Differing Behavior of Pyrrolidine and Pyperidine as Nucleophiles toward 2,4-Dinitrophenyl and 2,4-Dinitro-6-methylphenyl Phenyl Ethers

Article abstract of DOI:10.1021/ja00406a031

Kinetics of the hydroxydephenoxylation reactions of the two title ethers with NaOH and of their aminodephenoxylation reactions with pyrrolidine and piperidine have been determined.The solvent was 60percent dioxane/40percent water.The 6-methyl groups retard reactions with all three nucleophiles.The four aminodephenoxylation reactions are all catalyzed by NaOH, but the pattern of catalysis varies as the amine is changed and as 6-methyl group is introduced.The data are consistent with the S_NAr mechanism.Quantitative dissection of the data reveals that the rate of base-catalyzed transformation of the intermediate ? adduct to products is an order of magnitude faster, relative to the rate of reversion to reactants, for pyrrolidine than for piperidine reactions.As to the mechanism of base catalysis, these results are more consistent with rate-limiting nucleofuge detachment from the conjugate base of the ? adduct than with rate-limiting proton transfer from the ? adduct to base.