Improved studies of cross‐coupling reactions of 5‐(tri‐n‐butystannyl)‐ and 5,5′‐bis(tri‐n‐butylstannyl)‐2,2′‐bithiophene with aryl halides

Stille coupling under standard conditions proceeds in low yield when using hindered organostannanes (1) or (2) and aryl bromide partners. The inclusion of aryl iodide instead of aryl bromide with the same organostannanes, significantly improves the efficiency of the coupling, providing a variety of desired products in good to excellent yield. The yields of Stille coupling are compared to the different reactivity of aryl halides. This study of Stille coupling with different aryl halides are documented and rationalized.     

Palladium-catalyzed aminosulfonylation of aryl halides

The palladium-catalyzed three-component coupling of aryl iodides, sulfur dioxide, and hydrazines to deliver aryl N-aminosulfonamides is described. The colorless crystalline solid DABCO·(SO(2))(2) was used as a convenient source of sulfur dioxide. The reaction tolerates significant variation of both the aryl iodide and hydrazine coupling partners.     

Synthesis of symmetrical and unsymmetrical N,N'-diaryl guanidines via copper/N-methylglycine-catalyzed arylation of guanidine nitrate

CuI/N-methylglycine-catalyzed coupling reaction of guanidine nitrate with both aryl iodides and bromides takes place at 70-100 °C, affording symmetrical N,N'-diaryl guanidines with good to excellent yields. Unsymmetrical N,N'-diaryl guanidines can be assembled via monoarylation of guanidine nitrate with aryl iodides bearing a strong electron-withdrawing group and subsequent coupling with another aryl iodide.     

The Sonogashira coupling reaction catalyzed by ultrafine nickel(0) powder

The Sonogashira coupling reaction catalyzed by ultrafine nickel(0) powder has been developed; terminal alkynes couple with aryl, alkenyl iodide and aryl bromide in the presence of cuprous iodide, triphenylphosphine, potassium hydroxide and ultrafine particle nickel(0) to provide the corresponding cross-coupling products with high yields.     

Palladium‐Catalyzed [2+2+1] Spiroannulation via Alkyne‐Directed Remote C−H Arylation and Subsequent Arene Dearomatization

Palladium‐catalyzed alkene‐directed cross‐coupling of aryl iodide with another aryl halide through C?H arylation opens a unique avenue for unsymmetrical biaryl‐derived molecules. However, homo‐coupling of aryl iodides often erodes the overall synthetic efficiency. Reported herein is a highly chemoselective Pd⁰‐catalyzed alkyne‐directed cross‐coupling of aryl iodides with bromophenols, which was subsequently followed by phenol dearomatization to furnish a very attractive [2+2+1] spiroannulation. Notably, possible homo‐coupling of aryl iodides was not observed at all. Mechanistic studies indicated that a five‐membered aryl/vinyl palladacycle most likely accounts for promoting the key step of biaryl cross‐coupling.     

Synthesis of aryl azides and vinyl azides via proline-promoted CuI-catalyzed coupling reactions

The coupling reaction of aryl halides or vinyl iodide with sodium azide under catalysis of CuI/L-proline works at relatively low temperature to provide aryl azides or vinyl azides in good to excellent yields.     

A new synthesis of flavonoids via Heck reaction

Several naturally occurring flavonoids have been synthesised following a new proposed method based on the use of the Heck reaction. The key step involves the coupling of an aryl vinyl ketone with an aryl iodide. This procedure affords the flavonoid moiety in a single step.     

Two methods for direct ortho-arylation of benzoic acids

Two new palladium-catalyzed methods for the direct ortho-arylation of free benzoic acids have been developed. The first method employs stoichiometric silver acetate for iodide removal, aryl iodide as the coupling partner, and acetic acid solvent. This method is applicable to the arylation of electron-rich to moderately electron-poor benzoic acids and tolerates chloride and bromide substituents on both coupling partners. The second method involves the use of aryl chloride, cesium carbonate base, n-butyl-di-1-adamantylphosphine ligand, and DMF solvent and is suitable for both electron-rich and electron-poor benzoic acids. Mechanistic studies of the second method point to the heterolytic C-H bond cleavage as the rate-determining step.     

The copper-catalyzed N-arylation of indoles

A general method for the N-arylation of indoles using catalysts derived from CuI and trans-1,2-cyclohexanediamine (1a), trans-N,N'-dimethyl-1,2-cyclohexanediamine (2a), or N,N'-dimethyl-ethylenediamine (3) is reported. N-Arylindoles can be produced in high yield from the coupling of an aryl iodide or aryl bromide with a variety of indoles.     

Stereospecific Syntheses of Clomiphene and Tamoxifen via Stannylcupration of Diphenylacetylene

Stereospecific trans-stannylcupration of diphenylacetylene affords a 1,2-dimetallostilbene which may be elaborated into either Clomiphene or Tamoxifen through palladium-catalyzed coupling with an aryl iodide.     

