Dicyclohexylcarbodiimide → 3-(3-Pyridyl)-1-propyl (2s)-n-(tert-butyloxycarbonyl)-pyrrolidine-2-carboxylate

Participants

Reaction Steps

A mixture of N-(tert-butyloxycarbonyl)-(S)-proline (3.0 g; 13.9 mmol); 3-(3-Pyridyl)-1-propanol (2.90 g; 20.9 mmol), dicyclohexylcarbodiimide (4.59 g; 22.24 mmol), camphorsulfonic acid (1.08 g; 4.63 mmol), and 4-dimethylaminopyridine (0.60 g; 4.63 mmol) in dry methylene chloride (100 mL) was stirred overnight. The reaction mixture was diluted with methylene chloride (50 mL) and water (100 mL), and the layers were separated. The organic phase was washed with water (3×100 mL), dried over magnesium sulfate, and concentrated, and the crude residue was purified on a silica gel column eluting with ethyl acetate to obtain 4.60 g (95%) of the ester as a thick oil, 1H NMR (300 MHz, CDCl3): δ 1.45 (s, 9H); 1.70-2.05 (m, 5H); 2.32 (m, 1H); 2.71 (t, 2H); 3.50 (m, 2H); 4.15 (m, 2H); 4.18 (m, 1H); 7.24 (m, 1H); 7.51 (m, 1H); 8.48 (m, 2H).

Provenance & Evidence