Feofanov M, Akhmetov V, Takayama R, Amsharov K. Catalyst-Free Synthesis of O-Heteroacenes by Ladderization of Fluorinated Oligophenylenes.
Angew Chem Int Ed Engl 2021;
60:5199-5203. [PMID:
32924244 PMCID:
PMC7986400 DOI:
10.1002/anie.202007427]
[Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/19/2020] [Indexed: 01/19/2023]
Abstract
A novel catalyst-free approach to benzoannulated oxygen-containing heterocycles from fluorinated oligophenylenes is reported. Unlike existing methods, the presented reaction does not require an oxygen-containing precursor and relies on an external oxygen source, potassium tert-butoxide, which serves as an O2- synthon. The radical nature of the reaction facilitates nucleophilic substitution even in the presence of strong electron-donating groups and enables de-tert-butylation required for the complete annulation. Also demonstrated is the applicability of the method to introduce five-, six-, and seven-membered rings containing oxygen, whereas multiple annulations also open up a short synthetic path to ladder-type O-heteroacenes and oligodibenzofurans.
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