反应详情

A mixture of 3,3-difluoropyrrolidine hydrochloride (200 mg, 1.17 mmol), 3-oxoazetidine-1-carboxylic acid tert-butyl ester (284 mg, 1.99 mmol) and triethylamine (295 μL, 221 mg, 2.18 mmol) in DCE (10 mL) was stirred at room temperature for 1 h before the addition of sodium triacetoxyborohydride (745 mg, 3.52 mmol). The resulting mixture was stirred for 72 h then diluted with DCM and washed with H2O. The organic phase was dried (Na2SO4) and concentrated in vacuo. The resulting residue was purified by column chromatography (Si—PCC, EtOAc:cyclohexane, 0-50%) affording 3-(3,3-Difluoropyrrolidin-1-yl)azetidine-1-carboxylic acid tert-butyl ester as a colourless oil (193 mg, 63%). 1H NMR (CDCl3, 300 MHz): δ 3.95 (m, 2H), 3.82 (dd, J=8.9, 4.9 Hz, 2H), 3.32 (m, 1H), 2.91 (m, 2H), 2.82-2.63 (m, 2H), 2.33-2.32 (m, 2H) and 1.43 (s, 9H).

1. washwashed with H2O
2. dry with materialThe organic phase was dried (Na2SO4)
3. concentrationconcentrated in vacuo
4. customThe resulting residue was purified by column chromatography (Si—PCC, EtOAc:cyclohexane, 0-50%)