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A direct α‐alkenylation of nitrile compounds was realized with a palladium complex. This method exhibited excellent tolerance toward a variety of α‐aryl alkyl nitriles and vinyl bromides, leading to the formation of a series of α‐quaternary nitriles containing vinyl groups. Further manipulations of the obtained products were demonstrated, highlighting the potential synthetic utility of this method. [ABSTRACT FROM AUTHOR]

The Pd‐catalyzed vinylation reactions of aryl iodides using 1,2‐dibromoethane is developed for the synthesis of styrenes and stilbenes. In these reactions, vinyl bromide is generated from 1,2‐dibromoethane and then undergoes reductive cross‐coupling with aryl iodides, affording styrene products. Under slightly modified reaction conditions, styrenes can continue reacting with vinyl bromide to form E‐stilbenes, which provides a one‐pot synthetic method for stilbenes. Alcohols, including iso‐propanol and methanol, are employed as the reductant in these reductive cross‐coupling reactions. [ABSTRACT FROM AUTHOR]

This review summarizes the applications of vinyl sulfonate and vinyl acetate as green alternatives for vinyl bromide in cross-coupling reactions. In the first part, the preparation of vinyl sulfonates and their cross-coupling reactions are briefly discussed. Then, a brief review of vinyl acetate cross-coupling reactions, including cyclization reactions, the Fujiware–Moritani reaction, and transvinylation reactions are described. [ABSTRACT FROM AUTHOR]

The enantioselective reductive coupling of oxabenzonorbornadiene with vinyl bromide is developed with earth‐abundant nickel catalyst with copper as Lewis acid co‐catalyst. The asymmetric reductive coupling is applicable with a wide range of azabenzonorbornadienes and vinyl bromides under nickel/copper co‐catalytic system, affording the cis ring‐opening vinylation products in good yields with high optical purities. The present study has enabled straightforward stereoselective preparation of chiral 2‐vinyl‐tetrahydronaphthalens from vinyl halides. [ABSTRACT FROM AUTHOR]

The radical bromoallylation of alkynes, allenes, and vinylidene cyclopropanes proceeds efficiently in the presence of a radical initiator to give 2-bromo-substituted 1,4-, 1,5-, and 1,6-diene derivatives, respectively. Three-component reactions comprised of allenes, electron-deficient alkenes, and allyl bromides give 1,7-dienes in good yields. The bromoallylation of an arylalkene can override β-scission of the bromine radical from β-bromoalkyl radicals to give 5-bromoalkenes, whilst the bromoallylation of vinylcyclopropanes is accompanied by 5- exo ring closure to give 1-(bromomethyl)-2-vinylcyclopentane derivatives in good yields. All of the products contain a reactive vinyl bromide moiety, which can be readily functionalized by Pd-catalyzed cross-coupling and radical cascade reactions. 1 Introduction 2 Synthesis of 1,4-Dienes by Bromoallylation of Acetylenes 3 Synthesis of 1,5-Dienes by Bromoallylation of Allenes 4 Synthesis of 1,6-Dienes by Bromoallylation of Methylenecyclopropanes 5 Synthesis of 1,7-Dienes by Bromoallylation of Allenes and Electron-Deficient Alkenes 6 Bromoallylation of Arylalkenes and Vinylcyclopropanes 7 Conclusion [ABSTRACT FROM AUTHOR]

Herein, an efficient strategy to synthesize 2‐unsubstituted terminal 1, 3‐enynes in high yields by bimetallic Pd/Cu‐catalyzed Sonogashira coupling‐elimination reaction of iodobenzenes with 4‐bromobut‐1‐yne was reported. To our knowledge, this is the first report of 4‐bromobut‐1‐yne as an efficient 1, 3‐enynes reagent, and the method is more convenient and cost‐effective than other reported synthetic methods, which are hindered by the laborious preparation of starting materials, the high cost of bromoethene, and the inconvenient handling of gas acetylene. [ABSTRACT FROM AUTHOR]

