An indium-TMSCl promoted reaction of diphenyl diselenides and aldehydes: novel routes to selenoacetals and alkyl phenyl selenides

The reaction of diphenyl diselenides with aldehydes in the presence of In-TMSCl has been investigated. Aliphatic aldehydes provide the corresponding selenoacetals, whereas aromatic aldehydes lead predominantly to alkyl phenyl selenides under the same reaction conditions. This constitutes a new approach for the synthesis of selenoacetals and selenides from aldehydes.     

An indium-TMSCl promoted reaction of diphenyl diselenide and diorganyl disulfides with aldehydes: novel routes to selenoacetals, thioacetals and alkyl phenyl selenides

The reactions of diphenyl diselenide and dialkyl disulfides with aldehydes in the presence of In-TMSCl have been investigated. Aliphatic aldehydes provide the corresponding selenoacetals and aromatic aldehydes lead predominantly to benzyl phenyl selenides on reaction with diphenyl diselenide. However, the reaction of dimethyl disulfide and diphenyl disulfide with both aromatic and aliphatic aldehydes produce dithioacetals. This provides a novel route to the synthesis of selenoacetals, thioacetals and selenides from aldehydes.     

Nickel-catalyzed reactions of silacyclobutanes with aldehydes: ring opening and ring expansion reaction

[reaction: see text]. The nickel-catalyzed ring opening reaction of silacyclobutanes with aldehydes affords the corresponding alkoxyallylsilanes. In contrast, the ring expansion reaction of benzosilacyclobutene with aldehydes occurs under nickel catalysis to give oxasilacyclohexenes.     

A FACILE SYNTHESIS OF HETEROCYCLE SUBSTITUTED CHALCONE AND 5-NITROFURANYL OLEFIN DERIVATIVES

Reaction of heterocycle substituted telluronium salts with aroma-tic aldehydes under mild conditions gave corresponding chalcones.In thepresence of dibutyl telluride,2-bromomethyl-5-nitrofuran condensed easilywith aromatic aldehydes in THF to afford corresponding olefin derivativesas one-pot reaction.     

The oxidation of aldehydes to acids with calcium hypochlorite [Ca(OCl)2]

Calcium hypochlorite is an efficient reagent for the oxidation of aldehydes to the corresponding acids. Reactions are carried out at ambient temperature in aqueous acetonitrile-acetic acid solution. Aliphatic aldehydes and aromatic aldehydes with electron withdrawing groups afford good to excellent yields. Nuclear chlorination is the preferred reaction in aromatic aldehydes with electron donating groups.     

Reinvestigation of the grignard reactions with formic acid. A convenient method for preparation of aldehydes

Grignard reagents react with formic acid in tetrahydrofuran to produce aldehydes in relatively good yields Various aldehydes such as alkyl, aryl, allyl, benzyl and vinyl aldehydes were prepared from the corresponding Grignard reagents. The reaction with vinyl Grignard reagents proceeded with retention of configuration.     

Chemoselective Schmidt reaction mediated by triflic acid: selective synthesis of nitriles from aldehydes

An excellent utility of Schmidt reaction of aldehydes to access corresponding nitriles in an instantaneous reaction is demonstrated. The reaction of aldehydes with NaN(3) and TfOH furnishes the corresponding nitriles in near quantitative yields and tolerates a variety of electron-withdrawing and electron-donating substituents on the substrates. Formanilides, a common side product in Schmidt reaction, is not observed in this reaction. Besides these advantages, the salient feature of this reaction is that it exhibits a remarkable chemoselectivity, as acid and ketone functionalities are well tolerated under the reaction conditions. The reaction is easily scalable, high yielding, and nearly instantaneous.     

Direct α‐Alkylation of Aldehydes by Brønsted‐Acid Catalysis

A Brønsted acid catalyzed direct alkylation reaction of aldehydes was described. The 3,5‐dinitrobenzoic acid promoted the reaction between aldehydes and diarylmethanols to afford the corresponding alkylation products with middle to high yields (up to 91% yield).     

Synthetic applications of the amine-base treatment in the ozonolysis of substituted-allyl silyl ethers or -allyl esters via a novel ene-diol type rearrangement

The ozonolysis of substituted-allyl silyl ethers or -allyl esters followed by treatment with bases gave the corresponding α-silyloxy ketones or α-acyloxy ketones in good yields. The reaction is proposed to proceed via a novel ene-diol rearrangement of the corresponding α-silyloxy aldehydes or α-acyloxy aldehydes intermediates.     

A mild titanium-based system for the reduction of amides to aldehydes

A mild method for the reduction of amides to aldehydes using 1,1,3,3-tetramethyldisiloxane/titanium(IV) isopropoxide reducing system is described. The reaction occurs under mild conditions and allows the reduction of aromatic as well as aliphatic, tertiary amides to the corresponding aldehydes, in good yields. This methodology was extended to the reduction of aromatic secondary and primary amides to the corresponding aldehydes.     

Rhenium complex-catalyzed allylation of aldehydes with allyltributylstannane

It was confirmed that the rhenium complex, ReBr(CO)₅, catalyzed the allylation of aldehydes with allyltributylstannane to give the corresponding homoallylic alcohols in moderate to good yields. Similarly, the reaction of aldehydes with enol silyl ether was efficiently promoted by the rhenium catalyst to afford the corresponding β-hydroxy carbonyl compounds.     

