Phosphorus(V)-catalyzed deoxydichlorination reactions of aldehydes

A phosphine oxide-catalyzed conversion of aldehydes into 1,1-dichlorides is reported. The reaction proceeds via a phosphorus(V)-catalysis manifold in which phosphine oxide turnover is achieved using oxalyl chloride as a consumable reagent. The new method is applicable to a range of aldehydes and, in combination with palladium-catalyzed reductive dimerization, gives rise to a new catalytic approach to the synthesis of stilbenes and a short formal synthesis of resveratrol.     

Palladium(0)-catalyzed cascade one-pot synthesis of isoxazolidines

A highly diastereoselective cascade reaction protocol has been developed for the synthesis of isoxazolidine derivatives utilizing aryl halides, O-homoallyl hydroxylamine and palladium(0) in a one-pot reaction.     

Cobalt(II)-catalyzed chemoselective synthesis of acetals from aldehydes

The acetalization of aldehydes has been studied with methanol, ethanol, and 2-propanol using CoCl₂ in high yields under reflux conditions. The reaction is simple, efficient, chemoselective and does not involve any other additive.     

Indium(III)-catalyzed asymmetric hetero-Diels-Alder reaction of Brassard-type diene with aliphatic aldehydes

A highly diastereo- and enantioselective hetero-Diels-Alder (HDA) reaction of a Brassard-type diene with aliphatic aldehydes has been developed. The chiral N,N'-dioxide L2/In(OTf)(3) complex was efficient toward the obtention of the corresponding β-methoxy-γ-methyl α,β-unsaturated δ-lactones in good yields (up to 86%) as well as dr and ee values (up to 97:3 cis/trans and 94% ee). In addition, the product 4a could be easily transformed into the methyl-protected epi-prelactone B by hydrogenation.     

Rhenium(V)-catalyzed synthesis of 2-deoxy-alpha-glycosides

A mild method for the synthesis of 2-deoxysugars from the coupling of glycals with a range of nucleophiles is described. The method employs 1 mol % of an air- and moisture-tolerant rhenium-oxo complex [ReOCl3(SMe2)(Ph3PO)] as a catalyst for the formation of O-, N-, and S-alpha-glycosides. The catalytic system tolerates a number of commonly employed protecting groups, including isopropylidene acetals, alkyl and silyl ethers, acetates, and benzoates. Furthermore, the high-oxidation-state complex selectively catalyzes the coupling with the glycal acceptor in preference to oxidation of the glycals, alcohols, and even thiols.     

Iodine(V) reagents in organic synthesis. Dess-Martin periodinane mediated efficient one-pot oxidation of aldehydes to acyl azides

A mild, efficient and general method for the one-step preparation of acyl azides from aldehydes using Dess-Martin periodinane and sodium azide is described.     

Oxovanadium(V)-catalyzed enantioselective Meerwein-Ponndorf-Verley cyanation of aldehydes using acetone cyanohydrin

Oxovanadium(V)(salen) complex 4 was found to catalyze Meerwein-Ponndorf-Verley cyanation of aliphatic aldehydes with good to high enantioselectivity. This cyanation showed a positive nonlinear effect.     

Novel one-pot synthesis of aryltris(trimethylsilyl)silanes

The simple combination of tris(trimethylsilyl)potassium, ArMgBr, and ArBr provides a novel "one-pot" synthesis of aryl(tristrimethylsilyl)silanes. A mechanistic rationale for this conversion is proposed.     

A one-pot synthesis of bisarylhydrazones by Cu(I)-catalyzed aerobic oxidation

An efficient Cu(I)-catalyzed one-pot synthesis of N-substituted (or NH) bisarylhydrazones is reported. A further cyclization reaction could occur towards the synthesis of benzimidazoles or triazoles with elevated temperature. A plausible alkylation–oxidation–alkylation mechanism is proposed based on experimental results and literature.     

NO2-Fe(III)PcCl@C -catalyzed one-pot synthesis of tetrahydropyridine derivatives

Russian Journal of General Chemistry - A highly efficient, one-pot synthesis of functionalized tetrahydropyridines by multicomponent condensation of ethyl acetoacetate, two equivalents of aromatic...     

