Microwave-Assisted Improved Regioselective Synthesis of 12<i>H</i>-Benzopyrano[3,2-<i>c</i>][1]benzopyran-5-ones by Radical Cyclisation

<table>Method A: LiOH, TBAB, DMF, 40–50°C; Method B: MWI (4–10 min), TBAB, K<sub>2</sub>CO<sub>3</sub>.</table>

Organic Chemistry International

Scheme 1: Microwave-Assisted Improved Regioselective Synthesis of 12<i>H</i>-Benzopyrano[3,2-<i>c</i>][1]benzopyran-5-ones by Radical Cyclisation 