Copper-Catalyzed Cross-Coupling Research Articles

Photoinduced Copper-Catalyzed Cross-Coupling of Acylsilanes with Heteroarenes via Bimetallic Relay.

The transition metal-catalyzed direct coupling reactions involving electron-rich Fischer carbene species are largely underdeveloped and remain a big challenge. Here, a direct coupling reaction of azoles and azine N-oxides is reported with Fischer copper carbene species bearing an α-siloxy group i, which can be in situ generated from acylsilanes catalytically under photoirradiation and redox-neutral conditions. This coupling reaction between electron-rich α-siloxy Fischer Cu-carbene species with hard carbanion nucleophiles may undergo a bimetallic relay process, which is confirmed by the kinetic analysis and in situ NMR analysis. This reaction features mild conditions and remarkable heterocycle compatibility. Notably, this protocol tolerates a series of azole or azine N-oxide derivatives, including benzoxazole, benzothiazole, benzoimidazole, benzoisoxazole, oxazole, oxadiazole, triazolo[4,3-a]pyridine, purine, caffeine, pyridine N-oxide, quinoline N-oxide, pyrazine N-oxide, pyridazine N-oxide, etc. The synthetic value of this approach is demonstrated by the efficient synthesis of a histamine h4 receptor ligand and a marketed drug carbinoxamine.

Facile synthesis of diphosphoryl acetylenes through copper-catalyzed cross coupling

Organic molecules containing 1,2-diphosphonate moiety are of great value in organic synthesis. Diphosphoryl acetylenes (or named as ethyne-1,2-diyldiphosphonates) are a class of molecules utilized for synthesis of diverse phosphorus compounds applicable in multiple fields. However, present stoichiometric methods for the preparation of diphosphoryl acetylenes generally requires multiple steps or harsh conditions. Herein, we report a facile synthesis of diphosphoryl acetylenes, in which the readily available ethynyl phosphonates couple with dialkyl phosphonates through cheap copper catalysis. A series of diphosphoryl acetylenes in symmetric or unsymmetric fashions are facilely prepared. This protocol demonstrates advantages of mild reaction conditions, inert atmosphere-free, cheap catalyst, base-free, and high efficiency to serve as a practical method for synthesis of diphosphoryl acetylenes.

Total Synthesis of (-)-Fasicularin.

Asymmetric total synthesis of (-)-fasicularin was achieved in nine steps from a commercially available inexpensive material, by leveraging (1) an aryl radical-mediated, copper-catalyzed Sonogashira-type cross-coupling, (2) a Au-catalyzed tandem intramolecular alkyne hydroamination/iminium formation/intramolecular allylation, and (3) a tandem hydrogenation/hydrogenolysis/intramolecular reductive amination as key transformations.

Copper-Catalyzed Direct Cross-Coupling of Triazolopyridine with N-Tosylhydrazones

Copper-Catalyzed Direct Cross-Coupling of Triazolopyridine with N-Tosylhydrazones

Copper-Catalyzed Decarboxylation Cross-Coupling Cascade Reaction for Synthesis of Fused Dihydro-benzoxazinones.

A protocol for a tandem copper-catalyzed intermolecular decarboxylation cross-coupling cascade between o-bromobenzoic acids and proline or piperic acid has been disclosed. The developed protocol allows access to a variety of synthetically useful fused benzoxazinones scaffolds with high efficiency and good functional group compatibility. A mechanistically sequential approach for the decarboxylation and dehydration coupling process was presented.

Copper-Catalyzed Cross-Coupling of Benzyl Halides with (Me4N)SCF3

Copper-Catalyzed Cross-Coupling of Benzyl Halides with (Me4N)SCF3

Copper-Catalyzed Coupling between ortho-Haloanilines and Lactams/Amides: Synthesis of Benzimidazoles and Telmisartan.

An efficient copper-catalyzed synthesis of (annelated) benzimidazoles is reported. This transformation is based on a simple and straightforward one-pot sequence involving a copper-catalyzed cross coupling between o-haloanilines and lactams/amides followed by a subsequent cyclization under acidic conditions. A variety of (annelated) benzimidazoles could be easily obtained in high yields from readily available starting materials, and this procedure could be further applied to the synthesis of the antihypertensive blockbuster drug telmisartan.

Hydroxylamine Umpolung in Copper-Catalyzed Cross-Coupling Reactions to Synthesize N-Arylhydroxylamine Derivatives

Hydroxylamine Umpolung in Copper-Catalyzed Cross-Coupling Reactions to Synthesize <i>N</i>-Arylhydroxylamine Derivatives

Heterogeneous Copper-Catalyzed Cross-Coupling for Sustainable Synthesis of Chiral Allenes: Application to the Synthesis of Allenic Natural Products.

