A Versatile Copper Supported on MoO₃/SiO₂ Catalyst for Hydroamination

Introduction: Inter- and intramolecular hydroamination reactions serve as a prime example of sustainable organic chemistry. These reactions are catalytic, atom-economical (100% yield), and environmentally friendly, representing a process of fundamental simplicity where an amine is added to an alkyne substrate as well as alkenes or aromatic hydrocarbons. Method: To synthesize enamines with higher yield, which are important intermediates in many natural and synthetic compounds, copper supported on MoO₃/SiO₂ mixed oxides was used as a highly effective catalyst for the direct hydroamination of phenylacetylene and α-naphthylamine. The catalysts were thoroughly characterized using techniques such as FT-IR, XRD, Raman, XPS, and measurements of acidic strength. Result: Spectral data from FT-IR and Raman confirmed the successful incorporation of copper into the MoO3/SiO2 framework. The catalytic system exhibited significant enhancements in both conversion efficiency and selectivity for the desired products, attributed to the unique properties of the Cu- MoO3/SiO2 mixed oxide. This catalyst could be reused up to three cycles without any significant decline in activity, highlighting its environmental friendliness. Conclusion: The method offers advantages over conventional approaches, including simplicity, reduced reaction time, complete atom economy, mild conditions, broad substrate compatibility, recyclability, and an uncomplicated product isolation process.