Practical Synthesis of α-Trifluoromethylated Pyridines Based on Regioselective Cobalt-Catalyzed [2+2+2] Cycloaddition using Trifluoromethylated Diynes with Nitriles

Regioselective cobalt-catalyzed [2+2+2] cycloaddition using fluorine-containing diynes with nitriles was described. Cycloaddition of fluorinated diynes with nitriles under the influence of CoCl2(phen), zinc bromide, and zinc dust in dichloroethane at 80 degrees C for 3 h took place smoothly, exclusively affording the corresponding alpha-fluoroalkylated pyridines in excellent yields. In addition, dinitriles as substrate were also found to be suitable for this reaction, giving the corresponding fluoroalkylated bipyridine derivatives in excellent yields.

Automated summary

A regioselective cobalt-catalyzed [2+2+2] cycloaddition using fluorine-containing diynes with nitriles was successfully achieved, leading to the synthesis of α-fluoroalkylated pyridines in excellent yields. The reaction was conducted smoothly at 80 degrees C for 3 h using CoCl2(phen), zinc bromide, and zinc dust in dichloroethane. Additionally, dinitriles were also found to be suitable substrates for this reaction, yielding fluoroalkylated bipyridine derivatives in excellent yields.