Transition-metal-catalyzed[2+ 2+ 2] cycloaddition reactions that use two alkynes and a nitrile is the most straightforward and powerful strategy for the construction of multisubstituted pyridines with high atom efficiency.[1, 2] The iron-catalyzed [2+ 2+ 2] cycloaddition to form pyridines remains a great challenge in this field,[3, 4] although significant efforts have been made in various catalytic systems (eg Co,[5] Ru,[6] Rh,[7] Ni,[8] Ti,[9] Zr/Ni [10]) in the last ...
