Open AccessToward 2-Thiophyne: Ketocarbene versus Hetaryne Intermediates from 2-(Trimethylsilyl)thiophen-3-yl Triflate
Author(s) -
Iago Pozo,
Agustín Cobas,
Diego Peña,
Enrique Guitián,
Dolores Pérez
Publication year - 2021
Publication title -
organic letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.94
H-Index - 239
eISSN - 1523-7060
pISSN - 1523-7052
DOI - 10.1021/acs.orglett.1c02552
Subject(s) - trifluoromethanesulfonate , trimethylsilyl , chemistry , thiophene , trimethylsilyl trifluoromethanesulfonate , medicinal chemistry , trapping , stereochemistry , organic chemistry , catalysis , ecology , biology
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.