Convenient synthesis of furo[2,3-c][1,2]dioxoles from 1-aryl-2-allylalkane-1,3-diones

Treatment of 1-aryl-2-allylalkane-1,3-diones with I2/H2O2 system in the presence of catalytic amount of phosphomolybdic acid affords furo[2,3-c][1,2]dioxole derivatives. With other acidic catalysts such as BF3 · Et2O, SnCl4, H2SO4 or TsOH, mixtures with linear 4-acyloxy-2,5-diiodoalkan-1-ones are formed.