Microwave-assisted cross-coupling reaction of alkynylstibanes with aryl iodides in the presence of ammonium salt

The scope of microwave-assisted coupling reaction of alkynylstibane and aryl iodides to form diarylalkynes is presented. Highly efficient reaction took place smoothly in dimethyl sulfoxide in the presence of cetyltrimethylammonium bromide with much shorter time (1 min) and lower catalyst loading (0.5 mol%) than the conventional method (heating for 24 h with 10 mol% catalyst).     

Copper-mediated fluorination of aryl iodides

The synthesis of aryl fluorides has been studied intensively because of the importance of aryl fluorides in pharmaceuticals, agrochemicals, and materials. The stability, reactivity, and biological properties of aryl fluorides can be distinct from those of the corresponding arenes. Methods for the synthesis of aryl fluorides, however, are limited. We report the conversion of a diverse set of aryl iodides to the corresponding aryl fluorides. This reaction occurs with a cationic copper reagent and silver fluoride. Preliminary results suggest this reaction is enabled by a facile reductive elimination from a cationic arylcopper(III) fluoride.     

Palladium-catalyzed N-arylation of sulfoximines with aryl bromides and aryl iodides

Various N-arylated sulfoximines have been synthesized in high yield by a direct approach which is based on a palladium-catalyzed cross-coupling strategy. Aryl bromides of variable substitution pattern were found to be the most effective coupling partners, whereas aryl iodides showed a nonpredictable behavior requiring lithium or silver salts as additives to ensure product formation in acceptable yields. Coupling of (S)-2-(2'-bromophenyl)-4-tert-butyloxazoline with enantiomerically pure (-)-(RS)-S-methyl-S-phenylsulfoximine afforded the corresponding product in good yield as a single diastereomer, showing that the palladium-catalyzed arylation proceeds in a stereospecific manner. The reaction with dibromobenzenes yielded the monosulfonimidoyl arenes in all cases, suggesting that the introduction of the sulfonimidoyl moiety deactivates the arene, thus preventing a second coupling step.     

Copper-mediated difluoromethylation of aryl and vinyl iodides

Selectively fluorinated molecules are important as materials, pharmaceuticals, and agrochemicals, but their synthesis by simple, mild, laboratory methods is challenging. We report a straightforward method for the cross-coupling of aryl and vinyl iodides with a difluoromethyl group generated from readily available reagents to form difluoromethylarenes and difluoromethyl-substituted alkenes. The reaction of electron-neutral, electron-rich, and sterically hindered aryl and vinyl iodides with the combination of CuI, CsF and TMSCF(2)H leads to the formation of difluoromethyl-substituted products in high yield with good functional group compatibility. This transformation is surprising, in part, because of the prior observation of the instability of CuCF(2)H.     

Pd-carbene catalyzed carbonylation reactions of aryl iodides

A series of carbene complexes [PdBr(2)((i)Pr(2)-bimy)L] (C2-C13) with different types of co-ligands (L) have been tested for their catalytic activities in the carbonylative annulation of 2-iodophenol with phenylacetylene in DMF to afford the respective flavone 2a. Complex C12 with an N-phenylimidazole co-ligand showed the best activity and also afforded high yields when the substrate scope was extended to other aryl or pyridyl acetylenes. In addition, catalyst C12 was also efficient in the carbonylative annulation of 2-iodoaniline with acid chlorides giving the desirable 2-substituted 4H-3,1-benzoxazin-4-ones (4) in good yields. Additionally, this Pd-NHC complex also proved to be a very efficient catalyst for the hydroxycarbonylation of iodobenzene derivatives at low catalyst loading and under low CO pressure. These results demonstrate the versatility and efficiency of this phosphine-free Pd(II)-NHC complex in different types of carbonylations of aryl iodides under mild conditions.     

Copper-catalyzed coupling of hydroxylamines with aryl iodides

An efficient method for the copper-catalyzed N-arylation of hydroxylamines with aryl iodides is described. A variety of N- and O-functionalized hydroxylamines were transformed in good to excellent yield with a broad range of aryl coupling partners. Methods for the selective deprotection of either the N- or O-substituents for further functionalization are also described.     

Copper-catalyzed cross-coupling of aryl iodides and aryl acetylenes using microwave heating

An efficient copper-catalyzed cross-coupling of aryl iodides with aryl acetylenes under microwave irradiation is described. The reaction proceeds under microwave heating with 10 mol % CuI and 2 equiv Cs₂CO₃ in 43-87% yields.     

Cobalt-catalyzed annulation of aryl iodides with alkynes

A cobalt-catalyzed approach for the concise synthesis of naphthalenes by the annulation of aryl iodides with alkynes is disclosed. In the reaction, manganese reductant and MeCN solvent are necessary to proceed efficiently, which tolerates various functional groups, for example, boronate ester. Mechanistic investigation indicates that the transformation employs electrophilic aromatic substitution (S_EAr) in the aromatic C–H bond replacement step.     

