Dilithium aryl cyanocuprates from butyl aryl tellurides

Butyl aryl tellurides reacted with dilithium dimethyl cyanocuprate and with dilithium methyl(2-thienyl)cyanocuprate to give the corresponding dilithium aryl cyanocuprates, which were captured with enones leading to 4-aryl ketones in good yields.     

Metal-free synthesis of aryl esters by coupling aryl carboxylic acids and aryl boronic acids

A facile synthesis of aryl esters is developed by coupling aryl carboxylic acids and aryl boronic acids in the presence of PhI(OAc)₂ and carbonyl diimidazole. A wide range of functional groups were tolerant to the metal-free reaction condition that led to the desired products in good yields.     

Photolysis of aryl bromides and aryl chlorides in benzene

Conclusions As a result of photolysis of aromatic bromo- and chlorohydrocarbons in benzene solution, products of replacement of the halogen atoms by a phenyl group were obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 456–457, February, 1967.     

Electrophilic fluorination of aryl tin and aryl mercury derivatives

Cleavage of aryl-tin and aryl-mercury derivatives with CF₃OF occurs particularly readily and the mercury derivatives give the corresponding arylfluorine compounds in especially high yield.     

Acid-mediated aryl migration reaction of C-3 aryl substituted pyrrolidinoindolines

Aryl migration reactions of C-3 aryl substituted pyrrolidinoindoline compounds to provide highly conjugated C-2 aryl indole compounds have been discovered. The developed reactions have a wide substrate scope and proceed in high yield under simple acidic conditions. A unique cationic cyclopropane intermediate as the transition state is proposed.     

N-Directing group assisted rhodium-catalyzed aryl C-H addition to aryl aldehydes

Direct aryl C-H addition to aryl aldehydes to produce biaryl methanols was reported via Rh catalysis with an N-containing directing group. The method is highly atom-, step-, and redox-economic. The procedure is robust, reliable, and compatible with water and air.     

Nickel-catalyzed amination of aryl phosphates through cleaving aryl C-O bonds

The amination of triaryl phosphates was achieved using a Ni(II)-(σ-Aryl) complex/NHC catalyst system in dioxane at 110 °C in the presence of NaH as base. Electron-neutral, -rich, and -deficient triaryl phosphates were coupled with a wider range of amine partners including cyclic and acyclic secondary amines, aliphatic primary amines, and anilines in good to excellent yields.     

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.     

Triorganotin aryl selenides

The SnSe bond in trimethyltin aryl selenides is cleaved on reaction with selenenyl halides, sulphenyl halides, alkyl halides and allyl halides. Thus Me₃SnSePh reacts with PhSeCl, 4-Me-2-NO₂C₆H₃SCl, RI (R = CH₃ or Ph₃SnCH₂) and CH₂CHCH₂Br to give PhSeSePh, 4-Me-2-NO₂C₆H₃SSePh, RSePh and CH₂CHCH₂SePh, respectively. The diselenide, PhSeSePh, is also obtained from Me₃SnSePh on reaction with either 4-MeC₆H₄SO₂Cl or NaIO₄. Exchange reactions also occur between Me₃SnSePh and Ph₃SnCl or PhHgCl.     

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.     

Microwave-assisted selenium dioxide oxidation of aryl methyl ketones to aryl glyoxals

We report an improved procedure for the synthesis of phenyl glyoxal and a series of para-substituted aryl glyoxals by microwave-assisted selenium dioxide oxidation. The reaction time has been reduced from several hours to three minutes for activated aryl methyl ketone substrates and 18 min for deactivated substrates, with all reactions affording quantitative conversion into the corresponding aryl glyoxals.     

Conformation and stereodynamics of symmetrically ortho-disubstituted aryl carbinols and aryl ethers

By making use of low-temperature dynamic NMR spectroscopy, the rotation barriers about the sp3-sp2 bond have been determined in a number of hindered benzyl alcohols symmetrically substituted in the ortho positions, the substituents being F, Cl, Br, and Me. The free energies of activation covered the range 4.6-10.1 kcal mol-1. Ab initio computations matched satisfactorily the trend of these values and predicted the conformation adopted by these compounds. In one case, this result could be also confirmed by the X-ray diffraction structure. In the case of the corresponding methyl ethers two barriers could be measured, corresponding to the passage across two distinguishable transition states: the higher barriers covered the range 5.0-8.1 kcal mol-1 and the lower ones the range 4.7-6.2 kcal mol-1.     

A facile one-pot synthesis of alkyl aryl sulfides from aryl bromides

A convenient one-pot synthetic method for the formation of alkyl aryl sulfides from various alkyl halides and lithium aryl thiolates that are prepared in situ by direct halogen-lithium exchange is reported. In particular, the method overcomes many of the problems encountered in previous reports; it is very quick, catalyst-free, and does not involve use of unstable aryl thiols.     

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.     

Nickel catalyzed cross-coupling of aryl C-O based electrophiles with aryl neopentylglycolboronates

The efficiency of mesylates, sulfamates, esters, carbonates, carbamates, and methyl ethers as C-O-based electrophiles attached to the 1- or 2-position of naphthalene and to activated and nonactivated phenyl substrates was compared for the first time in Ni-catalyzed cross-coupling with phenyl neopentylglycolboronates containing electron-rich and electron-deficient substituents in their para-position. These experiments were performed in the presence of four different Ni(II)- and Ni(0)-based catalysts. Ni(II)-based catalysts mediate the cross-coupling of most 2-naphthyl C-O electrophiles with both arylboronic acids and with neopentylglycolboronates when K(3)PO(4) is used as base. The same catalysts are not efficient when CsF is used as base. However, Ni(0)-based catalysts exhibit selective efficiency, and when reactive, their efficiency is higher than that of Ni(II)-based catalysts in the presence of both K(3)PO(4) and CsF. These results provide both reaction conditions for the cross-coupling, and for the elaboration of orthogonal cross-coupling methodologies of various C-O based electrophiles with aryl neopentylglycolboronates. With the exception of mesylates and sulfamates the efficiency of all other 2-naphthyl C-O electrophiles was lower in cross-coupling with aryl neopentylglycolboronates than with arylboronic acids.