Synthesis of tervalent phosphorus esters in biphasic system using potassium phosphate as unique solid base

The synthesis of tervalent phosphorus esters continues to be a significant area of interest, much of it again directed toward the synthesis of phosphite ligands for metal‐catalyzed reactions. Typically, they were obtained through esterification of the corresponding phosphorus chlorides with the appropriate alcohols in the presence of an amine. In this paper, we present a new method for the synthesis of tervalent phosphorus esters, not yet mentioned in the literature, when potassium phosphate, as a unique base, is used in liquid–solid system. Symmetrical and unsymmetrical phosphites were obtained with good yields (65%–80%) using this method. The compounds were characterized by ³¹P NMR spectroscopy. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:360–364, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20438     

Oxidative coupling of thiols to disulfides using a solid anhydrous potassium phosphate catalyst

Thiols are oxidized to the corresponding disulfides with a mild base, anhydrous potassium phosphate, under ambient conditions in the presence of air.     

Synthesis of polyfunctional aliphatic carbonyl compounds under phase-transfer conditions

We have studied mono- and dialkylation of malonic, acetoacetic, and cyanoacetic esters with esters of haloacetic and -halopropionic acids and addition of the CH acids mentioned and their analogs to methyl and ethyl acrylate under phase-transfer catalysis conditions, and also deethoxycarbonylation of the obtained products. We have demonstrated for the first time the possibility of Dieckmann cyclization under phase-transfer catalysis conditions and have developed a simple method for the synthesis of 2,3-di(ethoxycarbonyl)cyclopentanone, a key intermediate in the syntheis of deoxyprostaglandins, by cyclization of triethyl 1,2,4-butanetricarboxylate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1073–1079, May, 1991.     

Synthesis of the p-toluenesulfonate of oleyl acohol under conditions of phase-transfer catalysis

The tosylation of oleyl alcohol under the conditions of phase-transfer catalysis has been studied. In this process oleyl p-toluenesulfonate of formed with a yield of up to 80%.Institute of Bioorganic Chemistry, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, 443–445, May–June, 1988.     

Synthesis of diaryl sulfides by the reactions of activated aryl halides with potassium ethyl dithiocarbonate under conditions of phase-transfer catalysis

Russian Chemical Bulletin -     

Synthesis of indan-based unusual alpha-amino acid derivatives under phase-transfer catalysis conditions

Conformationally constrained cyclic alpha-amino acid derivatives were synthesized under solid-liquid phase-transfer catalysis conditions. This methodology involves the bis-alkylation of ethyl isocyanoacetate with various alpha,alpha'-dibromo-o-xylene derivatives [alpha,alpha'-dibromo-o-xylene 5, 2,3-bis(bromomethyl)-1, 4-dimethoxybenzene 6, 1,2-bis(bromomethyl)-4,5-dibromobenzene 7, 2, 3-bis(bromomethyl)naphthalene 8, 1,8-bis(bromomethyl)-naphthalene 9, 6,7-bis(bromomethyl)-2,2-dimethyl-1H-phenalene-1,3(2H)-dione 10, 2, 3-bis(bromomethyl)-1,4-anthraquinone 11, 6, 7-bis(bromomethyl)quinoxaline 12, 3,4-bis(bromomethyl)furan 13, 1,2, 4,5-tetrakis(bromomethyl)benzene 28, and hexakis(bromomethyl)benzene 30] using potassium carbonate as a base and tetrabutylammonium hydrogensulfate as a phase-transfer catalyst to give corresponding isonitrile derivatives, which upon hydrolysis with HCl in ethanol gave amino esters. Using this method electron-deficient as well as electron-rich and halogen-substituted indan-based alpha-amino acids were prepared. The preparation of bis-indan as well as tris-indan alpha-amino esters is also described.     

Synthesis of jasminaldehyde using magnesium organo silicate as a solid base catalyst

Synthetic talc (magnesium organo silicates; MOS) was synthesized by sol–gel method under non-hydrothermal conditions and modified by introducing amine/diamine functionalities in the interlayer space. The applicability of amine/diamine functionalized MOS was studied as catalysts for the synthesis of jasminaldehyde or -pentylcinnamaldehyde by condensation of 1-heptanal with benzaldehyde. The effect of amine/diamine functionality, amount of catalyst, benzaldehyde to 1-heptanal molar ratio and temperature on the selectivity of jasminaldehyde was studied in detail. The highest conversion of 1-heptanal (99%) with 82% selectivity of jasminaldehyde was achieved using MOS3 as a catalyst. The rate constant for condensation of 1-heptanal with benzaldehyde was calculated under optimized reaction conditions. This is the first report on application of MOS as a solid base catalyst for the condensation of 1-heptanal with benzaldehyde.     

Synthesis of diethylamides of α-diethylaminocarboxylic acids using α-trichloromethylcarbinols and their acetates under phase-transfer catalysis conditions

Conclusions Trichloromethyicarbinols and their acetates react with diethylamine under phase-transfer catalysis conditions to give diethylamides of -diethylaminocarboxylic acids. The same products are formed in the reaction of aldehyde acylals with chloroform and diethylamine in the 50% aqueous NaOH-BTEAC phase-transfer catalytic system.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1190–1192, May, 1986.     

