The Construction Of C(Sp(3))-O Bond Via Copper Porphyrin Catalyzed Cross-Dehydrogenative Coupling Reaction: Substituent And Electronic Effect Of The Catalysts

The push-pull electronic and steric effect of copper porphyrin catalysts on the cross-dehydrogenative coupling (CDC) reaction between the hydroxyl group of phenol substrates and C(sp(3))-H bond have been investigated. Results showed that copper porphyrin bearing electron-withdrawing, bulky steric hindrance or heteroatom of pyridyl groups could increase the catalytic activity in the reaction. 5,10,15,20-(tetrakis(4-pyridyl)porphyrin)copper (CuTPyP) was found the best among all tested catalysts. Phenol substrates bearing various functional groups afforded moderate to excellent yields (99%). Significantly, as compared to other tested copper porphyrins, CuTPyP not only exhibited remarkable higher activity but also could shorten the reaction time from 12 to 6 h.