21547-36-4

Upstream product

• 623-26-7 terephthalonitrile 
• 67-56-1 methanol 
• 591-49-1 1-methylcyclohex-1-ene 
• 1129-35-7 4-cyanobenzoic acid methyl ester 
• 27607-77-8 trimethylsilyl trifluoromethanesulfonate 
• 94142-11-7 ((1S,2S)-2-Methoxy-cyclohexylmethylsulfanyl)-benzene 
• 79-22-1 methyl chloroformate 
• 333-27-7 methyl trifluoromethanesulfonate 
• 578-58-5 2-methylmethoxybenzene 
• 7443-70-1 cis-2-methylcyclohexanol 
• 74-88-4 methyl iodide 
• 77-78-1 dimethyl sulfate 
• 186581-53-3 diazomethane 
• 63823-55-2 (1S,2S)-2-Phenylsulfanylmethyl-cyclohexanol 

Relevant academic research and scientific papers

A mild route to solid-supported rhodium nanoparticle catalysts and their application to the selective hydrogenation reaction of substituted arenes

A clean route is described for the preparation of 1.3% (w/w) supported rhodium nanoparticle (3.0 ± 0.7 nm) catalysts onto commercial ion-exchange resins. Their application to the liquid-phase hydrogenation reaction of C=C bonds shows the most active species are obtained under catalytic conditions at room temperature and 1 bar H2. The heterogeneous catalyst shows excellent activity, selectivity and reusability in the hydrogenation reaction of alkenes and substituted arenes under very undemanding conditions. The results are discussed in terms of support effect on the catalytic efficiency.

NHC-stabilized ruthenium nanoparticles as new catalysts for the hydrogenation of aromatics

The application of ruthenium nanoparticles (RuNPs) stabilized by the N-heterocyclic carbenes (NHC) N,N′-di(tert-butyl)imidazol-2-ylidene (ItBu) and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene IPr as catalysts in the hydrogenation of several substrates is reported under various reaction conditions (solvent, substrate concentration, substrate/metal ratio, temperature). The RuNHC nanoparticles are active catalysts in the hydrogenation of aromatics and show an interesting ligand effect, RuIPr NPs being generally more active than RuItBu. The Royal Society of Chemistry 2013.

Ligand effect in the Rh-NP catalysed partial hydrogenation of substituted arenes

The Rh nanoparticles Rh1-Rh4 stabilised by the mono- and bidentate phosphine and phosphite ligands I-IV were synthesised, characterised and applied as catalysts in the partial hydrogenation of substituted arenes. In the case of disubstituted arenes, selectivities for the corresponding cyclohexene derivatives of up to 39% were achieved at ca. 40% conversion. The effect of parameters such as temperature and pressure was also examined. In the hydrogenation of styrene, very high selectivities for ethylbenzene were achieved with TOF values up to ca. 23500 h-1. All these results show that the catalytic performance of small Rh-NPs can be modulated by the appropriate choice of stabilising agents.

Diphosphite ligands derived from carbohydrates as stabilizers for ruthenium nanoparticles: Promising catalytic systems in arene hydrogenation

Ruthenium nanoparticles (RuNPs) were prepared through the hydrogenation of [Ru(COD)(COT)] (COD = 1,5-cyclooctadiene, COT = 1,3,5-cyclooctatriene) in the presence of diphosphites derived from carbohydrates as stabilizing agents, and interestingly, structur

Arene Hydrogenation with a Stabilised Aqueous Rhodium(0) Suspension: A Major Effect of the Surfactant Counter-Anion

A reduced aqueous colloidal suspension of rhodium shows an efficient activity in the catalytic hydrogenation of various benzene derivatives under biphasic conditions at room temperature and under atmospheric hydrogen pressure. The rhodium nanoparticles in the size range of 2-2.5 nm have been synthesised by reducing RhCl3 · 3 H2O with sodium borohydride and were stabilised by highly water-soluble N,N-dimethyl-N-cetyl-N-(2- hydroxyethyl)ammonium salts (HEA16X, X = Br, Cl, I, CH3SO 3, BF4). The major influence of the counter-ion of these surfactants on catalytic activity and recycling is described. The best results have been obtained with chloride ammonium salts HEA16Cl.

Stabilized rhodium(0) nanoparticles: A reusable hydrogenation catalyst for arene derivatives in a biphasic water-liquid system

A colloidal system based on an aqueous suspension of rhodium(0) nanoparticles proved to be an efficient catalyst for the hydrogenation of arene derivatives under biphasic conditions. The rhodium nanoparticles (2 - 2.5 nm) were synthesized by the reduction of RhCl3·3 H2O with sodium borohydride and were stabilized by highly water-soluble N-alkyl-N-(2- hydroxyethyl)ammonium salts (HEA-C(n)). These surfactant molecules were characterized by measurements of the surface tension and the aqueous dispersions with rhodium were observed by transmission electron cryomicroscopy. The catalytic system is efficient under ultramild conditions, namely room temperature and 1 atm H2 pressure. The aqueous phase which contains the protected rhodium(0) colloids can be reused without significant loss of activity. The microheterogeneous behavior of this catalytic system was confirmed on a mercury poisoning experiment.

