[CH2:1]([Mg]Br)[CH2:2][CH2:3][CH2:4][CH2:5][CH2:6][CH2:7][CH3:8].[CH2:11]1[CH2:15][O:14][CH2:13][CH2:12]1>>[CH2:1]([C:13]([CH2:12][CH2:11][CH2:15][CH2:1][CH2:2][CH2:3][CH2:4][CH3:5])=[O:14])[CH2:2][CH2:3][CH2:4][CH2:5][CH2:6][CH2:7][CH3:8]To a solution of the product of Example 1 (4.0 g, 14.5 mmol) in THF (100 mL) was added a solution of 2M octylmagnesium bromide in THF (20 mL, 40 mmol) dropwise. After stirring for 3.5 hr, the solution was quenched with saturated NH4Cl, acidified with 1N HCl, and was extracted with EtOAc. The combined organic layers were washed with brine and dried over MgSO4. The solvent was removed under reduced pressure and the residue was chromatographed on silica gel. Elution with 7.5% ethyl acetate in hexanes gave the bis-octyl ketone (III) (4.86 g, 88%) as an oil. 1H NMR (300 MHz, CDCl3) δ 4.55 (s, 2H, CH), 2.64 (dt, 4H, CH2), 1.62 (m, 4H, CH2), 1.42 (s, 6H, CH3), 1.27 (broad s, 20H, CH2), 0.88 (t, 6H, CH3); MS (CI,NH3) m/e 383 (M+1).
Wird geladen…