Butyl vinyl ether → Methyl 2-acetyl-5-methoxybenzoate

Participants

Reaction Conditions

Reaction Steps

A mixture of methyl 2-bromo-5-methoxybenzoate (1) (5.0 g, 20.4 mmol), butyl vinyl ether (13.1 mL, 102.0 mmol), Ph3P (802.3 mg, 3.1 mmol), Et3N (3.7 mL, 26.5 mmol), and Pd(OAc)2 (343.0 mg, 1.5 mmol) in MeCN (40 mL) is stirred under argon at 99° C. for 16.5 h and then cooled to room temperature. The residue is diluted with H2O (50 mL), and the resultant suspension is filtered through Celite® (H2O rinse). The filtrate is concentrated to dryness at reduced pressure. To the residue is added tetrahydrofuran (125 mL) and 10% HCl (125 mL). The mixture is stirred for 2 h before the tetrahydrofuran is removed at reduced pressure. This residue is extracted with ethyl acetate (100 mL, 70 mL, and 60 mL). The extract is washed (brine) and dried. After solvent removal at reduced pressure, the residue is purified on silica gel (16.7% to 33.3% ethyl acetate/hexane) to give 4.23 g (99%) of 2 as a yellow liquid. IR 2958, 1730, 1683, 1270 cm−1; 1H NMR (CDCl3) δ 2.55 (s, 3H, CH3CO), 3.90 (s, 3H, CH3O), 3.94 (s, 3H, CO2CH3), 7.04 (dd, J=8.7, 2.7 Hz, 1H, 4-PhH), 7.17 (d, J=2.7 Hz, 1H, 6-PhH), 7.61 ppm (d, J=8.7 Hz, 1H, 3-PhH).

Provenance & Evidence