反应详情

N-tert-butoxycarbonyl-piperazine (1.86 g, 10 mmol, Lancaster), N-Fmoc-4-oxo-piperidine (3.21 g, 10 mmol, Aldrich) and titanium(IV) isopropoxide (3.72 mL, Aldrich) were combined, and the mixture was stirred at room temperature for 1 h. Then ethyl alcohol (10 mL) was added followed by sodium cyanoborohydride (0.47 g, 7.48 mmol, Aldrich), and the mixture was stirred overnight. Water (2 mL) was added and the mixture was filtered. The solid was washed with ethyl alcohol and the filtrate was combined. The solvent was removed under reduced pressure and the residue was purified by flash chromatography (ISCO machine, silica gel, eluting with 20% ethyl acetate in hexane for a period of 30 min) to give 4-(1-Fmoc-piperidin-4-yl)-piperazine-1-carboxylic acid tert-butyl ester as a white foam (1.02 g).

1. stirringthe mixture was stirred overnight
2. filtrationthe mixture was filtered
3. washThe solid was washed with ethyl alcohol
4. customThe solvent was removed under reduced pressure
5. customthe residue was purified by flash chromatography (ISCO machine, silica gel
6. washeluting with 20% ethyl acetate in hexane for a period of 30 min)