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). Argon is passed through for about 10 min using a cannula. The solution is placed into an ultrasound 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 3.5 bar hydrogen pressure 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 for about 10 min
2. customThe solution is placed into an ultrasound 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)