Ethyl trimethylsilylacetate

Uses(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.

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

General DescriptionReaction of ethyl trimethylsilylacetate (ETSA) with dilute hydrochloric acid, dilute alkali, anhydrous HCl, anhydrous bromine and absolute ethanol has been reported. ETSA undergoes condensation with aromatic aldehydes in the presence of base catalyst to yield β-trimethylsiloxycarboxylates. Lithium ETSA reacts with ketones to yield α,β-unsaturated esters.

Preparationethyl trimethylsilylacetate synthesis: 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.