Methyl iodide → Ethyl 1-methyl-2-oxocyclopentane-1-carboxylate

関与物質

反応手順

To a stirred suspension of dry potassium carbonate (16.64 g, 120.4 mmol) in dry acetone (200 mL) under argon was added ethyl 2-oxocyclopentanecarboxylate (9.40 g, 60.2 mmol) followed by methyl iodide (7.5 mL, 120.4 mmol). The reaction was heated to reflux for 3 hours and then another portion of methyl iodide (7.5 mL, 120.4 mmol) was added and the reaction was refluxed overnight. The reaction mixture was cooled and then filtered through a silica gel pad and the solid was washed with acetone (100 mL×3). The organic phase was concentrated under reduced pressure and the residue dispersed in acetone (200 mL) and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate=100/1->50/1) to afford the title compound as a colorless liquid (8.35 g, Yield: 82%). 1H NMR (400 MHz, CDCl3) δ 4.22-4.10 (m, 2H), 2.57-2.40 (m, 2H), 2.36-2.27 (m, 1H), 2.11-2.00 (m, 1H), 1.98-1.83 (m, 2H), 1.31 (s, 3H), 1.25 (t, J=7.0 Hz, 3H) ppm.

情報源と証拠