Catalytic Olefination Reaction Research Articles

Visible Light-Mediated Quantum Dot Photocatalysis Enables Olefination Reactions at Room Temperature

The ability of quantum dots (QDs) to photocatalyze organic reactions is gaining attention because of their distinct light harvesting properties over traditional precious metal- and small molecule-based catalysts. However, establishing the potency of QD photocatalysts in diverse and useful organic transformations, as well as deciphering the charge transfer mechanism, is essential to cement their place as an efficient photocatalyst in synthetic chemistry. Here, we report the use of QDs in efficiently catalyzing a series of olefination reactions under visible-light irradiation at room temperature (90% yield). Spectroscopic and electrochemical studies reveal intriguing insights on the charge transfer mechanism involved in QD-photocatalyzed olefination. Interestingly, the dual role of triphenylphosphine─as a surface passivating agent and nucleophile─turned out to be decisive in directing the charge transfer process from the QD to the reactant. Benzyl triphenylphosphonium bromide salt was accepting the electrons from the photoexcited QDs, thereby initiating the catalytic olefination reaction. QD-photocatalyzed olefination was demonstrated with formaldehyde as well, resulting in the formation of industrially relevant terminal alkene, namely styrene. Moreover, the environmentally friendly indium phosphide (InP) QD also photocatalyzed the olefination reaction under mild reaction conditions, which proves the practical suitability of our study. This work presents an attractive and efficient way to introduce double bonds in organic molecules using QDs and visible light at room temperature.

An Efficient Approach to 2-CF3-Indoles Based on ortho-Nitrobenzaldehydes.

The catalytic olefination reaction of 2-nitrobenzaldehydes with CF3CCl3 afforded stereoselectively trifluoromethylated ortho-nitrostyrenes in up to 88% yield. The reaction of these alkenes with pyrrolidine permits preparation of α-CF3-β-(2-nitroaryl) enamines. Subsequent one pot reduction of nitro-group by Fe-AcOH-H2O system initiated intramolecular cyclization to afford 2-CF3-indoles. Target products can be prepared in up to 85% yields. Broad synthetic scope of the reaction was shown as well as some followed up transformations of 2- CF3-indole.

Efficient Multigram Approach to Acetylenes and CF3‐ynones Starting from Dichloroalkenes Prepared by Catalytic Olefination Reaction (COR)

A novel approach to terminal acetylenes based on catalytic olefination reaction COR of arylaldehydes to form dichloroalkenes followed by treatment with nBuLi was elaborated. This method is atom economical and displays high yields and effectivity. The corresponding alkynes can be prepared in up to 97 % yield. One pot procedure towards CF3‐ynones was elaborated to provide these products in up to 87 % yield starting from dichloroalkenes.

Conversion of carbonyl steroid derivatives to 1,1-dibromoalkenes by the catalytic olefination reaction and synthesis of functionally substituted steroids on their basis

Catalytic olefination of carbonyl steroid derivatives were used to obtain the corresponding 1,1-dibromoalkenes. For this, N-unsubstituted steroid hydrazones were involved into the reaction with tetrabromomethane in the presence of copper(i) chloride. The dibromides can be used for the synthesis of various functionalized steroids by conversion of a dibromomethylidene fragment to the carboxy, amide, and phosphonate groups.

Ionic liquids as a reusable media for copper catalysis. Green access to alkenes using catalytic olefination reaction

It was demonstrated that ionic liquids are superb recyclable media for copper catalyzed reactions using catalytic olefination reaction as an example. As a result a novel green access to the halogenoalkenes was elaborated. Possibility to perform up to five reaction cycles without catalyst leaching and decreasing of the yield was demonstrated. A number of various ionic liquids was screened and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim] [BF4]) was found the solvent with highest efficiency. Mild conditions, high atom economy comparing to other known methods, low amounts of wastes and possibility to recover ionic liquid are the advantages of the proposed method.

Freons in catalytic olefination reaction. Synthesis of fluorinated compounds from the products of olefination

Application of freons in catalytic olefination for production of fluorinated alkenes is discussed and also the synthesis of versatile fluorinated compounds on this basis.

Synthesis of dienes with tetrafluorophenylene bridge based on the catalytic olefination reaction. New promising monomers for the design of molecular architectures with halogen—halogen interactions

Catalytic olefination of tetrafluoroterephthalic aldehyde hydrazone was studied. Dienes with a tetrafluorophenylene bridge containing different substituents at the double bonds were obtained. Stereochemistry of the reaction, as well as molecular structure and crystal packing of the dienes were studied.

