Abstract:
A new pathway to the synthesis of N-arylindoles has been
developed that proceeds through an iron-catalyzed [2+2+2]
cycloaddition reaction between diynes and indole-N-alkynes.
The reaction is carried out in ethanol and employs a
catalyst system that consists of iron(II) chloride tetrahydrate
as the metal source, 2-[(2,6-diisopropylphenyl)iminomethyl]pyridine (dipimp) as the ligand, and zinc as the reducing
agent. The method provides efficient access to 3-carbonyl/
ester-substituted (indol-1-yl)arenes in good to excellent
yields under green reaction conditions, and these products
are structurally similar to other N-arylindole derivatives with
potential medicinal value.
