Copper nanoparticles stabilized on nitrogen-doped carbon nanotubes as efficient and recyclable catalysts for alkyne/aldehyde/cyclic amine A3-type coupling reactions

Metallic copper nanoparticles have been efficiently dispersed and stabilized on nitrogen-doped carbon nanotubes. They are about 8–10 nm in diameter and highly resistant against bulk oxidation. Their catalytic activity and recyclability have been investigated in A3-type coupling reactions for the synthesis of propargylamines. It was easily possible to prepare diastereomerically pure derivatives of proline and to efficiently recover and reuse the supported catalyst several times.