Abstract Iodine–ammonium acetate–mediated annealation of dimedone with aldehydes led to facile formation of spirodihydrofuran in good yields through tandem Knoevenagel–Michael iodonation and cyclodehydroiodonation reactions in a single pot.
Reaction of 5,5-dimethylcyclohexane-1,3-dione (dimedone), aldehydes and cyanogen bromide in the presence of triethylamine leads to the selective formation of spiro dihydrofurans in moderate to good yields at room temperature.