Cross-coupling of benzylic acetates with arylboronic acids: one-pot transformation of benzylic alcohols to diarylmethanes

Benzylic acetates reacted with arylboronic acids in the presence of a DPEphos-[Pd(eta3-C3H5)Cl]2 catalyst when tert-amyl alcohol was used as a solvent, and the catalytic cross-couplings produced diarylmethanes in high yields (up to 94% isolated yield).     

Synthesis of functionalised diarylmethanes via a cobalt-catalysed cross-coupling of arylzinc species with benzyl chlorides

A new cobalt-catalysed reductive coupling of aryl halides with benzyl chlorides is reported; a variety of diarylmethanes can be prepared in good to excellent yields under mild reaction conditions using CoBr(2) as catalyst and Zn dust; this new cobalt-catalysed coupling represents a practical and interesting alternative to previously known methods for the synthesis diarylmethanes.     

Potassium‐Zincate‐Catalyzed Benzylic C−H Bond Addition of Diarylmethanes to Styrenes

Direct functionalization of the benzylic C?H bond of diarylmethanes is an important strategy for the synthesis of diarylmethine‐containing compounds. However, the methods developed to date for this purpose require a stoichiometric amount (usually more) of either a strong base or an oxidant. Reported here is the first catalytic benzylic C?H bond addition of diarylmethanes to styrenes and conjugated dienes. A potassium zincate complex, generated from potassium benzyl and zinc amide, acts as a catalyst and displays good activity and chemoselectivity. Considering the atom economy of the reaction and the ready availability of the catalyst, this reaction constitutes a practical, efficient method for diarylalkane synthesis.     

Synthesis of diaryl acetates and oxindoles via a sequential VNS(Ar)-S(N)Ar three-component coupling reaction

[reaction: see text] The VNS and S(N)Ar reactions combine to form an efficient three-component one-pot route to diarylmethanes. The products of selected diaryl acetates provide modular 3-aryloxindole derivatives.     

A green and convenient protocol for the synthesis of diarylmethanes via a one-pot,three-component reaction catalyzed by a novel silica tungstic acid (STA) under solvent-free conditions

A cost-effective and eco-friendly synthesis of diarylmethanes derivatives has been developed through the Mannich type Friedel–Crafts addition reaction of tertiary aromatic amine formaldehydes with β-naphthol/indole using silica-supported tungstic acid (STA) as a recyclable heterogeneous acid catalyst in solvent-free condition. Here, we proposed two schemes using the same catalyst. The effects of different solvents have been studied and a comparison of silica-supported tungstic acid with different acid catalysts has also been made.     

An efficient synthesis of diarylmethanes via InCl3·4H2O-catalyzed dehydration of electron-rich arenes with trioxane

A facile, efficient and environmentally benign procedure for the synthesis of diarylmethanes via the reaction of arenes with trioxane catalyzed by InCl₃·4H₂O was developed. The reactions of aromatic compounds bearing electron-donating group proceeded smoothly affording the corresponding diarylmethanes in good to excellent yields.     

FeCl_3 catalyzed diarylmethanes formations

Under mild condition,using FeCl3 as catalyst,a series of functionalized diarylmethanes were prepared efficiently from the reactions of arenes with paraformaldehyde.This catalytic system is not sensitive to air and moisture.     

One-Pot Synthesis of Symmetrical and Unsymmetrical Diarylmethanes via Diborylmethane

A one-pot synthesis of diarylmethanes from air-stable diborylmethane via the Suzuki-Miyaura cross-coupling reaction is described. The present approach realizes the synthesis of various symmetrical and unsymmetrical diarylmethanes in good to excellent yields.     

Suzuki-Miyaura cross-coupling of benzylic phosphates with arylboronic acids

[reaction: see text] Suzuki-Miyaura cross-coupling of benzylic phosphates with arylboronic acids was investigated. Optimum conditions employed the simple catalytic system of palladium(II) acetate (1 mol %) and triphenylphosphine (4 mol %) with either potassium phosphate or potassium carbonate as the base and toluene as the solvent at 90 degrees C. Using the developed conditions, a series of structurally diverse diarylmethanes were prepared.     

