Category: chiral-catalyst

Reference of 23190-16-1, An article , which mentions 23190-16-1, molecular formula is C6H5CH(NH2)CH(C6H5)OH. The compound – (1R,2S)-(−)-2-Amino-1,2-diphenylethanol played an important role in people’s production and life.

Two isomers (E and Z) of benzoin oxime and 2-hydroxy-1-phenyl-1-propanone oxime were catalytically hydrogenated by using palladium on charcoal and erythro amino alcohols were obtained in about 80% diastereomeric excess. The syn-anti isomerization of these oximes in the presence of palladium on charcoal was also studied in connection with the stereoselectivity of the catalytic hydrogenation of the oximes.

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Chiral Catalysts,
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The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.33100-27-5, Name is 1,4,7,10,13-Pentaoxacyclopentadecane, molecular formula is C10H20O5. In a Article，once mentioned of 33100-27-5, Recommanded Product: 1,4,7,10,13-Pentaoxacyclopentadecane

Synthetic routes to the metallole species C4Me4E(H)R (9, E = Si, R = Si(SiMe3)3; 10, E = Si, R = Mes (mesityl); 11, E = Ge, R = Si(SiMe3)3; 12, E = Ge, R = Mes), C4R4E(SiMe3)2 (13, E = Si, R = Me; 14, E = Ge, R = Me; 19, E = Si, R = Et; 20, E = Ge, R = Et), and C4Me4E(R)E(R)Me4C4(15, E = Si, R = SiMe3; 16, E = Si, R = Me; 17, E = Ge, R = SiMe3; 18, E= Ge, R = Me) are described. In the presence of 18-crown-6, dihalides 1 and 2 are reduced by potassium in tetrahydrofuran to give crystalline samples of the silole dianion [K(18-crown6)+]2[C4Me4Si2-] (21) and the germole dianion [K4(18-crown-6)3][C4Me4Ge]2 (22). Compound 21 adopts an inverse sandwich geometry, while 22 is a dimer with a bridging [K(18-crown-6)K]2+ group and eta5-binding modes for all of the potassium atoms. The metallole dianions in these structures appear to possess delocalized pi-systems, as evidenced by nearly equivalent C-C bond lengths in the five-membered rings. Silolyl and germolyl anions have been obtained by various methods involving nucleophilic cleavage of bonds to germanium and silicon. Deprotonation of 11 and 12 in the presence of a crown ether gave the anions [K(18-crown-6)][C4Me4GeR] (23, R = Si(SiMe3)3; 24, R = Mes) and [Li(12-crown-4)2] [C4Me4GeR] (25, R = Si(SiMe3)3; 26, R = Mes). NMR parameters for these species, and X-ray structures for 25 and 26, indicate that the anionic rings possess pyramidal germanium centers and bond localization in the diene portion of the ring. Spectroscopic and X-ray crystallographic data for [Na(15-crown-5)][C4Me4GeMe] (28), prepared by reductive cleavage of the Ge-Ge bond in 18, reveal a similar structure for the germolyl ring. The latter compound possesses a Na···Ge interaction in the solid state. Silolyl and germolyl anions M[C4Me4E(SiMe3)] (30, E = Si, M = Li; 31, L = Si, M = K; 32, L = Si. M = Li( l2-crown-4)2; 33, L = Si, M = K(18-crown-6); 34, E = Ge, M = K; 35, L = Ge, M = K(18-crown-6)) have been prepared by nucleophilic cleavage of the E-SiMe3 bond in C4Me4E(SiMe3)2 with MCH2Ph (M = Li, K). By similar methods, the monoanionic species [K(18-crown-6)] [C4Me4E(SiMe3)C4Me4L] (36, E = Si; 37, E = Ge) were obtained. A crystal structure determination for 33 revealed a highly pyramidalized Si center (the angle between the C4Si plane and the Si-Si bond is 99.6) and pronounced double bond localization in the ring. Interaction between the [K(18-crown-6)]+ cation and the anion is rather weak, as indicated by the K···Si distance (3.604(2) A) and the atomic position for K. By variable-temperature 1H NMR spectroscopy, inversion barriers for the compounds [Li(12-crown-4)2][C4Et4ESiMe3] (38, E = Si; 40, E = Ge) and K[C4Et4ESiMe3](39, E = Si; 41, E = Ge) were estimated. Barriers for the germolyl anions 40 and 41 (10.5(1) and 9.4(1) kcal mol-1, respectively) are distinctly higher than those for the corresponding silolyl anions 38 and 39, as might be expected from periodic trends. The silolyl anions exhibited coalescence temperatures below the freezing point of tetrahydrofuran (165 K), but upper limits to the inversion barriers were estimated from spectra recorded at the lowest temperatures (? 8.4 kcal mol-1 for 38 and < 8.4 kcal mol-1 for 39). The measured inversion barriers for compounds 38-41 provide energy differences between the pyramidal anions and their corresponding planar (possibly aromatic) structures, and their low values may be attributed to stability imparted to the transition state by delocalization of pi-electron density in the ring. Note that a catalyst decreases the activation energy for both the forward and the reverse reactions and hence accelerates both the forward and the reverse reactions.Recommanded Product: 1,4,7,10,13-Pentaoxacyclopentadecane, you can also check out more blogs about33100-27-5

Reference：
Chiral Catalysts,
Chiral catalysts – SlideShare

Chemistry is an experimental science, and the best way to enjoy it and learn about it is performing experiments.Introducing a new discovery about 1806-29-7, Name is 2,2-Biphenol, Computed Properties of C12H10O2.

