Trimethylsilyl cyanide
| Trimethylsilyl cyanide | |
|---|---|
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| IUPAC name trimethylsilylformonitrile | |
| Other names Cyanotrimethylsilane; TMS cyanide; Trimethylsilylnitrile; Trimethylsilanecarbonitrile' Trimethylsilylcarbonitrile | |
| Identifiers | |
| Abbreviations | TMSCN |
| CAS number | 7677-24-9  |
| PubChem | 82115 |
| ChemSpider | 74110 |
| Jmol-3D images | {{#if:C[Si](C)(C)C#N|Image 1 |
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| Properties | |
| Molecular formula | C4H9NSi |
| Molar mass | 99.21 g mol−1 |
| Density | 0.793 g/mL at 20 °C |
| Melting point | 8 to 11 °C; 46 to 52 °F; 281 to 284 K |
| Boiling point | 114 to 117 °C; 237 to 243 °F; 387 to 390 K |
| Solubility in water | reacts with water |
| Solubility | organic solvents |
| Refractive index (nD) | 1.392 |
| Hazards | |
| R-phrases | R11 R26/27/28 R29 |
| S-phrases | S16 S36/37/39 S45 |
| Flash point | 1 °C; 34 °F; 274 K |
(verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | |
| Infobox references | |
Trimethylsilyl cyanide is the chemical compound with the formula (CH3)3SiCN. This volatile liquid consists of a cyanide group, that is CN, attached to a trimethylsilyl group. The molecule is used in organic synthesis as the equivalent of hydrogen cyanide. It is prepared by the reaction of lithium cyanide and trimethylsilyl chloride:[1]
- LiCN + (CH3)3SiCl → (CH3)3SiCN + LiCl
In its principal reaction, it adds across carbon-oxygen double bonds, for example in an aldehyde:
- RCHO + (CH3)3SiCN → RCH(CN)OSi(CH3)3
The product is an O-silylated cyanohydrin.
One use of this reagent is to convert pyridine-N-oxides into 2-cyanopyridine. This transformation is best done in dichloromethane solution using dimethyl carbamoyl chloride as the activating electrophile. It is possible to use benzoyl chloride but the yields and regioselectivity of the addition of the cyano group are lower.
Safety
Trimethylsilyl cyanide is treated with care since it hydrolyzes to give hydrogen cyanide:
- 2 (CH3)3SiCN + H2O → (CH3)3SiOSi(CH3)3 + 2 HCN
References
- ↑ Livinghouse, T. (1990), "Trimethylsilyl Cyanide: Cyanosilation of p-Benzoquinone", Org. Synth.; Coll. Vol. 7: 517