Duvinage D, Mebs S, Beckmann J. Isolation of an Antiaromatic 9-Hydroxy Fluorenyl Cation.
Chemistry 2021;
27:8105-8109. [PMID:
33835609 PMCID:
PMC8252458 DOI:
10.1002/chem.202100786]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Indexed: 11/12/2022]
Abstract
Fluorenyl cations are textbook examples of 4π electron antiaromatic five-membered ring systems. So far, they were reported only as short-lived intermediates generated under superacidic conditions or by flash photolysis. Attempts to prepare a m-terphenyl acylium cation by fluoride abstraction from a benzoyl fluoride gave rise to an isolable 9-hydroxy fluorenyl cation that formed by an intramolecular electrophilic attack at a flanking mesityl group prior to a 1,2-methyl shift and proton transfer to oxygen.
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