[CH:1]1([C:5]2[CH:14]=[CH:13][C:8]([C:9]([O:11][CH3:12])=[O:10])=[C:7]([CH2:15][CH3:16])[CH:6]=2)[CH2:4][CH2:3][CH2:2]1.[I:17]I.S(=O)(=O)(O)O>C(O)(=O)C>[CH:1]1([C:5]2[C:14]([I:17])=[CH:13][C:8]([C:9]([O:11][CH3:12])=[O:10])=[C:7]([CH2:15][CH3:16])[CH:6]=2)[CH2:2][CH2:3][CH2:4]1To a solution of methyl 4-cyclobutyl-2-ethylbenzoate (compound 181.3, 7.70 g, 35.3 mmol, 1.00 equiv) in acetic acid (80 mL) was added iodine (8.98 g, 35.4 mmol, 1.00 equiv), NaIO4 (3.78 g, 17.7 mmol, 0.50 equiv), and sulfuric acid (0.870 g, 8.87 mmol, 0.25 equiv). The reaction mixture was stirred at 60° C. overnight. After cooling to room temperature, the reaction was slowly quenched with Na2S2O3 (aq., sat.). The mixture was extracted with 200 mL of ethyl acetate and the organic layer was dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified by silica gel chromatography with ethyl acetate/petroleum ether (1:50) to furnish 10.5 g (86%) of the desired product as a colorless solid.
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