Reaction equation
S(C)C.[CH3:4][Li].[C:6]([NH:25][C@H:26]([CH2:29][CH3:30])[CH:27]=[O:28])([C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1)([C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1)[C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1.[NH4+].[Cl-]>CCOCC.CCCCCC>[C:6]([NH:25][C@H:26]([CH2:29][CH3:30])[C@@H:27]([OH:28])[CH3:4])([C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1)([C:19]1[CH:20]=[CH:21][CH:22]=[CH:23][CH:24]=1)[C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1Participants
Procedure
To a stirred suspension of CuBr.SMe2 (2.74 g, 2.2 eq, 13.33 mmol) in Et2O (100 mL) under an argon atmosphere at −70° C., was added methyllithium (1.6 M in Et2O, 16.6 mL, 4.4 eq, 26.56 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 (R)-2-(trityl-amino)-butyraldehyde (2 g, 1 eq, 6.05 mmol) in Et2O (25 mL) dropwise with stirring. The reaction mixture was stirred at this temperature for 2 h, when TLC (hexane:ether; 80:20) indicated that the reaction had gone to completion. 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 ether (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 (80:20) to afford the title compound as a light yellow oil. Yield: 1.91 g (91%). (80% de 2S,3R: 20% de 2R,3R). 1H-NMR (d6-DMSO, 250 MHz): δ 0.47 & 0.55 (2×t, J=7.43 & 7.27 Hz, —NHCH(CH2CH3)CH(CH3)OH), 0.99-1.12 (m, 5H, —NHCH(CH2CH3)CH(CH3)OH), 2.03 (m, 1H, —NHCH(CH2CH3)CH(CH3)OH), 3.32-3.51 (m, 1H, —NHCH(CH2CH3)CH(CH3)OH), 4.40 (d, 1H, J=3.79 Hz, —NHCH(CH2CH3)CH(CH3)OH), 7.14-7.51 (m, 15H, 3×Ph).
Workup
- customwas recooled to −70° C., to which
- stirringThe reaction mixture was stirred at this temperature for 2 h
- temperatureto warm to room temperature over 16 h
- extractionThe reaction mixture was extracted with ether (2×200 mL)
- washthe combined organic phase washed with brine (50 mL)
- dry with materialdried (MgSO4)
- customevaporated in vacuo
- customThe residue was purified by silica gel column chromatography
- washeluted with hexane:ether (80:20)
Sources & evidence
- ORD record
- ord-94525e022f56486bac757d9a780b898c
- Source dataset
- uspto-grants-2009_09
- Patent number
- US07582642B2
Linked notes
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