Prof. Daniel T. Gryko, Gana Sanil and Dr. Maciej Krzeszewski, together with colleagues from Warsaw University and from France, discovered the unprecedented tandem intramolecular hydroarylation of alkynes accompanied by a 1,2-aryl shift. Harnessing the unique electron-rich character of 1,4-dihydropyrrolo[3,2-b]pyrrole scaffold, they demonstrated that the hydroarylation of alkynes proceeds at the already occupied positions 2 and 5 leading to a 1,2-aryl shift. Remarkably, the reaction proceeds only in the presence of cationic gold catalyst, and it leads to heretofore unknown π-expanded, centrosymmetric pyrrolo[3,2-b]pyrroles. Computational studies of the reaction mechanism revealed that the formation of the six-membered rings accompanied with a 1,2-aryl shift is both kinetically and thermodynamically favorable over plausible formation of products containing 7-membered rings. The key input was provided by Prof. Witold Danikiewcz, Dr hab. Wojciech Chaładaj and Dr. Olga Staszewska-Krajewska.
The results were published in Angewandte Chemie Int. Ed. “Gold-Catalyzed 1,2-Aryl Shift and Double Alkyne Benzannulation”: https://onlinelibrary.wiley.com/doi/10.1002/anie.202311123