反应详情

温度

0 °C

Boron tribromide (32.9 ml of 1M soln, 32.9 mmol) was added to a solution of Compound 9 (4.51 g, 3.23 mmol) in CH2Cl2 (546 ml) under argon at −78° C. The reaction temperature was then raised slowly to 0° C. over a period of 3 hrs. Stirring was continued at 0° C. for 12–14 hrs or until completion of reaction. Unreacted boron tribromide was destroyed by adding methanol, solvent removed and the residual oil diluted with diethyl ether. The organic phase was washed with saturated NaHCO3, water and brine, dried and concentrated. The residue was resolved over silica gel eluting with diethylether/hexanes (4:6) to yield 0.675 g (74.1%) of Compound 16 as a waxy solid. Rf=0.28 (hexane:ethyl acetate 8:2) 1H NMR δ 6.79 (d, J=2.5 Hz, 2H), 6.23 (t, J=2H, 1H), 5.30 (br s, 2H), 3.38–3.19 (m, 4H), 2.25 (t, J=9.75 Hz, 2H), 1.29–1.18 (m, 4H), 0.83 (t, J=7 Hz, 3H); 13C NMR δ 156.24, 148.45, 107.23, 101.50, 73.90, 45.50, 39.01, 29.96, 22.74, 13.86; MS: (ESI, Neg.) m/z 269 ([M−H]−).

1. customwas continued at 0° C. for 12–14 hrs or until completion of reaction
2. customUnreacted boron tribromide was destroyed
3. additionby adding methanol, solvent
4. customremoved
5. additionthe residual oil diluted with diethyl ether
6. washThe organic phase was washed with saturated NaHCO3, water and brine
7. customdried
8. concentrationconcentrated