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