Synthesis of 2,4,6-Trisubstituted Pyrimidines through Copper-Catalyzed [4+2] Annulation of a,ss-Unsaturated Ketoximes with Activated Nitriles

The copper-catalyzed [4 + 2] annulation of a,ss-unsaturated ketoximes with activated nitriles for the rapid construction of 2,4,6-trisubstituted pyrimidines in moderate to good yields has been developed. The reaction features synthetic simplicity, good functional group tolerance, and gram-scale applicability. A plausible mechanism is proposed based on mechanistic investigations.