Pentaatomie heteroaromatic cations. Note III . A Convenient Synthesis of Aldehydes from Carboxylic Acids via 2-Substituted 1,3-Benzoxathiolium Perchlorates

A convenient method for the preparation of aldehydes from the corresponding carboxylic acids is presented. By reaction of the carboxylic acids with o-mercaptophenol and perchloric acid in phosphorus oxychloride, the corresponding 2-substituted 1,3-benzoxathiolium perehlorates were obtained. Reduction of the salts with lithium aluminium hydride in dry ether gave 2-substituted 1,3-benzoxathioles, which, when hydrolyzed by mercuric chloride, gave the corresponding aldehydes. Twenty five aldehydes of different structure were obtained in good yields, by a fast and simple procedure.     

Synthesis of 2-aryl(hetaryl)-1-hydroxyimidazoles by the reaction of aliphatic 1,2-hydroxylamino oximes with aromatic and heteroaromatic aldehydes

A reaction of aliphatic 1,2-hydroxylamino oximes bearing the hydroxylamino group at the secondary carbon atom with aromatic and heteroaromatic aldehydes in acetic acid leads to the corresponding 1-hydroxy-2-aryl(hetaryl)-4,5-dialkylimidazoles in high yields. α-Aryl(hetaryl)-nitrones initially formed by the condensation of 1,2-hydroxylamino oximes with aldehydes are quantitatively converted to the corresponding imidazoles.     

Ruthenium(II)-salen complexes-catalyzed olefination of aldehydes with ethyl diazoacetate

Several salen-ruthenium(II) complexes, which are derived from commercial ligands or simply ethylenediamine, can be successfully applied as catalysts for the olefination of a broad variety of aldehydes. Depending on the electron richness of the applied aldehydes, good to very good olefin yields and high E:Z selectivities are reached at 60 or 80 °C reaction temperature with ethyl diazo acetate being the reaction partner. The reaction rate depends on the electron donor capabilities of the aldehydes. Electron poor aldehydes undergo faster reactions than electron rich aldehydes, but both electron rich and bulky aldehydes can be transformed to corresponding olefins in very good yields and high E-selectivity.     

Reaction of Aromatic Aldehydes with Ammonium Acetate

By reaction of aromatic aldehydes with ammonium acetate a series of 1,2-diaryl-1,2-diaminoethanes and their derivatives was obtained. The mechanism of reaction was suggested and its principal stages were proved. Reactions with ammonium acetate of aromatic aldehydes containing ortho-substituents resulted in the corresponding 2,4,5-triaryl-4,5-dihydroimidazoles.     

用碲ylide合成杂环查尔酮,二烯酮和杂环烯类衍生物

最近,我们用碳酸钾作碱从碲盐在含微量甲酰胺的乙腈中,手室温条件下十分简便地合成了2-或2,4-不饱和腈,酮,酯和酰胺。杂环查尔酮和5-硝基呋喃烯类化合物都是具有生理活性的化合物。为扩大碲ylide的应用并研究杂环基团引入对碲ylide反应活性的影     

Preparation and reactivity of phenyltelluroalkylphosphine oxides. Vinylic tellurides

Phenyltelluromethyldiphenylphosphine oxide was prepared by the reaction of methyldiphenylphosphine oxide with base and PhTeBr. The telluromethylphosphine oxide reacts with aldehydes and ketones to give the corresponding vinylic tellurides, with preferential E stereochemistry for aryl aldehydes and Z for alkyl aldehydes.     

Highly efficient copper-catalyzed hydroacylation reaction of aldehydes with azodicarboxylates

The hydroacylation reaction of aldehydes with azodicarboxylates catalyzed by copper(II) acetate monohydrate has been reported. The reaction of various aldehydes gave the corresponding hydroacylation products in 60-98% yields under mild conditions. The method is simple, economical, and has practical advantages for the construction of the carbon-nitrogen bonds.     

Synthesis of the indene, THF, and pyrrolidine skeletons by Lewis acid mediated cycloaddition of methylenecyclopropanes with aldehydes, N-tosyl aldimines, and acetals

Methylenecyclopropanes (MCPs 1) react with aldehydes, N-tosyl aldimines, and acetals to give the corresponding indene, THF, and pyrrolidine cycloaddition products in the presence of BF3 x OEt2 under mild reaction conditions. Some special transformations of MCPs 1 with aldehydes have been reported in this paper. A plausible reaction mechanism has been discussed, which is based on a deuterium-labeling experiment and the Prins-type reaction mechanism.     

N-heterocyclic carbene (NHC)-catalyzed direct amidation of aldehydes with nitroso compounds

NHC-catalyzed direct amidation of aldehydes with nitroso compounds is a powerful method for the synthesis of N-arylhydroxamic acids. A variety of aryl, alkyl, alkenyl, and heterocyclic aldehydes were found to give excellent yields of the corresponding N-arylhydroxamic acids. This chemistry was also extended to the synthesis of chiral N-arylhydroxamic acids by kinetic resolution of alpha-branched aldehydes, a domino amidation-redox amination reaction of acrolein, and a three-component reaction for the synthesis of N-arylaziridines.