The role of hydrogen migration in the mechanism of alcohol elimination from MH+ ions of ethers upon chemical ionization

An enhanced elimination of alcohol under isobutane CI conditions, resulting in highly abundant [MH - ROH]+ ions, has been observed in several primary and secondary ethers having a tertiary β-position (methine), as compared with those with β-methylene. This elimination exhibits a significant degree of stereospecificity in stereoisomeric 2-methyl-1-methoxycyclohexanes 4 and 1-methoxy-trans-decalins 7, affording more abundant [MH - ROH]+ ions in the cis isomers 4c and 7tc than in their trans counterparts 4t and 7tt. These findings suggest involvement of a 1,2-hydride migration from the β- to α-position in the course of the alcohol elimination from the MH+ ions of the above cis-ethers, resulting in tertiary carbocation structures. The proposed mechanism of alcohol elimination is supported by a considerable deuterium isotope effect detected in β-deuterium-labeled cis-2-methyl-1-methoxycyclohexane and by a CID study of the structures of [MH - ROH]+ ions obtained from cis- and trans-1,2-dialkoxycyclohexanes. Ring contraction by a Meerwein-type rearrangement has also been observed in the latter system.

A catalytic stereo- and chemo-selective method for the reduction of substituted aromatics

Various substituted aromatics have been reduced using colloidal ruthenium under H2 pressure with good stereoselectivity (cis/trans up to 60). Interesting chemoselectivities are also observed.

The photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction (Part 4): methanol-olefins, methyl 4-cyanobenzoate

Dicyanobenzene-1,4 (1) and -1,2 are known to undergo substitution upon irradiation, in the presence of an olefin, in acetonitrile-methanol (3:1) solution.The products are 1:1:1 (methanol:olefin:aromatic) adducts, substituted on the aromatic ring with loss of a cyano group.This reaction, referred to as the photo-NOCAS (nucleophile-olefin combination, aromatic substitution) reaction, has been shown to be fairly general with regard to the olefin and the nucleophile that can be incorporated.Less is known about the scope of the reaction incorporating other electron-withdrawing substituted aromatic molecules.The purpose of this study was to determine if methyl 4-cyanobenzoate (10) would also take part in this reaction, to form 4-substituted aromatic esters.Irradiation of acetonitrile-methanol solutions of 10 and olefins 2,3-dimethyl-2-butene (2) and 1-methylcyclohexene (5) gave cyclic imine esters, 11 and 13, respectively, instead of photo-NOCAS products.The photo-NOCAS products were obtained when the codonor biphenyl (4) was added to the irradiation mixture.Formation of the cyclic imine ester is attributed to excitation of the charge-transfer complex formed between 10 and the olefin.The addition of biphenyl (4) serves to generate the contact radical ion pair (CRIP) upon irradiation of the charge-transfer complex between 10 and 4.This CRIP can dissociate to the solvent-separated radical ions, the radical cation of 4 can accept an electron from the olefin, and the olefin radical cation can go on to give the photo-NOCAS products.Irradiation of a solution of 10 and 2 in nonpolar solvent (benzene) gave the oxetane, believed to arise from the exciplex.In addition to photo-NOCAS products from 10, 4-cyanophenylketones 17 and 23 are also formed by attack of the β-alkoxyalkyl radical at the carboxyl carbonyl.The differences in behaviour between 1,4-dicyanobenzene (1) and methyl 4-cyanobenzoate (10) under these reaction conditions are described and explained.

THE PHOTOCHEMICAL NUCLEOPHILE-OLEFIN COMBINATION, AROMATIC SUBSTITUTION REACTION (PART 2): METHANOL-CYCLIC OLEFINS, 1,4-DICYANOBENZENE

Direct irradiation of acetonitrile-methanol (3:1) solutions of 1,4-dicyanobenzene and the cyclic olefins, cyclohexene, 1-methylcyclohexene, norbornene, and 2-methylnorbornene, leads to formation of regio- and stereoisomers of the 1:1:1 (alcohol : olefin : aromatic) adducts.This reaction can be photosensitized by electron transfer; addition of electron donors, biphenyl or phenanthrene, to the irradiation mixture generally increases the efficiency and yield of adduct formation.The efficiency of the reaction and the ratio of isomeric adducts are also affected by the addition of salts, particularly magnesium perchlorate.All of the possible regio- and stereoisomers from cyclohexene and 1-methylcyclohexene have been identified, two from cyclohexene and four from 1-methylcyclohexene.Three of the four possible isomers from norbornene were characterized; the endo, endo isomer was not detected.There are eight possible isomers from 2-methylnorbornene; six were detected and five have been isolated and identified.The two sterically hindered isomers, those having both the 4-cyanophenyl and the methoxy groups in the endo position, and exo-3-(4-cyanophenyl)-endo-2-methoxy-exo-2-methylnorbornane, were not characterized.The structures of the products were established largely on the basis of the 1H and 13C nuclear magnetic resonance spectra.The mechanism of the reaction is discussed, with emphasis on those factors that may affect the product ratio.The most striking observation is that the reaction is regioselective when magnesium perchlorate is added to the irradiation mixture.