反应详情

To a solution 2-(4-allyldimethylsilylphenyl)-1,3-dioxolane (3 Scheme 18, 456 mg, 2 mmol) in dry THF (10 mL) under a N2 atmosphere was added 9-BBN (4 mL, 0.5 M solution in THF, 2 mmol) dropwise at 0° C. The mixture was gradually warmed to room temperature and stirred for 5 h. Pd(PPh3)4 (70 mg), 4-bromopolystyrene (500 mg, 1.94 mmol/g), 2 N aqueous Na2CO3 (2 mL, 4 mmol), DMF (5 mL), were added. The reaction flask and reflux condenser were wrapped with aluminum foil, and the mixture was refluxed for 24 h. Pd(PPh3)4 (70 mg) was added to the reaction mixture which was refluxed again for 24 h. The resin was filtered and washed with THF (once), 1:1 THF/water (twice), water (twice), methanol (twice), CH2Cl2 (twice), then dried under reduced pressure. The resin (4 Scheme 18) was agitated in THF/1 N HCl (8:1) for 16 h at 30° C. After washing and drying, an aliquot of the resin (200 mg) was treated with a solution of CH2Cl2 (7 mL) and Br2 (150 μL) for 5 min. The cleavage solution was removed, and the resin was rinsed with CH2Cl2 (3 mL). Concentration of the combined filtrates gave the known 4-bromobenzaldehyde (1 Scheme 18, 11 mg, loading level was determined to be 0.30 mequiv/g); 1H NMR (300 MHz, CDCl3) δ 7.71 (d, J=8.30 Hz, 2 H), 7.77 (d, J=8.30 Hz, 2 H), 10.00 (s, 1 H).

1. temperatureThe reaction flask and reflux condenser
2. temperaturethe mixture was refluxed for 24 h
3. temperaturewas refluxed again for 24 h
4. filtrationThe resin was filtered
5. washwashed with THF (once), 1:1 THF/water (twice), water (twice), methanol (twice), CH2Cl2 (twice),
6. customthen dried under reduced pressure
7. stirringThe resin (4 Scheme 18) was agitated in THF/1 N HCl (8:1) for 16 h at 30° C
8. washAfter washing
9. customdrying
10. additionan aliquot of the resin (200 mg) was treated with a solution of CH2Cl2 (7 mL) and Br2 (150 μL) for 5 min
11. customThe cleavage solution was removed
12. washthe resin was rinsed with CH2Cl2 (3 mL)