Novel palladium complexes with bidentate phosphinite and mixed phosphine – phosphinite ligands of the general formula [(P^P)Pd(Me)Cl] were prepared. After halide abstraction, these complexes are highly active catalysts for the copolymerization of ethylene and CO, yielding high molecular weight polyketones with activities of up to 30000 mol per mol Pd. The preference of cis-or trans-coordination, depending on the chelate ring size, was investigated. In complexes with up to 11-membered chelates, a cis-fixation of the ligands is observed, whereas bigger chelates afforded catalytically inactive trans-complexes.

Balanced chemical reaction does not necessarily reveal either the individual elementary reactions by which a reaction occurs or its rate law.Computed Properties of C12H10O2. In my other articles, you can also check out more blogs about 1806-29-7

Reference：
Chiral Catalysts,
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A catalyst don’t appear in the overall stoichiometry of the reaction it catalyzes, but it must appear in at least one of the elementary reactions in the mechanism for the catalyzed reaction. 14098-44-3, Name is Benzo-15-crown-5, molecular formula is C14H20O5. In a Article，once mentioned of 14098-44-3, Recommanded Product: Benzo-15-crown-5

A convenient method for one-step coupling of benzoannelated crown ethers with 1,2,4-triazinones based on the reaction of nucleophilic addition to unsubstituted carbon atom of the triazine ring has been worked out. It has been shown that the reaction of 3-substituted 1,2,4-triazin-5(2H)-ones (1) with benzocrown ethers (benzo-12-crown-4, benzo-15-crown-5, benzo-18-crown-6) in the presence of acetic or trifluoroacetic anhydride is accompanied by acylation of triazine ring and results in formation of 3-(1-acyl-5-oxo-1,4,5,6-tetrahydro-1,2,4-triazin-6-yl)benzocrown ethers (7-12). The latters were converted to 3-(5-oxo-2,5-dihydro-1,2,4-triazin-6-yl)benzocrown ethers (18-20) using two alternative routes: the elimination of acetic or trifluoroacetaldehyde or the deacylation followed by the oxidation of the 1,4,5,6-tetrahydro derivatives (13-15).

Balanced chemical reaction does not necessarily reveal either the individual elementary reactions by which a reaction occurs or its rate law.Recommanded Product: Benzo-15-crown-5. In my other articles, you can also check out more blogs about 14098-44-3

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Chiral Catalysts,
Chiral catalysts – SlideShare

The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.94-91-7, Name is N,N’-Bis(salicylidene)-1,2-propanediamine, molecular formula is C17H18N2O2. In a Article，once mentioned of 94-91-7, Recommanded Product: 94-91-7

The Cu(II) complex compounds with bis(salicylidene)-1,2-propylenediamine and bis(salicylidene)-l,3-propylenediamine are synthesized for the first time. It is shown that conducting photosensitive polymers with electrochromic properties can be obtained by electrochemical synthesis. These polymers are found to be capable of reversible photo- and electro-induced processes of electron transfer in the bulk of a solid polymer matrix. The mechanism of polymer formation is studied depending on the potential, the time of electrode polarization, and the concentration of complex compounds in a solution.

Note that a catalyst decreases the activation energy for both the forward and the reverse reactions and hence accelerates both the forward and the reverse reactions.Recommanded Product: 94-91-7, you can also check out more blogs about94-91-7

Reference：
Chiral Catalysts,
Chiral catalysts – SlideShare

Electric Literature of 140924-50-1, An article , which mentions 140924-50-1, molecular formula is C48H54N6O4. The compound – (Dhq)2phal played an important role in people’s production and life.

A new asymmetric synthesis of bicyclic pyrazolidinones through an alkaloid-catalyzed formal [3 + 2] cycloaddition of in situ generated ketenes and azomethine imines is described. The products were formed in good to excellent yields (52-99% for 17 examples), with good to excellent diastereoselectivity (dr 5:1 to 27:1 for 11 examples), and with excellent enantioselectivity in all cases (?96% ee). This method represents the first unambiguous example of an enantioselective reaction between ketenes and a 1,3-dipole.

