反应详情

A mixture of lithium bromide (0.181 g, 2.08 mmol), tri-n-butylphosphine oxide (0.454 g, 2.08 mmol), and dry o-xylene (10 ml) is azeotropically dried for 1 hr. After cooling below the reflux point, a mixture of (R)-glycidyl butyrate (5.000 g, 34.68 mmol) and 3-fluorophenyl isocyanate (4.755 g or 3.96 ml, 34.68 mmol) in dry o-xylene (10 ml) is added over 10 min to the hot mixture (some refluxing observed during the addition). When the addition is complete, the mixture is heated to reflux for 2 hr and then allowed to cool to 20-25°. The solvent is removed under reduced pressure and the residue chromatographed over silica gel, eluting with hexane/ethyl acetate (6:1, 4:1, and then 2:1), to give the title compound, [α]25D -46.7° (c 1.0, CHCl3); IR (mineral oil mull) 1758, 1615, 1591, 1498, 1229, 1197, 1169 cm-1 ; NMR (CDCl3, 300 MHz) δ 7.44, 7.34, 7.23, 6.86, 4.88, 4.39, 4.32, 4.13, 3.82, 2.33, 1.63, 0.92; MS (m/z) 281, 193, 180, 150, 148, 137, 123, 95, 43; HRMS (m/z) 281.1068 (calc'd for C14H16FNO4 =281.1063).

1. customis azeotropically dried for 1 hr
2. temperatureAfter cooling below the reflux point
3. additionis added over 10 min to the hot mixture (some refluxing
4. additionobserved during the addition)
5. additionWhen the addition
6. temperaturethe mixture is heated
7. temperatureto reflux for 2 hr
8. temperatureto cool to 20-25°
9. customThe solvent is removed under reduced pressure
10. customthe residue chromatographed over silica gel
11. washeluting with hexane/ethyl acetate (6:1, 4:1