1,2-Dichloroethane → (R)-tert-butyl 3,3-dimethyl-1-oxo-1-(pyrrolidin-1-yl)butan-2-ylcarbamate

Participants

Reaction Steps

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.

Provenance & Evidence