反应详情

To chloro(1,5-cyclooctadien)rhodium(I) dimer (29 mg, 60 μmol) and (R)-(−)-1-[(S)-2-Di-tert.-butyl-phosphino)ferrocenyl]ethyldi-(4-trifluormethylphenyl)phosphine (81 mg, 120 μmol) under an argon atmosphere was added 2,2,2-trifluoroethanol (4 mL) and the solution was stirred for 40 minutes. To tert-butyl 3-amino-3-[5-(benzyloxy)pyridin-3-yl]prop-2-enoate (1.95 g/5.97 mmol) in degassed 2,2,2-trifluoroethanol (10 mL) in a pressure vessel was added the rhodium catalyst solution and the solution was stirred for 22 hours at 50° C. under hydrogen pressure of 10 bar. The addition of an identically prepared rhodium catalyst solution in 2,2,2-trifluoroethanol (4 mL) was repeated and stirring under 10 bar hydrogen pressure at 50° C. was continued for additional 16 hours. The solution was concentrated under reduced pressure and the residue was purified by chromatography on silica gel (ethyl acetate in hexane, 12 to 100% followed by methanol in ethyl acetate 0 to 15%) to yield 1.16 g of enantiomerically enriched tert-butyl (3S)-3-amino-3-[5-(benzyloxy)pyridin-3-yl]propanoate.

1. stirringthe solution was stirred for 22 hours at 50° C. under hydrogen pressure of 10 bar
2. waitwas continued for additional 16 hours
3. concentrationThe solution was concentrated under reduced pressure
4. customthe residue was purified by chromatography on silica gel (ethyl acetate in hexane, 12 to 100% followed by methanol in ethyl acetate 0 to 15%)