Lignin-Based Catalysts for C–C Bond-Forming Reactions

Abstract

Carbon–carbon (C–C) bond formation is the key reaction in organic synthesis to construct the carbon framework of organic molecules. The continuous shift of science and technology toward eco-friendly and sustainable resources and processes has stimulated the development of catalytic processes for C–C bond formation based on the use of renewable resources. In this context, and among other biopolymer-based materials, lignin has attracted scientific attention in the field of catalysis during the last decade, either through its acid form or as a support for metal ions and metal nanoparticles that drive the catalytic activity. Its heterogeneous nature, as well as its facile preparation and low cost, provide competitive advantages over other homogeneous catalysts. In this review, we have summarized a variety of C–C formation reactions, such as condensations, Michael additions of indoles, and Pd-mediated cross-coupling reactions that were successfully carried out in the presence of lignin-based catalysts. These examples also involve the successful recovery and reuse of the catalyst after the reaction.

Reactive Polymer Composite Microparticles Based on Glycidyl Methacrylate and Magnetite Nanoparticles

“…Numerous soluble and insoluble precursors were previously applied as a source of Pd(0) species that are responsible for activating substrates in these reactions. Among them, different modified polymeric, inorganic, and composite materials, including materials composed of magnetic nanoparticles, can be found [34,[74][75][76][77][78]. Therefore, the use of developed composite microparticles as a source of catalytically active palladium species appeared to be interesting.…”