Diethyl cyclopropane-1,1-dicarboxylate → HCID 68956592, compound

Participants

Reaction Steps

n-Butyllithium (2.5 M in hexane, 983.8 mL) is added to a solution of 1-[4-(tert-butyl-dimethyl-silanyloxy)-phenyl]-2-phenyl-ethanone oxime, which may be produced as in Example 136 (400 g) in THF (4 L) at 0° C. and the reaction solution is stirred for one hour at this temperature. Diethyl 1,1-cyclopropanedicarboxylate (227 mL) is added to the reaction solution, stirred for one hour at 0° C. and then the reaction is quenched with saturated ammonium chloride, diluted with ethyl acetate, washed with water, brine, dried over anhydrous sodium sulfate, filtered, and the filtrate evaporated under reduced pressure. The crude product is purified by column chromatography with 5-10% ethyl acetate in hexane to give a light yellow solid, which is triturated with pentane and filtered to give 1-{3-[4-(tert-butyl-dimethyl-silanyloxy)-phenyl]-5-hydroxy-4-phenyl-4,5-dihydro-isoxazol-5-yl}-cyclopropanecarboxylic acid ethyl ester (230.8 g.)

Provenance & Evidence