The Alkylidenphthalan–1-Alkylisobenzofuran Equilibrium: A Computational Study

Semiempirical (AM1, PM3) and density functional theoretical studies (B3LYP/6-31G*) are reported for the tautomerism of 2-methylidene-2,5-dihydrofurans (3a–e) and the corresponding 2-methylfurans (4a–e) and of benzannulated derivatives (5a–e, 6a–e, 7–14).