1879-52-3

Upstream product

• 2809-65-6 4-chloro-1-propynylbenzene 
• 1202-60-4 3-(4-chlorophenyl)-3-methyl-2-acrylic acid 
• 1745-18-2 1-allyl-4-chlorobenzene 
• 17847-85-7 triethyl(ethylidene)phosphorane 
• 104-88-1 4-chlorobenzaldehyde 
• 100-52-7 benzaldehyde 
• 1754-88-7 ethylenetriphenylphosphorane 
• 4736-60-1 ethyltriphenylphosphonium iodide 
• 1884-95-3 4-(4'-chlorophenyl)-3-methyl-3-buten-2-one 
• 1202-60-4 -2-methyl-3-(4-chlorophenyl)prop-2-enoic acid 
• 1135821-12-3 ethyl-(2-methoxy-phenyl)-diphenyl-phosphonium; iodide 
• 1135820-79-9 C₂₁H₂₂OP⁽¹⁺⁾*I^(1-) 
• 896-33-3 ethyltriphenylphosphonium chloride 
• 599-70-2 ethyl phenyl sulfone 

Downstream Products

• 50337-50-3 2-(4'-chlorophenyl)-3-methyloxirane 
• 1886-50-6 (+/-)-cis-1-(4-Chlorphenyl)-2-methyl-ethylenoxid 
• 135682-94-9 cis-4-chloro-β-methylstyrene oxide 
• 1879-53-4 E-1-(4-chlorophenyl)-1-propene 
• 1404433-42-6 (1R,2R,3S)-2,6-dimethylphenyl 2-(4-chlorophenyl)-3-methylcyclopropanecarboxylate 

Relevant academic research and scientific papers

Catalytic isomerization of hydrophobic allylarenes in aqueous microemulsions

In the course of our attempts to replace the traditional but environmentally disfavored organic solvents in organic processes by water, we studied the double bond isomerization of hydrophobic allylarenes, in aqueous microemulsions. The catalyst for these reactions was the rhodium-trichloride- Aliquat 336 ion pair encaged within hydrophobic silica sol-gel. During the entrapment of the rhodium compound, it was converted into supported catalytically active Rh(0) nanoparticles characterized by TEM and XPS studies. The transformations of the allylarenes to (E)- and (Z)-1-phenyl-1-propenes follows the first order rate law, and proved to be significantly affected by the electronic nature of the substrates and by the hydrophobicity of the sol-gel support. Upon completion of the isomerization the catalyst could be recovered and recycled at least six times without a decrease in the catalytic activity after the first catalytic run.

Cobalt-Catalyzed Z to e Isomerization of Alkenes: An Approach to (E)-β-Substituted Styrenes

An efficient cobalt-catalyzed Z to E isomerization of β-substituted styrenes using the amido-diphosphine ligand was developed, delivering the (E)-isomers with good functional tolerance and high stereoselectivity. The reaction could be scaled up to gram-scale with a catalyst loading of 0.1 mol %, using a mixture of (Z)- and (E)-alkene as the starting material. Preliminary mechanistic studies indicated that cobalt(I)-hydride and a benzylic-cobalt species were probably involved in the reaction, as supported by experiments and DFT calculations.

(E)-Selective Wittig Reactions between a Nonstabilized Phosphonium Ylide Bearing a Phosphastibatriptycene Skeleton and Benzaldehydes

Wittig reactions between benzaldehyde derivatives and a nonstabilized phosphonium ylide bearing a phosphastibatriptycene skeleton, regarded as a tridentate aryl ligand, gave (E)-alkenes with high selectivity in the presence of both lithium and sodium salts. As previously reported, reactions between a triphenylphosphonium ylide and benzaldehyde derivatives under the same conditions afforded mainly (Z)-alkenes. Variable-temperature (VT)31P{1H} NMR spectra showed two signals, assigned to cis- and trans-1,2-oxaphosphetanes, which were observed at different temperatures (–80 °C and –40 °C, respectively) in the Wittig reaction between benzaldehyde and the nonstabilized phosphonium ylide bearing the phosphastibatriptycene skeleton, in the presence of both lithium and sodium salts, and showed the existence of equilibrium between these products at –40 °C. On the other hand, this equilibrium was not clearly observed in the reaction between the triphenylphosphonium ylide and benzaldehyde, for which only one signal was detected. The observed intermediates were confirmed to be 1,2-oxaphosphetanes by deprotonation of the isolated β-hydroxyalkylphosphonium salts bearing a phosphastibatriptycene skeleton and a triphenylphosphine moiety, respectively. Crossover reactions were conducted in the deprotonations of β-hydroxyalkylphosphonium salts with TMS2NNa in the presence of p-chlorobenzaldehyde, resulting in the observation of signals corresponding to 1,2-oxaphosphetanes containing phenyl and p-chlorophenyl groups at the 4-positions, indicating the exchange process between benzaldehyde and p-chlorobenzaldehyde at –40 °C for the phosphastibatriptycene system and at 0 °C for triphenyl derivatives. These results clearly indicated that stereochemical drift occurred at those temperatures, even in reactions using nonstabilized phosphonium ylides. The stereochemical drift in the phosphastibatriptycene system occurred at a lower temperature than in the case of the triphenyl derivative, thus explaining the (E)-selective Wittig reactions between the benzaldehyde derivatives and the nonstabilized phosphastibatriptycene-based phosphonium ylide in the presence of lithium and sodium salts.

