4+2 Annulation of N-aryl cyclobutylanilines with alkynes under visible light: An organic reaction catalyzed by self-doped Ti3+@TiO2 visible light catalyst.

by Wang, Jiang; Feng, Pingyun; Zheng, Nan

We report an intermol. [4+2] annulation reaction of cyclobutylanilines with internal and terminal alkynes under visible light photolysis. A self-doped Ti3+@TiO2 catalyst which posses visible light absorption property was used as photoredox catalyst to harvest a scope of amine substituted cyclohexene derivatives A series of novel self-doped Ti3+@TiO2 catalysts which differs in the concentration of Ti3+ were studied with the annulation reaction to reach the conclusion that the concentration of Ti3+ in the catalyst has a key effect on the catalytic reactivity of the catalyst. Finally, mechanistic studies were conducted and showed that the annulation reaction was driven by singlet oxygen which was generated from the self-doped Ti3+@TiO2 catalysts.