反应详情

To tetrahydrofuran (5 ml) were successively dropwise added a 1.0M sodium hexamethyldisilazide--tetrahydrofuran solution (0.910 ml, 0.910 mmol) and methyl acetate (72.0 μl) at -78° C. The mixture was stirred for 30 minutes, and a tetrahydrofuran solution of (2S,4R)-N-tert-butoxycarbonyl-4-tert-butyldimethylsiloxyprolinal (200 mg, 0.607 mmol) was added thereto at the same temperature. This solution was stirred for 30 minutes. Saturated aqueous ammonium chloride was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, and dried over anhydrous magnesium sulfate. The solvent was removed in vacuo. The residue was purified by silica gel column chromatography (heptane-ethyl acetate=3:1) to give the title compound [232 mg, yield: 94.7%; (R)-isomer (polar compound):(S)-isomer (less polar compound)=6.27:1].

1. customat -78° C
2. stirringThis solution was stirred for 30 minutes
3. extractionthe mixture was extracted with ethyl acetate
4. washThe organic layer was washed with saturated aqueous sodium chloride
5. dry with materialdried over anhydrous magnesium sulfate
6. customThe solvent was removed in vacuo
7. customThe residue was purified by silica gel column chromatography (heptane-ethyl acetate=3:1)