Cu-Catalyzed Three-Component Cascade Annulation Reaction: An Entry to Functionalized Pyridines

A concise
copper-catalyzed N–O bond cleavage/C–C/C–N
bond formation procedure has been described for the synthesis of multisubstituted
pyridines. Various oxime acetates, activated methylene compounds,
and a wide range of aldehydes bearing aryl, heteroaryl, vinyl, and
trifluoromethyl groups were employed to provide the tri- or tetrasubstituted
pyridines with flexible substitution patterns. Moreover, this method
features inexpensive catalysts, no need for extra oxidant, and high
step-enconomy, which make it pratical and attractive.