反应详情

To a stirred solution of 4-(benzyloxy)tetrahydrofuran-2-yl acetate (3.57 g, 15.11 mmol) and allyltrimethylsilane (9.65 mL, 60.4 mmol) in CH2Cl2 (200 mL) at −78° C. was added a solution of tin(IV) bromide (7.95 g, 18.13 mmol) in CH2Cl2 (20 mL) over 15 min. After 1 h, the ice bath was removed and stirring continued at room temperature for 3 h. The CH2Cl2 was removed using a rotoevaporator and the residue taken up in 1:1 Et2O/hexane (200 mL), washed with sat. Na2CO3 (2×50 mL), water (2×50 mL) followed by brine (50 ml), then dried (Na2SO4), filtered and concentrated to give 2-allyl-4-(benzyloxy)tetrahydrofuran (3.15 g, 14.43 mmol, 95% yield). 1H NMR (400 MHz, CDCl3) δ: 7.27-7.39 (5 H, m), 5.76-5.90 (1 H, m), 5.03-5.15 (2 H, m), 4.49 (1.6 H, d, J=2.3 Hz), 4.43 (0.4 H, d, J=2.3 Hz), 4.17-4.23 (1 H, m), 4.01 (0.45 H, d, J=1.8 Hz), 3.98 (0.55 H, d, J=1.8 Hz), 3.85-3.94 (1 H, m), 3.73 (1 H, dd, J=9.8, 5.3 Hz), 2.43-2.53 (1 H, m), 2.30-2.40 (1 H, m), 2.19-2.28 (1 H, m), 1.69-1.77 (1 H, m). LCMS (M+H) calcd for C14H19O2: 219.14; found: 219.05.

1. customthe ice bath was removed
2. waitcontinued at room temperature for 3 h
3. customThe CH2Cl2 was removed
4. washwashed with sat. Na2CO3 (2×50 mL), water (2×50 mL)
5. dry with materialdried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated