Acetoacetic Acid → (1R,2S)-2-(3-fluorophenyl)-2-(hydroxymethyl)cyclopropyl]-methyl acetate

Participants

Reaction Conditions

Reaction Steps

((1S,2R)-1-(3-fluorophenyl)cyclopropane-1,2-diyl)dimethanol (5, 7.89 g, 0.040 mol, 1.0 equiv.) was dissolved in 2-methyl-THF (23.68 mL), under nitrogen. Lipase acrylic resin (Candida Antarctica Lipase B, Sigma-Aldrich, Saint Louis, Mo.) (417.5 mg, 5.0 wt %) was added. Vinyl acetate (5.56 mL, 0.060 mol, 1.5 equiv.) was added, and the reaction mixture was stirred at 20-25° C. while monitoring the ratio of mono-acetate and diacetate (8-9 h) by HPLC and TLC (EtOAc/Heptane=1/1). Upon reaction completion, the lipase was removed by filtration and rinsed with 2-methyl-THF (71.04 mL). The filtrate and the rinse were combined and washed with 15% NaCl aq. solution (27.63 mL) followed by sat. aqueous NaCl solution (23.68 mL). The solvent was removed under reduced pressure then azeotroped with 2-methyl-THF until KF is less than 1500 ppm to afford the title compound, ((1R,2S)-2-(3-fluorophenyl)-2-(hydroxymethyl)cyclopropyl)methyl acetate, 6 (9.59 g).

Provenance & Evidence