Trimethylsilylacetylene is an acetylene molecule protected on one end by the trimethylsilyl group. It is popularly used in alkynylations, e.g. the Sonogashira reaction. After desilylation (e.g. with TBAF), the ethynyl group is introduced. Using a protected alkyne, as opposed to acetylene gas, prevents further (undesired) coupling reactions and also has the benefit of being a liquid.
This compound is commercially available. It may also be prepared in a manner similar to other silyl compounds: deprotonation of acetylene with a Grignard reagent, followed by reaction with trimethylsilyl chloride.

Chemical Name	Ethynyltrimethylsilane
Synonyms	ethynyl(trimethyl)silane;(Trimethylsilyl)Acetylene;TriMethylsilylacetylene;
CAS No.	1066-54-2
Molecular Formula	C5H10Si
Molecular Weight	98.21840
PSA	0.00000
LogP	1.49700

BRN number	906752
MDL number	MFCD00008569
EINECS number	213-919-9

Appearance & Physical State	clear colorless liquid
Density	0.69
Boiling Point	53ºC
Melting Point	>0ºC
Flash Point	-34ºC
Refractive Index	1.3873-1.3903
Water Solubility	reacts
Stability	Materials containing similar functional groups can decompose at elevated temperatures. Has not been fully evaluated.
Storage Condition	2-8ºC
Vapor Pressure	4.18 psi ( 20 °C)

Hazard Class	3
Safety Statements	S16-S26-S36
HS Code	29310095
Packing Group	II
WGK Germany	-
RIDADR	UN 1993
Risk Statements	R11; R36/37/38
Hazard Codes	F
Symbol	GHS02, GHS07
Hazard Declaration	H225; H315; H319; H335
Caution Statement	P210; P261; P305 + P351 + P338
Signal Word	Danger