Visible‐Light‐Mediated [4+2] Annulation of N‐Cyclobutylanilines with Alkynes Catalyzed by Self‐Doped Ti3+@TiO2
Document Type
Article - Abstract Only
Publication Date
2017
Keywords
Annulation, Cyclobutylaniline, Photocatalysis, Singlet oxygen, Titanium, Visible light
Abstract
We herein report a visible‐light‐mediated heterogeneous [4+2] annulation of N‐cyclobutylanilines with alkynes catalyzed by self‐doped Ti3+@TiO2. The self‐doped Ti3+@TiO2 is stable under photooxidation conditions, easy to recycle, and can be used multiple times without appreciable loss of activity. Extensive mechanistic studies suggest that the annulation reaction is mediated by singlet oxygen, which is generated through the photosensitization of oxygen in the air by the self‐doped Ti3+@TiO2. In contrast, the homogeneous variant catalyzed by a far more expensive iridium complex proceeds under an inert atmosphere, which indicates a different mechanism. The substrate scopes of the two processes are comparable.
Citation
Wang, J., Mao, C., Feng, P., & Zheng, N. (2017). Visible‐Light‐Mediated [4+2] Annulation of N‐Cyclobutylanilines with Alkynes Catalyzed by Self‐Doped Ti3+@TiO2. Chemistry a European Journal, 23 (61), 15396-15403. https://doi.org/10.1002/chem.201701587
Comments
Principal Investigator: Nan Zheng
Acknowledgements: We thank the University of Arkansas, the Arkansas Bioscience Institute, the National Institute of Health (NIH) (grant number P30 GM103450) from the national Institute of General medical Science, and the NSF Career Award (Award Number CHE‐125539) for generous support of this research. Financial support of the project from the National Science Foundation (CHE‐1213795, P.F.) is also greatly appreciated.