Studies on the sequential multi-component coupling/Diels–Alder cycloaddition reaction

The synthesis of highly functionalized oxabicyclo[2.2.1]heptadiene derivatives through the sequential use of an Ugi or Passerini multi-component coupling reaction followed by an intramolecular acetylene/furan Diels–Alder reaction was investigated. The nature of the heteroatom in the tether was determined to play a critical role.