Data di Pubblicazione:
2021
Citazione:
Diversified Syntheses of Tetrathia[7]helicenes by Metal-Catalyzed Cross-Coupling Reactions / V. Pelliccioli, D. Dova, C. Baldoli, C. Graiff, E. Licandro, S. Cauteruccio. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1434-193X. - 2021:3(2021 Jan 22), pp. 383-395. [10.1002/ejoc.202001382]
Abstract:
Efficient and versatile synthetic routes to functionalized tetrathia[7]helicenes (7-THs) are described. The key intermediates of these methodologies are 2-bromo-3,3′-bibenzo[1,2-b:4,3-b′]dithiophenes (1), synthesized through a palladium-catalyzed homocoupling reaction between two benzo[1,2-b:4,3-b′]dithiophene units followed by a regioselective α-bromination. Direct palladium-catalyzed annulation of bromides 1 with internal alkynes provides a set of 7,8-disubstituted 7-THs 2 in moderate to good yields (46-80 %). Otherwise, 7-monosubstituted 7-THs 4 have been prepared through Sonogashira coupling of 1 with terminal alkynes, followed by platinum- or indium-promoted cycloisomerization of alkynyl intermediates 6. Finally, the versatility of bromides 1 has also been demonstrated by using them for the preparation of benzo (hetero) fused 7-TH derivatives 7 via Suzuki coupling with (hetero)arylboronic acids and the photocyclization of the obtained intermediates 9.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
C−C coupling; Helicene chemistry; Sulfur heterocycles; Synthetic methodologies; Thiahelicene;
Elenco autori:
V. Pelliccioli, D. Dova, C. Baldoli, C. Graiff, E. Licandro, S. Cauteruccio
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