反应详情

温度

-60 °C

n-Butyllithium (2.5 M, 15.0 mL, 36.0 mmol) is added drop wise to a solution of 2-ethylpyridine (4.1 mL, 36.0 mmol) in THF (56 mL) at −40° C. The resulting dark red solution is kept at −30° C. to −20° C. for 1 hour and then cooled to −60° C. A solution of benzaldehyde (3.7 mL, 36.0 mmol) in THF (10 mL) is added drop wise. The reaction mixture is allowed to warm up to 0° C. for 1 hour and then quenched with aqueous NH4Cl solution. The mixture is separated and the aqueous phase is extracted with ethyl acetate (2×50 mL). The extracts are combined, dried, concentrated and purified by column chromatography (hexane/ethyl acetate 10:1 to 1:1) to give 2 (7.0 g, 91%) as a yellow oil. This mixture contained two diastereoisomers (3:1). 1H NMR (300 MHz, CDCl3) for the major isomer: δ 1.14 (d, J=7.2 Hz, 3H), 2.98 (q, J=6.9 Hz, 1H), 4.70-4.75 (m, 1H), 5.13-5.16 (m, 1H), 6.80-7.39 (m, 8H), 8.34 (d, J=4.8 Hz, 1H).

1. temperatureto warm up to 0° C. for 1 hour
2. customquenched with aqueous NH4Cl solution
3. customThe mixture is separated
4. extractionthe aqueous phase is extracted with ethyl acetate (2×50 mL)
5. customdried
6. concentrationconcentrated
7. custompurified by column chromatography (hexane/ethyl acetate 10:1 to 1:1)