Dual C(sp3)-H Bond   Functionalization of N-Heterocycles through Sequential Visible-Light   Photocatalyzed Dehydrogenation/[2+2] Cycloaddition Reactions

Guo-Qiang Xu, Ji-Tao Xu, Zhi-Tao Feng, Hui   Liang, Zhu-Yin Wang, Yong Qin, and Peng-Fei Xu*

https://onlinelibrary.wiley.com/doi/full/10.1002/anie.201710523