Highly efficient gold(III)-catalyzed intermolecular hydroarylation of unactivated alkenes with arenes under mild conditions

A simple and efficient method for functionalization of electron-rich arenes and heteroarenes with unactivated alkenes by Au(III)-catalyzed intermolecular hydroarylation under mild reaction conditions was developed. This method features a short reaction time (5 h) under mild conditions and has a broad substrate scope, including electron-rich arenes and heteroarenes, terminal and internal substituted aryl alkenes, and unactivated aliphatic alkenes.     

An efficient method for the synthesis of dialkyl chlorophosphates from trialkyl phosphites using bis（trichloromethyl） carbonate

A mild and simple method for the synthesis of dialkyl chlorophosphates is described, bis（trichloromethyl） carbonate （BTC） is used as the effective reagent for the conversion of dialkyl phosphites to their corresponding dialkyl chlorophosphates under mild conditions.     

Selective N-arylation of aminobenzanilides under mild conditions using triarylbismuthanes

Diarylamines are prepared selectively in good yields under mild conditions by treatment of aminobenzanilides with triarylbismuthanes in the presence of copper(II) acetate and triethylamine. Arylation under these conditions occurs preferentially at the amino- rather than the amide-nitrogen of the benzanilide. Thus, heating an aminobenzanilide in dichloromethane under reflux in the presence of 1 equiv each of a triarylbismuthane, triethylamine, and copper(II) acetate affords the diarylamine in good yields. This method thereby provides a mild and expeditious route to functionalized diarylamines.     

Preparation of Silyl Ethers Using Hexamethyldisilazane in the Presence of N‐Bromosuccinimide under Mild and Solvent‐Free Conditions

A mild, simple, novel and highly efficient method for the rapid protection of various primary, secondary, tertiary aliphatic and aromatic alcohols using hexamethyldisilazane (HMDS) in the presence of N-bromosuccinimide (NBS) as an active, inexpensive, non-toxic and readily available catalyst under solvent-free conditions is described. Trimethylsilyl ethers were prepared in high to excellent yields with short reaction time under mild and almost neutral reaction conditions.     

Tetrabutylammonium salt induced denitration of nitropyridines: synthesis of fluoro-, hydroxy-, and methoxypyridines

An efficient method for the synthesis of fluoropyridines via the fluorodenitration reaction is reported. The reaction is mediated by tetrabutylammonium fluoride (TBAF) under mild conditions without undue regard to the presence of water. The fluorodenitration is general for 2- or 4-nitro-substituted pyridines, while 3-nitropyridines require attendant electron-withdrawing groups for the reaction to proceed efficiently. Nitropyridines also undergo hydroxy- and methoxydenitration under mild conditions in the presence of the corresponding tetrabutylammonium species. [reaction: see text]     

无溶剂条件下LiNTf2催化的醛和酮的非手性硅氰化反应研究

以LiNTf2为催化剂,在无溶剂条件下,醛或酮与三甲基氰硅烷(TMSCN)室温发生加成反应,得到相应的α-氰基硅醚.该法操作简便、反应条件温和、收率高、催化剂易回收和可以重复使用.     

Direct oxidative synthesis of nitrones from aldehydes and primary anilines using graphite oxide and Oxone

One-pot condensation/oxidation of aldehydes and primary anilines into nitrones using graphite oxide (GO) and Oxone as the oxidant under very mild reaction conditions is described. The proposed method provides a direct oxidative synthesis of various nitrones in good to excellent yields under metal-free conditions in short reaction times.     

Graphite oxide: a simple and efficient solid acid catalyst for the ring-opening of epoxides by alcohols

A simple, efficient, and general procedure for the ring-opening of epoxides with various alcohols to give the corresponding β-alkoxy alcohols using graphite oxide (GO) as the catalyst, under very mild reaction conditions is described. The method proceeds in good to excellent yields and in short reaction times at room temperature under metal-free conditions.     

Acylation of Alcohols and Amines with Vinyl Acetates Catalyzed by Cp(2)Sm(thf)(2)

Cp(2)Sm(thf)(2) was found to be an efficient catalyst for the acylation of alcohols and amines with esters under mild conditions. In the present acylation, vinyl and isopropenyl acetates served as good acylating agents. Thus, a variety of alcohols and amines underwent acylation with vinyl and isopropenyl acetates in the presence of Cp(2)Sm(thf)(2) to give the corresponding esters and amides in good to excellent yields. This catalytic acylation of alcohols and amines offers an additional useful method by the use of various esters, instead of acid anhydrides and acid chlorides, as acylating agents under very mild conditions.     

Practical Synthesis of 2-Iodosobenzoic Acid (IBA) without Contamination by Hazardous 2-Iodoxybenzoic Acid (IBX) under Mild Conditions

We report a convenient and practical method for the preparation of nonexplosive cyclic hypervalent iodine(III) oxidants as efficient organocatalysts and reagents for various reactions using Oxone^® in aqueous solution under mild conditions at room temperature. The thus obtained 2-iodosobenzoic acids (IBAs) could be used as precursors of other cyclic organoiodine(III) derivatives by the solvolytic derivatization of the hydroxy group under mild conditions of 80 °C or lower temperature. These sequential procedures are highly reliable to selectively afford cyclic hypervalent iodine compounds in excellent yields without contamination by hazardous pentavalent iodine(III) compound.     

