Trimethylsilyl cyanide

Trimethylsilyl cyanide
Names
	IUPAC name trimethylsilylformonitrile
	Other names Cyanotrimethylsilane; TMS cyanide; Trimethylsilylnitrile; Trimethylsilanecarbonitrile' Trimethylsilylcarbonitrile
Identifiers
CAS Number	7677-24-9 ;
3D model (JSmol)	Interactive image;
Abbreviations	TMSCN
ChemSpider	74110 ;
ECHA InfoCard	100.028.780
PubChem CID	82115;
CompTox Dashboard (EPA)	DTXSID9064766 ;
	InChI InChI=1S/C4H9NSi/c1-6(2,3)4-5/h1-3H3 Key: LEIMLDGFXIOXMT-UHFFFAOYSA-N ; Key: LEIMLDGFXIOXMT-UHFFFAOYAM;
	SMILES C[Si](C)(C)C#N;
Properties
Chemical formula	C4H9NSi
Molar mass	99.208 g·mol−1
Density	0.793 g/mL at 20 °C
Melting point	8 °C (46 °F; 281 K)
Boiling point	114 °C (237 °F; 387 K)
Solubility in water	reacts with water
Solubility	organic solvents
Refractive index (nD)	1.392
Hazards
Flash point	1 °C (34 °F; 274 K)
	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

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 dimethylcarbamoyl 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