[CH2:1]=[C:2]1[CH2:7][CH2:6][CH:5]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH2:4][CH2:3]1.Cl[CH2:14]I.C([Zn]CC)C.CCCCCC>ClCCCl.CCOC(C)=O.Cl>[CH2:14]1[C:2]2([CH2:3][CH2:4][CH:5]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[CH2:6][CH2:7]2)[CH2:1]1
At 0° C., to a solution of ethyl 4-methylenecyclohexanecarboxylate (0.08 g) in DCE (1 mL) was added chloroiodomethane (0.110 mL, 1.522 mmol), followed by the addition of 1 N diethylzinc in hexane (0.761 mL, 0.761 mmol). The reaction was stirred at 0° C. for 1 hr, then stirred at rt for 18 hrs. The reaction mixture was diluted with EtOAc and 1 N HCl, the organic phase was washed with sat. NaCl, dried over anhydrous Na2SO4, filtered and concentrated. The crude product was charged to a 25 g silica gel cartridge which was eluted with a 20 min gradient of 0-6% EtOAc in hexane to yield ethyl spiro[2.5]octane-6-carboxylate. 1H NMR (400 MHz, CDCl3) δ ppm 4.08-4.18 (2H, m), 2.32 (1H, tq, J=11.01, 3.53 Hz), 1.85-1.93 (2H, m), 1.53-1.74 (4H, m), 1.28-1.35 (2H, m), 1.22-1.28 (3H, m), 0.28 (2H, ddd, J=8.53, 5.52, 1.51 Hz), 0.17-0.25 (2H, m).
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