Catalytic selective bis-arylation of imines with anisole, phenol, thioanisole and analogues

The first highly efficient double Friedel-Crafts reaction of N-tosyl imines with anisole, phenol, thioanisole and analogues has been developed to produce the corresponding symmetric diarylmethanes and triarylmethanes with high regioselectivity in the presence of a catalytic amount of Bi(2)(SO(4))(3)-TMSCl at room temperature.     

Room-Temperature Bismuth-Catalyzed Bis-arylation of Carbonyl Compounds with Aryl Ethers and Phenols

Using Bi2（SO4）3 as the catalyst and TMSCl as the additive, a wide variety of aldehydes, ketones, and acetals were smoothly condensed with aryl ethers at room temperature to provide the corresponding diarylmethanes and triarylmethanes selectively in good to excellent yields.     

Boron trifluoride-induced, new stereospecific rearrangements of chiral epoxy ethers. Ready access to enantiopure 4-(diarylmethyl)-1,3-dioxolanes and 4,5-disubstituted tetrahydrobenzo[c]oxepin-4-ols

Upon treatment with BF3.Et2O at low temperature, enantiopure benzyl-type ethers of arylglycidols with electron withdrawing substituents at the skeletal aryl group and electron donating substituents at the benzyl group undergo stereospecific rearrangements of Friedel-Crafts type, leading to enantiopure 4-diarylmethyl-1,3-dioxolanes (2) or to enantiopure trans-4,5 disubstituted tetrahydrobenzo[c]oxepin-4-ols (5). The course of the reactions is controlled by the substitution pattern at the benzyl ether: While benzylic systems activated toward ipso substitution afford diarylmethanes 2 through a Friedel-Crafts reaction followed by fragmentation, benzylic systems activated toward ortho attack lead to enantiopure oxepinols 5 through a 7-endo-tet ring closure of Friedel-Crafts type.     

Synthesis of functionalized diarylmethanes via a copper-catalyzed cross-coupling of arylmagnesium reagents with benzylic phosphates

A combination of copper chloride, triethyl phosphite, and tetrabutylammonium iodide is a very efficient catalytic system for the synthesis of polyfunctionalized diarylmethanes, using the cross-coupling reaction of arylmagnesium halides with benzylic phosphates. The antibiotic Trimethoprim has been prepared using this Cu(I)-catalyzed cross-coupling in 52% overall yield (four steps).     

Oxidation of nitrobenzylic carbanions with dimethyldioxirane. new synthesis of quinomethanes and nitrobenzylic carbinols. First examples of methylation of carbanions with dimethyldioxirane.

The reaction of nitrobenzylic carbanions with dimethyldioxirane (DMD) results in oxidation at the carbanion center or at the nitronate center to give nitrobenzylic carbinols or quinomethanes, respectively. Minor amounts of the methylation products are also formed. Both of these processes were observed for carbanions of (p-nitroaryl)diarylmethanes. The outcome of the oxidation process is very sensitive to the reaction conditions.     

Direct C(sp3)−H difluoroallylation of diarylmethanes with α-(trifluoromethyl) styrenes at room temperature

A rapid and convenient method for the synthesis of 3,3-difluoroallylated diarylmethanes by reactions of diarylmethanes with α-(trifluoromethyl)styrenes in the presence of LiHMDS at room temperature was developed.     

通过η~3-苄基钯中间体零价钯催化的吲哚苄基化反应(英文)

本文报道了零价钯催化的吲哚苄基化反应,获得了优秀的区域选择性.使用Pd(PPh3)4作为催化剂,在温和反应条件下,以90%–99%的收率获得含有各类取代吲哚片段的三芳基甲烷化合物.     