Reagentless functionalization of gold nanoparticles via a 3 + 2 Huisgen cycloaddition

A mild method for functionalization of gold nanoparticles is reported. The reactions of azide functionalized nanoparticles with propynoic acid derivatives provide triazole functionalized nanoparticles under very mild reaction conditions. Characterization of the nanoparticle-bound triazoles using (1)H and (13)C NMR spectroscopy indicates that both the 1,4 and 1,5 triazole regioisomers are formed on the nanoparticle surface.     

A novel synthesis of bis-(α-hydroxyalkyl)phosphinic acids involving microwave irradiation

A simple, efficient, and general method has been developed for the synthesis of bis-(α-hydroxyalkyl)phosphinic acids from hypophosphorous acid using microwave irradiation. Bis-(α-hydroxyalkyl)phosphinic acids were obtained in high yield under mild conditions by reaction of hypophosphorous acid with aldehydes under microwave irradiation.     

Synthesis of Enol Esters from Copper(I) Carboxylates Generated from Copper(I) Trifluoromethanesulfonate Benzene Complex

A rapid method for the preparation of copper(I) carboxylates by use of copper(I) trifluoromethanesulfonate benzene complex followed by their conversion to enol esters under mild conditions is presented.     

Preparation and thermally promoted ripening of water-soluble gold nanoparticles stabilized by weakly physisorbed ligands

Here, we report on a facile method for the preparation of an aqueous dispersion of 3.6 nm gold nanoparticles electrostatically stabilized by a weakly physisorbed ligand, namely, 4-(dimethylamino)pyridine (DMAP). The nature and extent of the interaction of this ligand with the surface of a gold nanoparticle has been examined. We also report on the thermally promoted ripening of these nanoparticles under mild conditions to yield a dispersion of 11.3 nm gold nanoparticles. The role of the weakly physisorbed DMAP ligand in facilitating thermally promoted ripening under mild conditions has also been examined.     

Diphenylphosphinoylethylidene (DPE) acetals: an alternative protective strategy in glycochemistry

Diphenylphoshinoylethyne reacts with diols under basic conditions to produce cycloacetalic phosphine oxides. The reaction appears to be general and particularly effective with carbohydrate derivatives. The 2-(diphenylphoshinoyl)ethylidene (DPE) acetals produced are stable in acidic media while they can be cleaved under reductive and/or basic conditions: base-catalyzed transacetalization is a method of choice for their mild and effective deprotection.     

Synthesis of indanones by sequential Heck-reduction–cyclization–alkylation (HRCA) reactions

A simple and efficient synthesis of indanones, bearing a quaternary carbon centre, has been developed. The method features, in a one-pot process, the use of a multi-task palladium catalyst for the sequential Heck-reduction reactions, followed by a base-mediated cyclization–alkylation sequence. This methodology, called Heck-reduction–cyclization–alkylation (HRCA), is carried out under mild and simple experimental conditions with the use of inexpensive reagents. The mild conditions have been made possible by the use of diazonium salts that allow Heck couplings at moderate temperature (40 °C) under ligand-free conditions.     

Novel Syntheses of Heterocycles with N-(1-Haloalkyl)azinium Halides. Part V. Preparation of N-Substituted 1,4-Dihydropyridines

Thirty N-substituted Hantzsch 1,4-dihydropyridines were prepared under mild and neutral conditions from N-substituted enaminocarbonyl derivatives and aldehydes activated under the form of N-(1-chloroalkyl)pyridinium chlorides by means of thionyl chloride and pyridine. The scope of the method is discussed.     

水相中底物促进的铜催化氨基醇N-芳基化反应

在水相体系中, 利用铜催化一系列氨基醇类底物(1.2 mmol)与碘代芳烃(1.0 mmol)进行N-芳基化反应. 由于氨基醇具有双齿配位及相转移催化能力, 该反应利用氨基醇类底物自身的促进作用, 在不使用外加配体与相转移催化剂的温和条件下以高收率获得了氨基醇N-芳基化产物(64%-93%).     

超声辐射下醋酸钯催化Sonogashira偶联反应

超声辐射下无铜无胺无膦Pd(OAc)_2体系中进行Sonogashira偶联反应,建立了适用于碘代芳烃的Sonogashira芳基化反应的合成方法,此法具有反应条件温和、反应时间短、收率高的优点。     

Visible‐Light Photoredox‐Catalyzed and Copper‐Promoted Trifluoromethoxylation of Arenediazonium Tetrafluoroborates

We report the development of photoredox‐catalyzed and copper‐promoted trifluoromethoxylation of arenediazonium tetrafluoroborates, with trifluoromethyl arylsulfonate (TFMS) as the trifluoromethoxylation reagent. This new method takes advantage of visible‐light photoredox catalysis to generate the aryl radical under mild conditions, combined with copper‐promoted selective trifluoromethoxylation. The reaction is scalable, tolerates a wide range of functional groups, and proceeds regioselectively under mild reaction conditions. Furthermore, mechanistic studies suggested that a Cs[Cu(OCF₃)₂] intermediate might be generated during the reaction.