反应详情

温度

0 °C

To a solution of 2-iodo-5-(trifluoromethyl)benzonitrile (INTERMEDIATE 2, 42 g) in CH2Cl2 (300 mL) at −78° C. was added a solution of DIBAL in CH2Cl2 (175 mL, 1M) over 30 minutes. A precipitate formed. The reaction was warmed to 0° C. An additional 25 mL of the DIBAL solution was added dropwise over 30 minutes. The reaction was poured into 200 mL 2N aqueous HCl, diluted with ether and stirred 1 hour. TLC analysis indicates imine still present and an additional 100 mL 2N aqueous was added and the reaction stirred overnight. Imine was still present by TLC analysis and 200 mL 2N aqueous HCl was added and the mixture stirred 2 hours. The layers were separated and the aqueous layer back extracted with ether. The ether extracts were combined, washed with brine, dried over anhydrous MgSO4, filtered and concentrated. The product was purified by silica gel chromatography eluting with 95:5 hexanes/EtOAc to give 2-Iodo-5-(trifluoromethyl)benzaldehyde as a white solid. 1H NMR (500 MHz, CDCl3): (10.00 (s, 1H), 8.12 (s, 1H), 8.11 (d, J=8 Hz, 1H), 7.53 (dd, J=2 Hz, 8 Hz, 1H).

1. customA precipitate formed
2. additionan additional 100 mL 2N aqueous was added
3. stirringthe reaction stirred overnight
4. additionwas added
5. stirringthe mixture stirred 2 hours
6. customThe layers were separated
7. extractionthe aqueous layer back extracted with ether
8. washwashed with brine
9. dry with materialdried over anhydrous MgSO4
10. filtrationfiltered
11. concentrationconcentrated
12. customThe product was purified by silica gel chromatography
13. washeluting with 95:5 hexanes/EtOAc