The Rh (II)-catalyzed reaction of diazo 2-propynyl maolonamic acid ester derivatives produce furo [3, 4-c] furans in excellent yield. The methodology was applied to the synthesis of several polyheterocyclic systems by first generating a 2-alkoxy-substituted furan and then allowing it to undergo a subsequent intramolecular Diels-Alder cycloaddition. Ring opening of the resulting cycloadduct is followed by deprotonation to furnish a rearranged keto ...
