Iodonium ylide 2, derived from 1, 3-cyclohexadione, undergoes thermal [3+ 2]-cycloaddition with acetonitrile, carbon disulfide and p, p′-dimethoxythiobenzophenone with Cu (acac) 2 catalysis to form the corresponding 5-membered heterocycles and alkene respectively. Photochemically 2 reacts with various alkenes and dienes to form dihydrofuran derivatives, key intermediates for paniculide A, B and pentalene synthesis.