Copper-Catalyzed C-C(O)C Bond Cleavage of Monoalkylated β-Diketone: Synthesis of α,β-Unsaturated Ketones

A new and simple route for the synthesis of α,β-unsaturated ketones via cleavage of the C-C(O)C single bond of monoalkylated β-diketone has been described. The reaction was catalyzed by copper, a cheap transition metal in a weakly basic medium (K3PO4) at room temperature. To carry out this study, we first had to synthesize the monoalkylated β-diketones 1. Afterwards, α,β-unsaturated ketones 2 were obtained with high yields around 80%. Finally, all the products were characterized by 1H NMR, 13C NMR, and HRMS spectra. .

Microwave-assisted chemoselective copper-catalyzed amination of o-chloro and o-bromobenzoic acids using aromatic amines under solvent free conditions

Copper-catalyzed synthesis of N-aryl anthranilic acid derivatives using effective amination of 2-chloro and 2-bromobenzoic acid under microwave irradiation is reported. Some of the advantages of this method are high chemoselectivity, short reaction times, ease of work up procedure and elimination of the need for acid protection. 2009 Published by Elsevier B.V. on behalf of Chinese Chemical Society.

Copper-catalyzed 1,4-protosilylation and 1,4-protoborylation of enynic orthoesters for synthesis of functionalized 2,3-allenoates

Herein,copper-catalyzed 1,4-protosilylation and 1,4-protoborylation of enynic orthoesters have been developed.The enynic orthoesters as precursors of unstable enynic esters were applied to produce the functionalized 2,3-allenoate products.Meanwhile,the asymmetric 1,4-protosilylation of enynic orthoesters with Ph Me2Si-Bpin was also studied.The chiral monopyridine imidazoline ligand was efficient to provide the asymmetric 1,4-protosilylation products with high enantioselectivity.

Copper-catalyzed Meerwein carboarylation of alkenes with anilines to form 3-benzyl-3-alkyloxindole

A simple and direct route for double C–C bond formation by copper-catalyzed Meerwein carboarylation process has been developed. In the presence of Cu I(5 mol%), tert-butyl nitrite and anilines, a wide variety of N-arylacrylamides underwent tandem Meerwein arylation/C–H cyclization to produce pharmaceutically important 3-benzyl-3-alkyloxindole in moderate to good yield.

Practical copper-catalyzed N-arylation of amines with 20% aqueous solution of n-Bu_4NOH

N-Arylation of a wide variety of amines with phenylboronic acid catalyzed by copper acetate under 20%aqueous solution of n-Bu_4NOH was accomplished in good to excellent yields（up to 92%） and substrate conversions（up to 96%）.

Ligand-free Copper-catalyzed Synthesis of Symmetrical Diynes from 1,1-Dibromo-1 -alkenes

Symmetrical diynes were synthesized by ligand-free copper-catalyzed homocoupling reaction of 1,1-dibromo-1- alkenes using a DBU/DMSO system at room temperature in good to excellent yields.

Copper-Catalyzed Oxidative Dearomatization of 2-Naphthols via Etherification

Copper-catalyzed intermolecular oxidative-etherification type dearomatization reaction of 2-naphthols was developed.With air as the terminal oxidant,the reaction proceeded in excellent yields under mild conditions.In addition,the reaction between two different naphthol substrates occurred smoothly.A series of multifunctionalized β-naphthalenones,important scaffold existed widely in natural products and biologically active molecules,were synthesized efficiently.

Copper-Catalyzed Aerobic Oxidative Cleavage of Unstrained Carbon-Carbon Bonds of 1,1-Disubstituted Alkenes with Sulfonyl Hydrazides

Main observation and conclusion Alkoxy radical-mediated carbon-carbon bond cleavages have emerged as a powerful strategy to complement traditional ionic-type transformations.However,carbon-carbon cleavage reaction triggered by alkoxy radical intermediate derived from the combination of alkyl radical and dioxygen,is scarce and underdeveloped.Herein,we report alkoxy radical,which was generated from alkyl radical and dioxygen,mediated selective cleavage of unstrained carbon-carbon bond for the oxysulfonylation of 1,1-disubstituted alkenes,providing facile access to a variety of valuableβ-keto sulfones.Mechanistic experiments indicated alkoxy radical intermediate that underwent subsequent regioselectiveβ-scission might be involved in the reaction and preliminary computational studies were conducted to provide a detailed explanation on the regioselectivity of the C-C bond cleavage.Notably,the strategy was successfully applied for constructing uneasily obtained architecturally intriguing molecules.

