Oxime palladacycles revisited: stone‐stable complexes nonetheless very active catalysts

Abstract

Our review critically presents the main achievements, advantages, and limitations of oxime palladacycles as high-turnover catalysts for Heck, as well as homo- and cross-coupling reactions such as Suzuki-Miyaura, Stille, Ullmann-type, Cassar-Heck-Sonogashira, sila-Sonogashira, Glaser-type, Hiyama, and alkoxycarbonylation reactions. New developments in this area are reviewed from a mechanistic and synthetic point of view. The role of oxime palladacycles as a source of highly active zero-valent palladium species is also discussed.

Arylation of Allyl Alcohols in Organic and Aqueous Media Catalyzed by Oxime‐Derived Palladacycles: Synthesis of β‐Arylated Carbonyl Compounds

“…[25][26][27][28] In this work the application of the dimeric oxime-derived palladacycles 12-14 and the Kaiser oxime resin derivative 15 ( Figure 1) as precatalysts in the chemo-and regioselective arylation of allyl alcohols in organic and aqueous solvents, focused to the synthesis of barylated saturated aldehydes, and ketones, is described.…”

Graphene Oxide-Supported Oxime Palladacycles as Efficient Catalysts for the Suzuki–Miyaura Cross-Coupling Reaction of Aryl Bromides at Room Temperature under Aqueous Conditions

“…Very recently, we have shown that palladium nanoparticles (Pd NPs), supported on graphene and reduced graphene oxide, efficiently catalyze the Suzuki-Miyaura coupling between aryl bromides and potassium aryltrifluoroborates under aqueous and low loading conditions (0.1 mol % Pd) employing conventional or microwave heating [64]. Based on the experience and knowledge of our research group with oxime palladacycles as highly efficient precatalysts in cross-coupling reactions [65][66][67], herein we report a detailed study on the synthesis and characterization of new oxime palladacycle-graphene oxide non-covalent materials along with their catalytic activity in the Suzuki-Miyaura reaction.…”

“…Also, inductively coupled plasma mass spectrometry (ICP-OES) analysis of the washings after the fifth run showed 67 ppb of Pd leaching. Oxime palladacycles are considered reservoirs of highly active palladium nanoparticles [65][66][67]. Usually, PdNps supported on graphene materials are prepared by reduction of a Pd salt or Pd catalyst in the presence of the corresponding carbonaceous support [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61].…”

“…Based on the experience and knowledge of our research group with oxime palladacycles as highly efficient precatalysts in cross-coupling reactions [66][67][68], herein we report a detailed study on the synthesis and characterization of new oxime palladacycle-graphene oxide non-covalent materials along with their catalytic activity in the Suzuki-Miyaura reaction.…”

Phosphane-free Suzuki–Miyaura Coupling of Aryl Imidazolesulfonates with Arylboronic Acids and Potassium Aryltrifluoroborates under Aqueous Conditions

“…Thus, different studies have shown the ability of other functional groups, such as mesylates, 4 In our research group, the SuzukiMiyaura reaction has been studied during the past decade using oxime palladacycles 1 ( Figure 1) as efficient precatalysts for the coupling of vinyl-and aryl halides with boronic acids and potassium trifluoroborates in organic and aqueous solvents. 14,15 Herein we report the use of imidazolesulfonates as effective electrophilic coupling reagents in a phosphane-free SuzukiMiyaura reaction with boronic acids and potassium trifluoroborates catalyzed by oxime palladacycles 1 under aqueous conditions. Initial Suzuki cross-coupling studies were carried out over 1-naphthol derivatives 2 ( Table 1).…”