[CH2:1]([O:8][CH2:9][C@@H:10]([C:19](O)=[O:20])[NH:11][C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C(N(CC)CC)C.ClC(OCC)=O>O1CCCC1>[CH2:1]([O:8][CH2:9][C@H:10]([NH:11][C:12](=[O:13])[O:14][C:15]([CH3:17])([CH3:16])[CH3:18])[CH2:19][OH:20])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1O-benzyl-N-(t-butoxycarbonyl)-L-serine (2 g) was dissolved in tetrahydrofuran (20 ml), triethylamine (1.22 ml) was added, and ethyl chloroformate (713 μl) was further added dropwise at 0° C. After stirring the reaction mixture at room temperature for 30 min, the reaction mixture was filtered, and one piece of ice was added to the filtrate. Sodium borohydride (515 mg) was further added, and the mixture was stirred at room temperature for 6 hrs. The reaction mixture was diluted with ethyl acetate and, after washing with water, the organic layer was dried over anhydrous sodium sulfate. The solvent was evaporated and the obtained crude product was purified by silica gel chromatography (ethyl acetate-hexane) to give t-butyl (1R)-2-(benzyloxy)-1-(hydroxymethyl)ethylcarbamate (1.7 g)
読み込み中…