Copper(II) acetate promoted intramolecular diamination of unactivated olefins

A concise method for the synthesis of cyclic sulfamides and vicinal diamines is presented. This method is enabled by Cu(OAc)2 and demonstrates a new transformation for this metal. Both five- and six-membered vicinal diamine-containing heterocycles have been synthesized in good to excellent yields, and substrate-based asymmetric induction has been achieved. This is the first reported example of intramolecular diamination of olefins.     

Iodoetherification of unactivated alkenes catalyzed by diphosphine palladium(II) complexes

A palladium-catalyzed intramolecular iodoetherification of alkenes is reported. The reaction is efficient and highly diastereoselective for disubstituted alkenes. The tether length between the alcohol and alkene can be varied to produce tetrahydrofuran and tetrahydropyran rings. Diphosphine palladium(II) salts are highly active catalysts enabling future studies on the development of an enantioselective process.     

Highly stereoselective Ru(II)-Pheox catalyzed asymmetric cyclopropanation of terminal olefins with succinimidyl diazoacetate

The Ru(II)-Pheox complex is an efficient catalyst for the intermolecular cyclopropanation of various terminal olefins with succinimidyl diazoacetate. This catalytic system can perform under mild conditions, and the desired cyclopropane products are obtained in high yields with excellent diastereoselectivity and enantioselectivity.     

Efficient epoxidation reaction of terminal olefins with hydrogen peroxide catalyzed by an iron (II) complex

A highly active iron (II) complex that catalyzed epoxidation of terminal olefins with hydrogen peroxide was described. The catalytic system displayed excellent catalytic ability for the selective oxidation of terminal olefins to epoxides with high selectivity (up to 97.8%) in CH₃CN at 25?°C. The catalytic activity of three similarly structural iron (II) complexes was comparatively studied. The effect of various auxiliary ligands on epoxidation was investigated in detail.     

Addition of heterocycles to electron deficient olefins and alkynes catalyzed by gold(III)

A gold(III)-catalyzed hydroarylation of different olefins is reported here. AuCl₃ works as an excellent catalyst to mediate reactions between various heterocycles and electron deficient olefins and alkynes under mild conditions. This gold(III)-based method tolerates different functional groups such as aldehyde, carboxylic acid, nitrile, and is highly efficient. We have shown that some of these reactions complete in minutes at room temperature.     

Acetoxylation of olefins catalyzed by a palladium(II)-heteropolyacid system

The catalytic acetoxylation of ethylene and propylene occurs under the action of oxygen in the presence of Pd(II)+HPA-6, where HPA-6 is the heteropolyacid H₉PMo₆V₆O₄₀. In addition to the products of acetoxylation (alkenyl and allyl acetates), oxidation products (acetaldehyde and acetone) are also formed. The selectivity of acetoxylation increases upon the addition of NaOAc.

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— — Pd(II)+-6, -6 H₉PMo₆V₆O₄₀. (- ) — . NaOAc.

     

Addition of S-H bonds across electron-deficient olefins catalyzed by well-defined copper(I) thiolate complexes

A series of monomeric (NHC)Cu(SR) (R = Ph or CH2Ph; NHC = N-heterocyclic carbene) complexes have been synthesized and fully characterized including single-crystal X-ray diffraction studies. These complexes catalyze the addition of S-H bonds across electron-deficient olefins to regioselectively produce "anti-Markovnikov" products.     

Mechanism of Ru(III) catalysis in acid bromate oxidation of 2-methylcyclohexanol

Kinetic investigations on Ru(III) catalyzed oxidation of 2-methylcyclohexanol by acidic solution of potassium bromate has been made in the presence of mercuric acetate as scavenger for bromide ions. A transient complex, formed between Ru(III) species and 2-methylcyclohexanol in 11 ratio, disproportionates in a slow and rate-controlling step to give the corresponding ketone and ruthenium(III) hydride, which, on interaction with acid bromate in a fast step regenerates catalytic species of Ru(III) for the recycling.

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2- , Ru(III) - . , Ru(III) 2- 11, (, ), (III). , Ru(III) .

     

The hydroformylation reaction: catalysis by platinum(II)-tin(II) systems

The complexes [Pt(ER₃)(CO)Cl₂] (E = P, As; R = aryl, alkyl) are active precursors for the catalytic hydroformylation of olefins in the presence of added tin(II) chloride. The yield of aldehyde may be maximized by systematic parameter variation and is shown to be limited by the degree of steric crowding at the metal centre. Terminal aliphatic monoenes are hydroformylated readily with a high n : iso ratio; hindered internal olefins, cyclic and conjugated aromatic olefins are less readily hydroformylated, but with no competing hydrogenation. The catalyst system is active under mild conditions of temperature and pressure.     

Efficient aziridination of olefins catalyzed by mixed-valent dirhodium(II,III) caprolactamate

[reaction: see text] A mild, efficient, and selective aziridination of olefins catalyzed by dirhodium(II) caprolactamate [Rh(2)(cap)(4).2CH(3)CN] is described. Use of p-toluenesulfonamide (TsNH(2)), N-bromosuccinimide (NBS), and potassium carbonate readily affords aziridines in isolated yields of up to 95% under extremely mild conditions with as little as 0.01 mol % Rh(2)(cap)(4). Aziridine formation occurs through Rh(2)(5+)-catalyzed aminobromination and subsequent base-induced ring closure. An X-ray crystal structure of a Rh(2)(5+) halide complex, formed from the reaction between Rh(2)(cap)(4) and N-chlorosuccinimide, has been obtained.     

