Dimethylformamide → (R)-4-ethyl-1-[4-(trifluoromethyl)phenyl]-2-azetidinone

Participants

Reaction Steps

158.7 mg of sodium hydride (60 wt %; 3.97 mmol) was suspended in a mixed solution of dichloromethane (2.7 mL) and dimethylformamide (10.8 mL) and to the solution, a mixed solution of 1,346.2 mg (3.97 mmol) of (S)-N-[4-(trifluoromethyl)phenyl]-3-methanesulfonyloxypentanoic acid amide produced in Example 3, dichloromethane (2.7 mL) and dimethylformamide (10.8 mL) was added dropwise at room temperature for 15 minutes. After stirring at room temperature for further 1 hour, water (25 mL) was added and extraction was carried out with ethyl acetate. The organic layer was washed with saturated brine and the product was dried with anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure to obtain (R)-4-ethyl-1-[4-(trifluoromethyl)phenyl]-2-azetidinone as a brown solid (996.3 mg, crude yield: 87%). The optical purity of the product was determined by HPLC analysis (column; Daicel Chiral Pack AD-H 4.6×250 mm: eluent; hexane/isopropanol=95/5: flow rate; 1.0 mL/min: column temperature; 30° C.: detector; UV 210 nm: retention time; (S) antipode=7.6 minutes, (R) antipode=8.8 minutes) to be 83.0% ee. 1H-NMR (CDCl3, 400 MHz/ppm): δ 0.99 (3H, t), 1.63-1.73 (1H, m), 2.11-2.21 (1H, m), 2.79 (1H, dd), 3.23 (1H, dd), 4.07-4.13 (1H, m), 7.47 (2H, d), 7.58 (2H, d)

Provenance & Evidence