LiClO4-catalyzed highly diastereoselective synthesis of cis-aziridine carboxylates

Aldimines (generated in situ from aldehydes and amines) undergo ready addition with ethyl diazoacetate in the presence of a catalytic amount of lithium perchlorate in acetonitrile to afford the corresponding cis-aziridine carboxylates in high yields with high diastereoselectivity. 10 mol% LiClO₄ in acetonitrile provides a convenient catalytic media to perform the reactions under mild and neutral conditions.     

Studies on the Catalysis of Ene Reactions by Lithium Perchlorate in Different Solvents

Abstract

The catalytic effect of lithium perchlorate on ene reaction of cis-cyclooctene with diethyl azodicarboxylate, 4-phenyl-1,2,4-triazoline-3,5-dione and the metallo-ene reaction of diallyldibutyltin with diethyl azodicarboxylate has been studied in different solvents like acetonitrile, acetone, diethyl ether, dimethylformamide and ethyl acetate.     

高氯酸镁催化合成1,2,3,4-四氢嘧啶-2-酮

在高氯酸镁催化作用下,由醛、1,3-二羰基化合物、脲(硫脲)合成了一系列1,2,3,4-四氢嘧啶-2-酮,此合成方法反应温和、产率高,并且高氯酸镁具有能重复使用的优点.     

The effect of electrolyte-controlled growth morphology on the charge transport properties of poly(3-methylthiophene)

Poly(3-methylthiophene) films were potentiostatically and galvanostatically synthesized on platinum electrodes in acetonitrile using lithium perchlorate, lithium tetrafluoroborate, tetra-n-butylammonium perchlorate, and tetra-n-butylammonium tetrafluoroborate as supporting electrolytes. Cyclic voltammetric analyses of the polymer films indicate the synthesis is polymerization process dependent. Constant potential syntheses, which resulted in a higher current density and were carried out at higher potentials, yielded polymer films with a higher charge capacity. Chronocoulometric results show that the charge transport rates of the films were electrolyte dependent and that tetra-n-butylammonium tetrafluoroborate yielded poly(3-methyl-thiophene) with the highest charge transport rate. The charge transport rate was found to be electric field dependent for all cases, suggesting that the films resemble a porous electrode. Scanning electron microscope analyses of the films, prepared under various conditions, indicate that the synthesis method used, and the nature of the electrolyte, strongly influence morphology and charge transport.     

A survey of nonaqueous conditions for the anodic oxidation of N-butyl alcohol

A survey of nonaqueous conditions for the oxidation of n-butyl alcohol is reported. Oxidation may be effected in the neat alcohol or in moderately dilute solution in acetonitrile. High current yields of butyraldehyde are obtained in the neat alcohol, but in dilute solution n-butyl butyrate is the major product. Lithium fluoborate is superior to lithium nitrate or perchlorate as the supporting electrolyte.     

A perfluorinated micellar reaction system in lithium perchlorate/acetonitrile; enhanced efficiency in anodic electron-transfer and intermolecular cycloaddition

A micellar electrolytic reaction system composed of lithium perfluorooctanesulfonate (LiFOS), highly concentrated lithium perchlorate in acetonitrile, effectively dispersed slightly soluble compounds to promote anodic electron transfers, and it further accelerated the formation of desired cycloadducts between electrogenerated quinones and dienes.     

Solvent-Free Thiolysis of Epoxides under Lithium Perchlorate Catalysis

Solvent-free ring opening of 1,2-epoxides with thiols using catalytic amounts of lithium perchlorate affords high yields of β-hydroxy sulfides. Nucleophilic attack of the thiols occurs regioselectively at the sterically less hindered side of the epoxides.     

Solvent-Free Thiolysis of Epoxides under Lithium Perchlorate Catalysis

Summary. Solvent-free ring opening of 1,2-epoxides with thiols using catalytic amounts of lithium perchlorate affords high yields of β-hydroxy sulfides. Nucleophilic attack of the thiols occurs regioselectively at the sterically less hindered side of the epoxides.     