Room-temperature Kumada cross-coupling of unactivated aryl chlorides catalyzed by N-heterocylic carbene-based nickel(II) complexes

The Kumada cross-coupling reaction of a variety of unactivated aryl chlorides, vinyl chlorides, and heteroaryl chlorides catalyzed by nickel(II) complexes containing pyridine-functionalized NHC ligands is described. The catalysts are so active that the reactions proceed at room temperature in excellent yields.     

Further observations on water oxidation catalyzed by mononuclear Ru(II) complexes

A family of 28 mononuclear Ru(II) complexes have been prepared and characterized by (1)H NMR, electronic absorption, and cyclic voltammetry. These complexes are studied as catalysts for water oxidation. All the catalysts possess one tridentate ligand, closely related to 2,2';6,2'-terpyridine (tpy) and may be divided into two basic types. In the type-1 catalyst, the three remaining coordination sites are occupied by a bidentate closely related to 2,2'-bipyridine (bpy) and a monodentate halogen (Br, Cl, or I) or water molecule. In the type-2 catalyst, the three remaining coordination sites are occupied by two axial 4-picoline molecules and an equatorial halogen or water. In general the type-2 catalysts are more reactive than the type-1. The type-2 iodo-catalyst shows first-order behavior and, unlike the bromo- and chloro-catalysts, does not require water-halogen exchange to show good activity. The importance of steric strain and hindrance around the metal center is examined. The introduction of three t-butyl groups at the 4, 4', and 4' positions of tpy sometimes improves catalyst activity, but the effect does not appear to be additive.     

Methoxycarbonylation of olefins catalyzed by palladium(II) complexes containing naphthyl(diphenyl)phosphine ligands

Palladium(II) complexes containing phosphine donor ligands derived from naphthyl(diphenyl)phosphine were synthesized and characterized by NMR and elemental analysis. The complexes were studied as catalyst precursors in the methoxycarbonylation reaction of several aromatic and aliphatic olefins under mild conditions. The catalysts reported high chemoselectivities (over 96%) and regioselectivities between 44% and 93% for different olefins. The best results were obtained over a styrene substrate with 97% of conversion after 6 h of reaction, with high regioselectivity (93%). Kinetic studies permitted the determination of the rate law (v = k [substrate]^1.21±0.02 [catalyst]^0.94±0.11 [acid]^0.52±0.03 [MeOH]^0.53±0.05 [CO]^0.65±0.03) for methoxycarbonylation of styrene. Copyright © 2014 John Wiley & Sons, Ltd.     

Inspired by nature: light driven organometallic catalysis by heterooligonuclear Ru(II) complexes

In view of diminishing resources and an ever increasing demand for energy attention has been directed towards the development of new photocatalytic systems modelling natural photosynthesis. Recent investigations have shown that supramolecular devices consisting of photosynthetic reaction centres and catalyst metals--connected via bridging ligands--are capable of performing light driven catalytic reactions such as hydrogen production, reduction of CO(2), and conversion reactions of olefins.     

Asymmetric Henry reaction catalyzed by oxazolinyl Cu(II) complexes

A novel family of oxazolinyl copper(II) catalysts have been developed and used as Lewis acid catalysts in the asymmetric Henry reaction of various aldehydes with nitromethane. The corresponding nitroalcohol products were obtained in moderate yields (40–80%) and with moderate enantioselectivity (10–40% ee).     

Structure of 2-chloro-3-phenylbenzoic acid

The carbonylation reaction of 2,3-dichlorobiphenyl proceeds with a substitution of the chlorine atom in position 3 and results in the formation of 2-chloro-3-phenylbenzoic acid. The structure of this acid is revealed by single crystal XRD. It is determined by steric interactions of substituents in positions 2,4,2′, and 6′, a stable carboxyl supramolecular synthon, and weak interactions with the participation of the carbonyl oxygen atom and the chlorine atom. Original Russian Text Copyright ? 2009 by V. P. Boyarskiy, M. S. Fonari, K. Suwinska, and Yu. A. Simonov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 605–607, May–June, 2009.     

Ruthenium catalyzed addition reaction of carboxylic acid across olefins without beta-hydride elimination

The cationic ruthenium catalyst (Cp*RuCl2)2/AgOTf/Ligand promotes the addition reaction of carboxylic acids across olefins without beta-hydride elimination.     

Polymerization and reaction of tetraoxane with various olefins catalyzed by BF3O·(C2H5)2

The copolymerization of tetraoxane with various olefins by BF₃·O(C₂H₅)₂ in ethylene dichloride at 30°C has been studied. The gas chromatographic technique was employed for the determination of concentration of each compound. The rate of tetraoxane consumption was decreased by the addition of olefins in the order of; no addition > trans-stilbene > styrene > 1,1-diphenylethylene > 2-chloroethyl vinyl ether > cyclohexene ≥ indene ≥ α-methylstyrene. The formation of the methanol-insoluble copolymer of tetraoxane and olefin was not confirmed. However, 4-methyl-4-phenyl-1,3-dioxane and 4,4-diphenyl-1,3-dioxane were formed in the reaction of tetraoxane with α-methylstyrene and 1,1-diphenylethylene, respectively. 4,4-Diphenyl-1,3-dioxane was identified on the basis of the molecular weight measurement, elemental analysis and NMR and infrared spectroscopy. On the other hand, 1,3-dioxane derivatives were not formed in the reaction of tetraoxane with α,β-disubstituted olefins. Monomer composition dependence of the copolymerization of tetraoxane with 1,1-diphenylethylene or α-methylstyrene has been studied. The amount of 4,4-diphenyl-1,3-dioxane formed reached a maximum at a monomer composition of 1:1 in the reaction of tetraoxane with 1,1-diphenylethylene. The formation of cyclic dimer of α-methylstyrene was suppressed by tetraoxane.