128920-00-3

Upstream product

• 60319-07-5 trifluoromethanesulfonic acid 2,6-dimethoxyphenyl ester 
• 3757-88-8 tributylstannylethynylbenzene 
• 16932-44-8 2-iodo-1,3-dimethoxybenzene 
• 536-74-3 phenylacetylene 
• 28995-88-2 1-methyl-4-((phenylethynyl)sulfonyl)benzene 
• 151-10-0 1,3-Dimethoxybenzene 
• 1466-76-8 2-6-dimethoxybenzoic acid 

Downstream Products

• 1258379-83-7 (E)-(1-(2,6-dimethoxyphenyl)-2-phenylvinyl)triethylsilane 
• 1607839-53-1 4-methoxy-2-phenyl-3-(trifluoromethylthio)benzofuran 

Relevant academic research and scientific papers

Arylation of Terminal Alkynes by Aryl Iodides Catalyzed by a Parts-per-Million Loading of Palladium Acetate

Arylation of terminal alkynes (16 varieties) by aryl iodides (28 varieties) was achieved with a mol ppm loading level of palladium catalyst, where a variety of functional groups including heteroarenes were tolerated. Thus, the arylations were carried out in the presence of palladium acetate at ppm loadings and potassium carbonate in ethanol at 80 °C to give the corresponding internal alkynes in good to excellent yields. Synthesis of 2-phenyl-3-(phenylalkynyl)benzofuran was achieved by iterative use of the alkyne arylation under mol ppm catalytic conditions. Reaction-rate analysis, transmission electron microscopic (TEM) examination of the reaction mixture, and mercury-amalgamation test were performed to gain insight into the active species of the highly active ppm catalytic species. TEM examination of the reaction mixture revealed that palladium nanoparticles were generated in situ under the reaction conditions, and their cluster size was variable during the catalytic reaction. A variation in size of palladium particles suggested that the composition-decomposition process of Pd aggregates should take place in situ via monomeric palladium(0) species and/or fine palladium(0) clusters, which might be real catalytic species in this reaction.

Pd-Catalyzed Decarboxylative Sonogashira Reaction via Decarboxylative Bromination

The decarboxylative alkynylation of (hetero)aryl carboxylic acids with terminal alkynes has been achieved by using a Pd(PPh3)4/PCy3 catalyst. This Pd-catalyzed method exhibits good functional group tolerance for both coupling partners and enables chemical modification of complex molecules. The establishment of this decarboxylative alkynylation reaction is attributed to the discovery of a highly selective decarboxylative bromination of (hetero)aryl carboxylic acids with NBS (N-bromosuccinimide).

Iridium-Catalyzed Intramolecular Methoxy C?H Addition to Carbon–Carbon Triple Bonds: Direct Synthesis of 3-Substituted Benzofurans from o-Methoxyphenylalkynes

Catalytic hydroalkylation of an alkyne with methyl ether was accomplished. Intramolecular addition of the C?H bond of a methoxy group in 1-methoxy-2-(arylethynyl)benzenes across a carbon–carbon triple bond took place efficiently either in toluene at 110 °C or in p-xylene at 135 °C in the presence of an iridium catalyst. The initial 5-exo cyclization products underwent double-bond migration during the reaction to give 3-(arylmethyl)benzofurans in high yields.

Expanding the scope of arylsulfonylacetylenes as alkynylating reagents and mechanistic insights in the formation of Csp2-Csp and Csp 3-Csp bonds from organolithiums

We describe the unexpected behavior of the arylsulfonylacetylenes, which suffer an "anti-Michael" addition of organolithiums producing their alkynylation under very mild conditions. The broad scope, excellent yields, and simplicity of the experimental procedure are the main features of this methodology. A rational explanation of all these results can be achieved by theoretical calculations, which suggest that the association of the organolithiums to the electrophile is a previous step of their intramolecular attack and is responsible for the unexpected "anti-Michael" reactions observed for substituted sulfonylacetylenes. A calculated conclusion: A new transition-metal-free strategy for the synthesis of any kind of alkynyl derivatives in high yields in the reaction of organolithium species with arylsulfonylacetylenes is presented (see scheme). Theoretical calculations provide a rational explanation and suggest that association of the organolithium to the electrophile is a previous step of their intramolecular attack and is responsible for the "anti-Michael" reaction. Copyright

