Phenylsilane

Phenylsilane
skeletal formula of phenylsilane	ball-and-stick model of the phenylsilane molecule
Names
	Other names Silylbenzene
Identifiers
CAS Number	694-53-1 ;
3D model (JSmol)	Interactive image;
ChemSpider	12228 ;
ECHA InfoCard	100.010.703
PubChem CID	12752;
UNII	P2EX7Q1UYS ;
CompTox Dashboard (EPA)	DTXSID70870757 ;
	InChI InChI=1S/C6H8Si/c7-6-4-2-1-3-5-6/h1-5H,7H3 Key: PARWUHTVGZSQPD-UHFFFAOYSA-N ; InChI=1/C6H8Si/c7-6-4-2-1-3-5-6/h1-5H,7H3 Key: PARWUHTVGZSQPD-UHFFFAOYAT;
	SMILES c1ccccc1[SiH3];
Properties
Chemical formula	C6H8Si
Molar mass	108.215 g·mol−1
Appearance	Colorless liquid
Density	0.878 g/cm3
Boiling point	119 to 121 °C (246 to 250 °F; 392 to 394 K)
Solubility in water	Hydrolyzes
Hazards
Safety data sheet (SDS)	MSDS
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

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.

Synthesis and reactions

Phenylsilane is produced in two steps from Si(OEt)₄. In the first step, phenylmagnesium bromide is added to form Ph-Si(OEt)₃ via 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

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 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]

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 0-387-11675-3.
^ Fleck, T. J. Encyclopedia of Reagents for Organic Synthesis doi:10.1002/047084289X.rp101

[1] 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

[2] Weber, W. P. Silicon Reagents for Organic Synthesis. Springer-Verlag: Berlin, 1983. ISBN 0-387-11675-3.

[3] Fleck, T. J. Encyclopedia of Reagents for Organic Synthesis doi:10.1002/047084289X.rp101

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