CC(C)([O-])C.[K+].COP([CH2:13][C:14](=[O:20])[CH2:15][C:16]([CH3:19])([CH3:18])[CH3:17])(=O)OC.[C:21]1(=O)[CH2:28][CH2:27][CH2:26][CH2:25][CH2:24][CH2:23][C:22]1=[O:29]>C(O)(C)(C)C>[CH3:19][C:16]([CH3:17])([CH3:18])[CH2:15][C:14](=[O:20])[CH2:13][C:21]1[C:22](=[O:29])[CH2:23][CH2:24][CH2:25][CH2:26][CH2:27][CH:28]=1A solution of potassium tert-butoxide (0.192 g) in tert-butanol (10 mL) under an argon atmosphere was treated at 50° C. with (4,4-dimethyl-2-oxo-pentyl)-phosphonic acid dimethyl ester (0.38 g) and cyclooctane-1,2-dione (0,2 g), and the mixture was then heated at reflux for 12 h under an argon atmosphere. The reaction mixture was partitioned between water and AcOEt, the layers were separated, the aqueous layer extracted twice with AcOEt. The combined organic layers were washed with water, dried over Na2SO4, filtered and evaporated. The residue was purified by flash chromatography (heptane/AcOEt 100% to 95%) to give (Z)-2-(4,4-dimethyl-2-oxo-pentyl)-cyclooct-2-enone (0.076 g) as a light yellow oil. MS (ESI): 237.0 (MH+).
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