Vinyl Aldehydes Research Articles

Lewis Acid-Mediated Friedel-Crafts-Type Formylation of Alkenes with Dichloromethyl Methyl Ether in the Presence of Pyridines.

Various alkenes are formylated with dichloromethyl methyl ether (MOMCl2) by the combined use of SnCl4/2,6-dibromopyridine (B1) or AgOTf/pyridine (B4) via Friedel-Crafts-type reaction. The former reagent combination is mainly applied to α,α-diarylalkenes, while the latter one is applied not only to arylalkenes but also to some alkylalkenes. Vinyl aldehydes are exclusively obtained from alkenes that can possibly afford both allyl and vinyl aldehydes.

SYNTHESIS AND ANTIMICROBIAL EVALUATION OF NOVEL SCHIFF’S BASES DERIVED FROM 2, 6-DICHLORO-4-TRIFLUORO METHYL ANILINE

Schiff bases are the extremely useful class of organic compounds that are widely synthesized by condensation of primary amines with carbonyl compounds. Schiff bases are the appropriate compounds having unrivalled application in organic and inorganic chemistry. Schiff bases and their metal complexes are classified for their broad range of biological importance including antibacterial, antifungal, antiviral, anticancer, anti-HIV and antipyretic properties. Considering the numerous applications of Schiff’s bases in various fields of chemistry, there has been tremendous interest in developing efficient methods for their preparation. In the present investigation, we have designed a modish series of Schiff’s bases via reaction between various substituted aromatic vinyl aldehydes and 2,6- dichloro 4-trifluromethyl aniline in presence of acetic acid. These newly synthesized Schiff’s bases were characterized by spectral analysis and all compounds were screened for their antimicrobial activities.

Cyclization mechanisms of the cyclic dimer of aziridine aldehyde with vinyl aldehyde

Aziridine aldehydes are the notable representative of a limited number of reported amphoteric molecules containing aziridine and aldehyde groups, which can react both as an acid and as a base. In the present work, the intriguing dimerization mechanism of aziridine aldehyde free from any substituents and solvents, as well as the addition and cyclization mechanisms of its dimer with vinyl aldehyde in acetonitrile were investigated systematically. The NH bond of aziridine aldehyde couples with the CO bond in another aziridine aldehyde molecule, and then the OH bond couples to the adjacent CO bond to form a stable polycyclic dimer. In acetonitrile, aziridine aldehyde and CH2CHCHO are inclined to cyclize to polycyclic compounds. The addition reaction of the dimer and CH2CHCHO will form various enol and keto isomers, and the enol isomers cyclizing to 8-exo-trig aldol is energetically favorable.

Alkynylation of aldehydes mediated by zinc and allyl bromide: a practical synthesis of propargylic alcohols

A practical synthesis of propargylic alcohols was developed by alkynylation of aldehydes mediated by zinc and allyl bromide. Aromatic, aliphatic and vinyl aldehydes react with phenylacetylene or 1-hexyne to obtain various propargylic alcohols at room temperature in up to 98% yield. This method is characterized with inexpensive materials, wide substrate scope, and mild reaction conditions, and is also easy to scale up. In addition, this protocol is applicable to the alkynylation of α-ketone esters and epoxides to generate α-tertiary-hydroxy esters and α-alkynyl alcohols, respectively.

An efficient and convenient aldol addition of acyldiazomethane with aldehydes promoted by MgI2 etherate

AbstractThe aldol addition of acyldiazomethane with aromatic aldehydes, vinyl aldehyde and aliphatic aldehydes was carried out efficiently in the presence of MgI

ChemInform Abstract: Enantioselective Alkyne Addition to Aliphatic, Aromatic, and Vinyl Aldehydes Using Zn,iPrI, H8BINOL, and Ti(OiPr)4.

AbstractThe new catalytic system broadens the substrate scope of the title reaction.

Enantioselective Alkyne Addition to Aliphatic, Aromatic, and Vinyl Aldehydes Using Zn, (i)PrI, H8BINOL, and Ti(O(i)Pr)4.

A new catalytic system based on the readily available Zn, (i)PrI, H8BINOL, and Ti(O(i)Pr)4 has been developed which avoids the use of pyrophoric ZnEt2. It can effectively catalyze the reaction of various terminal alkynes with aromatic, aliphatic, and vinyl aldehydes to generate chiral propargylic alcohols at room temperature with up to 98% yield and 98% enantiomeric excess. This new system signifciantly expands the substrate scope of the previously reported system using Zn, EtI, BINOL, and Ti(O(i)Pr)4.

Enantio- and Diastereoselective Synthesis of 1,2-Hydroxyboronates through Cu-Catalyzed Additions of Alkylboronates to Aldehydes.

The first catalytic enantio- and diastereoselective synthesis of 1,2-hydroxyboronates is reported. Reactions are promoted by a readily available chiral monodentate phosphoramidite-copper complex in the presence of an alkyl 1,1-diboron reagent. Products contain two contiguous stereogenic centers and are obtained in up to 91% yield, >98:2 d.r., and 98:2 e.r. The reaction is tolerant of aryl and vinyl aldehydes, and the 1,2-hydroxyboronate products can be transformed into versatile derivatives. Mechanistic experiments indicate control of absolute stereochemistry of the α-boryl component.

