Zanetti D, Matuszewska O, Giorgianni G, Pezzetta C, Demitri N, Bonifazi D. Photoredox Annulation of Polycyclic Aromatic Hydrocarbons.
JACS AU 2023;
3:3045-3054. [PMID:
38034957 PMCID:
PMC10685425 DOI:
10.1021/jacsau.3c00438]
[Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 12/02/2023]
Abstract
The rise of interest in using polycyclic aromatic hydrocarbons (PAHs) and molecular graphenoids in optoelectronics has recently stimulated the growth of modern synthetic methodologies giving access to intramolecular aryl-aryl couplings. Here, we show that a radical-based annulation protocol allows expansion of the planarization approaches to prepare functionalized molecular graphenoids. The enabler of this reaction is peri-xanthenoxanthene, the photocatalyst which undergoes photoinduced single electron transfer with an ortho-oligoarylenyl precursor bearing electron-withdrawing and nucleofuge groups. Dissociative electron transfer enables the formation of persistent aryl radical intermediates, the latter undergoing intramolecular C-C bond formation, allowing the planarization reaction to occur. The reaction conditions are mild and compatible with various electron-withdrawing and -donating substituents on the aryl rings as well as heterocycles and PAHs. The method could be applied to induce double annulation reactions, allowing the synthesis of π-extended scaffolds with different edge peripheries.
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