Nickel(II)-catalyzed carbon-carbon bond formation reaction of functionalized organozinc reagents with aromatic aldehydes

In the presence of a silylating reagent and catalytic amount of Ni(acac)₂, organozinc halides reacted with aromatic aldehydes to give the corresponding dialkylation products in good to excellent yields under mild conditions.     

An efficient one-pot synthesis of C2-symmetric triazolophanes by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction

A facile and efficient one-pot synthesis of 12-15-membered triazolophanes has been accomplished using CuAAC methodology. The formation of triazolophanes was confirmed by spectral analysis and the products were isolated in good yield. The effect of solvents on this reaction was also studied.     

One pot synthesis of indene through copper(I)-catalyzed three-components coupling and cyclization reaction

A new and efficient synthesis of substituted indene has been achieved via copper(I)-catalyzed domino three-component coupling and cyclization reaction in moderate to good yield.     

A one-pot synthesis of 3-arylglutaric anhydrides by reaction of ketene with aromatic aldehydes and ketones

Aromatic aldehydes and ketones react with ketene under Lewis acid catalysis to produce β-lactones, which in situ react with another molecule of ketene to produce 3-arylglutaric anhydrides. The mechanism, scope, and limitation of this one-pot synthesis of 3-substituted glutaric anhydrides are discussed.     

Cu(II)-catalyzed acylation by thiol esters under neutral conditions: tandem acylation-wittig reaction leading to a one-pot synthesis of butenolides

The first catalytic acylation of alcohols with a thiol ester present in Wittig reagents under neutral conditions catalyzed by the Cu(II) salt through a push-pull mechanism is reported. Furthermore, a new methodology for the one-pot lactonization of acyloins by a copper catalyst is developed. The synthetic utility of this method for the synthesis of natural products is shown.     

Novel one-pot expeditious synthesis of 2,4-disubstituted thiazoles through a three-component reaction under solvent free conditions

An expeditious one pot method has been developed for the synthesis of 2,4-disubstituted thiazoles under solvent free conditions via a multicomponent approach. Substituted thiazoles were synthesized with high yields by the reaction of cyclic ketones, thiosemicarbazide, and phenacyl bromides or 3-(2-bromoacetyl)-2H-chromen-2-ones in a shorter reaction time with high purity via simple purification technique.     

Photoinduced one-pot synthesis of hydroxamic acids from aldehydes through in-situ generated silver nanoclusters

Hydroxamic acids have attracted significant attention due to their widespread use in applied chemistry. In this report, a modified Angeli–Rimini method has been achieved via the visible light-mediated catalytic transformation of a variety of heterocyclic, aromatic and aliphatic aldehydes 1a–j to their corresponding hydroxamic acids 2a–j in 81–93% yield. The unique ability of vitamin K₃ as a photoredox catalyst to expedite the development of completely new reaction mechanisms and to enable the construction of challenging carbon–nitrogen bonds has been investigated. It is shown for the first time that the vitamin K₃ and aldehyde are largely responsible for rapid in situ reduction of Ag⁺ ions to catalytic photoluminescent Ag nanoclusters that possess a bandgap energy of 2.87 eV and are less than 2 nm in size. A mechanism for this reaction has been proposed and is supported by UV–Vis, TEM, ESI/MS, FT-IR, ¹H NMR and ¹³C NMR analyses. The investigated method utilizes readily available reagents and produces the hydroxamic acids in high yields without the formation of side products, making it simple, practical and cost-effective.     

Chiral Palladium(II)-catalyzed asymmetric glyoxylate-Ene reaction: alternative approach to the enantioselective synthesis of alpha-hydroxy esters

An effective chiral palladium catalyst [Pd(CH(3)CN)(2)(S)-Tol-BINAP](SbF(6))(2) (2b) is developed for asymmetric glyoxylate-ene reactions. This palladium dicationic catalyst provides a simple but efficient approach to the asymmetric synthesis of alpha-hydroxy esters in excellent yields with high enantioselectivities at relatively higher reaction temperature (60 degrees C).