Development of New Methods for the Synthesis of N-Heteroarenes from Nitroarenes and Anilines

This thesis focuses on unlocking the reactivity embedded in nitroarenes and anilines to construct N-heterocycles. The first part of this work shows that exposure of nitrostilbenes to sodium tert-butoxide was found to produce N-hydroxyindoles at room temperature without an additive. Changing the counterion to potassium changed the reaction outcome to yield solely oxindoles through an unprecedented dioxygen-transfer reaction followed by a 1,2-phenyl migration. Mechanistic experiments using EPR spectroscopy, crown ether and isotopically labeled substrates established that these reactions proceed via radical intermediates and suggest that counterion coordination controls whether an oxindole or N-hydroxyindole product is formed. The next part of this work develops two novel electrochemical cyclization reactions for the synthesis of quinoline N-oxide and 3H-indoles. We found that the nitro radical anion from nitroarenes and nitrenoid or nitrene intermediates from anilines could be generated through SET process directly from electricity. The scopes and potential mechanisms are also investigated in this part. The last section in this thesis is exploring the application of a formerly developed Cu-catalyzed cross-coupling reactions to construct diarylamines. This reaction is optimized in a large-scale synthesis to show the robustness of this reaction system.