Visible-Light-Driven Multicomponent Cyclization by
Trapping a 1,3-Vinylimine Ion Intermediate: A Direct Approach to Pyrimido[1,2‑b]indazole Derivatives
posted on 2021-10-11, 18:04authored byXiao Geng, Zhaoliang Xu, Yiwen Cai, Lei Wang
Here
we develop a novel visible-light-driven three-component cyclization
by trapping an 1,3-vinylimine ion intermediate for the direct synthesis
of pyrimido[1,2-b]indazole derivatives from bromodifluoroacetic
acid derivatives, enaminones, and 3-aminoindazoles under mild conditions.
Notably, the robust methodology provides a valuable opportunity for
the introduction of aliphatic substituents and enables good compatibility
of complex bioactive molecules. Furthermore, this is the first example
of photoinduced multicomponent reaction by employing bromodifluoroacetic
acid derivatives as a C1-synthon.