ol7b04055_si_001.pdf (6.09 MB)
Synthesis of 4‑Difluoromethylquinolines by NHC-Catalyzed Umpolung of Imines
journal contribution
posted on 2018-01-23, 22:30 authored by Atanu Patra, Fabien Gelat, Xavier Pannecoucke, Thomas Poisson, Tatiana Besset, Akkattu T. BijuThe N-heterocyclic
carbene (NHC)-catalyzed umpolung of aldimines
for the synthesis of 4-difluoromethylquinoline derivatives is reported.
In the presence of NHCs, the intramolecular cyclization of aldimines
bearing a moderately electron-poor double bond due to the presence
of the −CF3 group likely proceeds via the intermediacy
of the aza-Breslow intermediate. The key to the success of this aza-Stetter
type transformation is the NHC generated from the bicyclic triazolium
salt using DBU as the base.