反应详情

To a solution of diisopropylamine (3.08 mL, 22 mmol) in dry THF (30 mL) was added dropwise 1.6M n-butyllithium (13.2 mL, 21 mmol) at -78° C. and the resulting solution was stirred for 30 min. To this LDA solution was added dropwise by cannula a solution of cyclohexanone (2.06 g, 21 mmol) in THF (30 mL) at -78° C. and the cooling bath was removed. After being stirred for 1 h, this solution was recooled to -78° C. A solution of phenyl vinyl sulfoxide (Aldrich, 3.34 g, 22 mmol) in THF (20 mL) was added, and the mixture was 4 allowed to reach rt over 5 h. Aqueous NaOH solution (1.0 N, 100 ml) was added, and the resulting mixture was stirred at rt for 1 h. The mixture was extracted with ethyl acetate, dried over anhydrous magnesium sulfate, and concentrated to give the crude product. Purification by silica gel chromatography (1:3=hexane:ethyl acetate) afforded 4.30 g (82%) of the desired keto phenyl sulfoxide 110 as inseparable mixture of the two diasteromers. 1H NMR (400 MHz, CDCl3); δ 1.30-2.55 (m, 11H), 2.72 (ddd,1H, J=5.2, 10.4, 12.8 Hz), 2.89-3.02 (m, 2H), 7.49-7.62 (m, 5H).

1. customthe cooling bath was removed
2. stirringAfter being stirred for 1 h
3. customwas recooled to -78° C
4. waitto reach rt over 5 h
5. stirringthe resulting mixture was stirred at rt for 1 h
6. extractionThe mixture was extracted with ethyl acetate
7. dry with materialdried over anhydrous magnesium sulfate
8. concentrationconcentrated
9. customto give the crude product
10. customPurification by silica gel chromatography (1:3=hexane:ethyl acetate)