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Chiral Catalysts,
Chiral catalysts – SlideShare

In an article, published in an article, once mentioned the application of 1436-59-5, Name is cis-Cyclohexane-1,2-diamine,molecular formula is C6H14N2, is a conventional compound. this article was the specific content is as follows.SDS of cas: 1436-59-5

Two series of ligands based on diaminocyclohexane (DACH) have been prepared and successfully complexed to AlIII and ZnII metal centres. Solution and solid-state studies reveal a tendency to form mono- or bis-ligated forms depending on the steric bulk of the ligand. These complexes have been tested for their ability to ring open rac-lactide. AlIII based complexes generally gave atactic PLA after a polymerisation time of 1?2 days. The ZnII complexes, were found to be more active and furnished PLA with a slight heterotactic bias.

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Chiral Catalysts,
Chiral catalysts – SlideShare

Electric Literature of 21436-03-3. Chemistry is an experimental science, and the best way to enjoy it and learn about it is performing experiments.Introducing a new discovery about 21436-03-3, Name is (1S,2S)-Cyclohexane-1,2-diamine

In this work, we demonstrate that useful C-C bond-forming photoredox catalysis can be performed in air using easily prepared gel networks as reaction media to give similar results as are obtained under inert atmosphere conditions. These reactions are completely inhibited in homogeneous solution in air. However, the supramolecular fibrillar gel networks confine the reactants and block oxygen diffusion, allowing air-sensitive catalytic activity under ambient conditions. We investigate the mechanism of this remarkable protection, focusing on the boundary effect in the self-assembled supramolecular gels that enhances the rates of productive reactions over diffusion-controlled quenching of excited states. Our observations suggest the occurrence of triplet-sensitized chemical reactions in the gel networks within the compartmentalized solvent pools held between the nanofibers. The combination of enhanced viscosity and added interfaces in supramolecular gel media seems to be a key factor in facilitating the reactions under aerobic conditions.

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Chiral Catalysts,
Chiral catalysts – SlideShare

In an article, published in an article, once mentioned the application of 1806-29-7, Name is 2,2-Biphenol,molecular formula is C12H10O2, is a conventional compound. this article was the specific content is as follows.Safety of 2,2-Biphenol

New bicyclic pentaoxyphosphoranes 1-3 containing ring sizes varying from five to seven membered were synthesized by oxidative addition of a quinone or a diol to a cyclic phosphite. Variable-temperature solution 1H and 13C NMR studies revealed the presence of dynamic intramolecular ligand exchange processes, one in which apical-equatorial ring interchange occurred between trigonal bipyramidal ground states and a higher temperature process supporting an exchange intermediate with the ring located diequatorially in a trigonal bipyramid. Activation energies for the latter process were determined. X-ray analysis supported the interpretation of the solution-state behavior and showed that saturated six-membered rings prefer a boat conformation occupying apical-equatorial positions in trigonal bipyramidal structures. The stability of the six-membered ring in this conformation is supported by the shorter P-O bond lengths found for this ring size compared to that for phosphoranes having five- and seven-membered rings. Phosphorane 1 crystallizes in the monoclinic space group P21/n with a = 10.633 (3), b = 17.648 (3), c = 13.601 (1) A, beta = 102.47 (1), and Z = 4. The bicyclic 2 crystallizes in the monoclinic space group P21/n with a = 10.459 (2), b = 12.712 (1), c = 19.949 (2) A, beta = 95.28 (1), and Z = 4. Bicyclic 3 crystallizes in the monoclinic space group P21/n with a = 9.655 (4), b = 11.662 (4), c = 22.720 (6) A, beta = 94.28 (3), and Z = 4. The bicyclic phosphorane 4 crystallizes in the orthorhombic space group Pbcn with a = 13.922 (4), b = 11.050 (2), c = 11.020 (3) A, and Z = 4. The final conventional unweighted residuals are 0.037 (1), 0.093 (2), 0.050 (3), and 0.062 (4).

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Chiral Catalysts,
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Application of 21436-03-3. Let’s face it, organic chemistry can seem difficult to learn. Especially from a beginner’s point of view. Like 21436-03-3, Name is (1S,2S)-Cyclohexane-1,2-diamine. In a document type is Article, introducing its new discovery.

Diamineruthenium(II) complexes containing the hemilabile methoxyethyldimethylphosphine ligand, [Cl2Ru(Ln)-(eta 1-Me2PCH2CH2OMe)2] (2Ln) (n = 1-12, Scheme 1), have been synthesized from the starting materials Me2PCH2CH2OMe, [Ru(COD)Cl 2]n, and the respective diamines L1-L 12. The structure of complex 2L5 reveals that two chlorides are in trans position, while in complex 2L11 the two chlorides favor a cis configuration. Most of the complexes are highly catalytic active in the hydrogen transfer reduction of acetophenone. The experimental study indicates that the replacement of phenyl groups for methyl functions in the ether-phosphine ruthenium(II) complexes resulted in a switch of the hydrogenation mechanism from direct hydrogenation to transfer hydrogenation. The reason is attributed to the better donor ability of methyl groups compared to phenyl substitutents. Thus the metal center becomes more electron-rich and inhibits the binding of dihydrogen to the ruthenium(II) complex fragment.

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Reference：
Chiral Catalysts,
Chiral catalysts – SlideShare