A Grubbs II catalyst mediated ring-closing metathesis (RCM) of monobrominated dienes is reported to proceed in moderate to good yields (40–80%) where the linking chain contains five atoms, leading to carbocyclic and heterocyclic seven-membered bromoolefins. Notably, RCM to form five-, six-, or eight-membered bromoolefins was unsuccessful, with the exception of one example where RCM afforded diethyl 3-bromocyclohex-3-ene-1,1-dicarboxylate. In this case, a bromomethyl-substituted cyclohexene was obtained as a byproduct. The utility of selected bromoolefin RCM products was demonstrated through their participation in Suzuki–Miyaura reactions. Vinylic halide exchange (Br → Cl) was noted as a side reaction under RCM conditions. [ABSTRACT FROM AUTHOR]

Annulation reactions of pyridine-2-sulfenyl bromide with vinyl and allyl ethers proceeded regioselectively, but with opposite regiochemistry. Reactions with vinyl ethers led to 3-organyloxy-2,3-dihydro[1,3]thiazolo[3,2-a]pyridin-4-ium bromides (91–99% yields), while allyl ethers gave 2-substituted derivatives of 2,3-dihydro[1,3]thiazolo[3,2-a]pyridin-4-ium (90–98% yields). Tricyclic condensed compounds were synthesized by reactions of pyridine-2-sulfenyl bromide with cyclic ethers (2,3-dihydrofuran, 3,4-dihydro-2H-pyran and 2,5-dihydrofuran). [ABSTRACT FROM AUTHOR]

Thiazole or 1,3-thiazole is a distinct heterocyclic compound which incorporates sulphur and nitrogen atoms. It is a vital framework present in numerous pharmacologically active compounds, be it of natural origin or of synthetic nature. Many thiazoles having antitumor and antiviral activities, originate from microbes and marine organisms. A variety of synthetic drugs, having thiazole group, like antimicrobial sulfathiazole, antibiotic penicillin, antidepressant pramipexole, antineoplastic agent bleomycin, antiretroviral drug ritonavir, histamine H2 receptor antagonist nizatidine, anti-inflammatory drug meloxicam, antifungal stilbene derivatives have been in the markets for quite some time. Hofmann and Hantzsch laid the groundwork for further development in the field of thiazole chemistry. The interaction of α-haloketones or α-halogenaldehyde and thioamide to obtain thiazoles is beautifully described by Hantzsch. Various studies have reported methods for the synthesis of the thiazoles; thioforamide, thiourea, α-thiocyanotoketones, and vinyl bromide have been extensively employed to synthesize thiazoles. The thiazoles have immense potential and this study tries to enlighten the crucial role of thiazoles for the betterment of society. The review provides different directions in the synthesis of novel thiazoles and also reveals diverse targets for augmentation in the field of designing of novel thiazoles. [ABSTRACT FROM AUTHOR]

A nickel-catalyzed cross-electrophile coupling is disclosed in which a range of vinyl bromides were utilized as electrophiles with oxalates derived from α-hydroxy carbonyls as precursors to carbonyl radical coupling partners. This method is compatible with a broad range of functional groups, providing a complementary solution for the construction of β,γ-unsaturated carbonyl compounds. [ABSTRACT FROM AUTHOR]

Even at low concentrations, poly-aromatic hydrocarbons found in soot have substantial health implications. Soot deposits have been reported and studied using FTIR and Raman spectroscopy. Using a CO2 photolysis laser, the samples were obtained via infrared multiphoton dissociation (IRMPD) of vinyl bromide (VBr, C2H3Br) molecules. The solid deposit formed in the IRMPD of VBr when a relatively high fluence of the order of 204 J.cm−2 was analyzed by FTIR, and it was discovered that the majority of its composition is aromatic and aliphatic hydrocarbons. Significant fullerene-type carbonaceous soot particles are also found, which could correspond to C60 and C70 or other carbonaceous agglomerates of a higher order; however, the disappearance of this fullerene on Raman spectra cast doubt on this explanation. Our samples' Raman spectroscopy has been compared to Tamor and Vassell's research, which may indicate that they have a lesser degree of hardness and density than these authors' results, indicating a larger hydrogen content in our samples. The optical gap has been calculated, yielding a very limited range of values ranging only between 1.0 and 1.2 eV, resulting in a crystalline size of 0.58 to 1.12 nm. [ABSTRACT FROM AUTHOR]