Practical and regioselective brominations of aromatic compounds using tetrabutylammonium peroxydisulfate

Direct bromination of wide range of aromatic compounds substituted with electron donating groups such as methoxy, hydroxy, or amino groups have been achieved with high regioselectivity by the reaction with Br₂ in the presence of tetrabutylammonium peroxydisulfate 1 under mild conditions in acetonitrile in excellent yields. The use of lithium bromide as a bromination reagent afforded high yields of monobromo compounds with complete regioselectivity under neutral and mild reaction conditions in acetonitrile.     

Regioselective reduction of 2-perfluoroalkanoylcyclohexane-1,3-diones and their enamino derivatives

Ionic hydrogenation of 2-perfluoroalkanoylcyclohexane-1,3-diones and their endocyclic enamino derivatives containing a secondary amino group by the action of triethylsilane in trifluoroacetic acid in the presence of a catalytic amount of lithium perchlorate involved regioselective reduction of the side-chain carbonyl group to hydroxy with formation of the corresponding hydroxy diketones and hydroxy amino ketones, respectively. Under analogous conditions endocyclic enamino derivatives possessing a tertiary amino group underwent deacylation to give enamino ketones.     

Photodimerization and photooxygenation of 9-vinylcarbazole catalyzed by titanium dioxide and magnesium perchlorate

<正>Photoreaction of 9-vinylcarbazole in acetonitrile in the presence of titanium dioxide and a catalytic amount of magnesium perchlorate gave 3,6-di(9-carbazolyl)-1,2-dioxane as a photooxygenated product via photodimerization of 9-vinylcarbazole.The photoreaction proceeds via an electron transfer mechanism,where magnesium perchlorate accelerated formation of the photo-oxygenated product.     

A novel synthesis of 2,4,4-trisubstituted 2-cyclopentenones by consecutive reaction of 1-chlorovinyl p-tolyl sulfoxides with acetonitrile and its homologues

1-Chlorovinyl p-tolyl sulfoxides were synthesized from several kinds of ketones and chloromethyl p-tolyl sulfoxide in three steps in high overall yields. Treatment of the 1-chlorovinyl p-tolyl sulfoxides with cyanomethyllithium (lithium α-carbanion of acetonitrile) at low temperature gave the adducts in almost quantitative yields. The adducts were then treated with LDA followed by excess lithium α-carbanion of the homologues of acetonitrile to afford 3,5,5-trisubstituted cyclopentadienyl enaminonitriles, which were hydrolyzed and heated under acidic conditions to give 2,4,4-trisubstituted 2-cyclopentenones in good overall yields.     

Bismuth Triflate–Catalyzed Friedel–Crafts Acylations of Sydnones

Friedel–Crafts acylations of various 3-arylsydnones at the C4 position have been achieved in good yields using 4 equivalents of an alkyl anhydride and 25 mol% each of bismuth triflate and lithium perchlorate in anhydrous acetonitrile at 95 °C. Acylations appear to be faster with arylsydnones bearing electron-donating moieties and sterically unencumbered anhydrides.     

A novel procedure for conversion of epoxides to α-hydroxyphosphonates with a trialkylphosphite mediated by LiClO4

A new method has been developed for the direct conversion of epoxides to α-hydroxyphosphonates by the reaction of a trialkylphosphite with the epoxide in 5 M lithium perchlorate in diethyl ether (LPDE). The reaction is highly regioselective and efficient with excellent yields under mild and neutral conditions.     

Lithium perchlorate suspend in methylene chloride, a mild, efficient and reusable catalyst for the synthesis of ferrocene aminonitrile derivatives

A practical and efficient method for the synthesis of α-aminonitriles of ferrocene by one-pot three-component reaction of ferrocenecarboxaldehyde, trimethylsilyl cyanide and amines catalyzed by lithium perchlorate suspend in CH₂Cl₂ is reported under mild and neutral reaction conditions in high yields and short reactions times.     

