One-pot Cascade Synthesis of Pyrano/Furanotetrahydroquinolines through Povarov Reaction Catalyzed by Fe(NO3)3@Al2O3

Fe(NO3)(3)@Al2O3 was synthesized as a green heterogeneous catalyst for Povarov reaction toward the one-pot cascade synthesis of cis-and trans-tetrahydroquinolines from aryl amines, aryl aldehydes, and electron-rich olefins (dihydropyran/dihydrofuran) under thermal conditions. The reaction is diastereoselective with trans product formed in preponderance. The products were characterized by H-1 NMR, C-13 NMR, IR, ESIMS, and elemental analysis. The characterization of Fe(NO3)(3)@Al2O3 was made by various techniques such as Fourier-transform infrared, inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, energy dispersive X-ray, scanning electron microscope, transmission electron micrographs, TGA, and vibrating sample magnetometer. High catalytic activity, easy recovery and reusability, eco-benign nature, and thermal and chemical stabilities are the key properties of the catalyst that makes it attractive from the viewpoint of green chemistry. [GRAPHICS] .