Copper-mediated C6-selective dehydrogenative heteroarylation of 2-pyridones with 1,3-azoles

Abstract

A copper-mediated C6-selective dehydrogenative heteroarylation of 2-pyridones with 1,3-azoles has been developed. The reaction proceeded smoothly by twofold C-H cleavage even in the absence of noble-metal catalysts. The observed site selectivity was directed by a pyridyl substituent on the nitrogen atom of the pyridone ring. This directing group was readily removed after the coupling event, thus leading to 2-pyridone derivatives with a free N-H group. Moreover, in some cases, catalytic turnover of the Cu salt was also possible with the ideal terminal oxidant: molecular oxygen in air.

Keywords: CH cleavage; arylation; copper; pyridones; synthetic methods.