反应详情

To a stirred suspension of CuBr.SMe2 (1.37 g, 2.2 eq, 6.66 mmol) in Et2O (100 mL) under an argon atmosphere at −78° C., was added isopropyllithium (0.7 M in pentane, 17.29 mL, 4 eq, 12.1 mmol) dropwise and the solution allowed to warm to room temperature. The mixture was recooled to −70° C., to which was added a solution of (S)-2-(trityl-amino)-butyraldehyde (1 g, 1 eq, 3.03 mmol) in Et2O (25 mL) dropwise with stirring. The reaction mixture was stirred at this temperature for 1 h, then allowed to warm to −55° C. and stirred at this temperature for 3 h. To the reaction mixture was added a saturated aqueous solution of NH4Cl (100 mL) and allowed to warm to room temperature over 16 h. The reaction mixture was extracted with Et2O (2×200 mL), and the combined organic phase washed with brine (50 mL), dried (MgSO4) and evaporated in vacuo. The residue was purified by silica gel column chromatography, eluted with hexane:ether (100:0→90:10) to afford the title compound as a colourless oil; Yield: 0.36 g (32%). (50% de 3R,4S: 50% de 3S,4S). 1H-NMR (d6-DMSO, 250 MHz): δ0.44 (t, 3H, J=6.79 Hz, —NHCH(CH2CH3)CH(CH(CH3)2)OH), 0.52 & 0.76 (2×d, 6H, J=6.63 Hz, —NHCH(CH2CH3)CH(CH(CH3)2)OH), 0.80-1.15 (m, 2H, —NHCH(CH2CH3)CH(CH(CH3)2)OH), 1.70 (m, 1H, —NHCH(CH2CH3)CH(CH(CH3)2)OH), 2.10 (m, 1H, —NHCH(CH2CH3)CH(CH(CH3)2)OH), 2.76 (m, 1H, —NHCH(CH2CH3)CH(CH(CH3)2)OH), 2.99 (m, 1H, —NHCH(CH2CH3)CH(CH(CH3)2)OH), 4.55 (d, 1H, J=5.84 Hz, —NHCH(CH2CH3)CH(CH(CH3)2)OH), 7.17-7.46 (m, 15H, 3×Ph).

1. customwas recooled to −70° C., to which
2. stirringThe reaction mixture was stirred at this temperature for 1 h
3. temperatureto warm to −55° C.
4. stirringstirred at this temperature for 3 h
5. temperatureto warm to room temperature over 16 h
6. extractionThe reaction mixture was extracted with Et2O (2×200 mL)
7. washthe combined organic phase washed with brine (50 mL)
8. dry with materialdried (MgSO4)
9. customevaporated in vacuo
10. customThe residue was purified by silica gel column chromatography
11. washeluted with hexane:ether (100:0→90:10)