Solketal → 4-(2,2-Dimethyl-[1,3]dioxolan-4-ylmethoxy)-3-oxo-butyric acid ethyl ester

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Reaction Steps

A solution of 2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane (13.2 g) in tetrahydrofuran (50 ml) was added dropwise to a stirred suspension of sodium hydride (8.0 g, 60% dispersion in oil) in tetrahydrofuran (150 ml) and the mixture was then treated dropwise with a solution of ethyl 4-chloroacetoacetate (16.5 g) in tetrahydrofuran (50 ml). The mixture was stirred at room temperature overnight and evaporated. The residue was quenched with 10% aqueous acetic acid and extracted twice into dichloromethane. The combined dichloromethane extracts were washed with saturated brine, dried over MgSO4 and evaporated. The residue was purified by chromatography on SiO2 (100 g) using toluene plus 0-20% ethyl acetate as the eluant. Appropriate fractions were combined and evaporated to give the title compound (5.6 g) as an oil. This compound was used in Preparations 3 and 4 without further purification.

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