[F:1][C:2]1[CH:23]=[CH:22][C:5]([O:6][CH2:7][CH:8]([O:15]COCCOC)[CH2:9][CH2:10][CH2:11][CH2:12][CH:13]=[O:14])=[CH:4][CH:3]=1.FC(F)(F)C(O)=O.[OH-].[Na+]>C(Cl)(Cl)Cl>[F:1][C:2]1[CH:3]=[CH:4][C:5]([O:6][CH2:7][CH:8]([OH:15])[CH2:9][CH2:10][CH2:11][CH2:12][CH:13]=[O:14])=[CH:22][CH:23]=1(±)-7-(4-fluorophenoxy)-6-(2-methoxyethoxymethoxy)heptan-1-al 45 (2 g, 6.1 mmol) and 2 ml of trifluoroacetic acid are added to 10 ml of chloroform. The reaction mixture is stirred for 24 hours and then is neutralized with 1% aqueous NaOH. The organic layer is washed with water, brine, dried (Na2SO4), concentrated. The crude trifluoroacetyl-aldehyde 46 is then dissolved in MeOH:H2O (1:1) and solid K2CO3 is added to maintain pH 8. The reaction is complete is approximately 15 minutes, as monitored by TLC (ethyl acetate:hexane 3:7). Methanol is removed in vacuo and remaining solution is extracted with ethyl acetate to give (±)-7-(4-fluorophenoxy)-6-(hydroxy)-heptan-al 47 (1.2 g, 82%).
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