Reactions of aryl and heteryl iodides with terminal acetylenes in the presence of co,catalyzed by palladium complexes

The influence of the nature of the solvent, of the base, the catalyst, the temperature, and the pressure of CO on reactions of aryl and heteryl iodides RI with terminal acetylenes RCCH in the presence of CO, catalyzed by palladium complexes is studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2548–2551, November, 1991.     

Efficient copper-catalyzed N-arylation of sulfoximines with aryl iodides and aryl bromides

Two simple and inexpensive systems for copper-catalyzed N-arylations of sulfoximines with aryl bromides and aryl iodides have been developed. Using 10 mol % of a copper(I) salt in combination with 20 mol % of a 1,2-diamine and Cs2CO3 provides N-arylated sulfoximines in high yields. Various functional groups and heteroatoms are tolerated. The method is complementary to the known protocols for N-arylations of sulfoximines, which require stoichiometric quantities of copper salts or cost-intensive palladium/BINAP catalysts.     

Further insight into aryl nitration of tetraphenylporphyrin

We report an in-depth study on meso-aryl nitration of tetraphenylporphyrin. In contrast to previous studies, new evidence reveals that tetrakis(p-nitrophenyl) derivative can be obtained as a major product. Successful isolation of the barely soluble product toward a remarkable yield of nearly 90% has been reached by means of a solid phase extraction technique. Distribution of different nitro-porphyrin components is reassessed with respect to varying acid content in the reactions. An ortho-effect model is proposed to describe the formation mechanism.     

水相中钯催化碘代芳烃Ullmann偶联反应研究

研究了吸电子基团的贫电碘代芳烃的Ullmann偶联反应,该反应使用Pd(OAc)2为催化剂,K2CO3为添加剂,以丙酮-水混合液为溶剂,不需要添加额外的还原剂,收率为55-87%。在通过了一系列的试验后,可以认为该反应中的溶剂及碱没有起还原作用,而是碘代芳烃自身作为还原剂,完成整个催化反应的,并首次提出了一种不需要外加还原剂的Pd(II)/Pd(IV)/Pd(II)的催化循环机理。     

The novel usage of thiourea nitrate in aryl nitration简

Thiourea nitrate （TN） was easily prepared from thiourea and nitric acid to explore its use as a new nitration reagent, Nitrations of various aromatic compounds utilizing TN in concentrated sulfuric acid were studied, TN could convert aromatic compounds to the corresponding nitrated derivatives with various abnormal yields under mild conditions. The results suggested that the reaction mechanism might be different from those of traditional nitration reagents.     

Copper-mediated direct arylation of benzoazoles with aryl iodides

The direct arylation of 1,3-benzoazole compounds with aryl iodides is effectively promoted by CuI with use of PPh₃ and Na₂CO₃ or K₃PO₄ as ligand and base, respectively, in DMF or DMSO to produce the corresponding 2-arylated products with good yields.     

Photochemical reactions of acyl iodides with aryl halides

Photochemical reactions of acyl iodides RC(O)I (R = Me, Ph) with aryl halides, fluoro-, chloro-, and bromobenzenes, 1,4-dibromobenzene, 2- and 3-bromotoluenes, and 4-bromo-1,2-dimethylbenzene, were studied. Acetyl iodide reacted with chloro- and bromobenzenes and 1,4-dibromobenzene according to the exchange pattern to give iodobenzene and 1,4-diiodobenzene, respectively. No halogen exchange was observed in the reactions of acetyl iodide with fluorobenzene and hexafluorobenzene. Benzoyl iodide failed to react with chloro- and brombenzene under UV irradiation but underwent polycondensation with formation of black nonfusible oligomers which were found to possess paramagnetic and semiconducting properties. Ultraviolet irradiation of a mixture of MeCOI with 2- or 3-bromotoluene, as well as with 4-bromo-1,2-dimethylbenzene, also led to the formation of polymeric products as a result of polycondensation of aryl iodides formed initially via replacement of bromine by iodine. Irradiation of benzoyl iodide in 2- or 3-bromotoluene involved recombination of benzoyl radicals to give benzil as the only product.     

Copper-catalyzed cross-coupling of diethyl phosphonate with aryl iodides

Cross-coupling of diethyl phosphonate with aryl iodides was performed using copper(I) iodide complexes with various bidentate ligands as catalysts.     

Copper-catalyzed coupling of aryl iodides with aliphatic alcohols

[reaction: see text] A simple and mild method for the coupling of aryl iodides and aliphatic alcohols that does not require the use of alkoxide bases is described. The reactions can be performed in neat alcohol. For more precious alcohols, the etherification was carried out in toluene as solvent using 2 equiv of alcohol. Additionally, the cross-coupling of an optically active benzylic alcohol with an unactivated aryl halide was demonstrated to proceed with complete retention of configuration.