On‐Water and Efficient Ullmann‐Type O‐Arylation Cross Coupling Reaction of Phenols and Aryl Tosylates in the Presence of Fe 3 O 4 @Starch‐Au as Nanocatalyst

Abstract Gold complex‐functionalized magnetic core‐shell nanoparticles (Fe 3 O 4 @Starch‐Au) were prepared by hydrothermal method and characterized by Fourier transform‐infrared (FT‐IR), X‐ray diffraction (XRD), thermo gravimetric (TGA), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), inductively coupled plasma (ICP), and energy‐dispersive X‐ray (EDX) analyses. The activity of the new synthesized catalyst was employed in cross‐coupling reactions of nontoxic aryl tosylates with phenols to provide the desired diaryl ethers through Ullmann‐type diaryl synthesis. The coupling of several aryltosylates and phenols including aromatic and heterocyclic ones are allowed to perform on water in remarkable yields. This work provides a facile, green, and environmentally friendly method, which is employed to present a precious catalyst that can be recovered six times.