反应详情

3-(2-Benzyloxyethyl)-2-methoxy-4-oxo-3,9-diaza-bicyclo[3.3.1]nonane-9-carboxylic acid benzyl ester (Compound 4, 0.34 g, 0.76 mmol) was dissolved in CH2Cl2 (5 mL) in a 25-ml flask under argon. BF3OEt2 (0.18 ml, 1.52 mmol) was added dropwise to the reaction flask (fumes were released) followed by triethylsilane (0.24 g, 1.52 mmol), and the solution was stirred overnight. The CH2Cl2 was evaporated and the residue was dissolved in EtOAc and washed with saturated NaHCO3 (2×10 mL). The mixture was extracted with EtOAc (3×10 mL). The organic layer was dried over Na2SO4 and concentrated. Purification of the residue by flash column chromatography with 20% EtOAc/hexanes gave Compound 5 (0.27 g, 89%, 1:1 mixture of enantiomers) as a clear oil. Rf=0.42 (50% EtOAc/hexanes); 1H NMR (major rotamer): δ 1.62-1.72 (m, 6H), 3.25-3.50 (m, 2H), 3.68-3.90 (m, 5H), 4.49 (s, 2H), 4.75 (s, 1H), 5.14 (s, 2H), 7.26-7.34 (m, 10 H).

1. additionBF3OEt2 (0.18 ml, 1.52 mmol) was added dropwise to the reaction flask (fumes were released)
2. customThe CH2Cl2 was evaporated
3. dissolutionthe residue was dissolved in EtOAc
4. washwashed with saturated NaHCO3 (2×10 mL)
5. extractionThe mixture was extracted with EtOAc (3×10 mL)
6. dry with materialThe organic layer was dried over Na2SO4
7. concentrationconcentrated
8. customPurification of the residue by flash column chromatography with 20% EtOAc/hexanes