Late-metal catalysts for ethylene homo- and copolymerization.

Iron Catalysis in Organic Synthesis

Precise control of polyolefin stereochemistry using single-site metal catalysts.

Surface functionalization of nano-magnetic nanoparticles is a well-designed way to bridge the gap between heterogeneous and homogeneous catalysis. The introduction of magnetic nanoparticles (MNPs) in a variety of solid matrices allows the combination of well-known procedures for catalyst heterogenization with techniques for magnetic separation. Magnetite is a well-known material, also known as ferrite (Fe3O4), and can be used as a versatile support for functionalization of metals, organocatalysts, N-heterocyclic carbenes, and chiral catalysts. It is used as a support for important homogeneous catalytically active metals such as Pd, Pt, Cu, Ni, Co, Ir, etc. to obtain stable and magnetically recyclable heterogeneous catalysts. Homogeneous organocatalysts can be successfully decorated with linkers/ligands on the surface of magnetite or alternatively the organocatalysts can be directly immobilized on the surface of magnetite. The functionalized magnetically retrievable catalysts or nanocatalysts that are increasingly being used in catalysis, green chemistry and pharmaceutically significant reactions are summarized in this review.

Nano-magnetite (Fe3O4) as a support for recyclable catalysts in the development of sustainable methodologies

2.3. [4 + 4] Cycloadditions 1058 2.4. Photocycloadditions of Aromatic Compounds 1058 2.4.1. Benzene Derivatives 1058 2.4.2. Condensed Aromatic Compounds 1060 3. Photochemical Rearrangements 1061 4. Cyclizations 1064 4.1. Pericyclizations 1064 4.2. Norrish−Yang Reaction 1066 5. Photochemical Extrusion of Small Molecules 1067 6. Photochemical Electron Transfer 1068 6.1. Photochemical Electron-Transfer Reactions with a Catalytic Sensitizer 1068

Photochemical Reactions as Key Steps in Organic Synthesis

Greatly improved activity in ruthenium catalysed butanone synthesis

The present application relates to a metal complex of Formula (I) and a catalyst composition for the carbonylation of alkenes comprising the metal complex, wherein the metal is a group 10 element such as palladium, platinum or nickel, and the complex comprises a bidentate phosphine ligand. The present invention also relates to a process for the preparation of a dicarboxylic acid or ester thereof from an alkenoic acid or ester thereof, or a process for the preparation of a carboxylic acid or ester thereof from an alkene or alkenoic acid with high selectivity and activity using said metal complex or catalyst composition. The present application also relates to a method of preparing Nylon 6-6 comprising the step of copolymerising adipic acid with hexamethylenediamine.

A catalyst for the carbonylation of alkenes

A new isomerizing ring‐closing amidocarbonylation reaction is reported using Pd catalysis with bulky diphosphane ligands. From terminal as well as internal pentenamide isomers (PAs), cyclic imides were obtained in good yield (92 %) with cationic Pd catalysts supported by bis‐PCg ligands (PCg=6‐phospha‐2,4,8‐trioxa‐1,3,5,7‐tetramethyladamant‐6‐yl). An excess of strong acid is required to obtain high selectivity for imide products. From a low‐temperature NMR study it was deduced that N coordination of the amide moiety is responsible for a high selectivity to cyclic imide products. In weakly acidic conditions, O coordination of the amide functionality leads to the formation of cyanoacids (i.e., 5‐cyanovaleric acid, 2‐methyl‐4‐cyanobutyric acid and 2‐ethyl‐3‐cyanopropionic acid). It is proposed that the formation of these cyanoacids occurs through a novel intramolecular tandem dehydrating hydroxycarbonylation reaction of PAs. This reaction also occurs in intermolecular versions of amidocarbonylation with mixtures of alkene and amide substrates. Experiments with N‐alkylated amides have been instrumental in developing mechanistic models. The strong acid co‐catalyst ensures double‐bond isomerization to occur faster than product formation, resulting in the same product mixture, irrespective of the use of terminal or internal pentenamides. The remaining challenge is to arrive at the desired adipimide by overcoming the undesirable regioselectivity caused by chelation of the amide.

/pdf/palladium-catalyzed-isomerization-cyclo-carbonylation-of-4jtovkt6yo.pdf

Palladium‐Catalyzed Isomerization/(Cyclo)carbonylation of Pentenamides: a Mechanistic Study of the Chemo‐ and Regioselectivity

Our interest in palladium-catalyzed olefin carbonylation was awakened by the discovery of a class of highly efficient cationic palladium catalysts for the alternating copolymerization of olefins with carbon monoxide (Equation 1) [1].

Palladium-Catalysed Synthesis of Mono-Esters, -Ketones and — Aldehydes/Alcohols

[RuCp(PP)] + complexes active for allylation of alcohols with allyl alcohol as the allylating agent were immobilized on solid supports. Two different immobilization methods have been applied: (1) via electrostatic interactions of the cationic complex on ion-exchange resins, where the anion is present on the support and (2) via a coordination bond with a ligand covalently-bound on the support. Both methods give high yields of immobilized complex through relatively simple procedures. The catalysts immobilized via ionic interactions prove to be able to allylate both 1-octanol and 4- tert -butylphenol with very low leaching of the catalyst, thus forming allyl octyl ether and C-allylated phenol, respectively. The accumulation of water in the highly hydrophilic resin precludes the O-allylation of phenol and also retards the C-allylation reaction. The catalysts immobilized via a coordination bond are not hydrophilic; with these catalysts selective O-allylation of phenols is achieved, with recycling of the catalysts over multiple runs. Leaching of the catalyst from the support is somewhat higher than for the electrostatically-bound catalyst and quarternisation (allylation) of the excess of phosphine groups present on the support plays an important role in the activity of the immobilized catalysts for the allylation reaction.

Eite Drent

Papers

Greatly improved activity in ruthenium catalysed butanone synthesis

A catalyst for the carbonylation of alkenes

Palladium‐Catalyzed Isomerization/(Cyclo)carbonylation of Pentenamides: a Mechanistic Study of the Chemo‐ and Regioselectivity

Palladium-Catalysed Synthesis of Mono-Esters, -Ketones and — Aldehydes/Alcohols

Immobilization of ruthenium catalysts for allylations with allyl alcohol