Cross-coupling Products In Good Yields Research Articles

ChemInform Abstract: CuI Assisted Desulfurative Sonogashira Reaction of Mercapto N‐Heterocyclic Derivatives with Alkynes.

A palladium catalyzed Sonogashira reaction of mercapto N-heterocyclic derivatives with terminal alkynes by using CuI as the desulfurative reagent was described in this report. It provided an effective strategy for obtaining sp–sp2 cross-coupling products in good yields. The reaction mechanism was also investigated by density functional theory (DFT) calculation.

Synthesis of 2,4-Diarylquinolines: Nickel-Catalysed Ligand-Free Cross-Couplings of 4-Chloro-2-Arylquinolines with Arylmagnesium Halides in 2-Methyltetrahydrofuran

A ligand-free and room temperature protocol for the synthesis of 2,4-diarylquinolines is described. Treatment of 4-chloro-2-arylquinolines with arylmagnesium halides in the presence of a catalytic amount of nickel(II) chloride without ligands in 2-methyltetrahydrofuran (2-MeTHF) afforded the corresponding cross-coupling products in good yields.

Cross-Coupling Reactions of Two Different Activated Alkenes through Tetrabutylammonium Fluoride (TBAF) Promoted Deprotonation/Activation Strategy: A Regioselective Construction of Quaternary Carbon Centers

A novel TBAF-promoted intermolecular crossed-conjugate addition has been developed. For a range of cyclic β-halo-α,β-unsaturated carbonyl compounds, the vinylogous enolates generated by deprotonation at the γ-position preferentially reacted with Michael acceptors at the α-position to deliver cross-coupling products in good yields.

Ligand-free copper(Ι)-catalyzed Sonogashira-type coupling of arylboronic acids with terminal alkynes

An efficient ligand-free CuI-catalyzed Sonogashira-type coupling reaction of arylboronic acids with terminal alkynes under air is described. The electron-deficient alkynes gave the desired cross-coupling products in good yields. Thus, it represents a simple and alternative method for the traditional Sonogashira reaction.

Rh-Catalyzed Negishi Alkyl-Aryl Cross-Coupling Leading to α- or β-Phosphoryl-Substituted Alkylarenes

The catalytic cross-coupling between ArZnX and ICH(2)(CH(2))(n)P(O)(OEt)(2) (n = 0-3) has been investigated to determine the utility of the Rh catalyst during the alkyl-aryl cross-coupling and to develop a new synthetic method for phosphoryl-substituted alkylarenes. Rh-dppf exhibits an excellent catalytic activity for the reaction with the alkylphosphonate of n = 1, whereas for the reaction with those of n = 2 or 3, beta-hydride elimination mainly takes place. As for the reaction with an alkylphosphonate of n = 0, a polarity inversion of the coupling components is necessary in order to provide the coupling products; the phosphoryl analogue of the Reformatsky reagent and ArI give the cross-coupling products in good yields through the catalysis by Rh-dppf.

Cross-Coupling Reactions of Aromatic and Heteroaromatic Silanolates with Aromatic and Heteroaromatic Halides

The alkali-metal salts (potassium and sodium) of a large number of aryl- and heteroarylsilanols undergo efficient cross-coupling with a wide range of aromatic bromides and chlorides under mild conditions to form polysubstituted biaryls. The critical feature for the success of these coupling reactions and their considerable scope is the use of bis(tri-tert-butylphosphine)palladium. Under the optimized conditions, electron-rich, electron-poor, and sterically hindered arylsilanolates afford cross-coupling products in good yields. Many functional groups are compatible with the coupling conditions such as esters, ketones, acetals, ethers, silyl ethers, and dimethylamino groups. Two particularly challenging substrates, (2-benzofuranyl)dimethylsilanolate and (2,6-dichlorophenyl)dimethylsilanolate prepared as their sodium salts showed excellent activity in the coupling reactions, in the former case also with aromatic chlorides. General methods for the efficient synthesis of a wide range of aromatic silanols are also described.

Synthesis of 2-Substituted Cyclohexene Derivatives through Cross-Coupling Reactions via π-Allylmetal Intermediate Using N-Heterocyclic Carbenes (NHCs) as Ligands

Palladium- or nickel-catalyzed cross-coupling reactions of 2-substituted cyclohexenes, which are generally less reactive than those having no substituent at the C2 position, with organotin reagents (Migita-Kosugi-Stille coupling) or with Grigard reagents (Kumada-Tamao-Corriu coupling) using a NHC as a ligand was investigated. It was found that NHCs are effective as ligands for these reactions, giving the corresponding cross-coupling products in good yields.