A facile synthesis of branched graft copolymers via combination of RAFT self-condensing vinyl polymerization and aldehyde–aminooxy reaction

A facile synthetic route to the branched graft copolymer BPDEM-g-PEO has been developed by combination of the RAFT-SCVP technique and aldehyde–aminooxy reaction.

ChemInform Abstract: One‐Pot Three‐Component Approach to the Synthesis of Polyfunctional Pyrazoles.

A simple, multicomponent, and straightforward reaction of vinyl azide, aldehyde, and tosylhydrazine affords the construction of 3,4,5-trisubstituted 1H-pyrazoles regioselectively in the presence of base with moderate to excellent yields. A range of functionality could be tolerated in this methodology, and a possible mechanism is proposed.

ChemInform Abstract: Chiral Primary‐Amine‐Catalyzed Conjugate Addition to α‐Substituted Vinyl Ketones/Aldehydes: Divergent Stereocontrol Modes on Enamine Protonation.

AbstractThe reactions of α‐substituted vinyl aldehydes are a summary of previous results and are not shown.

An efficient direct-aldol addition of methyl ketones with aldehydes promoted by MgI2 etherate

Direct aldol addition of ketones with aromatic aldehydes and vinyl aldehyde was carried out efficiently in the presence of MgI2 etherate and Et3N using untreated reagent grade CH2Cl2 under atmospheric conditions in a mild, efficient and highly chemoselective manner. Iodide counterion and non-coordinating reaction media (i.e., CH2Cl2) are among the critical factors for the unique reactivity of this reaction system.

ChemInform Abstract: Rearrangement of Pyran Derivatives Obtained from Vinyl Malononitriles and Aldehydes via Vinylogous Aldol Reaction: A Novel Facile Method for the Synthesis of Dienamides.

AbstractThe simple one‐pot procedure proceeds via vinylogous aldol reaction of vinyl malononitriles with aldehydes followed by electrocyclic cleavage of the resulting pyran intermediates.

Selective arylation of aldehydes with di-rhodium(II)/NHC catalysts

Here is described the preparation of four new rhodium(II) complexes bearing axial NHC ligands. The presence of electron-withdrawing bridging ligands resulted in an enhanced reactivity in the arylation of aldehydes with boronic acids when compared with the tetraacetate counterparts. Complex 15 (Rh2tfa4(IPr)2) proved to be the most active catalyst for this transformation allowing the selective conversion of aromatic, aliphatic and vinyl aldehydes into the respective alcohols in excellent yields. It was demonstrated that the good group tolerance could be further extended to aromatic and conjugated ketones. DFT calculations carried out on this system showed the complementarily of the bridging ligands and axial ligand in these dinuclear complexes. It was also disclosed that Rh(II)/NHC catalytic system can promote the racemization of 1-phenyl ethanol.

Rearrangement of Pyran Derivatives Obtained from Vinyl Malononitriles and Aldehydes via Vinylogous Aldol Reaction: A Novel Facile Method for the Synthesis of Dienamides

A novel one-pot approach to a variety dienamides from vinyl malononitriles and aldehydes via vinylogous aldol reaction was achieved by the electrolytic ring opening of the initially formed pyran derivatives under mild basic catalysis with good diastereoselectivity.

Synthesis and biological evaluation of β-chloro vinyl chalcones as inhibitors of TNF-α and IL-6 with antimicrobial activity

A series of β-chloro vinyl chalcones have been synthesized by Claisen–Schmidt condensation. β-chloro vinyl aldehyde has been synthesized by the Vilsmayer–Hack formylation reaction. The structures of the newly synthesized compounds were confirmed by 1H NMR, IR and Mass spectral analysis. All the compounds were evaluated for their anti-inflammatory activity (against TNF-α and IL-6) and antimicrobial (antibacterial and antifungal) activity. Compounds 5a, 5d, 5e, 5g and 5i exhibited promising activity against IL-6 with 58–83% inhibition at 10 μM concentration. None of the compound was found to be cytotoxic in CCK-8 cells at 10 μM concentration. Whereas compounds 5b, 5d, 5e and 5i showed very good antibacterial activity and compounds 5a, 5b, 5e and 5i showed good antifungal activity.

ChemInform Abstract: Synthesis of New β‐Hydroxy Amide Ligands and Their Ti(IV) Complex‐Catalyzed Enantioselective Alkynylation of Aliphatic and Vinyl Aldehydes.

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Synthesis of new β-hydroxy amide ligands and their Ti(IV) complex-catalyzed enantioselective alkynylation of aliphatic and vinyl aldehydes

Three new chiral β-hydroxy amide ligands were synthesized via the reaction of benzyl chloride and amino alcohols derived from l-tyrosine. The titanium(IV) complex of chiral ligand 8b was found to be an effective catalyst for the asymmetric alkynylation of aliphatic, vinyl and aromatic aldehydes. The propargyl alcohols were obtained in highly enantiomeric excesses (up to 96% ee) under optimized conditions.

Rapid and efficient entry to vinyl silanes from aldehydes employing a novel metalation–Peterson sequence

Bis(trimethylsilyl)chloromethane undergoes a rapid and selective metalation with s-BuLi, yielding the nucleophilic bis(trimethylsilyl)methyl anion and providing a straightforward general entry to vinyl silanes from aromatic, aliphatic and vinyl aldehydes.

Chiral Macrocycle‐Catalyzed Highly Enantioselective Phenylacetylene Addition to Aliphatic and Vinyl Aldehydes.

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