反应详情

Methyl (2Z)-2-[(tert-butoxycarbonyl)amino]-4,4-dimethylpent-2-enoate (example 4A, 60 g, 233.2 mmol) is dissolved in ethanol p.a./dioxane 3:1 (1000 ml). An argon protective gas atmosphere is passed through with a needle (˜10 min). The solution is placed in an ultrasonic bath (about 5 min) and (+)-1,2-bis[(2R,5R)-diethylphospholano]benzene(cyclooctadiene)rhodium(I) triflate (600 mg, 1% by weight) is added. The mixture is hydrogenated under a pressure of 3.5 bar of hydrogen and at RT for 3 days. The reaction mixture is filtered through kieselguhr, and the eluate is concentrated. The crude product is chromatographed (silica gel, eluent: cyclohexane/ethyl acetate 4:1). 60 g (99% of theory) of the title compound are obtained.

1. customis passed through with a needle (˜10 min)
2. customThe solution is placed in an ultrasonic bath
3. filtrationThe reaction mixture is filtered through kieselguhr
4. concentrationthe eluate is concentrated
5. customThe crude product is chromatographed (silica gel, eluent: cyclohexane/ethyl acetate 4:1)