Palladium-Catalyzed C(sp(3))-H Arylation of Diarylmethanes at Room Temperature: Synthesis of Triarylmethanes via Deprotonative-Cross-Coupling Processes

Although metal-catalyzed direct arylation reactions of non- or weakly acidic C-H bonds have recently received much attention, chemists have relied heavily on substrates with appropriately placed directing groups to steer reactivity. To date, examples of intermolecular arylation of unactivated C(sp(3))-H bonds in the absence of a directing group remain scarce. We report herein the first general, high-yielding, and scalable method for palladium-catalyzed C(sp(3))-H arylation of simple diarylmethane derivatives with aryl bromides at room temperature. This method facilitates access to a variety of sterically and electronically diverse hetero- and nonheteroaryl-containing triarylmethanes, a class of compounds with various applications and interesting biological activity. Key to the success of this approach is an in situ metalation of the substrate via C-H deprotonation under catalytic cross-coupling conditions, which is referred to as a deprotonative-cross-coupling process (DCCP). Base and catalyst identification were performed by high-throughput experimentation (HTE) and led to a unique base/catalyst combination [KN(SiMe(3))(2)/Pd-NiXantphos] that proved to efficiently promote the room-temperature DCCP of diarylmethanes. Additionally, the DCCP exhibits remarkable chemoselectivity in the presence of substrates that are known to undergo O-, N-, enolate-, and C(sp(2))-H arylation.     

ReCl（CO）5-catalyzed Reactions of Aromatic Compounds with 1,3,5-Trioxane or Aqueous Formaldehyde Affording Diarylmethanes

ReCI（CO）5 catalyzed the dehydration reaction of aromatic compounds with 1,3,5-trioxane or aqueous formaldehyde （37 wt%） under air. The reactions of a variety of aromatic compounds beating electron-donating group（s） with 1,3,5-trioxane afforded the corresponding diarylmethanes in moderate to good yields.     

Oxidative generation of diarylcarbenium ion pools

"Cation pools" of diarylcarbenium ions have been generated by the oxidative C-H bond dissociation of diarylmethanes using anodic oxidation. "Diarylcarbenium ion pools" thus generated react with various nucleophiles, such as allylsilanes, ketene silyl acetals, and aromatic compounds. The reductive homocoupling of the "diarylcarbenium ion pool" has been achieved. The dimer thus obtained also serves as a precursor of the "diarylcarbenium ion pool" via oxidative C-C bond dissociation. [reaction: see text]     

A novel amphiphilic chiral ligand derived from D-glucosamine. Application to palladium-catalyzed asymmetric allylic substitution reaction in an aqueous or an organic medium, allowing for catalyst recycling

A novel amphiphilic phosphinite-oxazoline chiral compound, 2-methyl-4,5-[4,6-O-benzylidene-3-O-bis[4-((diethylamino)methyl)phenyl]phosphino-1,2-dideoxy-alpha-D-glucopyranosyl]-[2,1-d]-2-oxazoline (1), has been prepared from natural D-glucosamine hydrochloride. The newly prepared complex, [Pd(2-methyl-4,5-[4,6-O-benzylidene-3-O-bis[(4-((diethylmethylammonium)methyl)phenyl)]phosphino-1,2-dideoxy-alpha-D-glucopyranosyl]-[2,1-d]-2-oxazoline)(eta3-C3H5)]3+ x 3BF4- (3), is soluble in water and an efficient catalyst for asymmetric allylic substitution reaction in water or an aqueous/organic biphasic medium (up to 85% ee). This catalytic system offers an easy separation of the aqueous catalyst phase from the product phase and allows recycling of the catalyst phase. In addition, compound 1 also works as an effective ligand for the palladium-catalyzed reaction under conventional homogeneous conditions in an organic medium, in which the catalyst (Pd-1 complex) can be recovered by simple acid/base extraction and reused in the second reaction.