SEARCH Articles Figures Tables 2.6- Dimethyl-4/7-pyran Acetylenedicarboxylate Acetylenedicarboxylates Pyrans, 3,4-dihydroreaction with dimethyl acetylenedicarboxylate dihydrooxacine synthesis Pyrans, 3,4-dihydroreaction with dimethyl acetylenedicarboxylate glycal synthesis Pyrans, 3,4-dihydroreaction with dimethyl acetylenedicarboxylate synthesis Pyrans, 3,4-dihydroreaction with dimethyl acetylenedicarboxylate via Diels-Alder reaction