Trimethylsilylacetylene
Trimethylsilylacetylene is the acetylene HC2Si3. It is a colorless liquid. Called "tms acetylene", it is used as a source of "HC2−". The trimethylsilyl group protected can be desilyated with TBAF. Using this protected alkyne, as opposed to acetylene itself, prevents further coupling reactions and also has the benefit of being a liquid. A less expensive alternative reagent is 2-methylbut-3-yn-2-ol, which after alkynylation is deprotected with base.
Trimethylsilylacetylene 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.
