Carbon Dioxide → 8-Oxatricyclo(7.4.0.0,2,7)trideca-1(9),2(7),3,5,10,12-hexaene-6-carboxylic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 1.6M n-butyllithium in hexane (18.5 ml) was added dropwise to a stirred solution of dibenzofuran (5.0 g) in anhydrous THF (25 ml) at −78° C. under a nitrogen atmosphere. The resulting suspension was allowed to warm to 20° C. where it was stirred for 3 h. It was then cooled to −78° C. and added to a mixture of excess solid carbon dioxide in diethyl ether (250 ml) under a nitrogen atmosphere. The resulting white suspension was allowed to stand for 1 h at 20° C. and was then diluted with 2M sodium hydroxide (500 ml). The aqueous extract was washed with ether (3×200 ml), acidified to pH 1 with 6M hydrochloric acid and extracted with ethyl acetate (3×200 ml). The combined organic extracts were washed with brine (50 ml), dried over magnesium sulphate and evaporated in vacuo to give the title compound as a white solid (3.64 g, 58%). LCMS: Rt 5.06 min; m/z 213 (MH+).

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