反应详情

A solution of compound 5 (1.09 g, 3.22 mmol) and CBr4 (1.28 g, 3.86 mmol) in CH2Cl2 (70 mL) was treated with a solution of Ph3P (1.27 g, 4.84 mmol) in CH2Cl2 (30 mL) dropwise at −78° C. After 30 min, the reaction mixture was slowly warmed up to room temperature for 2 h and then stirred for overnight. The reaction mixture was poured to the silica gel pad. The filtrate was concentrated to dryness. After concentration, the residue was purified with 0˜2% EtOAc in hexanes by silica gel column chromatography to give 1.28 g of product 6 (3.19 mmol, 99% yield); 1H NMR (CDCl3) δ 7.80˜7.65 (m, 4H), 7.50˜7.32 (m, 6H), 4.34 (t, J=1.9 Hz, 1H), 3.35 (t, J=5.8 Hz, 2H), 2.73 (tt, J=2.1, 6.0 Hz, 2H) 1.08 (s, 9H).

1. additionThe reaction mixture was poured to the silica gel pad
2. concentrationThe filtrate was concentrated to dryness
3. concentrationAfter concentration
4. customthe residue was purified with 0˜2% EtOAc in hexanes by silica gel column chromatography