RING-CHAIN TAUTOMERISM OF 1-HYDROXYPHTHALANS. AN EXAMINATION OF STRUCTURAL EFFECTS.

Article abstract of DOI:10.1016/S0040-4020(01)91115-9

1,3-Dihydro-1-isobenzofuranol,(1-hydroxyphthalan) and 2-(hydroxymethyl)-benzaldehyde exist in a tautomeric equilibrium.The effects of molecular structure on this equilibrium was examined using various derivatives of dihydroisobenzofuranol.Two effects of this molecular modification were identified: (i) 1-arylmethyl substituents favored the ring-opened tautomer if steric effects arose in the ring closed form and (ii) extending the conjugated system of the dihydroisobensofuran ring (i.e. dihydronaphto<2,3-c> furan also favored the ring opened form.These effects are discussed.