Meta‐Selective Copper‐Catalyzed C−H Arylation of Pyridines and Isoquinolines through Dearomatized Intermediates

C(sp2)−H functionalization offers an efficient strategy for the synthesis of various elaborated N‐containing heteroarenes. Along these lines, oxazino pyridines that can be readily prepared from pyridines, have been introduced as powerful substrates in radical‐ and ionic‐mediated meta‐C−H functionalization. However, the regioselective meta‐C−H arylation of pyridines remains a great challenge. Herein, a copper‐catalyzed meta‐selective C−H arylation of pyridines and isoquinolines through bench‐stable dearomatized intermediates is reported. Electrophilic aryl‐Cu(III) species, generated from readily accessible aryl I(III) reagents, enable the efficient meta‐arylation of a broad range of pyridines and isoquinolines. The method also allows the meta‐selective alkenylation of these heteroarenes using the corresponding alkenyl I(III)‐reagents. Late‐stage arylation of drug‐derived pyridines and larger‐scale experiments demonstrate the potential of this synthetic methodology. Meta‐arylated pyridines are prepared via bench stable oxazino pyridine intermediates with unsymmetrical iodonium salts using Cu‐catalysis. The strategy can be applied for meta‐alkenylation upon simply switching to the corresponding alkenyl I(III) reagents and both C‐H‐functionalizations also work on isoquinolines.