Metal-catalyzed thermal reactions of cyclic β-dicarbonyl phenyliodonium ylide with styrenes.

A cyclic β-dicarbonyl phenyliodonium ylide reacted with various substituted styrenes under Rh2(OAc)4 catalysis to give cyclopropanes and dihydrofurans in a highly regioselective fashion. When styrenes with electron-donating substituents or disubstituted were employed, only dihydrofurans were isolated instead. A mechanism involving two competing pathways rationalizes the results.