Cu-Catalyzed Concise Synthesis of Pyridines and 2-(1<i>H</i>)-Pyridones from Acetaldehydes and Simple Nitrogen Donors

Abstract

A highly selective copper-catalyzed concise synthesis of 3,5-diarylpyridine and 2-(1H)-pyridone has been achieved through cascade Chichibabin-type cyclization, C(sp3)–C(sp3) cleavage, and aerobic oxidation. Azide, ceric ammonium nitrate (CAN), and 2-aminopyridine are disclosed as efficient nitrogen donors in this Cu-catalysis using O2 as the oxidant. Water and molecular oxygen were employed as the oxygen source in the case of oxygenation.