Enantioselective cyanation of benzylic C—H bonds via copper-catalyzed radical relay

With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Liu Guosheng(刘国生)at Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,and Prof.Shannon Stahl at the University of Wisconsin-Madison,discovered a copper-catalyzed radical relay pathway for enantioselective conversion of benzylic C—H bonds

Stereoselective Synthesis of cis-2,5-Disubstituted Pyrrolidines via Copper-Catalyzed Cyclization of Alkenes

An efficient methodology for the stereoselective synthesis of cis-2,5-disubstituted pyrrolidines using copper catalyst was developed. The corresponding cis-2,5-disubstituted pyrrolidines could be obtained in reasonable yields and with good stereoselectivities in the presence of 4,4＇-di-tert-butyl-2,2＇-bipyridine as ligand and l-methyl-2-pyrrolidinone as solvent.

Copper-Catalyzed Highly Enantioselective 1,4-Protoboration of Terminal 1,3-Dienes

The copper-catalyzed,highly enantioselective 1,4-protoboration of terminal 1,3-dienes with proton source and B2Pin2 has been developed.Chiral allylic boronate reagents,which are significant precursors for many well-established transformations,were prepared by this novel method with good functional group tolerance and enantioselectivity.Further studies indicated the products could be used as versatile precursors for asymmetric transformations and natural products syntheses.The mechanism of this reaction was investigated by control and reaction monitoring experiments.

Microporous Nitrogen-Rich Polymers via Ullmann Coupling Reaction for Selective Adsorption of C_(2)H_(2) over CH_(4)

Acetylene purification from methane is challenging in the field of porous organic polymers(POPs).Herein,we have provided one-pot Ullmann coupling reaction to synthesize a series of POPs with rich N-sites,named FJU-POP-n,wherein the low-cost and non-toxic Cu(acac)2 and environmental-friendly glycerol are employed as catalyst and solvent,respectively.

1,1′-Binaphthyl-2,2′-diamine Dihydrochloride：an Efficient Ligand for the N-Arylation of Imidazole with Aryl/heteroaryl Halides Catalyzed by CuI

Employing 1,1′-binaphthyl-2,2′-diamine（BINAM） dihydrochloride as an efficient and commerciallyavailable ligand, relatively mild and highly efficient copper-catalyzed coupling reactions of imidazole with aryl andheteroaryl halides have been developed. Various N-arylimidazoles could be synthesized in moderate to excellentyields.

Copper（I）-Catalyzed Intramolecular N-N Coupling of Cyclopropyl O-Acyl Ketoximes： Synthesis of Spiro-fused Pyrazolin-5-ones

A convenient copper-catalyzed approach has been developed for the synthesis of substituted spiro-fused pyrazolin-5-ones from readily available cyclopropyl O-acyl ketoximes via an intramolecular N-N bond formation reaction. These catalytic reactions proceed in excellent yields with a broad scope.

Synthesis of 1,7-dimethoxy-2-hydroxyxanthone,a natural product with potential activity on erectile dysfunction

The natural product,1,7-dimethoxy-2-hydroxyxanthone（1）,isolated from Securidaca inappendiculate Hassk,has a potential in the treatment of erectile dysfunction due to its significant relaxation activity on rabbit Corpus cavernosum.However,the isolation of compound 1 is problematic because of its high similarity in structure to its analogs.In this paper,the first synthesis of 1 was reported featuring two key reactions：a copper-catalyzed coupling reaction and an intramolecular cyclization.

Easy One-Pot Synthesis of 1-Monosubstituted Aliphatic 1,2,3-Triazoles from Aliphatic Halides, Sodium Azide and Propiolic Acid by a Click Cycloaddition/Decarboxylation Process

1-Monosubstituted aliphatic 1,2,3-triazoles were synthesized by a one-pot reaction from aliphatic halides （C1 and Br）, sodium azide and propiolic acid. The yields ranged from moderate to good. The reaction was easily carried out in DMF with Cs2CO3 at 100 ℃ by copper-catalyzed click cycloaddition/decarboxylation.