Reaction Of Enamines Research Articles

Sunlight-driven synthesis of γ-diketones via oxidative coupling of enamines with silyl enol ethers catalyzed by [Ru(bpy)3]2+

A photosensitizer [Ru(bpy)(3)](2+) catalyzes oxidative coupling reaction of enamines with silyl enol ethers under visible light irradiation by a Xe lamp or sunlight to produce γ-diketones. A 2e-oxidation process involved in this reaction is achieved by a combination of the photoexcited [Ru(bpy)(3)](2+) species and duroquinone, a 2e-acceptor.

Enamines in Heterocyclic Synthesis: A Novel Simple and Efficient Route to Condensed Pyridazines

An efficient and easy preparation of enamine derivatives, via active methyl and methylene compounds by in situ-generated 1-(diethoxymethyl)piperidine, produced from the mixture of triethyl orthoformate/piperidine/DMF, are described. Some new pyridazinone derivatives have been synthesized from the reaction of enamines with hydrazine hydrate and cyanoacid hydrazide.

ChemInform Abstract: Synthesis of γ‐Amino Alcohols from Aldehydes, Enamines, and Trichlorosilane Using Lewis Base Catalysts.

The reaction of aldehydes, enamines, and trichlorosilane in the presence of a Lewis base catalyst, particularly N-methylpyrrolidinone and DMF, affords γ-amino alcohols with a high diastereoselectivity. The method consists of C–C bond formation between an aldehyde and an enamine, and a subsequent intramolecular reduction of the resulting iminium ion intermediate. In most cases, one diastereomer is exclusively generated, and we propose a transition state model for the intramolecular reduction of the iminium ion intermediate. Enamines, prepared beforehand from the corresponding ketone and amine, can be used in the reaction without purification. Furthermore, enantioselective catalysis using a chiral Lewis base catalyst is possible, although the enantioselectivity is modest. The current tandem method offers the first, concise synthetic method of γ-amino alcohols from aldehydes and enamines.

ChemInform Abstract: Reaction of Heterocyclic Enamines with Nitrile Oxide and Nitrilimine Precursors.

AbstractA range of novel heterocyclic compounds is prepared from alkylidenepyrrolidines and 1,3‐dipoles such as nitrile oxides, nitrilimines or their precursors.

Synthesis and Characterization of Poly(ε‐caprolactone‐co‐δ‐ valerolactone) with Pendant Carboxylic Functional Groups

AbstractIn this paper, aliphatic polyesters functionalized with pendant carboxylic groups were synthesized via several steps. Firstly, substituted cyclic ketone, 2‐(benzyloxycarbonyl methyl)cyclopentanone (BCP) was prepared through the reaction of enamine with benzyl‐2‐bromoacetate, and subsequently converted into the relevant functionalized δ‐valerolactone derivative, 5‐(benzyloxy carbonylmethyl)‐δ‐valerolactone (BVL) by the Baeyer‐Villiger oxidation. Secondly, the ring‐opening polymerization of BVL with ε‐caprolactone was carried out in bulk using stannous octoate as the catalyst to produce poly(ε‐caprolactone‐co‐δ‐valerolactone) bearing the benzyl‐protected carboxyl functional groups [P(CL‐co‐BVL)]. Finally, the benzyl‐protecting groups of P(CL‐co‐BVL) were effectively removed by H2 using Pd/C as the catalyst to obtain poly(ε‐caprolactone‐co‐δ‐valerolactone) bearing pendant carboxylic acids [P(CL‐co‐CVL)]. The structure and the properties of the polymer have been studied by Nuclear Magnetic Resonance (NMR), Fourier Infrared Spectroscopy (FT‐IR) and Differential Scan Calorimetry (DSC) etc. The NMR and FT‐IR results confirmed the polymer structure, and the 13C NMR spectra have clearly interpreted the sequence of ε‐caprolactone and 5‐(benzyloxycarbonylmethyl)‐δ‐valerolactone in the copolymer. When the benzyl‐protecting groups were removed, the aliphatic polyesters bearing carboxylic groups were obtained. Moreover, the hydrophilicity of the polymer was improved. Thus, poly(ε‐caprolactone‐co‐δ‐valerolactone) might have great potential in biomedical fields.

Synthesis of γ-amino alcohols from aldehydes, enamines, and trichlorosilane using Lewis base catalysts

The reaction of aldehydes, enamines, and trichlorosilane in the presence of a Lewis base catalyst, particularly N-methylpyrrolidinone and DMF, affords γ-amino alcohols with a high diastereoselectivity. The method consists of C–C bond formation between an aldehyde and an enamine, and a subsequent intramolecular reduction of the resulting iminium ion intermediate. In most cases, one diastereomer is exclusively generated, and we propose a transition state model for the intramolecular reduction of the iminium ion intermediate. Enamines, prepared beforehand from the corresponding ketone and amine, can be used in the reaction without purification. Furthermore, enantioselective catalysis using a chiral Lewis base catalyst is possible, although the enantioselectivity is modest. The current tandem method offers the first, concise synthetic method of γ-amino alcohols from aldehydes and enamines.

ChemInform Abstract: A One‐Pot Biginelli Synthesis of 6‐Unsubstituted 5‐Aroylpyrimidin‐2(1H)‐ones and 6‐Acetyl‐1,2,4‐triazin‐3(2H)‐ones.

AbstractThe three‐component reaction of enamines (I) or azaenamine (V) with aldehydes (II) and urea (III) lead to the desired pyrimidine (IV) or triazine (VI) derivatives, respectively.