The 4‐exo‐dig cyclocarbopalladation of vinyl bromides substituted with a triple or double bond resulted in impressive cascade reactions leading to different compounds under Suzuki cross‐coupling conditions upon a slight modification of the starting material. When the starting compound carries a triple bond, a single cascade occurs providing a structure containing an allene, a tetrasubstituted cyclopropane, and a cyclobutene with complete stereoselectivity. When the related starting material possessing a double bond is reacted under the same conditions in the presence of various vinyl boronic esters or acids, an efficient 8π‐electrocyclization provides tricyclic systems comprised of a cyclobutene unit, as well as a cyclooctatriene. Five carbons of the latter can be selectively decorated with different substituents depending on the choice of the starting material and the boronic coupling partner. [ABSTRACT FROM AUTHOR]

An O2‐assisted, four‐component reaction has been developed to synthesize a wide range of syn‐1,3‐amino alcohols in one step. The reaction proceeds by oxygenation of vinyl magnesium bromide (component‐I) with O2 (component‐II) to give a magnesium enolate of acetaldehyde, which undergoes addition to a chiral N‐tert‐butanesulfinyl imine (component‐III) followed by a sequential addition with excess vinyl magnesium bromide (component‐IV). The approach allows diastereoselective synthesis of anti/syn‐ and syn/syn‐3‐amino‐1,5‐diols in good yields with high diastereoselectivity. The method was illustrated in an efficient, four‐step synthesis of piperidine alkaloid (−)‐2′‐epi‐ethylnorlobelol. [ABSTRACT FROM AUTHOR]

An O2‐assisted, four‐component reaction has been developed to synthesize a wide range of syn‐1,3‐amino alcohols in one step. The reaction proceeds by oxygenation of vinyl magnesium bromide (component‐I) with O2 (component‐II) to give a magnesium enolate of acetaldehyde, which undergoes addition to a chiral N‐tert‐butanesulfinyl imine (component‐III) followed by a sequential addition with excess vinyl magnesium bromide (component‐IV). The approach allows diastereoselective synthesis of anti/syn‐ and syn/syn‐3‐amino‐1,5‐diols in good yields with high diastereoselectivity. The method was illustrated in an efficient, four‐step synthesis of piperidine alkaloid (−)‐2′‐epi‐ethylnorlobelol. [ABSTRACT FROM AUTHOR]

2,3-Dibromo-2-methylpropanamides with different substituents on the nitrogen atom were synthe-sized, and their transformations by the action of potassium tert-butoxide in THF were studied. 2,3-Dibromo-N-(4-methoxyphenyl)-2-methylpropanamide and 2,3-dibromo-N-(2,5-dibromo-4-methoxyphenyl)-2-methyl-propan-amide reacted with 1–2 equiv of t-BuOK to give the corresponding N-substituted 3-bromo-3-methyl- and 3-methylideneazetidin-2-ones with acceptable yields and selectivity. Increase of the amount of t-BuOK to 3–5 equiv led to significant reduction of the yield of vinyl bromides and 3-methylideneazetidin-2-ones. On the other hand, the reaction of 2,3-dibromo-N-(tert-butyl)-2-methylpropanamide with t-BuOK afforded 3-(tert-bu-toxymethyl)-1-tert-butylazetidin-2-one with a good yield and selectivity. [ABSTRACT FROM AUTHOR]

Aliphatic bromide was used as a halogenation reagent in the presence of DMSO, resulting in 2,2-diarylvinyl bromides from the corresponding 1,1-diarylethylenes. This protocol not only provides a convenient and straightforward strategy for the rapid construction of various 2,2-diarylvinyl bromides without bromine and extra oxidants, but also can improve the atom economy of Kornblum oxidative reaction. [ABSTRACT FROM AUTHOR]

An enantioselective synthetic approach for preparing manginoids and guignardones, two types of biogenetically related meroterpenoids, is reported. This bioinspired and divergent synthesis employs an oxidative 1,3‐dicarbonyl radical‐initiated cyclization and cyclodehydration of the common precursor to forge the central ring of the manginoids and guignardones, respectively, at a late stage. Key synthetic steps include silica‐gel‐promoted semipinacol rearrangement to form the 6‐oxabicyclo[3.2.1]octane skeleton and the Suzuki–Miyaura reaction of vinyl bromide to achieve fragment coupling. This synthesis protocol enables the asymmetric syntheses of four fungal meroterpenoids from commercially available materials. [ABSTRACT FROM AUTHOR]

