The Generation of Anthra[2,3-c]furan via Aromatic-Ring Homologation of Naphtho[2,3-c]furan

Abstract

Anthra[2,3-c]furan, a higher aromatic homologue of isobenzofuran, has been predicted to be a highly reactive polyene lacking any significant aromatic character despite being a 14 π-electron system. We have generated this previously inaccessible molecule by acid-catalyzed elimination of methanol from an acetal precursor, and have trapped it with several dienophiles. The overall reaction sequence describes an aromatic-ring homologenation of naphtho[2,3-c]furan to anthra[2,3-c]furan.