Phenylsilane
From Wikipedia, the free encyclopedia
| Phenylsilane | |
|---|---|
 |
 |
| Other names | Silylbenzene |
| Identifiers | |
| CAS number | [694-53-1] |
| Properties | |
| Molecular formula | C6H8Si |
| Molar mass | 108.22 g/mol |
| Appearance | Colorless liquid |
| Density | 0.878 g/cm³ |
| Melting point |
N/A |
| Boiling point |
119-121 °C (433-394 K) |
| Hazards | |
| R-phrases | 11-14/15-20/22-36/37/38 |
| S-phrases | 16-43 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Phenylsilane, also known as silylbenzene, a colorless liquid, is one of the simplest organosilanes with the formula C6H5SiH3. It is structurally related to toluene, with a silyl group replacing the methyl group. Both of these compounds have similar densities and boiling points due to these similarities. Phenylsilane is soluble in organic solvents.
[edit] Synthesis and reactions
Phenylsilane is produced in two steps from Si(OEt)4. In the first step magnesium bromobenzene is added to form Ph-Si(OEt)3. The approach of using a magnesium-bromine reagent is called a Grignard reaction. Reduction of the resulting Ph-Si(OEt)3 product with LiAlH4 affords phenylsilane[1].
Ph-MgBr + Si(OEt)4 → Ph-Si(OEt)3 + MgBr(OEt)
4 Ph-Si(OEt)3 + 3 LiAlH4 → 4 Ph-SiH3 + 3 LiAl(OEt)4
[edit] Uses
Phenylsilane can be used to reduce tertiary phosphine oxides to the corresponding tertiary phosphine.
P(CH3)3O + PhSiH3 --> P(CH3)3 + PhSiH2OH
The use of phenylsilane proceeds with retention of the configuration at the phosphine. For example, cyclic chiral tertiary phosphine oxides can be reduced to cyclic tertiary phosphines[2].
Phenylsilane can also be combined with cesium fluoride. In aprotic solvents, it becomes a nonnucleophilic hydride donor. Specifically, phenylsilane-caesium fluoride has been shown to reduce 4-oxazolium salts to 4-oxazolines. This reduction gives yields of 95%[3].
[edit] References
- ^ Minge, O.; Mitzel, N. W.; and Schmidbaur, H. Synthetic Pathways to Hydrogen-Rich Polysilylated Arenes from Trialkoxysilanes and Other Precursors. Organometallics 2002, 21, 680-684. DOI 10.1021/om0108595.
- ^ Weber, W. P. Silicon Reagents for Organic Synthesis. Springer-Verlag: Berlin, 1983. ISBN 0387116753.
- ^ Fleck, T. J. Encyclopedia of Reagents for Organic Synthesis DOI 10.1002/047084289X.rp101