An enantioselective synthetic approach for preparing manginoids and guignardones, two types of biogenetically related meroterpenoids, is reported. This bioinspired and divergent synthesis employs an oxidative 1,3‐dicarbonyl radical‐initiated cyclization and cyclodehydration of the common precursor to forge the central ring of the manginoids and guignardones, respectively, at a late stage. Key synthetic steps include silica‐gel‐promoted semipinacol rearrangement to form the 6‐oxabicyclo[3.2.1]octane skeleton and the Suzuki–Miyaura reaction of vinyl bromide to achieve fragment coupling. This synthesis protocol enables the asymmetric syntheses of four fungal meroterpenoids from commercially available materials. [ABSTRACT FROM AUTHOR]

Attosecond extreme ultraviolet (XUV) and soft x-ray sources provide powerful new tools for studying ultrafast molecular dynamics with atomic, state, and charge specificity. In this report, we employ attosecond transient absorption spectroscopy (ATAS) to follow strong-field-initiated dynamics in vinyl bromide. Probing the Br M edge allows one to assess the competing processes in neutral and ionized molecular species. Using ab initio non-adiabatic molecular dynamics, we simulate the neutral and cationic dynamics resulting from the interaction of the molecule with the strong field. Based on the dynamics results, the corresponding time-dependent XUV transient absorption spectra are calculated by applying high-level multi-reference methods. The state-resolved analysis obtained through the simulated dynamics and related spectral contributions enables a detailed and quantitative comparison with the experimental data. The main outcome of the interaction with the strong field is unambiguously the population of the first three cationic states, D1, D2, and D3. The first two show exclusively vibrational dynamics while the D3 state is characterized by an ultrafast dissociation of the molecule via C–Br bond rupture within 100 fs in 50% of the analyzed trajectories. The combination of the three simulated ionic transient absorption spectra is in excellent agreement with the experimental results. This work establishes ATAS in combination with high-level multi-reference simulations as a spectroscopic technique capable of resolving coupled non-adiabatic electronic-nuclear dynamics in photoexcited molecules with sub-femtosecond resolution. [ABSTRACT FROM AUTHOR]

Strong-field induced ionization and dissociation dynamics of vinyl bromide, CH2=CHBr, are probed using femtosecond extreme ultraviolet (XUV) transient absorption spectroscopy. Strong-field ionization is initiated with an intense femtosecond, near infrared (NIR, 775 nm) laser field. Femtosecond XUV pulses covering the photon energy range of 50-72 eV probe the subsequent dynamics by measuring the time-dependent spectroscopic features associated with transitions of the Br (3d) inner-shell electrons to vacancies in molecular and atomic valence orbitals. Spectral signatures are observed for the depletion of neutral C2H3Br, the formation of C2H3Br+ ions in their ground (X ) and first excited (à ) states, the production of C2H3Br++ ions, and the appearance of neutral Br (2P3/2) atoms by dissociative ionization. The formation of free Br (2P3/2) atoms occurs on a timescale of 330 ±150 fs. The ionic à state exhibits a time-dependent XUV absorption energy shift of ∼0.4 eV within the time window of the atomic Br formation. The yield of Br atoms correlates with the yield of parent ions in the à state as a function of NIR peak intensity. The observations suggest that a fraction of vibrationally excited C2H3Br+ (à ) ions undergoes intramolecular vibrational energy redistribution followed by the C-Br bond dissociation. The C2H3Br+ (X) products and the majority of the C2H3Br++ ions are relatively stable due to a deeper potential well and a high dissociation barrier, respectively. The results offer powerful new insights about orbital-specific electronic processes in high field ionization, coupled vibrational relaxation and dissociation dynamics, and the correlation of valence hole-state location and dissociation in polyatomic molecules, all probed simultaneously by ultrafast table-top XUV spectroscopy. [ABSTRACT FROM AUTHOR]

The transition-metal-catalyzed carboxylation of aryl and vinyl chlorides with CO2 is rarely studied, and has been achieved only with a Ni catalyst or combination of palladium and photoredox. In this work, the cobalt-catalyzed carboxylation of aryl and vinyl chlorides and bromides with CO2 has been developed. These transformations proceed under mild conditions and exhibit a broad substrate scope, affording the corresponding carboxylic acids in good to high yields. [ABSTRACT FROM AUTHOR]

