Nickel-Catalyzed [5+2] Cycloaddition of 10π-Electron Aromatic Benzothiophenes with Alkynes To Form Thermally Metastable 12π-Electron Nonaromatic Benzothiepines.
Tasuku InamiToshifumi TakahashiTakuya KurahashiSeijiro MatsubaraPublished in: Journal of the American Chemical Society (2019)
The nickel-catalyzed formal [5+2] cycloaddition of five-membered benzothiophenes and alkynes giving seven-membered benzothiepines via unprecedented dearomatization is reported. The reaction involves the carbothiolation of alkynes with sulfur-containing aromatic heterocycles affording sulfur-containing heterocyclic compounds via ring expansion. As a result, this method facilitates divergent access to thermally metastable benzothiepines. The structure of the thianickelacycle intermediate, which is formed via oxidative addition of the C-S bond in benzothiophenes to nickel(0), was confirmed by in situ X-ray absorption fine structure spectroscopy and density functional theory calculation.
Keyphrases
- density functional theory
- reduced graphene oxide
- oxide nanoparticles
- high resolution
- room temperature
- molecular dynamics
- electron transfer
- carbon nanotubes
- metal organic framework
- electron microscopy
- amino acid
- solar cells
- single molecule
- light emitting
- magnetic resonance
- magnetic resonance imaging
- gold nanoparticles
- mass spectrometry
- dual energy
- ionic liquid
- monte carlo
- transition metal