Hydrosilylation of Aldehydes and Ketones Catalyzed by a Terminal Zinc Hydride Complex, [κ3-Tptm]ZnH
摘要:
Tris(2-pyridylthio)methyl zinc hydride, [kappa(3)-Tptm]ZnH, is an effective catalyst for multiple insertions of carbonyl groups into the Si-H bonds of PhxSiH4-x (x = 1, 2). Specifically, [kappa(3)-Tptm]ZnH catalyzes the insertion of a variety of aldehydes and ketones into the Si-H bonds of PhSiH3 and Ph2SiH2 to afford PhSi[OCH(R)R'](3) and Ph,Si[OCH(R)R'](2), respectively. The mechanism for hydrosilylation is proposed to involve insertion of the carbonyl group into the Zn-H bond to afford an alkoxy species, followed by metathesis with the silane to release the alkoxysilane and regenerate the zinc hydride catalyst. Multiple insertion of prochiral ketones results in the formation of diastereomeric mixtures of alkoxysilanes that can be identified by NMR spectroscopy.
Catalytic reduction of carbon dioxide by a zinc hydride compound, [Tptm]ZnH, and conversion to the methanol level
作者:Serge Ruccolo、David Sambade、Daniel G. Shlian、Erika Amemiya、Gerard Parkin
DOI:10.1039/d1dt04156h
日期:——
The zinc hydride compound, [Tptm]ZnH, may achieve the reduction of CO2 by (RO)3SiH (R = Me, Et) to the methanol oxidation level, (MeO)xSi(OR)4−x, via the formate species, HCO2Si(OR)3. However, because insertion of CO2 into the Zn–H bond is more facile than insertion of HCO2Si(OR)3, conversion of HCO2Si(OR)3 to the methanol level only occurs to a significant extent in the absence of CO2.