反应详情

A solution of 48 (925 mg, 2.38 mmol) in THF (20 ml) was cooled to −50° C., and t-BuLi (1.7 M in pentane, 3.08 ml, 5.24 mmol) was dropwise added to the solution while maintaining the temperature below −40° C. After completion of the addition, the mixture was stirred at this temperature, and DMF (0.12 ml) in THF (5 ml) was added. The mixture was warmed slowly to room temperature. Aqueous solution of saturated ammonium chloride (50 ml) was added, and the mixture was extracted with ethyl acetate (50 ml). The organic layer was washed with saturated brine (50 ml), and after dryness, the solvent was removed in vacuo. The residue was purified by column chromatography to yield 669 mg (83.1%) of 49 as colorless oil. 1H NMR (CDCl3) δ: 1.47 (9H, s, tBu), 1.48 (6H, s, 2×CH3), 3.29, 3.66 (each 3H, s, CH3), 3.84 (2H, s, CH2), 4.60, 4.95 (each 2H, s, CH2), 7.81 (1H, d, J=2.2 Hz, Ar—H), 7.84 (1H, d, J=2.2 Hz, Ar—H), 9.92 (1H, s, CHO).

1. temperaturewhile maintaining the temperature below −40° C
2. additionAfter completion of the addition
3. additionwas added
4. extractionthe mixture was extracted with ethyl acetate (50 ml)
5. washThe organic layer was washed with saturated brine (50 ml)
6. customafter dryness, the solvent was removed in vacuo
7. customThe residue was purified by column chromatography