Preparation of stimulus-responsive,polyfluorene-wrapped carbon nanotubes via palladium cross coupling

Decoration of carbon nanotube surfaces without damaging nanotube optoelectronic properties is an ongoing challenge. Here, we utilize Sonogashira coupling chemistry to decorate the nanotube surface without perturbing optoelectronic properties. Reactive, noncovalently functionalized polymer–nanotube complexes were prepared using a polyfluorene with aryl iodide groups in its side chains. The aryl iodides enable Pd cross coupling between polymer–nanotube complexes and small molecules or polymers derivatized with an alkyne. Modestly efficient coupling was found to occur under dilute conditions at elevated temperatures. Successful coupling between aryl iodide and alkyne partners was observed using infrared spectroscopy via the appearance of carbonyl stretches that originate from covalently linked, carbonyl-containing alkynes, and thermogravimetric analysis was used to measure reaction conversion under various conditions. Grafting of the hydrophobic polymer–nanotube complex with poly(ethylene glycol) enabled the dispersion to be transferred from organic to aqueous solution. This chemistry resulted in no damage to the nanotube sidewall, as evidenced by Raman spectroscopy. The aryl iodide-containing polyfluorene–nanotube complex was also coupled to a photoswitchable alkyne-containing spiropyran moiety and it was found that the photoswitch retained its functionality after coupling to the polymer–nanotube complex. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2723–2729     

Catechol violet as new, efficient, and versatile ligand for Cu(I)-catalyzed C-S coupling reactions

Combination of CuI and Catechol violet (CuI-CV) was employed as catalyst for the first time in the C-S coupling reaction of a wide variety of aromatic halides, such as aryl iodides, bromo pyridines, activated aryl chlorides, and vinyl iodide with thiols to afford the corresponding thioethers in good to excellent yields. Broad range of functional group tolerance present in both the coupling partners has been observed in this reaction protocol.     

CuI-catalyzed Synthesis of Aryl Thiocyanates from Aryl Iodides

Aryl thiocyanates are important compounds not only for their interesting biological properties, but also because of their use as a versatile starting material for many sulfur- containing aromatic compounds, including sulfonyl cyanides, sulfonic acids, sul…     

Palladium-catalysed coupling of terminal alkynes with aryl halides aided by catalytic zinc

The palladium-catalysed coupling of aryl halides with terminal alkynes can be performed using base, zinc chloride and sodium iodide. This protocol represents a convenient method for the generation of nucleophilic acetylides in situ.     

Sonogashira Coupling Reaction with Palladium Powder and Potassium Fluoride in Methanol

A Sonogashira coupling reaction of aromatic halides with terminal alkynes in the presence of palladium powder,potassium fluoride,cuprous iodide and triphenylphosphine in methanol,giving the corresponding coupling products aryl alkynes in good to excellent yiekls,was investigated.     

Convergent approach to the maduropeptin chromophore: aryl ether formation of (R)-3-aryl-3-hydroxypropanamide and cyclization of macrolactam

Efficient enantioselective syntheses of the functionalized phenol and diethynylcyclopentene moiety of the maduropeptin chromophore were achieved. Their CsF-mediated coupling yielded a sterically congested aryl propargyl ether. The subsequent intramolecular Sonogashira coupling reaction between the vinyl iodide and diethynyl groups occurred at the appropriate position to yield a macrolactam, which was accompanied by Pd-mediated enyne-yne benzannulation.     

An efficient,regio- and stereoselective palladium-catalyzed route to tetrasubstituted olefins

An efficient, regio- and stereoselective palladium-catalyzed route to tetrasubstituted olefins has been developed, which involves the intermolecular coupling of an aryl iodide, an internal alkyne, and an arylboronic acid. The reaction involves cis-addition of the aryl group from the aryl halide to the less hindered or less electron-poor end of the alkyne, while the aryl group from the arylboronic acid adds to the other end. [reaction: see text]     

A novel Heck reaction catalyzed by Co hollow nanospheres in ligand-free condition

Heck reaction catalyzed by cobalt hollow nanospheres has been developed; the coupling of alkenes with aryl iodide or aryl bromide in the presence of potassium carbonate provides the corresponding products with moderate to good yields, which reveals obvious advantages such as low-cost catalyst, ligand-free condition, the recyclability of the catalyst and simple experimental operation.     

Cross-coupling of alkynylsilanols with aryl halides promoted by potassium trimethylsilanolate

The palladium-catalyzed cross-coupling of aliphatic alkynylsilanols with aryl iodides has been demonstrated with potassium trimethylsilanolate as the coupling promoter and copper(I) iodide as a cocatalyst. The cross-coupling proceeds at room temperature in good to excellent yield with a range of aryl iodides. A comparison of the reactivity of alkynylsilanols, trimethylsilylalkynes, and terminal alkynes under fluoride and fluoride-free conditions was performed to elucidate the role of silicon in the Sonogashira reaction.     

Stereoselective cross-coupling reaction of 1,1-Diboryl-1-alkenes with electrophiles: a highly stereocontrolled approach to 1,1,2-triaryl-1-alkenes

Palladium-catalyzed cross-coupling reaction of 1,1-diboryl-1-alkenes with aryl and alkenyl iodides was found to proceed stereoselectively, giving rise to the corresponding mono-coupled product as a single diastereomer with E-configuration. Second coupling of the initial product with another aryl iodide affords diverse triarylalkenes in their stereochemically pure form. This highly stereoselective approach for triarylalkenes allows one to synthesize both diastereomers in one pot from 1,1-diboryl-1-alkenes.