反应详情

TPP (4.45 g, 9.34 mmol) was added to a 0° C. solution of alcohol 6 (2.00 g, 7.78 mmol) in dry CH2Cl2 (50 mL). After 10 min, CBr4 (3.10 g, 9.34 mmol) was added and the stirring was continued at 0° C. After 2 h, water (20 mL) was added and the reaction mixture was extracted with EtOAc (3×50 mL). The combined extracts were washed with water (2×20 mL), brine (20 mL), dried over Na2SO4, and concentrated under reduced pressure. The residue was purified by SiO2 column chromatography using 30-35% ethyl acetate/hexane to afford 7 (2.20 g, 91%). TLC:EtOAc/hexanes (3:7), Rf˜0.40; 1H NMR (400 MHz, 45/55 mixture of rotamers) δ 4.60-4.70 and 3.96-4.10 (m, 1H, rotamers), 3.46 and 3.36 (t, J=5.8 Hz, rotamers), 3.02-3.10 (m, 2H), 2.30 and 2.22 (t, J=7.9 Hz, 2H), 1.80-1.97 (m, 2H), 1.40-1.70 (m, 6H), 1.20-1.40 (m, 6H), 1.16 and 1.10, (d, J=7.3 Hz, 6H, rotamers), 0.86 (t, J=7.3 Hz, 3H); 13C NMR (100 MHz, rotamers) δ 172.79, 172.39, 48.17, 45.47, 43.32, 40.70, 33.89, 33.87, 33.49, 32.48, 32.30, 31.81, 31.78, 30.78, 29.27, 28.74, 26.05, 25.84, 25.69, 25.54, 22.64, 21.47, 20.62, 14.17.

1. customwas continued at 0° C
2. waitAfter 2 h
3. extractionthe reaction mixture was extracted with EtOAc (3×50 mL)
4. washThe combined extracts were washed with water (2×20 mL), brine (20 mL)
5. dry with materialdried over Na2SO4
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by SiO2 column chromatography