C([O:3][C:4]([C:6]1([NH:11][C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[CH2:8][CH:7]1[CH:9]=[CH2:10])=O)C.[BH4-].[Li+].CCCCCC.C(OCC)(=O)C.S(=O)(=O)(O)O>C1COCC1.[NH4+].[NH4+].[O-][Mo]([O-])(=O)=O.S([O-])([O-])(=O)=O.[Ce+3].S([O-])([O-])(=O)=O.S([O-])([O-])(=O)=O.[Ce+3]>[C:15]([O:14][C:12](=[O:13])[NH:11][C:6]1([CH2:4][OH:3])[CH2:8][CH:7]1[CH:9]=[CH2:10])([CH3:18])([CH3:16])[CH3:17]
To a solution of 1-tert-butoxycarbonylamino-2-vinyl-cyclopropanecarboxylic acid ethyl ester (0.51 g, 2.0 mmol) in THF (10 ml) at 0° C. was added a 2M solution of lithiumborohydride (4 ml, 8 mmol). The reaction mixture was monitored by TLC (7:3 hexane-ethyl acetate, stained using ammoniummolybdate-cerium sulfate in aq. 10% sulfuric acid) and after stirring overnight at rt, the reaction was carefully quenched using aq. 10% citric acid (25 ml, dropwise addition at 0° C.). The obtained mixture was washed with dichloromethane (3×10 ml), and the combined organic layers were dried (Na2SO4), filtered and concentrated. Flash chromatography of the residue using 1:1 hexane-ethyl acetate as eluent, followed by concentration of the appropriate fractions and drying the residue in vacuum overnight, gave the product as a colourless syrup (0.407 g, 1.91 mmol, 96%).
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