A Facile One-pot Synthesis of Highly Functionalized Isoxazolyl Imidazo[1,2-a] Pyridines Through CuI-Promoted Cyclization

A copper iodide‐promoted cyclization for the synthesis of isoxazolyl imidazo[1,2‐a] pyridines 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j in a one‐pot procedure has been investigated by interaction of 2‐aminopyridines 1a, 1b, 1c, 1d, 1e with nitrostyrylisoxazoles 2a, 2b, 2c, 2d, 2e, 2f under aerial oxidation condition. Similarly, the one‐pot reaction of 2‐amino pyridines 1a, 1b, 1c, 1d, 1e with 4‐bromonitrostyrylisoxazole 2d in the presence of copper iodide under aerial oxidation condition, followed by reaction with phenyl acetylenes in situ afforded highly functionalized imidazo[1,2‐a]pyridines 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10i, 10j by the Sonogashira coupling.