SOLVOLYSIS OF 3-ALKENYL-2-CYCLOHEXENYL ESTERS

Article abstract of DOI:10.1016/S0040-4020(01)81740-3

In an attempt to study possible ?-participation in allyl-dervatives, 3-alkenyl-5,5-dimethyl-2-cyclohexenyl p-nitrobenzoates 4 and 2-alkenyl-3-methyl-2-cyclohexenyl p-nitrobenzoates 5 were solvolyzed in 97 wt percent trifluoroethanol and 80 vol percent ethanol.Water soluble 1-methyl-3-(3-alkenyl-5,5-dimethyl-2-cyclohexenyl)pyridinium iodides 6 were solvolyzed in water and in aqueous solvents, as well as under micellar conditions.All esters show in each of the solvents normal values of secondary α-deuterium isotope effects (k_H/k_D = 1.17-1.23).Also in comparison to saturated analogues the investigated esters show a lower solvolytic reactivity.On the basis of these results it was concluded that the solvolysis proceeds via a stepwise mechanism involving a resonance-stabilized cyclohexenyl cation as the reaction intermediate.