反应详情

To a stirred solution of (3R)-3-(trityl-amino)-pentan-2-one (0.87 g, 1 eq, 2.54 mmol) in Et2O (100 mL) under an argon atmosphere at room temperature, was added methylmagnesium iodide (3 M in ether, 2.54 mL, 3 eq, 7.62 mmol) dropwise. The solution was placed in a preheated oil bath at 45° C. and refluxed at this temperature for 16 h. The mixture was recooled to 0° C., H2O (100 mL) added, the solution filtered through Celite, and the Celite washed with more Et2O (50 mL). The combined organic phase was separated, the aqueous phase was extracted with Et2O (2×50 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 light yellow oil. Yield: 0.21 g (23%). 1H-NMR (d6-DMSO, 250 MHz): δ 0.26 (t, J=7.42 Hz, —NHCH(CH2CH3)CH(CH3)OH), 1.00 & 1.25 (2×s, 6H, —NHCH(CH2CH3)C(CH3)2OH), 0.72-1.43 (m, 2H, —NHCH(CH2CH3)C(CH3)2OH), 1.84 (m, 1H, —NHCH(CH2CH3)C(CH3)2OH), 2.90 (m, 1H, —NHCH(CH2CH3)C(CH3)2OH), 4.32 (s, 1H, —NHCH (CH2CH3)C(CH3)2OH), 7.17-7.46 (m, 15H, 3×Ph).

1. customThe solution was placed in a preheated oil bath at 45° C.
2. temperaturerefluxed at this temperature for 16 h
3. customwas recooled to 0° C.
4. filtrationthe solution filtered through Celite
5. washthe Celite washed with more Et2O (50 mL)
6. customThe combined organic phase was separated
7. extractionthe aqueous phase was extracted with Et2O (2×50 mL)
8. washthe combined organic phase washed with brine (50 mL)
9. dry with materialdried (MgSO4)
10. customevaporated in vacuo
11. customThe residue was purified by silica gel column chromatography
12. washeluted with hexane:ether (100:0→90:10)