反应详情

To a solution of rac-methyl-N-(diphenylmethylene)phenylalaninate (0.50 g, 1.4 mmol) (for synthesis see: O'Donnell et al, J. Org. Chem. 1982, 47, 2663-2666) in 6 mL DMF at 0° C. was added 95% NaH (0.14 g, 5.6 mmol). After 30 min, butyl iodide was added via syringe to the dark red reaction. After 30 min at 0° C., the reaction was warmed to rt for 14 h, then quenched by the addition of water. The aqueous layer was extracted with EtOAc (2×), the combined organics were washed with brine, dried over Na2SO4, filtered and concentrated. Purification by silica gel chromatography (40 g silica, 0->8% EtOAc/hexanes) afforded methyl-α-butyl-N-(diphenylmethylene)phenylalaninate as a viscous oil. 1H NMR (400 MHz, CDCl3) δ 7.57 (m, 2H), 7.37-7.17 (m, 11H), 7.05-7.03 (m, 2H), 3.36 (d, J=11.5 Hz, 1H), 3.32 (d, J=11.5 Hz, 1H), 3.24 (s, 3H), 1.78 (m, 2H), 1.41 (m, 2H), 1.29-1.24 (m, 2H), 0.89 (t, J=7.2 Hz, 3H). LC/MS M+H=400.

1. waitAfter 30 min at 0° C.
2. customquenched by the addition of water
3. extractionThe aqueous layer was extracted with EtOAc (2×)
4. washthe combined organics were washed with brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. customPurification by silica gel chromatography (40 g silica, 0->8% EtOAc/hexanes)