Electron-Transfer-Induced Reductive Dealkoxylation of Alkyl Aryl Ethers. III. Reductive Cleavage of Methoxy-Substituted N,N-Dimethylanilines

The reactivity of the three isomeric methoxy-substituted N, N-dimethylanilines (N, N-dimethylanisidines) and of N, N-dimethyl-2,6-dimethoxyaniline in the reduction with alkali metals in aprotic solvents was investigated. N, N-Dimethyl-p-methoxyaniline was found to be unreactive, while the other substrates underwent exclusive cleavage of carbon-oxygen bond(s), with the following order of reactivity: 2,6-dimethoxy>o-methoxy>m-methoxy>p-methoxy. Both the relative reactivity and the regioselectivity of cleavage (demethoxylation vs. demethylation) was found to parallel closely that of the corresponding di- and trimethoxy-substituted substrates. These results suggest that intermediates with different electron distribution or even different intermediates are involved in the reductive cleavage of aryl-oxygen and aryl-nitrogen bonds