Triethylamine → (+)-(4R,5R)-5-(3-Methoxyphenyl)-4-(3-(phenylethynyl)phenyl)oxazolidin-2-one

Participants

Reaction Steps

A suspension of (+)-(4R,5R)-4-(3-bromophenyl)-5-(3-methoxyphenyl)oxazolidin-2-one (2.4 g, 6.89 mmol) in triethylamine (24 mL, 172 mmol) was purged with nitrogen for 1 h (volume dropped by ca. 5 mL). The reaction was treated with triphenylphosphine (0.152 g, 0.579 mmol) and ethynylbenzene (0.776 mL, 7.07 mmol), and purged 10 minutes longer. To this was added PdCl2(PPh3)2 (0.034 g, 0.048 mmol) and copper(I) iodide (7.88 mg, 0.041 mmol). After purging 10 min longer, the reaction was warmed to a vigorous reflux. The reaction was heated at reflux overnight. In the morning, the reaction was cooled to room temperature, diluted with diethyl ether, washed with water (3×), then brine, dried over magnesium sulfate, and concentrated. Column chromatography (25%-->40% EtOAc/Hex) gave 2.2 g (80%) as a colorless foam solid. 1H-NMR (CDCl3, 500 MHz) δ 7.56 (m, 4H), 7.36-7.45 (m, 4H), 7.34 (m, 1H), 7.30 (m, 1H), 6.92-6.98 (m, 1H), 6.85-6.90 (m, 2H), 5.93 (bs, 1H), 5.31 (d, J=7.3, 1H), 4.78 (d, J=7.3, 1H), 3.84 (s, 3H). 13C-NMR (CDCl3, 126 MHz) δ 160.2, 158.6, 138.92, 138.85, 132.3, 131.8, 130.2, 129.6, 129.4, 128.7, 128.5, 126.4, 124.6, 122.9, 118.1, 115.0, 111.2, 90.6, 88.6, 85.9, 64.6, 55.5. Mass spec.: 370.18 (MH)+.

Provenance & Evidence