SEARCH Articles Figures Tables Diels acid Diels hetero Diels intramolecular Diels intramolecular reaction Diels-Alder reaction acids Hetero intramolecular Hetero-Diels-Alder Hetero-Diels-Alder reaction Hetero-Diels-Alder reactions intramolecular Intramolecular Diels-Alder Intramolecular Diels—Alder reactions Lewis acid Intramolecular hetero-Diels-Alder Lewis acids Diels-Alder reaction Lewis acids hetero-Diels-Alder reaction Lewis reactions