Hydrochloric Acid → (R)-3-(tert-butyl-dimethyl-silanyloxy)-2-hydroxy-propionic acid methyl ester

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To a solution of (R)-2,2-dimethyl-[1,3]dioxolane-4-carboxylic acid methyl ester (2.5 g, 15.6 mmol) in methanol (15 mL) was added HCl in dioxane (4N, 5 mL, 20 mmol) and the reaction mixture was stirred at RT for 5 h. The reaction mixture was concentrated in vacuo, the resultant residue dissolved in THF (20 mL) and imidazole (1.28 g, 18.7 mmol) and tert-butylchlorodimethylsilane (2.47 g, 16.4 mmol) added. The reaction mixture was stirred at RT for 16 h. The reaction mixture was diluted with ethyl acetate (10 mL) and the mixture washed with water extracting with ethyl acetate (3×10 mL). The combined organic extracts were washed with brine, dried (MgSO4) and concentrated in vacuo. The residue was subjected to flash chromatography (SiO2 gradient 0-50% EtOAc in cyclohexane) to yield (R)-3-(tert-butyl-dimethyl-silanyloxy)-2-hydroxy-propionic acid methyl ester as a colorless oil (2.29 g, 63%). 1H NMR (400 MHz, CDCl3) 4.26-4.20 (1H, m), 3.93 (1H, dd, J=10.1, 3.4 Hz), 3.86 (1H, dd, J=10.1, 2.8 Hz), 3.79 (3H, s), 3.01 (1H, d, J=7.8 Hz), 0.88 (9H, s), 0.06 (3H, s), 0.04 (3H, s)

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