[Cl:1][C:2]1[CH:3]=[C:4]([CH:9]=[C:10]([OH:13])[C:11]=1[OH:12])[C:5]([O:7][CH3:8])=[O:6].I[CH:15]1[CH2:19][CH2:18][CH2:17][CH2:16]1.C(=O)([O-])[O-].[K+].[K+]>CN(C=O)C>[Cl:1][C:2]1[CH:3]=[C:4]([CH:9]=[C:10]([O:13][CH:15]2[CH2:19][CH2:18][CH2:17][CH2:16]2)[C:11]=1[O:12][CH:15]1[CH2:19][CH2:18][CH2:17][CH2:16]1)[C:5]([O:7][CH3:8])=[O:6]A mixture of methyl 3-chloro-4,5-dihydroxybenzoate (3) (300 mg, 1.48 mmol), iodocyclopentane (558 μL, 4.44 mmol) and potassium carbonate (614 mg, 4.44 mmol) in DMF (10 mL) was stirred at 70° C. for 46 h. The reaction mixture was cooled to room temperature and then partitioned between 1M HCl (75 mL) and EtOAc (100 mL). The phases were separated and the organic phase was washed with brine (2×75 mL) then dried over MgSO4 and filtered. The solvent was removed in vacuo and the residue was purified by silica gel chromatography (40 g, 0-100% EtOAc in isohexane) to give methyl 3-chloro-4,5-bis(cyclopentyloxy)benzoate (4) (427 mg, 1.26 mmol, 85% yield): m/z 339 [M+H]+ (ES+); 1H NMR (400 MHz, CDCl3) δ: 7.66 (1H, d), 7.45 (1H, d), 5.05-4.98 (1H, m), 4.87-4.83 (1H, m), 3.89 (3H, s), 1.95-1.55 (16H, m).
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