Ambident nucleophilic reactivity in σ-complex formation. Part 5. Reaction of 1-phenyl-2,4,6-trinitrobenzene with methoxide and phenoxide ions

Abstract

The reactions of 1-phenyl-2,4,6-trinitrobenzene (4) with methoxide and phenoxide ions in DMSO and DMSO–methanol solutions have been investigated. MeO− gives rise to a 1,3 adduct through kinetic control and a 1,1 adduct through thermodynamic control. These processes persist also in the reaction of 4 with potassium phenoxide in DMSO–methanol. However, reaction of 4 with potassium phenoxide in DMSO gives rise to a 1,3 adduct as the only observed species in which phenoxide is bonded to the nitroaromatic moiety via the para phenoxy carbon, in accord with previous observations on the ambident reactivity of phenoxide ion. The results are considered in terms of various steric and electronic effects and it is concluded that F-strain, relief of steric compression, and delocalizability considerations play dominant roles in accounting for the observed reaction course.