Binap, (A+-)- → (S)-1-[2-(tert-Butoxycarbonyl)-3-(2-methoxyethoxy)propyl]-1-cyclopentanecarboxylic acid cyclohexylamine salt

Beteiligte Stoffe

Reaktionsschritte

Chloro(1,5-cyclooctadiene)rhodium(I)dimer (15.2 mg, 0.03 mmole) and (S)-(-)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (42.2 mg, 0.06 mmole) were charged to a 50 mL three necked flask equiped with gas inlet and outlet lines and the third neck sealed with a rubber septum. The system was flushed with nitrogen, methanol (10 mL) was added and the mixture purged with nitrogen for 30 minutes. The reaction was hydrogenated at atmospheric hydrogen pressure and room temperature for 1 hour. At this point a solution of (E)-1-[2-(tert-butoxycarbonyl)-3-(2-methoxyethoxy)prop-1-enyl]-1-cyclopentanecarboxylic acid cyclohexylamine salt (0.5 g, 1.17 mmol) in methanol (10 mL) was added and the mixture hydrogenated at atmospheric pressure and room temperature for 5 days. The reaction mixture was purged with nitrogen and concentrated under reduced pressure to give a brown solid (Ratio S:R 89:11). The crude product was recrystallised from ethyl acetate (3.5 ml) and hexane (3.5 ml) to give the title compound (0.37 g, 74%). (Ratio S:R 92:8), Rf =0.29 (ethyl acetate/hexane, 1:1+1% acetic acid).

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