METHYL 2-METHYL-4-OXOCYCLOHEX-2-ENECARBOXYLATE → Cyclohexanecarboxylic acid, 2,2-diMethyl-4-oxo-, Methyl ester

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Reaction Conditions

Reaction Steps

Copper iodide (121.8 g, 639.54 mmol) was suspended in Et2O (800 mL). Methyllithium (1.6 M in diethyl ether, 800 mL, 1.28 mol) was added dropwise at −40° C. over 3 hours. A solution of methyl 2-methyl-4-oxocyclohex-2-enecarboxylate (53.8 g, 319.88 mmol) in Et2O (400 mL) was added at −40° C. over 2 minutes. The resulting solution was stirred 5 hours at −20° C. The mixture was diluted with saturated aqueous ammonium chloride (2.5 L) and extracted with EtOAc (3×2 L). The combined organic extracts were dried over Na2SO4, filtered, and concentrated in vacuo. The residue was purified via silica gel column chromatography (1:20 EtOAc/petroleum ether). Methyl 2,2-dimethyl-4-oxocyclohexanecarboxylate was obtained as a yellow oil. MS ESI calcd. for C10H17O3 [M+H]+ 185. found 185. 1H NMR (600 MHz, CDCl3) δ 3.49 (s, 3H), 2.43-2.40 (m, 1H), 2.35-2.29 (m, 1H), 2.21-2.17 (m, 1H), 2.11-2.04 (m, 1H), 2.00-1.96 (m, 1H), 1.91-1.85 (m, 1H), 0.85 (s, 3H), 0.77 (s, 3H).

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