Classical Crabbé type SN 2' substitutions of propargylic substrates has served as one of the standard methods for the synthesis of allenes. However, the stereospecific version of this transformation often requires either stoichiometric amounts of organocopper reagents or special functional groups on the substrates, and the chirality transfer efficiency is also capricious. Herein, we report a sustainable methodology for the synthesis of diverse 1,3-di and tri-substituted allenes by using a simple and cheap cellulose supported heterogeneous nanocopper catalyst (MCC-Amp-Cu(I/II)). This approach represents the first example of heterogeneous catalysis for the synthesis of chiral allenes. High yields and excellent enantiospecificity (up to 97 % yield, 99 % ee) were achieved for a wide range of di- and tri-substituted allenes bearing various functional groups. It is worth noting that the applied heterogeneous catalyst could be recycled at least 5 times without any reduced reactivity. To demonstrate the synthetic utility of the developed protocol, we have applied it to the total synthesis of several chiral allenic natural products.

Recent Advances in Transition-Metal-Catalyzed Sonogashira Cross-Coupling Reactions of Alkyl Electrophiles

AbstractCatalytic Sonogashira cross-coupling reactions represent an efficient and versatile approach for constructing complex alkynes from readily available starting materials. Despite notable progress in this field, the development of transition-metal-catalyzed Sonogashira cross-coupling reactions of alkyl electrophiles remains limited. This limitation primarily stems from the low reactivity and pronounced propensity of these compounds towards β-H elimination. To overcome these challenges, researchers have investigated the use of palladium, nickel, and copper catalysts for Sonogashira reactions of alkyl electrophiles. Furthermore, significant strides have been made in achieving asymmetric Sonogashira cross-coupling reactions of electrophiles. This short review provides an overview of recent breakthroughs in this area.1 Introduction2 Palladium-Catalyzed Sonogashira Cross-Coupling of Alkyl Halides3 Nickel-Catalyzed Sonogashira Cross-Coupling of Alkyl Halides4 Copper-Catalyzed Sonogashira Cross-Coupling of Alkyl Electrophiles4.1 Copper-Catalyzed Racemic Sonogashira Cross-Coupling of Alkyl Electrophiles4.2 Copper-catalyzed Asymmetric Sonogashira Cross-Coupling of Alkyl Electrophiles5 Conclusions and Perspectives

C(sp)-C(sp3) Bond Formation through Ligand- and Additive-Free CuO-Mediated Decarboxylative Direct Cross-Coupling of Coumarin-/Chromone-3-carboxylic Acids and Terminal Alkynes.

A practical and efficient method for the synthesis of functionalized 4-(aryl-/heteroaryl-ethynyl)chroman-2-ones and 2-(aryl-/heteroaryl-ethynyl)chroman-4-ones through copper-catalyzed decarboxylative direct cross-coupling of coumarin-/chromone-3-carboxylic acids with terminal alkynes, leading to the formation of C(sp)-C(sp3) bonds, has been unearthed. Advantages of this protocol include avoidance of any ligands and bases, a broad substrate scope, tolerance of diverse functional groups, and good to excellent yields.

Copper-(Photo)Catalyzed Radical Reactions with Organic Halides

AbstractCopper is one of the most efficient and attractive metals for catalysis. In addition to their availability, low cost and limited toxicity, copper complexes are utilized to catalyze a broad variety of reactions, including examples involving radicals. For such reactions, organic halides are by far the most versatile and attractive substrates. Our contributions to the catalysis of radical reactions from organic halides with copper complexes are summarized in this account.1 Introduction2 Copper-Catalyzed Radical Cross-Coupling Reactions3 Copper-Catalyzed Radical Reactions4 Copper-Catalyzed Radical Carbonylative Cross-Coupling Reactions5 Photoinduced, Copper-Catalyzed Radical Reactions6 Conclusions and Outlook

A Robust Copper-Catalyzed Cross-Coupling of Glycosyl Thiosulfonate and Boronic Acids Enables the Construction of Thioglycosides.

An efficient and stereoretentive copper-catalyzed cross-coupling of glycosyl thiosulfonate and boronic acid for the construction of thioglycosides is described. The good functional group compatibility of this method allows the preparation of many bioactive aryl/alkenyl thioglycosides, including the hSGLT1 inhibitor.

Copper-Catalyzed Monofluoroalkylation of Allyl Phosphates with Nucleophilic Ethyl 2-Fluoro-2-(trimethylsilyl)acetate.

