2751-87-3Relevant academic research and scientific papers
Catalytic CO2 hydrosilylation with [Mn(CO)5Br] under mild reaction conditions
García, Juventino J.,González, Tania
supporting information, (2021/06/07)
Carbon dioxide hydrosilylation with earth-abundant transition-metal catalysts is an attractive alternative for the design of greener and cost-effective synthetic strategies. Herein, simple [Mn(CO)5Br] is an efficient precatalyst in the hydrosilylation of carbon dioxide with Et3SiH under mild reaction conditions. Using THF as a solvent, triethylsilylformate Et3SiCH(O)O was obtained in 67% yield after 1 h at 50 °C and 4 bar of CO2 pressure. The selectivity of the reaction was tuned by changing the solvent to a mixture of THF and toluene producing bis(triethylsilyl)acetal (Et3SiO)2CH2 in 86% yield. The CO2 hydrosilylation was also effective at room temperature and atmospheric pressure using either THF or the mixture THF/toluene as the solvent resulting in high Et3SiH conversion (92%–99%) but with a decrease in the selectivity. Radical trapping experiments indicated the participation of radical species in the catalytic mechanism. To the best of our knowledge, this is the first report on CO2 hydrosilylation catalyzed by transition-metal radical intermediates.
Iodine- or Iodine Monobromide-Catalyzed Alkoxy-Alkoxy Exchange Reactions of Alkylalkoxysilanes: Formation of the Catalyst-Alkoxysilane Complexes and the Reaction Mechanism
Ito, Katsuko,Ibaraki, Takeshi
, p. 2853 - 2858 (2007/10/02)
The formation of charge-transfer complexes of iodine and of iodine monobromide with alcohols and alkoxysilanes has been established spectroscopically, and the formation constants of iodine-ethoxytriethylsilane and iodine-diethoxydimethylsilane complexes has been determined as 0.55+/-0.01 and 0.61+/-0.02, respectively.On the basis of these observations and the kinetic information recently reported, the previously proposed mechanism for the iodine or iodine monobromide catalyzed alkoxy-alkoxy exchange reactions of alkoxysilanes is dicussed afresh.It has been confirmed that a mechanism involving a four-centered transition state containing a CT-complex is most favorable.
Alcoholysis Equilibria of Triethylalkoxysilanes Catalyzed by Iodine or Iodine Monobromide
Ito, Katsuko,Ibaraki, Takeshi
, p. 2973 - 2975 (2007/10/02)
The equilibrium constants K of alcoholysis of triethylalkoxysilanes were determined at 20 degC and 40 degC.Iodine monobromide was used to promote the reactions associated with the tertiary alkoxyl groups, while the other reactions proceeded in the presence of iodine.The K values of the reaction systems with ethoxyl or propoxyl-primary, secondary, and tertiary alkoxyl pairs were 1 or above, about 0.5, and about 0.05, respectively.These values reflect the extent of the binding abilities of the alkoxyl groups to silicon, which is in the expected order of primary>secondary>tertiary alkoxyl groups.A mechanism is postulated for the reaction which involves participation by the iodine or iodine monobromide.
