Rh-Catalyzed One-Pot Reductive Alkylation of Malononitrile Under Transfer Hydrogenation Conditions

Dihydroartemisinin can be converted to its ether derivatives in good yields by reaction with different alcohols in the presence of a catalytic amount of dodecatungstophosphoric acid hydrate. Easy handling, trouble-free workup by filtration, excellent yields, and very short reaction times are some of the highlights of this protocol.     

Formation of 7,9-Disubstituted Xanthinium Compounds Under Mild Conditions by Alkylation of Silylated Xanthines

Silylated, 3-unsubstituted xanthine derivatives afford 7,9-diallyl and 7,9-dibenzylxanthinium compounds upon the reaction with excess 2-propenyl (allyl) or benzyl bromide at room temperature.     

相转移催化下4-氯苯磺酰基乙酸异丙酯的烷基化反应

在有机合成中可用芳磺酰基作暂时性活化基团。芳磺酰基乙酸酯是具有活性亚甲基的弱酸性化合物。通常要在氢化钠、醇钠存在下才能起烷基化反应。Ono等曾报道4-甲苯磺酰基乙酸甲酯在DBu存在下进行烷基化反应,但反应时间长。近年来,相转移催化在有机反应中的应用受到重视,然而用固液相转移催化法使芳磺酰基乙酸酯起烷基化反应还未见报道。我们在K₂CO₃/DMF体系中,用TEBA作催化剂,研究了4-氯苯磺酰基乙酸异丙酯与不同类型卤代烃所起的烷基化反应。合成了尚未见报道的一或二烷基化产物。     

Synthesis of Diarylselenides and Diarylsulfides Under Phase Transfer Conditions

Diarylselenides and diarylsulfides are synthesized from the corresponding diaryldiselenide and diaryldisulfide by reduction with aminoiminomethanesulfinic acid, and reaction with activated aryl halides under phase transfer conditions. The reactions yields vary from good to excellent.     

Alkylation of Aryl and Hetaryl Ketoximes with Alkyl Iodides Prepared In Situ from Alkyl Chlorides Under Phase Transfer Catalysis Conditions

Two simple one-pot phase transfer catalytic methods for the preparation of ketoxime O-ethers from the corresponding ketoximes and alkyl iodides prepared in situ from alkyl chlorides were developed. The corresponding aryl and hetaryl ketoxime O-ethers were obtained in 15–83% yields.     

Acylation of Phosphorus Substituted Ch-Acids Under Phase Transfer Catalysis Conditions

Abstract.

Acylation of phosphoryl- and thiophosphoryl acetonitriles under phase transfer catalysis (PTC) conditions leads in high yields to C-acylated products existing as Z-isomers of the corresponding enol forms. They are stabilized by strong intramolecular H-bonds. On the contrary, acylation of phosphorylacetone proceeds mainly at the oxygene atom and gives Z and E enolacetate. Phosphorus trichloride was used as an acylating agent under PTC conditions. S-Alkyldichlorophosphites were obtained by the reaction with mercaptanes. Alcohols react with PCl₃ in the presence of sodium carbonate to result in dialkylphosphites.     

Reaction of Dichlorocarbene with Substituted Cyclopentadienones Under Phase Transfer Conditions

The cycloaddition reactions involving dichlorocarbene generated under phase transfer conditions have been studied extensively in the past few years due to the simplicity of the procedure involved.¹ The facile formation of dichlorocyclopropanes provides an easy entry to functionalised aromatics and expanded carbocyclic compounds.² The dichlorocarbene generated under phase transfer conditions is capable of adding even to electron deficient olefins. We describe here the cyclo-addition reaction of dichlorocarbene to tetrasubstituted cyclopentadienones.     

A Facile Synthesis of Unsymmetrical Sulfides Under Phase Transfer Conditions

An efficient synthesis of unsynmetrical sulfides (3) is described by reacting S-alkylisothiouroniu″ salts (1) with alkyl halides (2) under liquid-liquid phase transfer catalyst conditions.     

Alkylation of 3-Acetylthiophene Under Phase-Transfer Conditions

Reactions of 3-acetylthiophene with C₁-C₄-alkyl iodides in a two-phase benzene/solid KOH system in the presence of l8-crown-6 afford di-C-alkylated derivatives-(3-thienyl)COCHR₂ in satisfactory yields (～50%) with high regioselectivity (70–100%).     

