The enones (II), which were obtained from dimethyl 4, 5-isopropylidenedioxy-2-oxopentylphosphonate (Ia) and various aldehydes, were easily converted to 2-alkenylfurans (III) by treatment with p-TsOH in MeOH. In a similar manner, the furfuryl phosphonate (IVa) and the 3-methylfurfuryl phosphonate (IVb) were obtained from Ia and its 3-methylated analogue (Ib), respectively.