[OH:1][C@H:2]([CH3:9])[CH2:3][C:4]([O:6][CH2:7][CH3:8])=[O:5].N1C=CN=C1.[CH:15]([Si:18](Cl)([CH:22]([CH3:24])[CH3:23])[CH:19]([CH3:21])[CH3:20])([CH3:17])[CH3:16].O>CN(C)C=O>[CH:15]([Si:18]([CH:22]([CH3:24])[CH3:23])([CH:19]([CH3:21])[CH3:20])[O:1][C@H:2]([CH3:9])[CH2:3][C:4]([O:6][CH2:7][CH3:8])=[O:5])([CH3:17])[CH3:16]0.077 mol (10.0 g) of ethyl(R)-3-hydroxybutyrate is dissolved in 90 ml of dimethylformamide and 0.151 mol (10.3 g) of imidazole is added. The mixture is cooled to 0° C. under protective gas in an ice bath and 0.083 mol (16.05 g) of triisopropylsilyl chloride is added dropwise over 5 min. The mixture is stirred at room temperature for a further 5 hours, hydrolyzed with water, the product is extracted with tert-butyl methyl ether, and the organic phase is dried using Na2SO4 and concentrated under reduced pressure on a rotary evaporator.
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