ChemInform Abstract: Phosphorylation of Nitrogen-Bearing Unsaturated and Aromatic Compounds.

Abstract The enamine reaction provides a valuable method for the selective alkylation and acylation of aldehydes and keto-nes. Similar procedure of phosphorylation is not practically studied. Using 1,3,3-trimethyl-2-methyleneindoline (Fischer's base) as the model enamine we investigated conditions of phosphorylation as well as stereochemistry, and reactions of obtained products of type 1. It was found that properties of some compounds were similar to those of amides of phosphorus acids (vinilologie).

ChemInform Abstract: A Versatile Approach to 2‐Substituted 3‐Trifluoromethyl‐1,3‐diols Based on the Reaction of Trifluoroacetaldehyde Ethyl Hemiacetal with Enamines Derived from Aldehydes.

AbstractThe reaction of enamine (I) with ethyl hemiacetal (II) followed by acid hydrolysis and subsequent reduction of the intermediate aldehyde gives rise to the diastereomeric mixture of diols (III) and (IV).

ChemInform Abstract: N‐Trimethylsilyloxyenamines as New Aldehyde Enolate Synthons: General, Efficient and Diastereoselective Aldol Reaction with Ketals and Acetals.

AbstractThe aldol reaction of enamines (IV) and (IX) with ketals or acetals leads to aldonitrones (VI) and (X), resp., in moderate to high yields.

Reactions of imines with 2,2-difluoro-2-fluorosulfonylacetyl fluoride

Selected N-alkyl ketoimines having at least one methyl group at the imino carbon were reacted in a Stork enamine reaction with 2,2-difluoro-2-fluorosulfonylacetyl fluoride to yield enaminones carrying one fluorosulfonyldifluoromethylene function. In the case of N-tertbutyl methyl aldimine two of these groups were present in a triketone derivative. Taking a ethylene bis(imine) also a ring closure reaction was observed, proven by X-ray structure analysis.

A One‐Pot Biginelli Synthesis of 6‐Unsubstituted 5‐Aroylpyrimidin‐2(1H)‐ones and 6‐Acetyl‐1,2,4‐triazin‐3(2H)‐ones

AbstractThe three‐component Biginelli‐like cyclocondensation reaction of enamines 1, urea, and aldehydes in dioxane/acetic acid efficiently afforded the corresponding 6‐unsubstituted 3,4‐dihydropyrimidin‐2(1H)‐ones 2 in good yields (Scheme 1, Table). The corresponding reaction of azaenamine (=hydrazone) 7 with benzaldehyde and urea afforded 6‐acetyl‐1,2,4‐triazin‐3(2H)‐ones in good yields (Scheme 3).

ChemInform Abstract: Reaction of Enamines with Trifluoromethyl Containing Carbonyl Reagents.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reaction of enamines with trifluoromethyl containing carbonyl reagents

The reaction of linear push–pull enamines bearing a methyl group at the α-position with a set of trifluoromethylated carbonyl compounds was investigated. It has been found that the reaction proceeds at the methyl group of the enamines. The first computational study of the reaction between push–pull enamines and strong electrophilic reagents was reported. Out of three pathways considered DFT and MP2 calculations support ene-mechanism previously suggested based on experimental results only.

Paternò-Büchi Reactions of Silyl Enol Ethers and Enamides

3-(Silyloxy)oxetanes are obtained by irradiating mixtures of aromatic aldehydes and silyl enol ethers in benzene as the solvent. The reactions occur with high simple diastereosciectivity and, when R' is chiral, with high facial diastereoselectivity. Under similar conditions, but in acetonitrile rather than benzene as the preferred solvent, the Paternoo-Buchi reaction of N-acyl enamines (enamides) gives the corresponding protected 3-aminooxetanes. The cis-products are obtained with significant simple diastereoselectivity.

Synthesis, structure and thermal decomposition of cycloalkanone enamine peroxides

Reactions of cycloalkanone enamines with H 2 O 2 gave bis(1-morpholinocyclopent-1-yl)- and bis(1-morpholinocyclohex-1-yl)-peroxides, which were studied by NMR spectroscopy and X-ray diffraction. Thermolysis of bis(1-morpholinocyclohex-1-yl)-peroxide in n -hexane resulted in two major products, viz. , cyclohexanone and morpholine.

ChemInform Abstract: A New Approach to 3‐Substituted Indoles Through Palladium‐Catalyzed C—H Activation Followed by Intramolecular Amination Reaction of Enamines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reactions of Conjugate Phosphinyl- and Phosphonyl-Nitroso Alkenes with Enamines. Preparation of N-Hydroxypyrrole Derivatives

The synthesis of highly functionalized N-hydroxypyrrole derivatives by the formal [3+2] cycloaddition reaction of enamines and nitroso alkenes derived from phosphine oxides and phosphonates is reported. Intermediate phosphorylated nitrones, whose formation can be explained by a conjugate addition of enamines to phosphorylated nitroso alkenes and formation of the five-membered heterocycles, are isolated.

A New Approach to 3-Substituted Indoles through Palladium-Catalyzed C-H Activation Followed by Intramolecular Amination Reaction of Enamines

Palladium-catalyzed C-H activation followed by intramolecularamination reaction of enamine compounds was achieved using a Pd(OAc) 2 (10mol%)/Cu(OAc) 2 (100 mol%)catalyst system in DMSO. This work introduces an entirely new approachto 3-substituted indoles.

ChemInform Abstract: Base‐Promoted Reaction of Dichlorocarbene Adducts or Cyclic Enamines: A New Route to Annulated Pyrroles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.