Silver-mediated fluorodestannylation of an electron-rich thieno[3,2- b ]thiophene diverts to oxygenation: an α-fluorothiophenone instead of an aryl fluoride
Abstract
Fluorination of the terminal acceptor unit is a reliable way to deepen the LUMO level and enhance the electron mobility of quinoidal n-type organic semiconductors, yet no fluorinated analogue of the thieno[3,2- b ]thiophene-fused acceptor TTC has been reported. Two routes to such an acceptor were examined. In a late-stage approach, the tricyclic 1,3-dione core was assembled first; under Pd(0)-catalyzed stannylation conditions, however, its doubly activated methylene group rather than the C–Br bond was engaged, as confirmed by a control experiment with a monoketone analogue. In an early-stage approach, a bicyclic thienothiophene stannane was subjected to silver-mediated fluorodestannylation with Selectfluor TM . Instead of the expected aryl fluoride, an α-fluorothiophenone was isolated and its structure established by HRMS and multinuclear NMR spectroscopy. Its formation is consistent with the interception of the aryl–silver intermediate by oxygen, followed by tautomerization and α-fluorination. In the absence of silver, the stannane underwent oxidative homocoupling without fluorine incorporation. These results reveal a limitation of silver-mediated fluorodestannylation on π-excessive fused thiophenes.
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BibTeX
@article{chuan2026silvermediated,
title = {{Silver-mediated fluorodestannylation of an electron-rich thieno[3,2- b ]thiophene diverts to oxygenation: an α-fluorothiophenone instead of an aryl fluoride}},
author = {Hai-Tung Chuan and Li-Shin Shen and Huai-En Yu and Chia-Chi Chen and Jin-Pei Deng and Rong-Jiun Sheu and Chung-Shan Yu},
journal = {Beilstein Journal of Organic Chemistry},
year = {2026},
month = nov,
doi = {10.3762/bjoc.22.124},
url = {https://www.beilstein-journals.org/bjoc/articles/22/124},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Silver-mediated fluorodestannylation of an electron-rich thieno[3,2- b ]thiophene diverts to oxygenation: an α-fluorothiophenone instead of an aryl fluoride
AU - Hai-Tung Chuan
AU - Li-Shin Shen
AU - Huai-En Yu
AU - Chia-Chi Chen
AU - Jin-Pei Deng
AU - Rong-Jiun Sheu
AU - Chung-Shan Yu
PY - 2026
DA - 2026/11/02
JO - Beilstein Journal of Organic Chemistry
DO - 10.3762/bjoc.22.124
UR - https://www.beilstein-journals.org/bjoc/articles/22/124
AB - Fluorination of the terminal acceptor unit is a reliable way to deepen the LUMO level and enhance the electron mobility of quinoidal n-type organic semiconductors, yet no fluorinated analogue of the thieno[3,2- b ]thiophene-fused acceptor TTC has been reported. Two routes to such an acceptor were examined. In a late-stage approach, the tricyclic 1,3-dione core was assembled first; under Pd(0)-catalyzed stannylation conditions, however, its doubly activated methylene group rather than the C–Br bond was engaged, as confirmed by a control experiment with a monoketone analogue. In an early-stage approach, a bicyclic thienothiophene stannane was subjected to silver-mediated fluorodestannylation with Selectfluor TM . Instead of the expected aryl fluoride, an α-fluorothiophenone was isolated and its structure established by HRMS and multinuclear NMR spectroscopy. Its formation is consistent with the interception of the aryl–silver intermediate by oxygen, followed by tautomerization and α-fluorination. In the absence of silver, the stannane underwent oxidative homocoupling without fluorine incorporation. These results reveal a limitation of silver-mediated fluorodestannylation on π-excessive fused thiophenes.
SN - 1860-5397
ER -