反应详情

To a solution of dry diisopropylamine (5.0 mL, 35.7 mM) in dry tetrahydrofuran (150 mL) at -78° C., was added dropwise a 2.3N solution of n-butyllithium in hexane (15.5 mL, 35.7 mM). After the reaction solution was stirred for 15 minutes, a solution of 2,2,5-trimethyl-3(2H)-furanone (30 g, 23.8 mM) in tetrahydrofuran (25 mL) was added dropwise. Hexamethylphosphoramide (6.4 mL, 34.7 mM) was then added dropwise after 30 minutes. Finally, p-methylthiobenzaldehyde (43 g, 28.5 mM) in tetrahydrofuran (25 mL) was added in one portion. The reaction solution was stirred 15 minutes when trifluoroacetic anhydride (10.5 mL, 75 mM) was added in one portion. Again, the reaction solution was stirred 15 minutes when triethylamine (5.9 mL, 48 mM) was added and was allowed to warm to room temperature. Then the reaction mixture was partitioned between saturated aqueous sodium chloride (50 mL) and diethyl ether (50 mL). The organic layer was separated and washed with saturated aqueous sodium bicarbonate (2×25 mL) and saturated aqueous sodium chloride (25 mL). The organic layer was dried over magnesium sulfate, filtered and concentrated under reduced pressure to give an amber liquid. The crude product was purified by chromatography (silica gel, pet. ether-ethyl acetate) to afford yellow crystals (3.0 g, 48% yield), m.p. 98°-99.5° C.

1. additionwas added in one portion
2. additionwas added
3. customThen the reaction mixture was partitioned between saturated aqueous sodium chloride (50 mL) and diethyl ether (50 mL)
4. customThe organic layer was separated
5. washwashed with saturated aqueous sodium bicarbonate (2×25 mL) and saturated aqueous sodium chloride (25 mL)
6. dry with materialThe organic layer was dried over magnesium sulfate
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure
9. customto give an amber liquid
10. customThe crude product was purified by chromatography (silica gel, pet. ether-ethyl acetate)