Premium
Visible‐Light‐Mediated [4+2] Annulation of N ‐Cyclobutylanilines with Alkynes Catalyzed by Self‐Doped Ti 3+ @TiO 2
Author(s) -
Wang Jiang,
Mao Chengyu,
Feng Pingyun,
Zheng Nan
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201701587
Subject(s) - annulation , singlet oxygen , iridium , catalysis , visible spectrum , photochemistry , doping , homogeneous , oxygen , substrate (aquarium) , chemistry , inert , materials science , organic chemistry , physics , optoelectronics , oceanography , thermodynamics , geology
We herein report a visible‐light‐mediated heterogeneous [4+2] annulation of N ‐cyclobutylanilines with alkynes catalyzed by self‐doped Ti 3+ @TiO 2 . The self‐doped Ti 3+ @TiO 2 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 Ti 3+ @TiO 2 . 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.