An efficient method for C(sp3)-CHF bond formation was successfully developed by copper-catalyzed cross-coupling of allyl phosphate with 2-fluoro-2-(trimethylsilyl)acetate. Under moderate circumstances, the conversion was carried out in a good strategic range to provide a series of monofluoroalkylation products in high yields, which also demonstrates the practicality of gram-scale reactions.

Terminal Alkynes as One-Carbon Donors in [5+1] Heteroannulation: Synthesis of Pyridines via Ynimine Intermediates and Application in the Total Synthesis of Anibamine B.

Transition-metal-catalyzed [4+2] heteroannulation of α,β-unsaturated oximes and their derivatives with alkynes has been developed into a powerful strategy for the synthesis of pyridines. It nevertheless lacks regioselectivity when unsymmetrically substituted alkynes are used. We report herein the unprecedented synthesis of polysubstituted pyridines by a formal [5+1] heteroannulation of two readily accessible building blocks. A copper-catalyzed aza-Sonogashira cross-coupling between β,γ-unsaturated oxime esters and terminal alkynes affords ynimines, which, without isolation, undergo an acid-catalyzed domino reaction involving ketenimine formation, 6π-electrocyclization and aromatization to afford pyridines. Terminal alkynes served as a one-carbon donor to the pyridine core in this transformation. Di- through pentasubstituted pyridines are accessible with complete regioselectivity and excellent functional-group compatibility. The first total synthesis of anibamine B, an indolizinium alkaloid with potent antiplasmodial activity, was accomplished featuring this reaction as a key step.

Copper-Catalyzed Carbonylative Cross-Coupling of Alkyl Iodides with Alcohols and Sodium Hydroxide: Synthesis of Esters and Carboxylic Acids

AbstractA general and inexpensive catalytic system is reported for the copper-catalyzed carbonylative coupling between alkyl iodides and alcohols or sodium hydroxide. Upon reaction with catalytic amounts of copper(I) chloride and N,N,N′,N′′,N′′-pentamethyldiethylenetriamine under a mild pressure of carbon monoxide (5 bar), a range of secondary and tertiary alkyl iodides are readily converted into the corresponding esters and carboxylic acids without competing direct nucleophilic substitution. Main advantages of this procedure include its broad applicability, the use of an especially inexpensive and available catalytic system, and its user-friendliness.

Diversified Synthesis of All-Carbon Quaternary gem-Difluorinated Cyclopropanes via Copper-Catalyzed Cross-Coupling.

The construction of all-carbon quaternary centers in small-ring systems is important but challenging in organic synthesis. Herein, by taking gem-difluorocyclopropyl bromides (DFCBs) as a type of general and versatile building block, we developed a practical method for building all-carbon quaternary centers in gem-difluorinated cyclopropanes (DFCs). The reaction relies on the involvement of a gem-difluorocyclopropyl radical intermediate, which can couple with a wide range of nucleophiles under copper catalysis.

Aryl Radical Enabled, Copper-Catalyzed Sonogashira-Type Cross-Coupling of Alkynes with Alkyl Iodides.

Despite the success of Sonogashira coupling for the synthesis of arylalkynes and conjugated enynes, the engagement of unactivated alkyl halides in such reactions remains historically challenging. We report herein a strategy that merges Cu-catalyzed alkyne transfer with the aryl radical activation of carbon-halide bonds to enable a general approach for the coupling of alkyl iodides with terminal alkynes. This unprecedented Sonogashira-type cross-coupling reaction tolerates a broad range of functional groups and has been applied to the late-stage cross-coupling of densely functionalized pharmaceutical agents as well as the synthesis of positron emission tomography tracers.

Efficient Synthesis and Functionalization of 3-Bromonaphtho[2,3-b]thiophene

AbstractNaphtho[2,3-b]thiophene is a linear sulfur-containing polycyclic aromatic hydrocarbon. Naphtho[2,3-b]thiophene and its derivatives are commonly accessed by a Bradsher cyclization. Synthesis of the Bradsher cyclization substrate typically requires harsh conditions, including several oxidation state changes. Here, we report an improved, multigram synthesis of 3-bromonaphtho[2,3-b]thiophene, exploiting a copper-catalyzed cross-coupling to prepare the Bradsher substrate in three steps from commercial materials while minimizing redox reactions. In this work, the 3-bromonaphthothiophene is further functionalized via lithium–halogen exchange, with the key finding being a specific order of addition in lithiation is required to avoid undesired rearrangement reactions. Transformation to a versatile set of derivatives, including a naphthothiophene-containing chiral amine, is illustrated.

Photoinduced copper-catalyzed asymmetric radical three-component cross-coupling of 1,3-enynes with oxime esters and carboxylic acids

A regio- and enantioselective radical three-component coupling of 1,3-enynes, oxime esters, and carboxylic acids through photoinduced copper catalysis is reported.