A mild and useful nickel‐catalyzed electrochemical phosphonylation of aryl and vinyl bromides is described. We show that alkyl H‐phenylphosphinates can be coupled electrochemically with functionalized aryl and vinyl bromides using very simple conditions (Fe/Ni anode, bench‐stable nickel pre‐catalyst, undivided cell, galvanostatic electrolysis) to furnish the corresponding aryl and vinyl phosphinates in satisfactory to good yields. Couplings can also be applied to heteroaromatic bromides with some limitations like increased propensity to hydro‐dehalogenation. [ABSTRACT FROM AUTHOR]

The synthesis of vinyl sulfones via silver-promoted cross-coupling of vinyl bromides with sulfonyl hydrazides was realized. Water was used as the sole solvent. Multisubstituted vinyl sulfones were easily prepared with excellent alkyl group tolerance. A mechanism involving nucleophilic attack of a sulfinate anion was proposed. [ABSTRACT FROM AUTHOR]

3‐(Hetero)aryl propenals or propenones are efficiently prepared by a Heck reaction of (hetero)aryl bromides and acrolein or vinyl ketones using Beller's CataCXium® Ptb ligand under Jeffery's and Fu's conditions. The formation of these three‐carbon building blocks is embedded into consecutive three‐ and pseudo‐four‐component syntheses of 3‐(hetero)aryl and 3,5‐diarylpyrazoles with a broad substitution pattern in moderate to excellent yield. [ABSTRACT FROM AUTHOR]

A novel fluorinated reagent for the synthesis of gem‐difluorostyrenes and their heterocyclic analogues – 2,2‐difluorovinyl pinacolborane (CF2=CHBPin) was developed. In particular, borylation of 1,1‐difluoroethylene with isopropoxy pinacolborane afforded the title compound on a multigram scale as stable, easy‐to‐handle liquid which can be stored at +4 °C for months. The Pd(dppf)Cl2‐catalyzed cross‐coupling of this reagent with (het)aryl and vinyl bromides works well with broad spectrum of substrates and is characterized by good yields, functional group tolerance, sufficient reproducibility, as well as scalability. [ABSTRACT FROM AUTHOR]

The synthesis of a C1–C14 fragment of the macrolide antibiotic gulmirecin B through formation of the C7–C8 bond by addition of a vinyllithium intermediate to a C1–C7 aldehyde was investigated. This crucial coupling was successful with a vinyllithium reagent corresponding to a C8–C12 fragment. The C8–C12 vinyl bromide was prepared from l -malic acid. The C1–C7 aldehyde building block was synthesized from hex-5-enoic acid by using an Evans alkylation, a cross-metathesis, and an asymmetric dihydroxylation as key steps. [ABSTRACT FROM AUTHOR]

Hexabromocyclododecanes (HBCDs) have been frequently detected in environment. The isomerization between HBCDs and thermodynamic properties of unimolecular and bimolecular decomposition reactions of (−)-α-HBCD and (−)-γ-HBCD have been investigated using the quantum chemical method. The results show that isomerization via 1,2-shift of Br atoms occurs between the (−)-α/(−)-γ, (+)-α/(+)-γ, and (+)-β/(−)-β counterparts of HBCDs. Self-decomposition of HBCDs to pentabromocyclododecenes and HBr progresses slowly at low temperature but becomes competitive with the isomerization reactions at high temperature. The generated products are also toxic pollutants to the aquatic organisms. The reaction of two commonly detected HBCDs, (−)-γ-HBCD and (−)-α-HBCD, with OH radical and H atom have been studied. (−)-γ-HBCD has bigger rate constants in the reaction with OH radical and H atom than (−)-α-HBCD all over studied temperature. After a series of unimolecular or bimolecular reactions, the formed pentabrominated intermediate can decompose into ethane, vinyl bromide, and 1,2-dibromoethylene after sufficient heat adsorption. [ABSTRACT FROM AUTHOR]

