Vinyl aryl ethers from copper-catalyzed coupling of vinyl halides and phenols

A general procedure for vinyl aryl ether bond formation by direct coupling of vinyl halides and phenols under mild Ullmann-type reaction conditions has been developed. Using copper chloride as the catalyst and cesium carbonate as the base, vinyl bromides or iodides were reacted with phenols in refluxing toluene to produce vinyl aryl ethers in good to excellent yields.     

Palladium-catalyzed regiocontrolled alpha-arylation of trimethylsilyl enol ethers with aryl halides

Inter- and intramolecular arylations of trimethylsilyl enol ethers with aryl halides are accomplished regiospecifically in the presence of a palladium catalyst and tributyltin fluoride in refluxing benzene or toluene. The optimal catalyst system called for the use of Pd2(dba)3 and tri-tert-butylphosphine in ca. 1:2 ratio. Aryl iodides, bromides, and chlorides are all effective arylation partners in this reaction. [reaction: see text]     

Palladium-catalyzed phosphorus-carbon bond formation: cross-coupling reactions of alkyl phosphinates with aryl, heteroaryl, alkenyl, benzylic, and allylic halides and triflates

The direct formation of H-arylphosphinates and related compounds can be accomplished using palladium catalysis. This full paper examines the scope and some mechanistic aspects of this phosphorus-carbon bond forming reaction. The reactions of alkenyl and allylic halides are also described for the first time. This novel cross-coupling provides a convenient access to a variety of substituted H-phosphinates.     

Palladium-catalyzed direct arylation of nitro-substituted aromatics with aryl halides

Direct arylation reactions of nitrobenzenes and aryl halides occur in good yield and high ortho regioselectivity. These reactions can be performed on gram scale with as few as 3 equiv of the nitro arene relative to the aryl halide. The synthetic utility of this method is demonstrated via rapid synthesis of a Boscalid intermediate.     

Copper-catalyzed synthesis of phenols from aryl halides and 4-methoxylbenzyl alcohol

A catalytic method was developed to synthesize substituted phenols from the corresponding aryl bromides and chlorides under mild conditions (yields = 34–92%). 4-Methoxylbenzyl alcohol was used as water surrogate and CuI/3,4,7,8-tetramethyl-1,10-phenanthroline was used as catalyst to achieve the C–O cross-coupling.     

Palladium-catalyzed silylations of hydrosilanes with aryl halides using bulky alkyl phosphine

[Reaction: see text]. A palladium-catalyzed direct trialkylsilyl transfer to aryl halides has been developed. In the presence of Pd(t-Bu3P)2 and K3PO4, electron-rich para- or meta-substitute aryl iodides were coupled efficiently with triethylsilane, triphenylsilane, and dimethylphenylsilane to afford the corresponding silylated products in moderate to good yields.     

Copper-catalyzed aerobic oxidation and cleavage/formation of C-S bond: a novel synthesis of aryl methyl sulfones from aryl halides and DMSO

With atmospheric oxygen as the oxidant, a novel copper(I)-catalyzed synthesis of aryl methyl sulfones from aryl halides and widely available DMSO is described. The procedure tolerates aryl halides with various functional groups (such as methoxy, acetyl, chloro, fluoro and nitro groups), which could afford aryl methyl sulfones in moderate to high yields. The copper-catalyzed aerobic oxidation and the cleavage/formation of C-S bond are the key steps for this transformation.     

Palladium-catalyzed benzylic direct arylation of benzyl sulfones with aryl halides

An effective palladium catalyst system for the direct arylation of benzyl sulfones with aryl halides has been developed. The catalytic reaction provides a facile route to diarylmethyl sulfones. The products can be transformed further via desulfonylative functionalization mediated by aluminum compounds.     

The selective reaction of aryl halides with KOH: synthesis of phenols, aromatic ethers, and benzofurans

The direct and selective synthesis of phenols from aryl/heteroaryl halides and KOH has been achieved through the use of highly active monophosphine-based catalysts derived from Pd(2)dba(3) and ligands L1 or L2 and the biphasic solvent system 1,4-dioxane/H(2)O. We have also demonstrated a one-pot method of phenol formation/alkylation for the preparation of alkyl aryl ethers from aryl halides. In many instances, this protocol overcomes limitations in existing Pd-catalyzed coupling reactions of aliphatic alcohols with aryl halides. Finally, we demonstrate that substituted benzofurans can be prepared efficiently via a Pd-catalyzed phenol formation/cyclization protocol starting from 2-chloroaryl alkynes.     

A novel dual-nano assisted synthesis of symmetrical disulfides from aryl/alkyl halides

Here, we have reported a novel approach towards dual-nano assisted synthesis of disulfides from coupling of alkyl/aryl halides and sulfur nanoparticles. The indium oxide nanoparticles as catalyst expedite the conversion and sulfur nanoparticle notably enhances the miscibility, providing a faster, high yielding and cost-effective process in ethanol-water system. The method has synthetic advantages in terms of mild reaction framework, catalyst regeneration, and absence of any sulfide or polysulfide linkage as by-product leading to a column free synthesis. A variety of alkyl, aryl and heteroaryl symmetrical disulfides are obtained in good to excellent yields up to exceeding 98%.     

Palladium-catalyzed direct hydroxymethylation of aryl halides and triflates with potassium acetoxymethyltrifluoroborate

Suzuki-Miyaura cross-coupling reactions of aryl halides and triflates with potassium acetoxymethyltrifluoroborate afforded the corresponding aryl and heteroaryl methanol products in moderate to excellent yields.     

Palladium-catalyzed direct arylation of aryl(azaaryl)methanes with aryl halides providing triarylmethanes

Direct arylation of aryl(azaaryl)methanes with aryl halides takes place at the benzylic position in the presence of a hydroxide base under palladium catalysis to yield triarylmethanes.     

An efficient and mild iron-mediated synthesis of alkenyl halides via direct C-C bond formation of benzyl alcohols and aryl alkynes

This work demonstrated an efficient and mild method for preparing various substituted alkenyl halides via direct C-C bond formation of benzyl alcohols and aryl alkynes in CH₂Cl₂ at 50 °C by using 50 mol % of FeCl₃·6H₂O or FeBr₃. Compared with the systems using excessive boron trihalides and stoichiometric n-BuLi to prepare substituted alkenyl halides, the present procedure would provide an excellent alternative due to the environmentally benign system and atom efficiency.     

Palladium-catalyzed C-N bond formation via direct C-H bond functionalization. Recent developments in heterocyclic synthesis

The formation of carbon-nitrogen bonds by reaction between a nitrogen atom and an unactivated carbon-hydrogen bond is a highly atom-economical process that attracted the attention of the chemists in the last two decades. The widely useful amination and hydroamination reactions, which furnish acyclic or cyclic products, give access to various nitrogen-containing basic and fine chemicals. This review highlights recent progress in the development of palladium-catalyzed reactions that occur by direct functionalization of simple carbon-hydrogen bonds to give heterocyclic products. Pd(0)- and Pd(II)-catalyzed reactions are described separately, emphasizing the different behavior of the metal in these two oxidation states.     

Palladium-catalyzed intramolecular delta-lactam formation of aryl halides and amide-enolates: syntheses of cherylline and latifine

[reaction: see text] Palladium-catalyzed intramolecular carbon-carbon bond formation of aryl halides and amide-enolates gave 4-arylisoquinoline derivatives in good yields, which were further converted into the isoquinoline alkaloids cherylline and latifine.