Computational study of the catalytic olefination reaction

Catalytic olefination of hydrazones was computed to proceed with effective activation barrier of 19.9 kcal mol –1 . Initially the catalyst- assisted abstraction of Cl – anion from CCl 4 occurs that is accompanied by simultaneous C–C bond formation; then proton is eliminated by ammonia present in the reaction mixture yielding a neutral intermediate; the second CuCl-assisted abstraction of Cl – anion from CCl 3 group is followed by synchronous reaction that affords the olefination product and releases N 2 together with CuCl.HCl.

SYNTHESIS OF HETEROCYCLIC COMPOUNDS USING THE NENAJDENKO-SHASTIN REACTION

The use of a catalytic olefination reaction (the Nenajdenko-Shastin reaction) in the synthesis of heterocyclic compounds is discussed. Author: V. M. Muzalevskiy. English translation in Chemistry of Heterocyclic Compounds , 2012, 48 (1), pp 117-125 http://link.springer.com/article/10.1007/s10593-012-0975-5

ChemInform Abstract: Catalytic Olefination Reaction. Synthesis of Fluorinated Ethers and Thioethers.

Novel synthetic approaches involving catalytic olefination to access fluorinated propyl, allyl, and propargyl ethers and thioethers were developed.

Design and Synthesis of a New Family of Fluorinated Liquid Crystals

A convenient and simple three-step pathway to the new family of CF(2)CF(2)S-bridged alkanes and CF(2)S-, CF(2)O-bridged alkenes and alkynes was elaborated by using catalytic olefination reaction as a key step of the synthetic sequence. The obtained compounds revealed attractive liquid crystalline characteristics.

ChemInform Abstract: Synthesis of Heterocyclic Compounds Using the Nenajdenko—Shastin Reaction

AbstractReview: 44 refs.

Catalytic olefination reaction. Synthesis of fluorinated ethers and thioethers

Novel synthetic approaches involving catalytic olefination to access fluorinated propyl, allyl, and propargyl ethers and thioethers were developed.

Synthesis of heterocyclic compounds using the Nenajdenko-Shastin reaction

The use of a catalytic olefination reaction (the Nenajdenko-Shastin reaction) in the synthesis of heterocyclic compounds is discussed.

Synthesis of para-divinylbenzene by the catalytic olefination reaction

The catalytic olefination reaction of a dihydrazone of terephthalic aldehyde with a variety of polyhalogenoalkanes has been investigated. It has been demonstrated that the reaction leads to a wide range of para-divinylbenzene derivatives containing different functional groups.

Synthesis and characterization of a cyclic vinylpalladium(ii) complex: vinylpalladium species as the possible intermediate in the catalytic direct olefination reaction of enamide

A six-membered cyclic vinylpalladium complex was synthesized via alkenyl C–H bond direct palladation, which was probed in detail by 1H NMR spectroscopy and characterized by X-ray analysis. The cyclic vinylpalladium complex was propounded to be the intermediate during the olefination reaction of enamides. An efficient catalytic system for oxidative cross-coupling reaction of enamides with electron-deficient olefins catalyzed by palladium(II) acetate and 1 atm oxygen as sole oxidant was developed. The corresponding products were obtained in moderate to good yields under mild conditions.

Cu and Au nanocomposites in catalytic olefination reaction

Metal-vapor synthesis-prepared Cu, Ag, Au and bimetallic Au–Cu (optimal) nanocomposites catalyse olefination of hydrazones with polyhalomethanes.

Novel efficient synthesis of β-fluoro-β-(trifluoromethyl)styrenes

CF 3CFBr 2 was employed in catalytic olefination reactions of aromatic aldehydes. In situ prepared hydrazones of aldehydes were transformed to β-fluoro-β-(trifluoromethyl)styrenes by reaction with CF 3CFBr 2 under CuCl catalysis. Based on this reaction, a novel stereoselective approach towards β-fluoro-β-(trifluoromethyl)styrenes was elaborated. Nucleophilic vinylic substitution of fluorine by secondary amines, thiolates and alkoxides in β-fluoro-β-(trifluoromethyl)styrenes was also tested.

A catalytic, highly stereoselective aldehyde olefination reaction

A catalytic aldehyde olefination reaction has been discovered. A Cu(II) complex (5 mol %) derived from a salen-quinine mixed ligand catalyzed the reaction between aldehydes and two molecules of acetyl chloride to produce trans C–C double bonds exclusively. The new catalytic aldehyde alkenation reaction presumably goes through a C-3 acylated β-lactone intermediate that loses one molecule of CO 2.

Stereoselective synthesis of 1-bromo-1-fluorostyrenes

The effective and stereoselective one-pot synthesis of 1-bromo-1-fluorostyrenes from aromatic aldehydes based on a catalytic olefination reaction was elaborated.