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.     

Pd-catalyzed selective hydrosilylation of aryl ketones and aldehydes

Pd salts in combination with triethylsilane as hydride source and DMF as solvent has been found to be excellent catalytic combination that selectively reduces aryl ketones and aldehydes under mild conditions to afford triethylsilyloxy compounds in excellent yields. Product selectivity to the respective benzyl alcohols can however be achieved when the reaction was performed in DMF/H₂O (4:1) as solvent system.     

Catalyzed asymmetric aryl transfer reactions to aldehydes with boronic acids as aryl source

Chiral diaryl methanols are important intermediates for the synthesis of biologically active compounds. Here, we describe a flexible method for their catalyzed asymmetric synthesis from readily available starting materials. Noteworthy is the fact that with a single catalyst both enantiomers of the product are accessible simply by choosing the appropriate combination of aryl boronic acid or aldehyde as aryl donor and acceptor, respectively. The catalysis with a planar-chiral ferrocene is easy to perform and yields a broad range of products with excellent enantioselectivities (up to 98% ee).     

Iron-mediated allylation of aryl aldehydes in aqueous media

Iron metal was found to be able to mediate the allylation reaction of aryl aldehydes in aqueous media with sodium fluoride as the promoter. The possible implication of an allyliron intermediate was examined.     

A facile one-carbon homologation of aryl aldehydes to amides

The easily accessible 2-aryl-1,1-dibromo-1-alkenes can be converted to amides under unusually mild conditions in good to excellent yields. Both electron-donating and electron-withdrawing substitutions on the aromatic rings are tolerated, and the reaction works well with hindered alkylamines. This simple homologation could find broad applications. [reaction: see text]     

Asymmetric additive-free aryl addition to aldehydes using perhydrobenzoxazines as ligands and boroxins as aryl source

A highly efficient enantioselective aryl addition to aldehydes using boroxins as aryl source and conformationally restricted perhydro-1,3-benzoxazines as ligands is reported. Both enantiomeric forms of chiral arylphenylmethanols and 1,1'-disubstituted diarylmethanols are afforded with excellent yields and enantioselectivities using the same ligand by means of an appropriate combination of boroxin and aromatic aldehyde. The enantiocontrol is not significantly influenced by electronic effects or steric hindrance, even with substituted boroxins. Very homogeneous ee's are reached when substituted arylboroxins are employed, without the use of any class of additive or pre-treatment.     

A new reaction of aryl aldehydes with aryl acetylenes in the presence of boron trihalides

[reaction: see text]. The reactions of aryl aldehydes with 2 equiv of arylacetylenes in the presence of boron trichloride yield (E,Z)-1,3,5-triaryl-1,5-dichloro-1,4-pentadienes. Reactions carried out in the presence of boron tribromide generate the corresponding (Z,Z)-1,3,5-triaryl-1,5-dibromo-1,4-pentadienes.     

Catalytic enantioselective arylation of aryl aldehydes by chiral aminophenol ligands

The catalytic enantioselective arylation of aryl aldehydes using boronic acids as the source of transferable aryl groups is described; the reaction is found to proceed in good yields and in good to high enantioselectivities (up to 99% ee) in the presence of a chiral aminophenol ligand.     

Direct asymmetric aldol reaction of aryl ketones with aryl aldehydes catalyzed by chiral BINOL-derived zincate catalyst

Direct asymmetric aldol reaction of aryl ketones with aryl aldehydes catalyzed by chiral metal complex is reported for the first time herein. Two novel semicrown chiral ligands 1a and 1b were synthesized from (S)- and (R)-BINOL, respectively, and then employed to catalyze the direct asymmetric aldol addition of aryl ketones to aryl aldehydes. Introduced with 2.0 equiv of diethylzinc, 1b had higher enantioselectivity than 1a. Up to 97% yield and up to 80% enantioselectivity were achieved.     

Direct acylation of aryl bromides with aldehydes by palladium catalysis

A new protocol for the direct acylation of aryl bromides with aldehydes is established. It appears to involve palladium-amine cooperative catalysis, affording synthetically important alkyl aryl ketones in moderate to excellent yields in a straightforward manner, and broadening the scope of metal-catalyzed coupling reactions.     

The palladium-catalyzed conjugate addition type reaction of aryl iodides with α,β-unsaturated aldehydes

α,β-Enals have been shown to react with aryl iodides in the presence of a palladium catalyst with selective formation of conjugate addition type products.     

FeCl3催化Et2Zn与芳香醛的加成反应研究

以FeCl_3作为催化剂, 研究了Et_2Zn与芳香醛的加成反应, 考察了催化剂、溶剂、催化剂与Et_2Zn用量及温度对该反应的影响. 实验结果表明: 在60℃, 1.2当量Et_2Zn, 甲基环戊基醚为溶剂的反应条件下, 10 mol% FeCl_3可以较高效的将各种芳香醛转化为仲醇.     

Bismuth triflate catalyzed condensation of δ-hydroxy-α,β-unsaturated aldehydes with aryl amines

α,β-Unsaturated aldehydes bearing a δ-hydroxyl group undergo a tandem Michael and intramolecular Friedel-Crafts type cyclization with arylamines in the presence of 5 mol % of Bi(OTf)₃ under mild conditions to afford a new class of chiral tetrahydroquinolines in good yields with high stereoselectivity. Structural assignments and the stereochemistry of the products was achieved using various 1D and 2D-NMR experiments.     

A simple,one-pot oxidative esterification of aryl aldehydes through dialkyl acetal using hydrogen peroxide

Research on Chemical Intermediates - A simple and an efficient one-pot procedure has been developed to synthesize various aryl carboxylic esters directly from aryl aldehydes using hydrogen peroxide...     

Palladium-catalyzed C2-acylation of indoles with aryl and alkyl aldehydes

A palladium-catalyzed C2-acylation of indoles with aryl and alkyl aldehydes via C–H functionalization is reported. The method shows excellent functional group tolerance and provides a straightforward way for the preparation of 2-aroylindoles.     

An efficient one-pot synthesis of 3-aryl-5-methylisoxazoles from aryl aldehydes

An efficient protocol for the one-pot preparation of alkyl 3-aryl-5-methylisoxazole-4-carboxylates from aryl aldehydes is described. This method is readily amenable to the large scale preparation of isoxazoles as well as the parallel synthesis of isoxazole libraries.     

Boron trihalide mediated haloallylation of aryl aldehydes: reaction and mechanistic insight

The reaction of aryl aldehydes with allylsilanes in the presence of boron trihalides produces haloallylated products. Mechanistic details are presented.