Furthermore, the cross-couplings of the cyclic vinyl bromides, such as 3-bromo-1,2-dihydronaphthalene and 3-bromo-3-fluoro-1,2-dihydronaphthalene, with B 1-ZnCl b also proceeded smoothly to yield the corresponding -boryl-substituted allylic boronate esters B 3k b and B 3l b in 90% and 65% yields, respectively. Keywords: Palladium; Negishi coupling; Allylboronate ester; gem-diborylalkane; Cross-coupling EN Palladium Negishi coupling Allylboronate ester gem-diborylalkane Cross-coupling 499 501 3 03/22/21 20210301 NES 210301 We have developed Pd-catalyzed Negishi cross-coupling of diborylmethylzinc chloride with vinyl bromides. GLO:1CJF/01mar21:bkcs12212-fig-0003.jpg PHOTO (COLOR): 3 Further transformations of -boryl-substituted allylic boronate ester 3m. gl In conclusion, we have reported the Pd-catalyzed cross-coupling of vinyl bromides with diborylmethylzinc halides B 1-ZnX b . As depicted in Scheme 2, the coupling reactions of ( I E i )-vinyl bromides bearing various alkyl substituents at the -position proceeded without difficulties, giving -boryl-substituted allylic boronate esters B 3a b - B 3e b in good-to-moderate yields. [Extracted from the article]

The synthesis of di-cationic surfactants were occurred by the reaction of three straight-chain amide derivatives with (2-bromoethyl)trimethylammonium bromide. After characterization of these di-cationic surfactants using FT-IR and NMR, the corrosion inhibition tests were performed at room temperature (25°C) in 1.0, 2.0 and 4.0 M of HCl solutions for different immersion times. Over 92% of corrosion inhibition efficiencies were obtained from the weight loss measurements. As evidence for the preventing of the oxidation on carbon steel, very small amount of corrosion rates were measured from the weight loss values. To establish the inhibition efficiency results in 1.0, 2.0 and 4.0 M of HCl solutions, SEM analysis of the metal coupons used were performed. [ABSTRACT FROM AUTHOR]

A new fluorosulfonylation reagent 1-bromoethene-1-sulfonyl fluoride was developed (1-Br-ESF). This unique reagent possesses three addressable handles (vinyl, bromide, and sulfonyl fluoride) and has great potential to function as a tris-electrophile and as a sulfur(vi) fluoride exchange (SuFEx) clickable material to enrich the SuFEx tool cabinet. The application of this reagent for regioselective synthesis of 5-sulfonylfluoro isoxazoles has been realized through a [3+2] cycloaddition with N-hydroxybenzimidoyl chlorides. This practical protocol provides a general and direct route to functionalized isoxazoles possessing sulfonyl fluoride moieties. [ABSTRACT FROM AUTHOR]

An N-vinylation of imidazole and benzimidazole with a paramagnetic vinyl bromide was investigated. Among the tested procedures, Pd-catalyzed reaction was the most powerful one. The N-vinylation of 2-aminobenzimidazole with a β-bromo-α,β-unsaturated pyrroline nitroxide aldehyde offered 1,1,3,3-tetramethyl-1H-benzimidazo[1,2-a]pyrrolo[3,4-e]pyrimidin-2(3H)-yloxyl radical and the corresponding non-cyclized Schiff base. The reaction of a β-bromo-α,β-unsaturated pyrroline nitroxide aldehyde with imidazole gave β-imidazo-α,β-unsaturated pyrroline nitroxide aldehyde, which was reduced to the alcohol and converted to an unstable allyl chloride. [ABSTRACT FROM AUTHOR]

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Herein, a general procedure to access CF2PO(OEt)2-containing molecules is reported. The reagent CuCF2PO(OEt)2 is accessible by a simple protocol and a broad range of substrates can be functionalised. The procedure allows the conversion of aryl diazonium salts, as well as aryl, heteroaryl, vinyl and alkynyl iodonium salts, into the corresponding fluorinated molecules at room temperature. Mechanistic studies were performed to gain a better understanding of the reaction pathway. Under similar conditions, vinyl and aryl iodides, allyl halides, and benzyl bromides were also functionalised, and the scope and limitations of the reaction were studied. Finally, the procedure was extended to disulfides to offer new access to SCF2PO(OEt)2-containing molecules. [ABSTRACT FROM AUTHOR]

