Heck and Sonogashira Reactions on Magnetic Cobalt Nanoparticles
Pd/Cu-Free Heck and Sonogashira Cross-Coupling Reaction by Co Nanoparticles Immobilized on Magnetic Chitosan as Reusable Catalyst.
Green Chem. 2017;
16 May 2017 (online)
Key wordschitosan - Heck reaction - Sonogashira coupling - cobalt catalysis - nanoparticles - heterogeneous catalysis
A magnetic, chitosan-supported, methyl salicylate–cobalt complex ([email protected]/CS) was prepared as shown in eq. 1. [email protected]/ CS catalyzed the Heck reaction of aryl halides with terminal olefins to give the corresponding internal alkenes in ≤92% yield (eq. 2, 26 examples). [email protected]/CS also promoted the Sonogashira reaction of aryl iodides or bromides with arylacetylenes to give the corresponding diarylacetylenes in ≤80% yield (eq. 3, 15 examples).
The catalyst was characterized by means of FT-IR, TGA, EA, XRD, FE-SEM, SEM-EDX, TEM, magnetization curve, and ICP analyses. In the Heck reaction of iodobenzene with methyl acrylate, the catalyst was recovered and reused four times without loss of its catalytic activity.