Regioselective Co(III)-Catalyzed C–H Functionalization of 2-Pyridones with Allenes

A novel and efficient Co-catalyzed strategy for the direct regioselective C6-H allylation and dienylation of 2-pyridones is proposed. This method employs a simple Co catalyst system to efficiently provide diverse C6-allylated derivatives with excellent regioselectivity and <i>Z</i>-selectivity (<i>Z</i>:<i>E</i> > 20:1). Concurrently, linear 1,3-dienylated products are generated in good yields with outstanding regioselectivity and stereoselectivity (predominantly <i>E</i>,<i>E</i>-dienes). DFT calculations also clarified the origin of the high selectivity. This reaction proceeds under mild conditions and tolerates various functional groups. Late-stage modifications and photophysical property studies showing controlled fluorescence characteristics highlight the practical value of this strategy.