Trimethylsilyl bromide is an organosilicon compound with formula . It is a colorless liquid.
Trimethylsilyl bromide can be synthesized by halogen exchange between trimethylsilyl chloride and either magnesium bromide in diethyl ether or sodium bromide in acetonitrile.
It can also be synthesized by reaction between hexamethyldisilane and bromine in benzene, with no byproducts.
Trimethylsilyl bromide can be prepared in a laboratory scale from trimethylsilyl-4-bromo-2-alkenoates in almost quantitative yield.
It can also be synthesized by reaction of hexamethyldisiloxane and aluminium bromide.
Trimethylsilyl bromide is a colorless liquid very sensitive to light, air and moisture. It fumes in air upon hydrolysis, producing hydrobromic acid. Upon prolonged storage it becomes yellow to orange because of releasing of bromine. Reacts violently with water.
Trimethylsilyl bromide is used as a mild and selective reagent for cleavage of lactones, epoxides, acetals, phosphonate esters and certain ethers. It is effective reagent for formation of silyl enol ethers. Trimethylsilyl bromide is as a mild, stereoselective anomeric brominating agent. Stereoselective bromination of anomeric glycosyl acetates is achieved with trimethylsilyl bromide under mild conditions and in the presence of various protecting groups commonly employed in carbohydrate chemistry.