SEARCH Articles Figures Tables Acidity in Diels-Alder Catalysts Diels-Alder Diels acid Diels-Alder reaction acids In Diels-Alder reactions In Lewis acids In the Diels-Alder In the Diels-Alder reaction Lewis acid catalyst, in the Lewis acids Diels-Alder reaction Lewis acids in Diels-Alder reaction Lewis catalysts Lewis reactions