Diversity-Oriented Synthesis of Poly-substituted Benzofuran Derivatives Bearing Amino Groups at 2- or 3-Positions: Rh- or Ni-Catalyzed Cycloisomerization between Ynamides and Enol Ethers

Amino-substituted benzofuran derivatives have attracted attention in recent years due to their remarkable biological activity. Synthetic methods for amino-substituted benzofuran derivatives have been reported, but these methods and the structural diversity of their products are limited. Herein, we report a divergent synthetic strategy for the efficient construction of amino-substituted benzofuran derivatives. We developed a novel rhodium- or nickel-catalyzed cycloisomerization between ynamides and enol ethers, enabling the selective synthesis of poly-substituted benzofuran derivatives bearing an amino group at either the 2- or 3-position from the same starting materials.