Copper‐Catalyzed Regioselective Cascade Alkylation and Cyclocondensation of Quinoline N ‐Oxides with Diazo Esters: Direct Access to Conjugated π‐Systems

An inexpensive copper‐catalyzed cascade regioselective alkylation, followed by cyclocondensation of quinoline N ‐oxides with α‐diazo esters has been achieved successfully to provide heteroarene‐containing conjugated π‐systems. The developed method is simple, straightforward, and economical with a broad range of substrate scope. The dual role of copper catalyst in the C−H bond functionalization and in Lewis acid‐promoted cyclization was explored.