SEARCH Articles Figures Tables 2- furan, Diels-Alder Diels furan Diels intramolecular Diels intramolecular reaction Diels-Alder reaction 2- furans Diels-Alder reactions of furans Intramolecular Diels-Alder Intramolecular Diels-Alder reactions furan Of Diels-Alder reactions