Engineering P450 Peroxygenase to Catalyze Highly Enantioselective Epoxidation of cis-β-Methylstyrenes

P450 119 peroxygenase and its site-directed mutants are discovered to catalyze the enantioselective epoxidation of methyl-substituted styrenes. Two new site-directed P450 119 mutants, namely T213Y and T213M, which were designed to improve the enantioselectivity and activity for the epoxidation of styrene and its methyl substituted derivatives, were studied. The T213M mutant is found to be the first engineered P450 peroxygenase that shows highly enantioselective epoxidation of cis-β-methylstyrenes, with up to 91 % ee. Molecular modeling studies provide insights into the different catalytic activity of the T213M mutant and the T213Y mutant in the epoxidation of cis-β-methylstyrene. The results of the calculations also contribute to a better understanding of the substrate specificity and configuration control for the regio- and stereoselective peroxygenation catalyzed by the T213M mutant.

Direct Olefination of Alcohols with Sulfones by Using Heterogeneous Platinum Catalysts

Carbon-supported Pt nanoparticles (Pt/C) were found to be effective heterogeneous catalysts for the direct Julia olefination of alcohols in the presence of sulfones and KOtBu under oxidant-free conditions. Primary alcohols, including aryl, aliphatic, allyl, and heterocyclic alcohols, underwent olefination with dimethyl sulfone and aryl alkyl sulfones to give terminal and internal olefins, respectively. Secondary alcohols underwent methylenation with dimethyl sulfone. Under 2.5 bar H2, the same reaction system was effective for the transformation of alcohol OH groups to alkyl groups. Structural and mechanistic studies of the terminal olefination system suggested that Pt0 sites on the Pt metal particles are responsible for the rate-limiting dehydrogenation of alcohols and that KOtBu may deprotonate the sulfone reagent. The Pt/C catalyst was reusable after the olefination, and this method showed a higher turnover number (TON) and a wider substrate scope than previously reported methods, which demonstrates the high catalytic efficiency of the present method. Olefination of alcohols: The first heterogeneous catalytic terminal and internal olefination of primary alcohols and methylenation of secondary alcohols with sulfones, a reusable carbon-supported Pt catalyst, and KOtBu is reported (see scheme).

Nickel-Catalyzed Allylic C(sp2)–H Activation: Stereoselective Allyl Isomerization and Regiospecific Allyl Arylation of Allylarenes

Stereoselective allyl isomerization and regiospecific allyl arylation reactions of allylarenes with a catalytic system comprising nickel(II) with an aryl Grignard reagent were studied. Both reactions are triggered by allylic internal C(sp2)–H activation by in-situ-formed Ni0, which is inserted into the C–H bond at the 2-position of the allyl moiety without a directing group. The isomerization of allylarene to 1-propenylarene favors the E isomer and proceeds with quantitative conversion. The arylation takes place through oxidative cross-coupling of allylarenes with excess Grignard reagent. It occurs regiospecifically at the position of C(sp2)–H activation and represents a new method for the synthesis of 1,1-disubstituted olefins. The results of deuterium labeling experiments reveal an alkenyl/alkyl mechanism involving allylic internal C(sp2)–H activation and multiple intermolecular 1,2-, 1,3-, and 2,3-hydride shifts. These methods represent new approaches to the functionalization of olefins, and the mechanistic investigations could be helpful for the discovery and design of new strategies for olefin functionalization.

Use of silver carbonate in the Wittig reaction

An efficient synthesis of olefins by the coupling of stabilized, semistabilized, and nonstabilized phosphorus ylides with various carbonyl compounds in the presence of silver carbonate is reported. Wittig olefination of aromatic, heteroaromatic, and aliphatic aldehydes (yields >63%) and a ketone (yield 42%) are demonstrated. These reactions proceed overnight at room temperature, under weakly basic conditions, and as such extend the applicability of the Wittig reaction to base-sensitive reactants.

Stereoselective Wittig olefination reactions employing a novel ortho-P-aryl alkoxide effect

Non-stabilized ortho-P-alkoxy-substituted ylides react with aromatic and aliphatic aldehydes providing (E)-olefins with high stereocontrol, also allowing easy phosphine oxide removal in certain cases.

Synthesis of enantiopure 2-amino-1-phenyl and 2-amino-2-phenyl ethanols using enantioselective enzymatic epoxidation and regio- and diastereoselective chemical aminolysis

Several enantiopure 1,2-amino alcohols have been prepared by combining a stereoselective enzymatic epoxidation of styrenes with regio- and stereoselective chemical reactions. An interesting reactivity has been noted concerning the reaction of epoxides and NH3 under microwave activation.

WITTIG-REAKTION VON TRIPHENYLPHOSPHONIO-ALKYLIDEN MIT SUBSTITUIERTEN BENZALDEHYDEN: HAMMETT-BEZIEHUNG UND TEILWEISE REVERSIBILITAT DER ADDUKT-BILDUNG

Bei Abwesenheit loslicher Lithium-Salze vereinigen sich Triphenylphosphonio-methylid und -ethylid bereits bei -75 deg C mit Aldehyden. Elektronenanziehende Liganden beschleunigen, elektronenspendende Liganden verzogern die Anlagerung der Ylide an die substituierten Benzaldehyde.Die Addukte(Oxaphosphetane) zerfallen erst oberhalb -30 deg C zu Olefin und Triphenylphosphinoxid.Wird vor dem Zerfall ein zweiter Aldehyd oder ein zweites Ylid zugesetzt, so findet ein teilweiser Austausch der Komponenten statt.