反应详情

526 mg (2.0 mmol) of 1-phenyl-1-t-butoxycarbonylamino-2-hydroxybut-3-ene, syn form, 20 cm3 of dry methylene chloride, 1.9 cm3 (20.0 mmol) of distilled ethyl vinyl ether and 50.2 mg (0.2 mmol) of pyridinium p-toluenesulphonate (PPTS) are introduced successively into a 50 cm3 single-necked flask placed under an argon atmosphere and equipped with a magnetic stirring system. The resulting homogeneous reaction mixture is left to react for 4.5 hours at a temperature of about 20° C. When the reaction is complete, 1 drop of pyridine is added and the reaction mixture is then diluted in 60 cm3 of methylene chloride. The organic phase is washed twice with water and twice with a saturated aqueous solution of sodium chloride and then dried over anhydrous sodium sulphate. After filtration, the solvents are driven off under reduced pressure on a rotary evaporator. The residue obtained is purified by passage over a column of silica gel using a hexane/ether mixture (8/2 by volume) as the eluent. 580 mg (1.73 mmol) of 1-phenyl-1-t-butoxycarbonylamino-2-(1-ethoxyethoxy)but-3-ene are obtained with a yield of 87% in the form of two epimers in a ratio of 55/45, said product having the following characteristics:

1. customequipped with a magnetic stirring system
2. waitThe resulting homogeneous reaction mixture is left
3. customto react for 4.5 hours at a temperature of about 20° C
4. washThe organic phase is washed twice with water and twice with a saturated aqueous solution of sodium chloride
5. dry with materialdried over anhydrous sodium sulphate
6. filtrationAfter filtration
7. customthe solvents are driven off under reduced pressure on a rotary evaporator
8. customThe residue obtained
9. customis purified by passage over a column of silica gel using a hexane/ether mixture (8/2 by volume) as the eluent