[Cl:1][C:2]1[CH:20]=[C:19]([F:21])[CH:18]=[CH:17][C:3]=1[O:4][C:5]1[CH:12]=[CH:11][CH:10]=[C:9]([C:13]([F:16])([F:15])[F:14])[C:6]=1[CH:7]=[O:8].CC(=CC)C.P([O-])(O)(O)=[O:28].[Na+].Cl([O-])=O.[Na+].Cl>CC(O)(C)C.O.CC#N>[Cl:1][C:2]1[CH:20]=[C:19]([F:21])[CH:18]=[CH:17][C:3]=1[O:4][C:5]1[CH:12]=[CH:11][CH:10]=[C:9]([C:13]([F:16])([F:15])[F:14])[C:6]=1[C:7]([OH:28])=[O:8]To a solution of 2-(2-chloro-4-fluoro-phenoxy)-6-(trifluoromethyl)benzaldehyde (31 g, 97.29 mmol) in tBuOH (155.0 mL), water (100.8 mL), CH3CN (155.0 mL) and 2-methyl-2-butene (51.45 mL, 486.4 mmol) was added sodium dihydrogen phosphate (35.02 g, 291.9 mmol) and the mixture was cooled to 0° C. Sodium chlorite (26.40 g, 291.9 mmol) was added in one portion and the mixture was stirred at 25° C. for 1 hour. The pH of the reaction was adjusted to 2-3 with 1N HCl and the layers were separated. The aqueous layer was extracted with EtOAc (3×). All the organic layers were combined, and solid sodium sulfite (˜5 g) was added followed by brine (50 ml) and 1N NaOH (10 ml) and the mixture was shaken until the yellow color disappeared. The layers were separated and the organic was washed with brine, dried over Na2SO4, filtered through a short plug of silica and evaporated to dryness to give 2-(2-chloro-4-fluoro-phenoxy)-6-(trifluoromethyl)benzoic acid (40 g, 98%) as an oil that was used in the next step without further purification. ESI-MS m/z calc. 334.00. found 335.1 (M+1)+; Retention time: 1.58 minutes (3 minutes run).
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