Intramolecular hetero-Diels-Alder reactions of functionalized α,β-unsaturated carbonyl compounds: Polycyclic 2H-pyran derivatives

Article abstract of DOI:10.1007/PL00010261

The reaction of benzoylacetonitrile, methyl cyanoacetate, and ethyl benzoylacetate with 2-allyloxy-and 2-(3-methyl-2-butenyloxy)-benzaldehyde as well as 2-(3-methyl-2-butenyloxy)-1-naphthaldehyde afforded the corresponding Knoevenagel condensation products. Some of those underwent spontaneous intramolecular cycloaddilion to give cis-fused 2H-pyran derivatives as major products. One-pot reactions of 1,3-cyclohexanedione and 5,5-dimethyl-1,3-cyclohexancdione with 2-(3-inethyl-2-butenyloxy)-benzaldehyde and 2-(3-methyl-2-butenyloxy)-1-naphthaklehyde resulted in Diels-Alder cycloadducts.