A Convenient Synthesis of the Symmetrical bis-Sulfides Under Phase Transfer Conditions

Phase transfer catalysis has been found to be effective for the preparation of symmetrical bis-sulfides (4) in high yields by a one-pot proudure which consists of generating the thiolate ions from s-alkylisothiouronium salys (2) and then reacting with alkyl halides (3).     

Solid-Liquid Phase Transfer Catalytic Synthesis VIII: The Rapid Alkylation of Ethyl Phenylsulfonylacetate Under Microwave Irradiation

Rapid alkylations of ethyl phenylsulfonylacetate with a series of halides were performed in 960 W domestic microwave oven, and the isolated yield of α-monoalkylated product varying from 76 to 86%.     

Dihalocyclopropanation of Phenylthio or Butylthiocycloalkenes Under Phase Transfer Conditions. Opening of Cyclopropanes Under Microwave Irradiation

Dihalocarbenes (X=C1,Br) generated under phase transfer conditions added to phenylthio or butylthiocylcloalkenes give corresponding 1,1-dihalo-2-thiobutyl or thiophenyl-cyclopropanes. The ring opening of dichlorophenylthiocyclopropanes (2a, 2b, 2c) was obtained by using silver tetrafluoborate on alumina under microwave irradiation.     

Alkylation of Imidazole by Solid-Liquid Phase Transfer Catalysis in the Absence of Solvent

Phase Transfer Catalysis in the absence of solvent is described as a useful and general method for the selective N-alkylation of imidazole. In all cases high yields are obtained while quaternization is avoided.     

Montmorillonite Supported Borohydride: A New Reducing Agent for Reductions Under Phase Transfer Conditions

A few cyclic and acyclic ketones were reduced in dichloro-methane, using reducing agents prepared from reusable montmorillonite clay supported phase transfer catalyst. A high percentage of axial attack (76–100%) by hydrides on substituted cyclohexanones observed, has been rationalised on the basis of a four center cyclic transition state for the clay absorbed ketone.     

Phase Transfer Catalysis without Solvent. Alkylation of Phenol and Derivatives

The alkylation of phenol, hydroquinone and p-aminophenol is performed by phase transfer catalysis without solvent. High yields of α,ω-diphenoxyalkanes, hydroquinone diethers and high selective mono O-alkylation of p-aminophenol are obtained in very mild conditions.     

A Facile Method for the Syntheses of Dialkyl Disulfides from Sulfur Under Phase Transfer Conditions

A convenient reaction of alkyl halides with sulfur in alkaline medium has been found to afford disulfides in good to excellent isolated yield under phase transfer conditions.     

Efficient and Convenient Synthesis Ultrasound and Solid-liquid Phase of Diethers from Furoin Under Transfer Catalysis Conditions

Compounds having an active hydroxy group, such as, acyloins can be easily alkylated by alkyl halides in the presence of a phase transfer catalyst （PTC）. The reaction is usually carried out in the presence of con-centrated aqueous sodium or potassium hydroxide and a phase transfer catalyst, such as, quaternary ammonium salts^[1-3] species, miscible which facilitate the interphase transfer of making reactions between reagents in two im-phases possible. The reaction involves a series of equilibrium and mass-transfer steps.     

Phase Transfer Catalyzed Alkylation: An Efficient Protection of Acid Labile Hemiketals

The reaction of hemiketals (1–6) with sodium hydroxide and methyl iodide in the presence of TBAI as a catalyst furnished methoxy hemiketals (7–10) in more than 90% yield.     

Efficient and Convenient Synthesis of Diethers from Furoin Under Ultrasound and Solid-liquid Phase Transfer Catalysis Conditions

Introduction Compounds having an active hydroxy group, such as, acyloins can be easily alkylated by alkyl halides in the presence of a phase transfer catalyst (PTC). The reaction is usually carried out in the presence of concentrated aqueous sodium or potassium hydroxide and a phase transfer catalyst, such as, quaternary ammonium salts[1-3], which facilitate the interphase transfer of species, making reactions between reagents in two immiscible phases possible. The reaction involves a series of equilibrium and mass-transfer steps.