Nickel‐Catalyzed Regioselective Cyclotrimerization of Terminal Alkynes to 1,3,5‐Trisubstituted Benzenes

Herein, we report a synthetic strategy for the efficient construction of 1,3,5‐trisubstituted benzene derivatives via nickel‐catalyzed regioselective cyclotrimerization of terminal alkynes. The reaction proceeds smoothly employing Ni(dppf)Cl 2 as the catalyst and pinacolborane (HBpin) as an additive, with the highest yield up to 84%. This transformation features mild conditions, easy operation, excellent regioselectivity, and high functional group tolerance. We conduct preliminary mechanistic studies via isotope labeling experiments.