Computational, Mechanistic, and Experimental Insights into Regioselective Catalytic C–C Bond Activation in Linear 1-Aza-[3]triphenylene

[Image: see text] C–C bond activation by transition metal complexes in ring-strained compounds followed by annulation with unsaturated compounds is an efficient approach to generate structurally more complex compounds. However, the site of catalytic C–C bond activation is difficult to predict in unsymmetrically substituted polycyclic systems. Here, we report a study on the (regio)selective catalytic cleavage of selected C–C bonds in 1-aza-[3]triphenylene, followed by annulation with alkynes, forming products with extended π-conjugated frameworks. Based on density functional theory (DFT) calculations, we established the stability of possible transition metal intermediates formed by oxidative addition to the C–C bond and thus identified the likely site of C–C bond activation. The computationally predicted selectivity was confirmed by the following experimental tests for the corresponding Ir-catalyzed C–C cleavage reaction followed by an alkyne insertion that yielded mixtures of two mono-insertion products isolated with yields of 34–36%, due to the close reactivity of two bonds during the first C–C bond activation. Similar results were obtained for twofold Ir- or Rh-catalyzed insertion reactions, with higher yields of 72–77%. In a broader context, by combining DFT calculations, which provided insights into the relative reactivity of individual C–C bonds, with experimental results, our approach allows us to synthesize previously unknown pentacyclic azaaromatic compounds.