Gold-Catalyzed 1,2-Aryl Shift and Double Alkyne Benzannulation.

Area of Science:

• Organic Chemistry
• Materials Science
• Catalysis

Background:

• The 1,4-dihydropyrrolo[3,2-b]pyrrole scaffold possesses unique electron-rich properties.
• Intramolecular hydroarylation of alkynes is a key synthetic transformation.

Purpose of the Study:

• To develop a novel synthetic route to π-expanded, centrosymmetric pyrrolo[3,2-b]pyrroles.
• To explore the utility of a gold catalyst in tandem reactions involving aryl shifts.

Main Methods:

• Tandem intramolecular hydroarylation of alkynes catalyzed by cationic gold.
• Synthesis of 13 diverse products bearing six conjugated rings.
• Computational studies (DFT) to elucidate reaction mechanism and properties.

Main Results:

• Discovery of a novel reaction pathway leading to π-expanded pyrrolo[3,2-b]pyrroles via a 1,2-aryl shift.
• Demonstration of functional group compatibility, enabling tunable photophysical properties.
• Observation of high fluorescence quantum yields in the synthesized N-doped nanographenes.

Conclusions:

• The developed gold-catalyzed reaction provides access to unprecedented N-doped nanographenes.
• The synthesized materials exhibit promising photophysical properties for potential applications.
• The reaction mechanism favors six-membered ring formation with a 1,2-aryl shift.