Ru-Catalyzed Dehydrogenative Silylation of POSS-Silanols with Hydrosilanes: Its Introduction to One-Pot Synthesis

Abstract

A commercially available and stable ruthenium dodecacarbonyl catalyst (Ru3(CO)12) allows very efficient and convenient access to functionalized silsesquioxanes (SQs) containing siloxane moiety (Si–O–Si) via dehydrogenative coupling of POSS-silanols with hydrosilanes. With the aid of SiH-containing silsesquioxanes, an unprecedented one-pot procedure has been revealed, and the usefulness of this approach was demonstrated by the synthesis of various derivatives via O-silylation, as well as CC and CN hydrosilylation.

Silylation of Alcohols, Phenols, and Silanols with Alkynylsilanes – an Efficient Route to Silyl Ethers and Unsymmetrical Siloxanes

“…Recently, our group developed a variety of synthetic procedures utilizing mainly hydro- [61][62][63][64] and allylsilanes in the O-silylation reactions. [65][66][67][68][69][70] Given all this, we decided to investigate the possibility of obtaining the Si-OR and Si-O-Si′ moieties by using alkynylsilanes in a reaction with hydroxy-substituted com- pounds.…”

Dumbbell‐Shaped, Graft and Bottlebrush Polymers with All‐Siloxane Nature: Synthetic Methodology, Thermal, and Rheological Behavior

“…It is also worth noting that the synthesizing of well‐defined siloxane (macro)structures with SiO R groups ( R = H, Me, Et) as the building blocks is a challenge in organosilicon chemistry; at the same time, they are “greener” reagents than chlorosilanes, silazanes, etc. [ 44–57 ]…”

“…[44,45] Thus, a few main types of processes for synthesizing (macro) structures with a SiOSi group can be distinguished: [44,45] 1) polycondensation of chloro-and alkoxysilanes; 2) metathesis (or redistribution) of (cyclo)siloxanes; 3) condensation of silanols or silanolates with chlorosilanes; 4) processes based on the Piers-Rubinsztajn reaction, that is, reactions of hydride silanes with alkoxysilanes or silanols. [46][47][48][49][50][51][52][53][54][55] As a rule, the processes belonging to groups (1) and 2are not applicable for synthesizing individual siloxanes or polysiloxanes with a required structure as they give equilibrium mixtures of cyclic, linear, and branched products with different molecular weights, depending on the structure of the starting compounds and reaction conditions. The processes of groups 3and 4are more applicable for the controlled synthesis of siloxanes with well-defined structures.…”

“…It is also worth noting that the synthesizing of well-defined siloxane (macro)structures with SiOR groups (R = H, Me, Et) as the building blocks is a challenge in organosilicon chemistry; at the same time, they are "greener" reagents than chlorosilanes, silazanes, etc. [44][45][46][47][48][49][50][51][52][53][54][55][56][57] To summarize the above, the development of a methodology for the synthesis of both well-defined all-siloxane branched building blocks and macrostructures based on them with an all-siloxane backbone (without a hydrocarbon or carbosilane moiety in the macromolecule skeleton) is a complex synthetic problem. However, this approach is promising and much-indemand.…”

B(C6F5)3-Catalyzed Dehydrocoupling of POSS Silanols with Hydrosilanes: A Metal-Free Strategy for Effecting Functionalization of Silsesquioxanes

“…So far, our research group has proposed various catalytic methodologies for the functionalization of silanols − and silsesquioxanes containing silanol Si–OH (silanol) groups, known as POSS silanols. , We discovered that POSS silanols undergo a reaction with 2-methylallyl-substituted organometalloidal reagents in the presence of a Lewis acid Sc­(OTf) 3 or the heterogeneous catalyst Nafion. − Moreover, we also published the dehydrogenative coupling of POSS silanols with commercially available silanes. This process can be catalyzed by Ru 3 (CO) 12 , Cu­(OTf) 2 , or KO t Bu. In light of this fact, materials science and silsesquioxane chemistry are constantly being developed, and the design of novel, effective, and mild catalytic routes that lead to functionalized silsesquioxanes is of high relevance.…”