Pd−P(t-Bu)3-Catalyzed Consecutive Cross-Coupling of p-Phenylenedizinc Compound with Two Different Electrophiles Leading to Unsymmetrically 1,4-Disubstituted Benzenes

Pd-P(t-Bu)3 was found to be a chemoselective catalyst for the reaction of p-phenylenedizinc compound with equimolar amounts of carbon electrophiles to afford the single cross-coupling products in good yields, effectively suppressing the formation of double cross-coupling products. The subsequent additions of other electrophiles to the resulting solutions caused the second cross-coupling of the incipient products to take place, achieving a novel and efficient one-pot synthesis of unsymmetrically 1,4-disubstituted benzenes. The origin of the observed high chemoselectivity was speculated.

Palladium-Catalyzed Cross-Coupling of Aryl or Vinyl Iodides with Ethyl Diazoacetate

Pd(PPh3)4-catalyzed reaction between aryl or vinyl iodides and ethyl diazoacetate (EDA) leads to the formation of cross-coupling products in good yields.

A Novel Cu(II)-Catalysed Sonogashira Reaction

In the presence of triphenylphosphine, a novel Cu(II)-catalysed Sonogashira reaction of aryl iodides and bromides with terminal alkynes has been developed, which generates the corresponding cross-coupling products in good yields.

Iron-Catalyzed Cross-Coupling between Alkenyl and Dienyl Sulfonates and Functionalized Arylcopper Reagents

Functionalized arylcopper reagents react readily with alkenyl sulfonates in the presence of catalytic amounts of Fe(acac)3 (10 mol%) providing the expected cross-coupling products in good yields. Ester or cyano group are tolerated. This cross-coupling can be performed with dienyl sulfonates leading to the corresponding substituted dienes.

Trimethylsilyl Triflate Mediated New Carbon—Carbon Bond Forming Reactions Between Benzyl Diphenylphosphinates and Organosilicon Compounds.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Trimethylsilyl Triflate Mediated New Carbon–Carbon Bond Forming Reactions between Benzyl Diphenylphosphinates and Organosilicon Compounds

Abstract The trimethylsilyl triflate mediated reaction of benzyl diphenylphosphinate with allyltrimethylsilane or trimethylsilyl enolate afforded the corresponding cross-coupling products in good yields.

Copper(I) tert‐Butoxide‐Promoted 1,4‐ Csp2‐to‐O Silyl Migration: Generation of Vinyl Copper Equivalents and Their Stereospecific Cross‐Coupling with Allylic, Aryl, and Vinylic Halides.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Copper(I) tert-butoxide-promoted 1,4 C sp 2-to-O silyl migration: generation of vinyl copper equivalents and their stereospecific cross-coupling with allylic, aryl, and vinylic halides.

Successive treatment of the (Z)-gamma-trimethylsilyl allylic alcohols with copper(I) tert-butoxide and allylic halides followed by the tetrabutylammonium fluoride-assisted hydrolysis produced the allylation products, 2,5-alkadien-1-ols, with complete retention of configuration. Similar treatment of the organometallic intermediates with aryl and vinylic halides in the presence of palladium(0) catalyst gave the corresponding cross-coupling products in good yields. The stereoselective preparation of the starting materials is also described.

Palladium‐Catalyzed Coupling Reaction of Alkenylgalliums with Aryl Halides.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Palladium-Catalyzed Coupling Reaction of Alkenylgalliums with Aryl Halides

Treatment of aryl halides with alkenylgallium dichloride, prepared from GaCl 3 and alkenylmagnesium bromide, in the presence of a catalytic amount of palladium provided cross-coupling products in good yields.

Reactions of Vinyl and Aryl Triflates with Hypervalent Tin Reagents

The reaction of hypervalent tin reagents (n-Bu4N)+(R13SnF2)- (R1 = aryl, benzyl) with vinyl and aryl triflates affords the corresponding cross-coupling products in good yields and short reaction times. The method described represents an important improvement over the classical Stille reaction. The hypervalent reagents are easily prepared by reaction of R13SnF and n-Bu4NF.

Cobalt-catalyzed alkenylation of organomagnesium reagents

Alkenyl iodides, bromides and chlorides react with organomagnesium reagents in THF, in the presence of Co(acac)2 and NMP (9 to 4 equiv.), to give the cross-coupling products in good yields. The reaction is chemoselective (aryl or alkyl bromides, esters and ketones) and stereoselective (≥99.5%).

Palladium catalyzed coupling reactions of β-perfluoroalkyl-substituted alkyl halides with organostannanes

β-Perfluoroalkyl-substituted alkyl halides reacted with organostamnanes such as allylphenylethynyl-, β-phenylethenyl-, and phenyl-tributyltin in the presence of palladium-phosphine complexes to give the corresponding cross-coupling products in good yields. When the reaction was carried out under CO pressure, carbonylative coupling of the halides took place affording the corresponding fluorine-contaming ketones in good yields.