CuFe2O4-catalyzed one-pot synthesis of α-substituted 2-benzofuranmethamines via tandem A3 coupling, 5-exo-dig cyclization, and 1,3-allylic rearrangement

Abstract

A one-pot strategy was developed for the synthesis of α-substituted 2-benzofuranmethamines from salicylaldehydes, phenylacetylenes, and cyclic secondary amines using CuFe₂O₄ as a bifunctional catalyst. The reaction proceeds at 80 °C in 1,4-dioxane using Cs₂CO₃ as a base, enabling sequential A³-coupling, 5-exo-dig cyclization, and 1,3-allylic rearrangement in a single operation. Unlike previous methods, this protocol employs non-precious metal catalysts and mild reagents, operates under moderate conditions, and provides direct access to α-substituted 2-benzofuranmethamines in good yields (80–96%) with broad substrate compatibility. Furthermore, the catalyst is magnetically recoverable and exhibits excellent reusability over five consecutive cycles without significant loss of activity.