[CH:1]1([CH2:5][C:6]2[CH:15]=[CH:14][C:9]([C:10]([O:12][CH3:13])=[O:11])=[C:8]([CH3:16])[CH:7]=2)[CH2:4][CH2:3][CH2:2]1.[I:17]I.S(=O)(=O)(O)O>CC(O)=O>[CH:1]1([CH2:5][C:6]2[C:15]([I:17])=[CH:14][C:9]([C:10]([O:12][CH3:13])=[O:11])=[C:8]([CH3:16])[CH:7]=2)[CH2:4][CH2:3][CH2:2]1To a round-bottom flask was added a solution of methyl 4-(cyclobutylmethyl)-2-methylbenzoate (compound 189.1, 8.40 g, 38.5 mmol, 1.00 equiv) in AcOH (150 mL). NaIO4 (5.00 g, 23.4 mmol, 0.50 equiv), iodine (10.0 g, 39.4 mmol, 1.00 equiv), and sulfuric acid (0.3 mL) were added to the reaction mixture. The resulting solution was stirred at 60° C. for 12 h. After cooling to room temperature, the reaction was quenched with 200 mL of NaHSO3 (aq). The mixture was extracted with 2×200 mL of ethyl acetate, and the combined organic layers were dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified using silica gel column chromatography with ethyl acetate/petroleum ether (20:1) as eluent to furnish 8.00 g (60%) of methyl 4-(cyclobutylmethyl)-5-iodo-2-methylbenzoate as a white solid.
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