Cover Picture: On the Nature of the Active Species in Palladium Catalyzed Mizoroki–Heck and Suzuki–Miyaura Couplings – Homogeneous or Heterogeneous Catalysis, A Critical Review: (Adv. Synth. Catal. 6/2006)

Highly porous chitosan microspheres supported palladium catalyst for coupling reactions in organic and aqueous solutions

“…The Heck reaction is a palladium catalyzed cross-coupling of aromatic halides with alkenes as shown in Scheme 2 [23,24] and it has been considered as the most powerful and versatile method for the construction of the sp 2 esp 2 carbonecarbon bonds for the synthesis of stereoselective alkenes with various interesting pharmacological, biological, or physical properties [25]. Although the Heck reaction tolerates a wide variety of functional groups on both reactants, it generally requires ligands such as phosphines to stabilize the palladium-based catalytic center to prevent the formation of the palladium black since palladium aggregation will dramatically decrease the catalytic activities.…”

Increased Conversion in the Heck Reaction Under Irradiation with Light

“…Since the Heck type reaction was first published almost 40 years ago [4,5], several thousand articles referring to it have been published. Many of these articles deal with the development of new palladium catalysts (both homogeneous and heterogeneous) [6][7][8][9], reaction conditions such as solvents, bases, and additives, mechanistic and kinetic studies, and the use of microwave irradiation as the heat source [10][11][12][13]. However, to our knowledge, no one has investigated how ultraviolet (UV) and/or visible (vis) irradiation influences the Heck reaction.…”

A novel SiO2 supported Pd metal catalyst for the Heck reaction

“…Since ligand-free Pd turned out to be feasible for the Heck reaction on aryl iodides [5], extensive studies of ligandfree Pd catalyzed Heck reactions on aryl halides have increasingly been appearing [2,[6][7][8][9][10]. Due to the drawbacks with homogeneous catalysts, it has been desirable to develop heterogeneous Heck reaction catalysts for industrial applications and notable progress has been seen in this area [6,9,10]. Instead of organic ligands, ligand-free catalyst systems use inexpensive bases such as NaOAc, Na 2 CO 3 , NaHCO 3 , Ca(OH) 2 , K 3 PO 3 , and amines, etc.…”