Methyl iodide → Ethyl 2-(4-methylphenyl)propanoate

Beteiligte Stoffe

Reaktionsschritte

Under N2 atmosphere, a solution of ethyl p-tolyl-acetate (2.72 g, 15.2 mmol) in anhydrous THF (70 mL) was cooled to −40° C. and a solution of LDA (7.6 mL, 15.25 mmol) was added drop-wise over 30 minutes. The reaction mixture was stirred for 1 h, and methyl iodide (3.03 g, 21.30 mmol) was added drop-wise, followed by the addition of DMPU (1 mL). The reaction mixture was allowed to warm to rt, after 1 h and stirred overnight. The reaction mixture was poured into water (30 mL) and extracted with ethyl acetate (3×10 mL). The combined organic layers were washed with saturated NH4Cl solution (10 mL), 1 M HCl (10 mL), saturated NaHCO3 solution (10 mL), and brine (10 mL), then dried over MgSO4, and concentrated in vacuo. The residue was distilled in high vacuo (bp. 59-63° C./0.2 mmHg) to furnish 2-p-tolyl-propionic acid ethyl ester (2.5 g, 86.0%) as an oil. 1H NMR (300 MHz, CDCl3/TMS): δ (ppm) 7.18 (d, 2H, J=8.1), 7.10 (d, 2H, J=8.1), 4.09 (m, 2H), 3.67 (q, 1H, J=7.2), 2.29 (s, 3H), 1.47 (d, J=7.2 Hz, 3H), 1.20 (t, J=5.7 Hz, 3H). 13C NMR (75 MHz, CDCl3/TMS): δ (ppm) 174.71, 137.80, 136.63, 129.33, 129.14, 127.36, 60.66, 45.18, 21.05, 18.70, 14.15. [Lit. ref.: Ghosh, S.; Pardo, S. N.; Salomon, R. G. J. Org. Chem. 1982, 47, 4692-4702.].

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