Arylsulfonylacetylenes as alkynylating reagents of C sp 2 -H bonds activated with lithium bases

Chameleon: A new strategy for the synthesis of a wide variety of alkynyl derivatives by the reaction of substituted arylsulfonylacetylenes with organolithium species is described (see scheme). The high yields, the simplicity of the experimental procedure, the broad scope of this reaction, and the formation of Csp-C sp 2 bonds without using transition metals are the main features of this methodology. Copyright

Highly convenient, clean, fast, and reliable Sonogashira coupling reactions promoted by aminophosphine-based pincer complexes of palladium performed under additive-and amine-free reaction conditions

Sequential addition of 1,1',1″-phosphine-triyltripiperidine and 1,3-diaminobenzene or resorci-nol to toluene solutions of (cyclooctadiene) palladium dichloride [Pd(cod)(Cl)2] under nitrogen in "one pot" almost quantitatively yielded the aminophos-phine-based pincer complexes {[C6H3-2,6-(XP{piperi-dinyl}2) 2]Pd(Cl)} (X = NH 1; X = O 2). Complex 1 (and to a minor extent 2) proved to be efficient Sonogashira catalysts, which allow the quantitative coupling of various electronically deactivated and/or sterically hindered and functionalized aryl iodides and aryl bromides with several alkynes as coupling partners within very short reaction times and low catalyst loadings. Importantly, in contrast to most of the Sonogashira catalysts, which either are both air-and moisture-sensitive and/or require the addition of co-catalysts, such as copper(I) iodide [Cul], for ex- ample, or a large excess of an amine, the coupling reactions were carried out without the use of amines, co-catalysts or other aditives and without exclusion of air and moisture. Moreover, the desired products were exclusively formed (no side-products were detected) without employing an excess of one of the substrates. Ethylene glycol and potassium phosphate (K3PO4) were found to be the ideal solvent and base for this transformation. Experimental observations strongly indicate that palladium nanoparticles are not the catalytically active form of 1 and 2. On the other hand, their transformation into another homogeneous catalytically active species cannot be excluded.

Palladium-Catalyzed Cross-Coupling Reactions of Highly Hindered, Electron-Rich Phenol Triflates and Organostannanes

The palladium-catalyzed cross-coupling reaction of highly hindered, electron-rich phenol triflates and organostannanes (Stille reaction) has been studied in a systematic manner.The following are its salient features: (1) electron-rich phenol triflates require triphenylphosphine to undergo palladium-catalyzed cross-couplings; (2) in general, efficient reactions take place only when larger-than-usual amounts (10-15percent) of palladium are employed.On the reagent side, alkyl- (methyl only), allyl-, vinyl- and alkinylstannanes undergo efficient cross-couplings with the titlesubstrates.However, some limitations to this novel entry to 2-substituted resorcinols exist in regard to both substrates and reagents.Thus, conformationally rigid (hexasubstituted) aryl triflates behave poorly, demethylation being an important side reaction.Moreover, alkyl groups other than methyl cannot be introduced because β elimination occurs more rapidly.The potentially powerful synthesis of hindered biaryls has also been studied briefly.In the present conditions, the reaction appears to be limited by the presence of ortho substituents on the arylstannane moiety.

Palladium catalyzed cross-coupling of phenol triflates with organostannanes. A versatile approach for the synthesis of substituted resorcinol dimethyl ethers.

2,6-Dimethoxy-substituted phenol triflates undergo efficient Pd(0) catalyzed cross coupling with organostannanes, thus providing an easy access to substituted resorcinol dimethyl ethers, a common building block of many aromatic polyketides.