A Mild Synthesis of Unsymmetrical Bisalkoxysilanes through Catalyzed Alcoholysis of Hydridosilanes Containing C−C Multiple Bonds and Aryl Halides

Selective oxidation of silanes into silanols with water using [MnBr(CO)5] as a precatalyst

The development of earth-abundant catalysts for the selective conversion of silanes to silanols with water as an oxidant generating valuable hydrogen as the only by-product continues to be a challenge. Here, we demonstrate that [MnBr(CO)₅] is a highly active precatalyst for this reaction, operating under neutral conditions and avoiding the undesired formation of siloxanes. As a result, a broad substrate scope, including primary and secondary silanes, could be converted to the desired products. The turnover performances of the catalyst were also examined, yielding a maximum TOF of 4088 h^-1. New light was shed on the debated mechanism of the interaction between [MnBr(CO)₅] and Si-H bonds based on the reaction kinetics (including KIEs of PhMe₂SiD and D₂O) and spectroscopic techniques (FT-IR, GC-TCD, ¹H-, ²⁹Si-, and ¹³C-NMR). The initial activation of [MnBr(CO)₅] was found to result from the formation of a manganese(i) hydride species and R₃SiBr, and the experimental data are most consistent with a catalytic cycle comprising a cationic tricarbonyl Mn(i) unit as the active framework.

Silylation reactions on nanoporous gold via homolytic Si-H activation of silanes

We report compelling evidences that dihydrosilanes are activated in a homolytic fashion on the surface of nanoporous gold (NPG), which produces hydrogen radical and silicon moieties covalently linked to the surface of the NPG. This new reactivity has led to the development of novel silylation reactions on gold.

Si–H bond activation is an important process implicated in many useful synthetic applications including silylation and transfer hydrogenation reactions. Herein we discovered homolytic activation of Si–H bonds on the surface of nanoporous gold (NPG), forming hydrogen radicals and [Au]–[Si] intermediates. By virtue of this new reactivity, we achieved highly selective mono and sequential alcoholysis of dihydrosilane. In addition, the amphiphilic nature of the [Au]–[Si] intermediate allows for a new bis-silylation reaction of cyclic ethers. The present work showcased that the surface reactivity of nanocatalysts may provide exciting opportunity for new reaction discovery.

[Tris(alkoxydimethylsilyl)methyl]alkylferrocenes as New Ferrocenyl Multifunctional Silyl Ethers

[Tris(trimethylsilyl)methyl]alkylferrocenes and [tris(dimethylsilyl)methyl]alkylferrocenes were synthesized by treatment of tris(trimethylsilyl)methyllithium and tris(dimethylsilyl)methyllithium in THF with 3-bromopropylferrocene or 4-bromobutylferrocene at 0°C. [Tris(alkoxydimethylsilyl)methyl]alkylferrocenes were obtained by dehydrocoupling with various aliphatic and benzylic alcohols in the presence of the Karstedt catalyst (platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane in xylene) in good to excellent yields. 4-[Tris(benzyloxydimethylsilyl)methyl]butylferrocene was also prepared from the transetherification of 4-[tris(methoxydimethylsilyl)methyl]butylferrocene with benzyl alcohol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene as catalyst.