A new iron(III)-catalyzed synthesis of beta-oxo sulfones is described that employs vinylarenes and readily available dimethyl sulfoxide (DMSO) with hydrazine and oxygen as the oxidant. The reaction tolerates various functional group substituents on the vinylarene substrates to afford beta-oxo sulfones in moderate to good yields. The cleavage and formation of the C-S bond are the key steps of this transformation