IRANIAN JOURNAL OF CATALYSIS Sulfuric acid ([3-(3-silicapropyl)-sulfanyl]propyl)ester as recyclable catalyst for the silylation of hydroxyl groups (original) (raw)
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Chinese Journal of Catalysis, 2008
Many primary, secondary, tertiary alcohols, and phenolic hydroxyl groups were effectively converted to their corresponding trimethylsilyl ethers using hexamethyldisilazane in the presence of catalytic amounts of tribromoisocyanuric acid and DABCO-bromine under mild conditions at room temperature with short reaction times in good to excellent yields. Excellent chemoselective silylation of hydroxyl groups in the presence of other functional groups were also observed.
Chinese Journal of Catalysis, 2011
Various alcohols and phenols were trimethylsilylated in excellent yields using hexamethyldisilazane in the presence of catalytic amounts of environmentally friendly, hydrophobic, highly thermal stable, and completely heterogeneous sulfonic acid functionalized mesostructured SBA-15 in dichloromethane at ambient temperature. Primary, bulky secondary, tertiary, and phenolic hydroxyl functional groups were transformed to the corresponding trimethylsilyl ethers in excellent yields. The simple experimental procedure was accompanied by easy recovery and the catalyst was reusable (at least 18 reaction cycles); these are attractive features of this protocol.
Canadian Journal of Chemistry, 2008
A highly efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, benzylic, secondary, hindered secondary, tertiary, phenols, and oximes with hexamethyldisilazane (HMDS), using Al(H2PO4)3 as a recyclable heterogeneous catalyst at room temperature in a few minutes with excellent yields under solvent-free conditions is described.Key words: trimethylsilylation, hexamethyldisilazane, aluminum tris(dihydrogen phosphate) [Al(H2PO4)3], solvent-free, hydroxyl groups.
Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 2012
The protection of alcohols with hexamethyldisilazane (HMDS) in the presence of P 2 O 5 /SiO 2 at very mild and ambient condition with short reaction times is accomplished in excellent yields. P 2 O 5 /SiO 2 catalyst is an efficient solid acid and heterogeneous catalyst for this transformation and easily recovered and reused for several times without significant decrease in its activity. Selectivity studies showed competitive reaction of primary alcohols over secondary alcohols and phenols.
Journal of the Chinese Chemical Society, 2009
Silica-supported tin chloride [SiO 2 -Sn(Cl) 4-n ] has been prepared by mixing tin chloride with activated silica gel in toluene under refluxing conditions for one day. A range of primary, secondary, and tertiary alcohols as well as phenolic hydroxyl groups were converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of silica-supported tin chloride at room temperature. An excellent chemoselective silylation of hydroxyl groups in the presence of other functional groups was also observed. This catalyst could be recycled and reused fifteen times without loss of efficiency.
Chemistry (Weinheim an der Bergstrasse, Germany), 2016
Trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, and triisopropylsilyl 2-methylprop-2-ene-1-sulfinates were prepared through (CuOTf)2 ⋅C6 H6 -catalyzed sila-ene reactions of the corresponding methallylsilanes with SO2 at 50 °C. Sterically hindered, epimerizable, and base-sensitive alcohols gave the corresponding silyl ethers in high yields and purities at room temperature and under neutral conditions. As the byproducts of the silylation reaction (SO2 +isobutylene) are volatile, the workup was simplified to solvent evaporation. The developed method can be employed for the chemo- and regioselective semiprotection of polyols and glycosides and for the silylation of unstable aldols. The high reactivity of the developed reagents is shown by the synthesis of sterically hindered per-O-tert-butyldimethylsilyl-α-d-glucopyranose, the X-ray crystallographic analysis of which is the first for a per-O-silylated hexopyranose. The per-O-silylation of polyols, hydroxy carboxylic acids, and c...