反应详情

In a dry flask under nitrogen, (S)-oxazaborolidine (4.81 mmol) was dissolved in dry CH2Cl2 (12 mL). This solution was maintained between −20° C. and −25° C. as a solution of tert-butyl (3-acetyl)benzoate (4.20 mmol) in dry CH2Cl2 (12 mL) was added dropwise over 20 minutes. The reaction mixture was then allowed to warm to room temperature for 45 minutes. This mixture was then cooled to −78° C. and methanol (20 mL) added dropwise. The mixture was allowed to warm to room temperature. Solvent was removed under reduced pressure then the residue dissolved in methanol and concentrated under reduced pressure twice more. The dried residue was purified by silica gel chromatography in 10-30% ethyl acetate/hexanes to yield 865 mg of the title compound. 1H NMR (500 MHz, CDCl3): δ 8.00 (m, 1H); 7.92 (m, 1H); 7.58 (d, J=7.5 Hz, 1H); 7.42 (t, J=7.7 Hz, 1H); 4.98 (m, 1H); 1.62 (s, 9H); 1.54 (d, J=6.4 Hz, 3H).

1. additionwas added dropwise over 20 minutes
2. temperatureThis mixture was then cooled to −78° C.
3. temperatureto warm to room temperature
4. customSolvent was removed under reduced pressure
5. dissolutionthe residue dissolved in methanol
6. concentrationconcentrated under reduced pressure twice more
7. customThe dried residue was purified by silica gel chromatography in 10-30% ethyl acetate/hexanes