Reaction Of Vinyl Halides Research Articles

An organocatalytic method for constructing pyrroles via the cycloisomerisation of Z-1-iodo-4-N-methylbenzenesulfonyl-1,6-enynes.

A new cycloisomerisation of Z-1-iodo-4-N-methylbenzenesulfonyl-1,6-enynes to functionalized pyrroles was realized in the presence of an organomolecule (4,4'-bis(1,1-dimethylethyl)-2,2'-bipyridine) and KOtBu. The transformations were performed efficiently to produce different kinds of functionalized pyrroles within 10 min. This is the first example of an organomolecule promoted methodology with vinyl iodides from a non-aromatic system to an aromatic system, which offers an excellent option toward establishing a new horizon for cross-coupling reactions of vinyl halides. Preliminary mechanistic studies were performed and a crude radical pathway was proposed.

Construction of Substituted Benzenes via Pd-Catalyzed Cross-Coupling/Cyclization Reaction of Vinyl Halides and Terminal Alkynes.

A tandem Sonogashira coupling/cyclization/aromatization sequence of β-halo vinyl sulfones/ketones with terminal alkynes has been developed for the construction of benzene rings. Polysubstituted functionalized benzenes containing a sulfonyl or an acyl group could be obtained in up to 95% yield.

ChemInform Abstract: Synthesis of Alkenyl Sulfides Through the Iron‐Catalyzed Cross‐Coupling Reaction of Vinyl Halides with Thiols.

AbstractThe combination FeCl3/Xantphos efficiently promotes the coupling with vinyl iodides and bromides as well as the vinyl chloride (VI).

ChemInform Abstract: Palladium-Catalyzed Reaction of Vinylic Halides with Allylic Alcohols: A Highly Chemo-, Regio-, and Stereocontrolled Synthesis of Conjugated Dienols.

ChemInform Abstract: Palladium-Catalyzed Reaction of Vinylic Halides with Allylic Alcohols: A Highly Chemo-, Regio-, and Stereocontrolled Synthesis of Conjugated Dienols.

ChemInform Abstract: Coupling Reaction of Vinyl Halides with Ketones or Aldehydes Mediated by Samarium Diiodide.

The Barbier- or Grignard-type reaction of vinyl iodides with ketones or aldehydes proceeds on treatment with samarium diiodide in benzene containing hexamethylphosphoric triamide (HMPA) to afford the corresponding coupling compounds (allyl alcohols). The reaction was shown to involve vinyl samariums as an intermediate.

ChemInform Abstract: First Application of an Efficient and Versatile Ligand for Copper‐Catalyzed Cross‐Coupling Reactions of Vinyl Halides with N‐Heterocycles and Phenols.

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.

Structure of the 1,N2-Ethenodeoxyguanosine Adduct Opposite Cytosine in Duplex DNA: Hoogsteen Base Pairing at pH 5.2

The exocyclic 1,N2-ethenodeoxyguanosine (1,N2-ϵdG) adduct, arising from the reaction of vinyl halides and other vinyl monomers, including chloroacetaldehyde, and lipid peroxidation products with dG, was examined at pH 5.2 in the oligodeoxynucleotide duplex 5′-d(CGCATXGAATCC)-3′·5′-d(GGATTCCATGCG)-3′ (X = 1,N2-ϵdG). Previously, X(anti)·C(anti) pairing was established in this duplex, containing the 5′-TXG-3′ sequence context, at pH 8.6 [ShanmugamG., GoodenoughA. K., KozekovI. D., HarrisT. M., GuengerichF. P., RizzoC. J., and StoneM. P. (2007) Chem. Res. Toxicol.21, 1601−161117941687]. At pH 5.2, the 1,N2-ϵdG adduct decreased the thermal stability of the duplex by ∼13 °C. The 1,N2-ϵdG adduct rotated about the glycosyl bond from the anti to the syn conformation. This resulted in the observation of a strong nuclear Overhauser effect (NOE) between the imidazole proton of 1,N2-ϵdG and the anomeric proton of the attached deoxyribose, accompanied by an NOE to the minor groove A20 H2 proton from the complementary strand. The syn conformation of the glycosyl bond at 1,N2-ϵdG placed the exocyclic etheno moiety into the major groove. This resulted in the observation of NOEs between the etheno protons and the major groove protons of the 5′-neighboring thymine. The 1,N2-ϵdG adduct formed a Hoogsteen pair with the complementary cytosine, characterized by downfield shifts of the amino protons of the cytosine complementary to the exocyclic adduct. The pattern of chemical shift perturbations indicated that the lesion introduced a localized structural perturbation involving the modified base pair and its 3′- and 5′-neighbor base pairs. A second conformational equilibrium was observed, in which both the modified base pair and its 3′-neighboring G·C base pair formed tandem Hoogsteen pairs. The results support the conclusion that at neutral pH, in the 5′-TXG-3′ sequence, the 1,N2-ϵdG adduct exists as a blend of conformations in duplex DNA. These involve the interconversion of the glycosyl torsion angle between the anti and the syn conformations, occurring at an intermediate rate on the NMR time scale.

Selenium catalyzed conversion of vinyl halides into α-alkoxy acetals

The reaction of vinyl halides with phenylselenenyl chloride in alcohols affords α-alkoxy acetals and diphenyl diselenide which can be oxidized to PhSe cations by nitrate or persulfate anions. The reaction can be carried out with catalytic amounts of PhSeCl or PhSeSePh. The reaction proceeds through the formation of the methoxyselenenylation product which then suffers solvolysis. Under controlled conditions, the 1-phenyl-1-methoxy-2-bromo-2-phenylselenenyl ethane was isolated from the reaction of β-bromostyrene and PhSeCl in methanol. Several deselenenylation reactions of this α-halogenoselenide are reported.

Reaction of diazoalkanes with unsaturated compounds. Report 4. Cyclopropanation of vinyl- and allylhalides with diazomethane in the presence of copper (I) chloride and triphenylphosphite

Reaction of vinylhalides (vinylbromide, 1-chloro-1-cyclopropylethylenes) with CH2N2 in the presence of (PhO)3P·CuCl leads to formation of the corresponding halocyclopropanes with 13–15% yields, while reaction of CH8N2 with alkylbromide under the same conditions gives the product of formal methylene introduction, 4-bromobut-1-ene (yield 58%) with insignificant formation (∿1%) of bromomethylcyclopropane.

The reaction of vinyl halides with mercury(II) salts

The reaction of vinyl halides with mercuric salts in water to give the corresponding carbonyl compounds is non-catalytic, and the postulated mechanism includes an oxymercuration-dehalogenation step.