4071-88-9

clear colorless liquid

bp 157–158 °C; d 0.876 g cm?3.

(silylating agent; source of an ethyl acetate anion equivalent. Ethyl trimethylsilylacetate is reactive to nucleophiles and readily undergoes desilylation reactions with acid or alkali, ethanol, and bromine .

Ethyl trimethylsilylacetate is used in the synthesis of ethyl-2,2-dibromo-2-(trimethylsilyl)acetate. It was also used to silylate the enolizable aldehydes and ketones.

Available by a Reformatsky reaction from ethyl bromoacetate, and by reaction of trimethylsilylmethylmagnesium chloride with ethyl chloroformate. An alternative approach requires the treatment of ethyl acetate with triphenylmethylsodium followed by chlorotrimethylsilane The use of a nitrogen base with ethyl acetate in THF followed by reaction with chlorotrimethylsilane results in a mixture of C- and O-silylation. The use of HMPA as additive in the reaction medium increases the amount of O-silylation to 90%. Similar methods can be used to prepare analogs.

Purify it by distilling ca 10g of reagent through a 15cm, Vigreux column (p 11) and then redistilling it through a 21cm glass helices-packed column [Hauze & Hauser J Am Chem Soc 75 994 1953]. Alternatively, dissolve it in Et2O, wash with H2O, dilute Na2CO3, dry over Na2CO3, evaporate Et2O, and distil it through a column of 15 theoretical plates. [Gold et al. J Am Chem Soc 70 2874 1948, Beilstein 4 IV 3974.]