Synthesis of ketobemidone precursors via phase-transfer catalysis

Hydrochloride salts of N-substituted-bis-(2-chloroethyl)amines can be condensed with m-methoxyphenyl-acetonitrile or 1-phenyl-2-alkanones under phase-transfer conditions to yield precursors of the powerful analgesic compounds - the ketobemidones.     

Reactions of alkyl hetaryl ketones with carbon tetrachloride under liquid/solid phase-transfer catalysis conditions

Summary Reactions of methyl and ethyl hetaryl ketones in the CCl₄/solid KOH system in the presence of 18 crown-6 at room temperature yield the corresponding 2-hetaryl-2-trichloromethyloxiranes in 8–22% yields. Reactions of sterically hindered ketones of the type (hetaryl)COCHR₂ (R = Me, Et) with CCl₄/OH- form the corresponding a-hydroxy ketones of the type (hetaryl)COC(OH)R₂ in 28–44% yields.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 312–315, March, 1994.     

Pd-catalyzed allylation of CH acids under phase-transfer conditions

The composition of the products obtained by Pd-catalyzed allylation of diethyl (alkyl)-malonates and ethyl cyanoacetate with allylic acetates under phase-transfer conditions using potassium carbonate or phosphate as bases depended strongly on the nature of the reactants and the ligands used. The highest yields and the fraction of the “linear” regioisomers were achieved in the reactions of prenyl or 3-methylbut-1-en-3-yl acetates in the presence of phosphordiamidite ligands.     

Catalytic asymmetric syntheses of isoxazoline-N-oxides under phase-transfer conditions

Catalytic asymmetric syntheses of various isoxazoline-N-oxides have been accomplished by asymmetric phase-transfer conjugate addition of bromomalonate to nitroolefins and subsequent ring-closing O-alkylation.     

Synthesis of monoazacrown ethers under phase-transfer catalysis

A procedure has been proposed for the synthesis of monoazacrown ethers by reaction of N-benzyldiethanolamine with oligo(ethylene glycol) bis-p-toluenesulfonates in a two-phase system aromatic hydrocarbon-50% aqueous alkali, followed by removal of the benzyl group by catalytic hydrogenolysis. The maximal yields of N-benzylaza-12-crown-4, -18-crown-6, and -21-crown-7 were achieved by adding 4?C10 equiv of LiCl, BaBr₂, and CsCl, respectively, to the reaction mixture, which probably indicated template effect.     

Clean one-pot synthesis of 1,2,4-oxadiazoles under solvent-free conditions using microwave irradiation and potassium fluoride as catalyst and solid support

Potassium fluoride was found to be an efficient catalyst and solid support for the synthesis of 3,5-disubstituted-1,2,4-oxadiazoles. In this work, a one-pot method for the synthesis of these compounds from the reaction of nitriles with hydroxylamine hydrochloride and acyl chloride in the presence of potassium fluoride under solvent-free conditions using microwave irradiation has been developed. The advantages of using potassium fluoride as a solid support in comparison to conventional solid supports are simple operation and convenient separation of the products.     

Stereoselective synthesis of dihydrofurans under phase-transfer catalyzed conditions

Treatment of cyclic or acyclic -haloenones with various carbon nucleophiles involving active methylene functions afforded the corresponding dihydrofurans in a stereoselective manner with good to high yields. This reaction system can provide a general and practical methodology for the construction of dihydrofuran rings.     

Synthesis of some electron-rich aryl(hetaryl)oxiranes under phase-transfer and homogeneous conditions

Reactions of mono-, di-, and trimethoxybenzaldehydes with trimethylsulfonium methyl sulfate readily occur under mild homogeneous and heterogeneous phase-transfer conditions to give the corresponding aryloxiranes whose yields are comparable with those typical of severe Corey-Chaykovsky reaction conditions. The phase-transfer version ensures better purity of the epoxy derivatives and is the only possible way of preparing 1-methyl-3-(oxiran-2-yl)-1H-indole.     

The interaction of dihydrofurylsilanes with dichlorocarbene under phase-transfer conditions

Dichlorocarbene generated in a two-phase catalytic system reacts with 3-trimethylsilyl-2,5-dihydrofuran to give both possible products of mono-insertion into the CH bond in positions 2 and 5 of the ring, together with a CC bond adduct. Reaction of 2-trimethylsilyl-4,5-dihydrofuran with dichlorocarbene leads to 2,3-dichloro-2-trimethylsilyl-5,6-dihydro-2H-pyran, which is formed via isomerization of the primary bicyclic adduct.     

Direct transformation of benzilic amines to carbonyls using polyacrylamide-bound tungstate under phase-transfer catalysis conditions

A recyclable catalytic system under heterogeneous phase-transfer catalysis conditions was designed by using polyacrylamide-bound tungstate. A convenient method for the oxidative direct transformation of benzilic amines to carbonyls with hydrogen peroxide was then developed.