DABCO‐Promoted Bicyclization/Rearrangement Reaction Synthesis of Tetrasubstituted Furans and Furo[3,4‐d]pyrimidine‐2,4‐diones from 1,4‐Enediones

Abstract A DABCO‐promoted bicyclization/rearrangement reaction has been developed for the synthesis of tetrasubstituted furans from 1,4‐enediones at room temperature. This transformation involves aza‐Michael addition, intramolecular bicyclization, and rearrangement processes. In addition, the 4‐ureidofuran‐3‐carboxylate ester products can further be converted to furo[3,4‐ d ]pyrimidine‐2,4‐diones through intramolecular substitution cyclization under heating conditions.