[CH:1]1([C:4]2[CH:13]=[CH:12][C:7]([C:8]([O:10][CH3:11])=[O:9])=[C:6]([CH3:14])[CH:5]=2)[CH2:3][CH2:2]1.[I:15]I.S(=O)(=O)(O)O.O>CC(O)=O>[CH:1]1([C:4]2[C:13]([I:15])=[CH:12][C:7]([C:8]([O:10][CH3:11])=[O:9])=[C:6]([CH3:14])[CH:5]=2)[CH2:2][CH2:3]1To a solution of methyl 4-cyclopropyl-2-methylbenzoate (compound 86.1, 2.68 g, 13.4 mmol, 95%) in AcOH (50 mL) were added NaIO4 (1.51 g, 7.08 mmol), iodine (3.58 g, 14.1 mmol), and sulfuric acid (106 μL, 2.0 mmol, 0.15 equiv). The reaction mixture was stirred overnight at 110° C. After cooling to ambient temperature, water (100 mL) was slowly added and the mixture was extracted with ethyl acetate (100 mL). The organic layer was washed with Na2S2O3 (aq., sat., 3×30 mL) and brine (30 mL), dried (Na2SO4), filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography with ethyl acetate/petroleum ether (1/50) as the eluent to yield 2.0 g (45%) of the title compound as a colorless oil.
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