反应详情

A 50 mL round-bottomed flask was charged with Boc-D-tert-leucine (1.00 g, 4.32 mmol), HOBT (728 mg, 4.76 mmol), EDC (912 mg, 4.76 mmol) and pyrrolidine (0.57 mL, 6.89 mmol). Then added DMF (18 mL) followed by N,N-diisopropylethylamine (1.1 ml, 6.3 mmol). The yellow reaction mixture was stirred at room temperature overnight then quenched with H2O and extracted with Et2O (2×). The combined organic layers were washed twice with H2O and once with brine then dried over Na2SO4, filtered and concentrated. The residue was purified by chromatography over 40 g SiO2 with EtOAc/hexanes (gradient: 0-30% EtOAc) to afford 1.0 g (83%) of (R)-tert-butyl 3,3-dimethyl-1-oxo-1-(pyrrolidin-1-yl)butan-2-ylcarbamate as an off-white solid.

1. customthen quenched with H2O
2. extractionextracted with Et2O (2×)
3. washThe combined organic layers were washed twice with H2O and once with brine
4. dry with materialthen dried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated
7. customThe residue was purified by chromatography over 40 g SiO2 with EtOAc/hexanes (gradient: 0-30% EtOAc)