Ortho-alkynylated α-bromocinnamates can be converted by a visible-light-mediated photocascade reaction with molecular oxygen into either indenones or dihydroindeno[1,2-c]chromenes. The one-step process features key photochemical steps, that is, the initial activation of vinyl bromides through energy transfer to give α-ketoradicals in a reaction with molecular oxygen, followed by α-oxidation of an arene moiety by 6-π electrocyclization, and subsequent hydroxylation by an electron-transfer process from the same photocatalyst leads to the dihydroindeno[1,2-c]chromenes. [ABSTRACT FROM AUTHOR]

A series of new 3-substituted-4-iodo-(2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-1-yl)oxidanyl compounds is synthesized to achieve NH2- and SH-specific spin labels. The new vinyl iodides are tested in Sonogashira and Buchwald-Hartwig cross-coupling reactions to produce a paramagnetic ß-amino acid ester, pyrroline nitroxidecondensed heterocycles, including a paramagnetic a,a'-dipyridyl ligand and a spin-labeled sulfonamide. [ABSTRACT FROM AUTHOR]

An efficient method for the stereoselective synthesis of vinyl iodides is described. The reactions of vinyl bromides with potassium iodide proceed smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding vinyl iodides stereospecifically and in satisfactory to excellent yields. [ABSTRACT FROM AUTHOR]

The use of pyridine as the sole ligand for the reductive vinylation of unactivated secondary alkyl halides under Ni-catalyzed conditions has been developed. Both alkyl- and aryl-substituted vinyl bromides are suitable, in which alkyl-decorated α-alkenyl bromides resulted in the α-products in good results. [ABSTRACT FROM AUTHOR]

A simple formylation reaction of aryl halides, aryl triflates, and vinyl bromides under synergistic nickel- and organic-dye-mediated photoredox catalysis is reported. Distinct from widely used palladium-catalyzed formylation processes, this reaction proceeds by a two-step mechanistic sequence involving initial in situ generation of the diethoxymethyl radical from diethoxyacetic acid by a 4CzIPN-mediated photoredox reaction. The formyl-radical equivalent then undergoes nickel-catalyzed substitution reactions with aryl halides and triflates and vinyl bromides to form the corresponding aldehyde products. Significantly, besides aryl bromides, less reactive aryl chlorides and triflates and vinyl halides serve as effective substrates for this process. Since the mild conditions involved in this reaction tolerate a plethora of functional groups, the process can be applied to the efficient preparation of diverse aromatic aldehydes. [ABSTRACT FROM AUTHOR]

This work emphasizes the synthesis of substituted vinyl arenes by reductive coupling of aryl halides with vinyl bromides under mild and easy-to-operate nickel-catalyzed reaction conditions. A broad range of aryl halides, including heteroaromatics, and vinyl bromides were employed to yielding products in moderate to excellent yields with high functional-group tolerance. The nickel-catalytic system displays good chemoselectivity between the two C(sp2)-halide coupling partners, thus demonstrating a mechanistic pathway distinct from other stepwise protocols. [ABSTRACT FROM AUTHOR]

Constant-current electrolysis of vinyl bromide in DMF containing 0.1 m Bu4NBF4 by using an undivided cell equipped with a platinum plate cathode and a magnesium rod anode in the presence of an electron-transfer mediator, methyl 4- tert-butylbenzoate, and carbon dioxide resulted in selective generation of a vinyl radical, for which cyclization followed by fixation of carbon dioxide with a carbon-carbon bond formation gave γ,δ-unsaturated carbo- and heterocycle carboxylic acids in moderate to good yields. The vinyl radical could be selectively generated under the electrolysis conditions, and the following reaction of the anion species, generated by one-electron reduction of the resulting cyclized radical, with carbon dioxide took place efficiently. These results and cyclic voltammetry indicate that methyl 4- tert-butylbenzoate plays an important role in the generation of vinyl radicals from vinyl bromides. The resulting cyclized γ,δ-unsaturated carboxylic acid was successfully applied to stepwise and direct iodo-lactonization to give the corresponding bicycle γ-lactones in good yields. [ABSTRACT FROM AUTHOR]

