Toward 2‑Thiophyne: Ketocarbene versus Hetaryne Intermediates from 2‑(Trimethylsilyl)thiophen-3-yl Triflate

The reaction of 2-(trimethylsilyl)­thiophen-3-yl triflate with CsF in the presence of 2,3,4,5-tetraphenylcyclopentadienone affords 4,5,6,7-tetraphenylbenzo­[b]­thiophene, as it would be expected from the hypothesized generation and trapping of 2-thiophyne. However, a detailed experimental and comput...

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Bibliographic Details
Published in:Organic letters 2021-10, Vol.23 (19), p.7376-7380
Main Authors: Pozo, Iago, Cobas, Agustín, Peña, Diego, Guitián, Enrique, Pérez, Dolores
Format: Article
Language:English
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Summary:The reaction of 2-(trimethylsilyl)­thiophen-3-yl triflate with CsF in the presence of 2,3,4,5-tetraphenylcyclopentadienone affords 4,5,6,7-tetraphenylbenzo­[b]­thiophene, as it would be expected from the hypothesized generation and trapping of 2-thiophyne. However, a detailed experimental and computational study discards the intermediacy of this elusive 5-membered hetaryne. Instead, a complex mechanism involving the generation of an intermediate ketocarbene, which adds to the cyclopentadienone to give an isolable tricyclic intermediate, followed by thermal rearrangements, is proposed.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.1c02552