Imidazole → Butanoic acid, 3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-, ethyl ester, (3R)-

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Reaction Steps

tert-Butylchlorodimethylsilane (547 g, 3.63 mol) was added to a stirred solution of (R)-ethyl 3-hydroxybutanoate (400 g, 3.03 mol) in DCM (800 mL) under nitrogen at 0° C. Imidazole (412 g, 6.05 mol) was added portion wise over 20 min to the reaction mixture during which time the mixture became a thick white slurry. Additional DCM (175 mL) was added and the mixture was allowed to warm to room temperature and stirred for 16 h. The white solid was removed by filtration, rinsed with DCM (500 mL), partitioned between water (1 L) and DCM (500 mL), and the aqueous layer was further extracted with additional DCM (500 mL). The filtrate was combined with the organic layers and washed with water (500 mL) and brine, dried over MgSO4 and filtered. The product was concentrated and dried under high vacuum to yield (R)-ethyl 3-(tert-butyldimethylsilyloxy)butanoate (777.5 g), containing unidentified impurities. The analytical data of the crude product complied with data reported in the literature. The material was used without additional purification.

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