[Mg].[CH:2]1(Br)[CH2:7][CH2:6][CH2:5][CH2:4][CH2:3]1.[CH2:9]([O:11][C:12](=[O:18])[C:13](OCC)=[O:14])[CH3:10].Cl>C1COCC1>[CH:2]1([C:13](=[O:14])[C:12]([O:11][CH2:9][CH3:10])=[O:18])[CH2:7][CH2:6][CH2:5][CH2:4][CH2:3]1To a suspension of magnesium turnings (2.20 g, 90.32 mmol) in THF (100 mL) was added cyclohexyl bromide (9.27 mL, 75.27 mmol). The mixture was sonicated (note 1) for 30 min, the supernatant liquid was decanted into an addition funnel and added to a solution of diethyloxalate (22.0 g, 146.14 mmol) in THF (240 mL) at −10° C. over one hour. After 30 minutes, 10% HCl (75 mL) was added the mixture was and stirred 15 minutes. Layers were separated and the aqueous layer was extracted with Et2O (100 mL). Combined organics were washed (brine), dried over Na2SO4, and concentrated in vacuo. The residue was purified by flash chromatography (EtOAc/hexanes), affording the title compound as a clear oil. 1H NMR (400 MHz, CDCl3) δ ppm 1.15-1.40 (m, 5H) 1.56-1.94 (m, 8H) 2.97-3.05 (m, 1H) 4.30 (q, J=7.32 Hz, 2H).
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