

“…The chemicals were purchased from the following sources: dichloromethane (DCM), tetrahydrofuran (THF), diethyl ether, ethanol, toluene, n ‐hexane, benzene‐ d 6 , chloroform‐d, tricyclohexylphosphine, potassium carbonate, tetrakis(triphenylphosphine)palladium(0) [Pd(PPh 3 ) 4 ], 1,4‐dibromobenzene, potassium tert ‐butoxide, terephthalic aldehyde, methyltriphenylpho sphonium bromide, 1,5‐cyclooctadiene, 4‐bromostyrene, 4‐vinylphenyl‐boronic acid, calcium hydride, molecular sieves, and anhydrous magnesium sulfate from Aldrich, vinylmethyldichlorosilane and vinylphenyl dichlorosilane from ABCR, triethylamine and silica gel 60 from Fluka, tetrasilanolphenyl POSS (DDSQ‐4OH) from Hybrid Plastics, Grubbs first‐generation benzylidene catalyst from Apeiron Synthesis, ruthenium(III) chloride hydrate from Lancaster. [RuHCl(CO)(PCy 3 ) 2 ], as well as divinyl‐substituted double‐decker silsesquio xanes ( DDSQ‐2Vi ) ( 1A , 1B ) were prepared according to the literature procedure. All solvents were dried over CaH 2 prior to use and stored under argon over type 4A molecular sieves.…”

Synthesis of Polysilsesquioxanes with Double-Decker Silsesquioxane Repeating Units

“…The problems caused by the multi-functionality of POSS could be readily eradicated by replacing POSS with double-decker silsesquioxane (DDSQ) having two definite polymerizable functional groups. Recently some researchers synthesized polysilsesquioxane having DDSQ units in the main chain [19][20]. They used bi-functional DDSQ unit having organic spacers.…”