[Cl:1][C:2]1[CH:3]=[C:4]([CH2:12][OH:13])[CH:5]=[C:6]([C:8]([F:11])([F:10])[F:9])[CH:7]=1.O=[Si]=O.[Cr](Cl)([O-])(=O)=O.[NH+]1C=CC=CC=1>C(Cl)Cl.C(OCC)C>[Cl:1][C:2]1[CH:3]=[C:4]([CH:5]=[C:6]([C:8]([F:9])([F:10])[F:11])[CH:7]=1)[CH:12]=[O:13]To a stirred suspension of (3-chloro-5-(trifluoromethyl)phenyl)methanol (Reference Example 30, 1.98 g, 9.40 mmol) and celite 545 (6.00 g) in methylene chloride (60.0 mL) was added pyridinium chlorochromate (6.10 g, 28.30 mmol) at room temperature. After 1 h, the reaction mixture was diluted with diethyl ether (200 mL), and filtered through silica gel and the filter cake was washed with 1:1 solution of diethyl ether/hexanes. The filtrate was concentrated under reduced pressure and the residue was purified by flash column chromatography (silica gel, hexanes/ethyl acetate 49:1) to provide 3-chloro-5-(trifluoromethyl)benzaldehyde (1.15 g, 56% (overall for 3 steps)) as a pale yellow oil.
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