Реакция #10259

Уравнение реакции

ester

(3R,5R)-3,5-Bis[(tert-butyldimethylsilyl)oxy]-1-hydroxy-4-methylenecyclohexanecarboxylic Acid Methyl Ester

THF

→

[(3R,5R)-3,5-Bis[(tert-butyldimethylsilyl)oxy]-1-hydroxy-4-methylenecyclohexyl]methanol

Условия реакции

Обработка

1. 1
   ДругоеThe cooling bath was removed after 1 h
2. 2
   Экстракцияthe mixture was extracted with ethyl acetate and ether
3. 3
   Сушкаdried (MgSO4)
4. 4
   Другоеevaporated
5. 5
   ДругоеFlash chromatography of the residue with hexane/ethyl acetate (9:1) afforded unreacted substrate (12 mg)

Методика

(i) To a stirred solution of the ester 3 (90 mg, 0.21 mmol) in anhydrous THF (8 mL) lithium aluminum hydride (60 mg, 1.6 mmol) was added at 0° C. under argon. The cooling bath was removed after 1 h and the stirring was continued at 6° C. for 12 h and at room temperature for 6 h. The excess of the reagent was decomposed with saturated aq. Na2SO4, and the mixture was extracted with ethyl acetate and ether, dried (MgSO4) and evaporated. Flash chromatography of the residue with hexane/ethyl acetate (9:1) afforded unreacted substrate (12 mg) and a pure, crystalline diol 4 (35 mg, 48% based on recovered ester 3): 1H NMR (CDCl3+D2O) δ 0.079, 0.091, 0.100, and 0.121 (each 3H, each s, 4×SiCH3), 0.895 and 0.927 (9H and 9H, each s, 2×Si-t-Bu), 1.339 (1H, t, J˜12 Hz), 1.510 (1H, dd, J=14.3, 2.7 Hz), 2.10 (2H, m), 3.29 and 3.40 (1H and 1H, each d, J=11.0 Hz), 4.66 (1H, t, J˜2.8 Hz), 4.78 (1H, m), 4.92 (1H, t, J=1.7 Hz), 5.13 (1H, t, J=2.0 Hz), MS m/z (relative intensity) no M+, 345 (M+-t-Bu, 8), 327 (M+-t-Bu-H2O, 22), 213 (28), 195 (11), 73 (100).

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