[F:1][C:2]([C:5]1[CH:6]=[C:7]([CH:10]=[CH:11][CH:12]=1)[C:8]#N)([F:4])[CH3:3].[H-].C([Al+]CC(C)C)C(C)C.C(=O)=[O:24].CC(O)=O>C1(C)C=CC=CC=1.O>[F:1][C:2]([C:5]1[CH:6]=[C:7]([CH:10]=[CH:11][CH:12]=1)[CH:8]=[O:24])([F:4])[CH3:3]Dissolve 3-(1,1-difluoro-ethyl)-benzonitrile (4.39 g, 26.26 mmol) in toluene (44 mL). Place the reaction under nitrogen, cool to −78° C. in a dry-ice bath, then add diisobutylaluminum hydride (52.5 mmol, 1 M solution in toluene) dropwise over 30 minutes with stirring. Stir the reaction in the dry-ice bath for 30 minutes, then add glacial HOAc (14 mL) dropwise to control foaming, followed by water (100 mL). Stir the reaction mixture overnight at room temperature. Separate the layers; extract the cloudy aqueous with toluene. Wash the toluene extracts with brine, dry the organics over magnesium sulfate, filter, and evaporate to afford 3-(1,1-difluoro-ethyl)-benzaldehyde as a pale yellow oil. (4.0 g, 90%). 1H NMR (400 MHz, CDCl3): δ 10.03 (s, 1H), 8.00 (s, 1H), 7.92 (d, J=7.5 Hz, 1H), 7.75 (d, J=7.5 Hz, 1H), 7.58 (t, J=7.7 Hz, 1H), 1.98-1.89 (m, 3H).
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