Triethylamine → 5-ethenyl-2,2-dimethyl-4H-1,3-benzodioxin-4-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 2,2-dimethyl-5-trifluoromethanesulfonyloxy-4H-1,3-benzodioxin-4-one (9.90 g, 30.3 mmol), tributyl(vinyl)tin (10.10 g, 31.9 mmol), lithium chloride (8.70 g, 205 mmol), and triethylamine (5.0 mL, 36.0 mmol) in 1,4-dioxane (300 mL) was deoxygenated by bubbling nitrogen through the mixture for 1 h. To the mixture was added tetrakis(triphenylphosphine)palladium (3.40 g, 2.90 mmol) and the mixture was heated at 100° C. for 3 h. The mixture was allowed to cool to rt and was filtered. The filtrate was concentrated and purified by flash chromatography (1:12, EtOAc/hexanes) to provide 5-ethenyl-2,2-dimethyl-4H-1,3-benzodioxin-4-one (5.00 g, 81%) as a yellow oil: 1H NMR: (CDCl3) δ 1.72 (s, 6H), 5.43 (dd, J=11.0, 1.3 Hz, 1H), 5.72 (dd, J=17.5, 1.3 Hz, 1H), 6.89 (d, J=8.0 Hz, 1H), 7.27 (d, J=8.0 Hz, 1H), 7.47 (t, J=8.0 Hz, 1H), 7.73 (dd, J=17.5, 11.0 Hz, 1H).

Provenance & Evidence