Facile synthesis of tricyclo[5.4.0.0 1,5]undec-9-ene-8,11-diones from phenols with an olefin bearing an electron-attracting group at the side chain

Abstract

3,4-Dimethoxyphenol with a trans p-nitrostyryl group at the side chain was electrolyzed in acetic anhydride containing nBu 4NBF 4 to afford a tricyclo[5.3.1.0 1,5]undec-9-ene-8,11-dione, while the cis isomer was converted into a tricyclo[5.4.0.0 1,5]undec-9-ene-8,11-dione as a major product. In the case of several phenols with an α,β-unsaturated ketone or ester grouping, the corresponding tricyclo[5.4.0.0 1,5]undec-9-ene-8,11-diones were also obtained in good yields.