L-Proline-Functionalized Fe3O4 Nanoparticles as an Efficient Nanomagnetic Organocatalyst for Highly Stereoselective One-Pot Two-Step Tandem Synthesis of Substituted Cyclopropanes

In this study, a series of highly stereoselective polysubstituted cyclopropane derivatives (trans-2,3-dihydro-spiro[2-aroyl-3-aryl-cyclopropane]1,2-indene-1,3-diones) were synthesized via a one-pot two-step tandem reaction starting from phenacyl bromide derivatives, 1,3-indanedione and aromatic aldehydes in ethanol using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a co-catalyst and Fe3O4\SiO2\propyltriethoxysilane\L-proline as a nanomagnetic organocatalyst. This synthesized nanocatalyst was characterized by Fourier transforms infrared (FT-IR) spectroscopy, energy dispersive X-ray (EDX) analysis and scanning electron microscopy (SEM) images to confirm the formation of the nanocomposite. The catalyst can be easily recovered by simple magnetic decantation and their catalytic activity remains unaltered after ten consecutive cycles, making them environmentally-friendly and widely applicable due to their efficiency, ease of handling and cost effectiveness.