Interactions Between Tetra(trifluoromethylsulfonyl)-1,4,8,11-tetraazocyclotetradecane and Perchlorate Anion in Propylene Carbonate, Nitromethane, Acetonitrile, and Tetrahydrofuran

Electrical conductance measurements are reported for lithium perchlorate andthe anion receptor tetra(trifluoromethylsulfonyl)-1,4,8,11-tetraazocyclotetradecane(TTCD) in different aprotic solvents (propylene carbonate, nitromethane,acetonitrile, and tetrahydrofuran). The data have been analyzed by a suitablemethod based on the Lee-Wheaton theory on mixed electrolytes in order to obtainthe true thermodynamic formation constants of macrocyclic-anion complexes andthe ion pairs of both the uncomplexed (ClO₄ ^–)and complexed (TTCD-ClO₄ ^–)anions. The results show that the anion-ligand formation constants increase withdecreasing dielectric constant and that the presence of the ligand increases theionization of lithium perchlorate and enhances the transference number of lithiumion. These findings are of particular interest in view of the technologicalapplication of anion receptors in electrolyte solutions for lithium batteries.     

Catalytic nucleophilic activation of acetonitrile via a cooperative catalysis of cationic Ru complex, DBU, and NaPF6

The development of an efficient catalytic system for the direct addition of acetonitrile under mild amine basic conditions is described. A cooperative catalysis of CpRu complex, DBU, and NaPF₆ enables chemoselective and catalytic generation of nucleophiles from barely acidic acetonitrile, which is integrated into the addition to aldehydes, imines, and activated ketones. Mechanistic investigations revealed that the three catalyst components work together to achieve high catalytic efficiency.     

A novel synthesis, including asymmetric synthesis, of 2,4,4-trisubstituted 2-cyclopentenones based on the reaction of 1-chlorovinyl p-tolyl sulfoxides with acetonitrile and its homologues

Reaction of 1-chlorovinyl p-tolyl sulfoxides, which were synthesized from chloromethyl p-tolyl sulfoxide and ketones in high overall yields, with cyanomethyllithium (lithium α-carbanion of acetonitrile) gave adducts in high to quantitative yields. The adducts were treated with LDA followed by lithium α-carbanion of the homologues of acetonitrile to give 3,5,5-trisubstituted enaminonitriles in good to high yields. Hydrolysis of the enaminonitriles under acidic conditions gave 2,4,4-trisubstituted 2-cyclopentenones in good yields. By using the optically active chloromethyl p-tolyl sulfoxide and unsymmetrical ketones, this procedure gave the optically pure 2,4,4-trisubstituted 2-cyclopentenones. The scope and limitations of this method and the mechanism of the reactions are also discussed. These procedures offer a new and effective method for the synthesis of 2,4,4-trisubstituted 2-cyclopentenones from four components, ketones, chloromethyl p-tolyl sulfoxide, acetonitrile, and its homologues.     

LiClO4 Accelerated Michael addition of amines to α,β-unsaturated olefins under solvent-free conditions

Several primary and secondary amines were added to α,β-unsaturated esters, nitriles, amides, and ketones to give the corresponding saturated amines mediated by solid lithium perchlorate under solvent-free and environmentally friendly conditions at room temperature.     

Anodic modification of proline derivatives using a lithium perchlorate/nitromethane electrolyte solution

[reaction: see text] N-Acyliminium cation of prolines was efficiently generated to accumulate in an undivided cell at 0 degrees C by an anodic oxidation of N-acylprolines or alpha'-phenylsulfanylated N-acylproline derivatives in a lithium perchlorate/nitromethane solution. The iminium cation intermediates gave modified prolines by a reaction with nucleophiles under mild conditions.