Alternative synthetic approaches to (±)-euryfuran via the furan ring transfer reaction

Two effective synthetic approaches to (±)-euryfuran 1 are described. One synthetic route makes use of sequential furan ring transfer reaction type I and type III as key steps followed by Eschenmoser-type [3,3]sigmatropic rearrangement, and another route proceeded through furan ring transfer reaction type I and annulation with ethyl vinyl ketone subsequently.