反应详情

To a stirred mixture of 1-(tert-butoxycarbonyl)-4,4difluoro-2-pyrrolidinylmethanol (600 mg, 2.53 mmol), methyl 4-hydroxybenzoate (462 mg, 3.03 mmol), Ph3P (795 mg, 3.03 mmol) in THF (10 ml) was added DIAD (597 ul, 3.03 mmol) at room temperature. The mixture was heated at reflux for 3 h with stirring. After cooling to room temperature, the mixture was concntrated in vacuo. The residue was chromatographed on silica gel with hexane-EtOAc (4:1) as eluent to give methyl 4-[1-(tert-butoxycarbonyl)-4,4-difluoro-2-pyrrolidinylmethoxy]benzoate (831 mg, 88%) as a colorless oil. 1H-NMR (CDCl3) δ 1.48 (s, 9 H), 2.53–2.61 (m, 2 H), 3.63–4.41 (series of m, total 8 H), 6.94 (d, J=8.8 Hz, 2H), 7.99(d, J=8.8 Hz, 2H).

1. temperatureThe mixture was heated
2. temperatureat reflux for 3 h
3. customThe residue was chromatographed on silica gel with hexane-EtOAc (4:1) as eluent