反应详情

To a solution of (R)-4-benzyl-3-((2R,3R,4S)-4-(benzyloxy)-3-((2-methylallyl)oxy)-2-(4-methylbenzyl)pentanoyl)oxazolidin-2-one (9.36 g, 17.3 mmol) in aqueous THF (4:1 THF/H2O; 86 mL) was added lithium borohydride (34.6 mL of 2.0 M in THF, 69.1 mmol) dropwise at −5° C., and the resulting yellow solution was vigorously stirred. After 1 h the yellow color (dba) had dissipated and the reaction was allowed to slowly warm to room temperature. The reaction was stirred for an additional 5 h and then poured into ice cold saturated aqueous NH4Cl (250 mL). The phases were separated and the aqueous was extracted with CH2Cl2 (3×100 mL). The combined organics phases were dried over Na2SO4, filtered, and concentrated to a light yellow oil (10.11 g), which was purified by both reverse phase (RP; Cl 8, 0→100% CH3CN/H2O) and normal phase (NP: SiO2, 0→30% EtOAc/CH2Cl2) to give (2S,3R,4S)-4-(benzyloxy)-3-((2-methylallyl)oxy)-2-(4-methylbenzyl)pentan-1-ol (4.04 g, 48% from Ex. 2, Step 1) as a colorless liquid: 1H NMR (400 MHz, CDCl3) δ 7.32 (m, 5H), 7.06 (m, 4H), 4.98 (m, 1H), 4.87 (m, 1H), 4.64 (d, J=11.6 Hz, 1H), 4.44 (d, J=11.6 Hz, 1H), 4.08 (d, J=11.6 Hz, 1H), 3.97 (d, J=12.1 Hz, 1H), 3.78 (p, J=6.2 Hz, 1H), 3.56 (m, 3H), 2.88 (dd, J=13.8, 4.7 Hz, 1H), 2.53 (dd, J=13.8, 10.1 Hz, 1H), 2.30 (s, 3H), 2.18 (ddd, J=14.4, 7.7, 4.3 Hz, 1H), 2.01 (dd, J=6.2, 4.9 Hz, 1H), 1.76 (s, 3H), 1.33 (d, J=6.2 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 142.41, 138.50, 137.87, 135.28, 129.00, 128.37, 127.75, 127.57, 111.86, 83.08, 75.92, 75.73, 70.79, 62.83, 44.60, 32.63, 21.05, 20.99, 19.84, 16.33; ESIMS m/z 391 ([M+Na]+).

1. stirringThe reaction was stirred for an additional 5 h
2. customThe phases were separated
3. extractionthe aqueous was extracted with CH2Cl2 (3×100 mL)
4. dry with materialThe combined organics phases were dried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated to a light yellow oil (10.11 g), which
7. customwas purified by both reverse phase (RP; Cl 8, 0→100% CH3CN/H2O) and normal phase (NP: SiO2, 0→30% EtOAc/CH2Cl2)