Cesium carbonate → ((E)-5-(3-methoxyphenyl)pent-4-en-1-ynyl)trimethylsilane

Participants

Reaction Conditions

Reaction Steps

To a dried 40 mL scintillation vial fitted with a Teflon coated cap is added 3-methoxycinnamyl acetate (619 mg, 3.0 mmol), toluene (20 mL), 3-(trimethylsilyl)propiolic acid (512 mg, 3.6 mmol), cesium carbonate (1.17 g, 3.6 mmol), and tetrakis(triphenylphosphine)palladium (0) (346 mg, 0.3 mmol, 10 mol %). The vessel is evacuated and back-filled with Argon and then heated to 75° C. for 18 h. Upon cooling to room temperature, the reaction mixture is quenched with H2O (5 mL) and extracted with diethyl ether (2×10 mL). The combined organics are washed with brine, dried over MgSO4, filtered, and concentrated. The crude oil is purified by flash chromatography (12 g RediSep flash cartridge, hexanes to 1.5% ethyl acetate/hexanes) to give 307 mg (42%) of ((E)-5-(3-methoxyphenyl)pent-4-en-1-ynyl)trimethylsilane as an oil. 1H NMR (acetone-d6, 400 MHz) δ 7.23 (d, J=8.1 Hz, 1H), 6.99-6.97 (m, 2H), 6.80 (m, 1H), 6.65 (dt, J=15.7, 1.7 Hz, 1H), 6.26 (dt, J=15.7, 5.7 Hz, 1H), 3.8 (s, 3H), 3.19 (dd, J=5.7, 1.8 Hz, 2H), 0.16 (s, 9H). Reference: Tunge, J. A.; rayabarapu, D. K. J. Am. Chem. Soc. 2005, 127, 13510-13511.

Provenance & Evidence