Palladium‐Catalysed Cross‐Coupling and Related Processes: Some Interesting Observations That Have Been Exploited in Synthetic Chemistry

Abstract

Palladium-catalysed cross-coupling reactions are routinely used in the synthesis of important organic and organometallic compounds, including advanced materials and natural products. Industry and academia depend heavily on these ubiquitous transformations. Their success is quite remarkable, but not without their share of problematic and sometimes unusual observations, which continue to probe our fundamental understanding of these reactions. Through an identification of side-reactions, our train of thought of a wellknown reaction can be challenged. In this review we identify exemplary processes and show how they have been ex-

Phenyl–Acetylene Bond Assembly: A Powerful Tool for the Construction of Nanoscale Architectures

“…If the yields are still not satisfactory, either the design of new ligands for the palladium complex should be considered or a change in the retrosynthetic strategy is required. In this review we wish to focus on the strategic approach and not on the optimisation of the palladium catalyst, as this has already been extensively covered in other reviews 46,52,53…”

Palladium nanoparticles immobilized on amphiphilic and hyperbranched polymer‐functionalized magnetic nanoparticles: An efficient semi‐heterogeneous catalyst for Heck reaction

“…This leads not only to loss of expensive metal and ligands, but also to contamination of the final product by leached metal, which makes the homogeneous catalysts inapplicable especially for large‐scale production. For this reason, many attempts have been made to immobilize metal complexes on a wide variety of solid supports, such as silica‐based materials, magnetic nanoparticles, self‐assembled monolayers, carbon nanomaterials, dendrimers and functional polymers . However, the reactivity and selectivity of the heterogenized catalysts are significantly lower than those of their homogeneous analogues …”

Selective arene functionalization through sequential oxidative and non-oxidative Heck reactions

“…Thus, 2a was converted in one flask to 4a by conducting the deacetylation-diazotation as described above using BF 3 ÁMeOH and tert-butyl nitrite, followed by addition of Pd(OAc) 2 and methyl acrylate after completion of the diazotation. This method turned out to be indeed a viable alternative to the two step synthesis, because 4a could be isolated in a yield of 61% from 2a.…”