Modeling the high-pressure polymerization of ethene is of vital importance in order to avoid costly high-pressure experiments when it comes to process optimization and product design. However, closing the heat balance when modeling high-pressure tubular reactors with a counter-current jacket cooling is still difficult. In this contribution the influence of thermo-physical properties - namely viscosity and heat capacity - on the simulation results was investigated. Various literature sources were evaluated and a variety of simulations were conducted, showing that both properties influence the resulting temperature profiles and conversions visibly, while the molecular weight distribution was not affected. Uncertainties of the heat capacity of 5 % could be compensated by varying initiator efficiency and fouling layer thickness within physically reasonable boundaries. [ABSTRACT FROM AUTHOR]

A new decarboxylative perfluoroalkylation of vinyl bromides has been developed. The use of copper(I) trifluoroacetate complex (phen)Cu(O2CCF3) ( 1) and perfluorocarboxylate complexes [(phen)2Cu](O2CRF) ( 2; RF=C2F5, n-C3F7, n-C4F9, n-C5F11) as reagents allows for the efficient synthesis of trifluoromethylated and perfluoroalkylated olefins, respectively. Vinyl bromides comprising a range of functionalities (e.g., methoxy, ester, nitrile, nitro, trifluoromethyl, chloride, and benzo[ d][1,3]dioxole) were successfully accommodated. The decarboxylative trifluoromethylation and perfluoroalkylation reactions also proceeded with retention of the double-bond stereochemistry of alkenes after the reaction was completed. [ABSTRACT FROM AUTHOR]

Synthetic procedure to access the first representatives of a new series of 3-monosubstitued functional derivatives of 1-alkoxy-1-triazene 2-oxides, i.e., 1-alkoxy-3-(2-hydroxyethyl)- and 1-alkoxy-3-(2-acetoxyethyl)-1-triazene 2-oxides, were elaborated. 1-Alkoxy-3,3-bis(2-hydroxyethyl)-1-triazene 2-oxides were used to derive 3-(2-acetoxyethyl)-, 3-(2-bromoethyl)- and 3-(2-cyanoethyl)substituted 1-alkoxy-3-(2-acetoxyethyl)-1-triazene 2-oxides. [ABSTRACT FROM AUTHOR]

Hexa- peri-hexabenzocoronene (HBC)-based donor-acceptor dyads were synthesized with three different acceptor units, through two pathways: 1) 'pre-functionalization' of monobromo-substituted hexaphenylbenzene prior to the cyclodehydrogenation; and 2) 'post-functionalization' of monobromo-substituted HBC after the cyclodehydrogenation. The HBC-acceptor dyads demonstrated varying degrees of intramolecular charge-transfer interactions, depending on the attached acceptor units, which allowed tuning of their photophysical and optoelectronic properties, including the energy gaps. The two synthetic pathways described here can be complementary and potentially be applied for the synthesis of nanographene-acceptor dyads with larger aromatic cores, including one-dimensionally extended graphene nanoribbons. [ABSTRACT FROM AUTHOR]

Enantioenriched secondary and tertiary alkyl pinacolboronic esters undergo enantiospecific deborylative alkynylation through a Zweifel-type alkenylation followed by a 1,2-elimination reaction. The process involves use of α-lithio vinyl bromide or vinyl carbamate species, for which application to Zweifel-type reactions has not previously been explored. The resulting functionalized 1,1-disubstituted alkenes undergo facile base-mediated elimination to generate terminal alkyne products in high yield and excellent levels of enantiospecificity over a wide range of pinacolboronic ester substrates. Furthermore, along with terminal alkynes, internal and silyl-protected alkynes can be formed by simply introducing a suitable carbon- or silicon-based electrophile after the base-mediated 1,2-elimination reaction. [ABSTRACT FROM AUTHOR]

We have developed an efficient method for the synthesis of trisubstituted (E)-vinyl bromides by a Friedel-Crafts-type addition of alkynes to oxocarbenium ions formed in situ from acetals. The success of this reaction relies on the identification of magnesium bromide etherate as both a Lewis-acid promoter and a source of bromide. This reaction employs simple inexpensive starting materials and proceeds under mild conditions to allow the preparation of a range of vinyl bromide products in high yields and high E/Z selectivities. Furthermore, the vinyl bromides also contain an allylic ether functional group. Both the vinyl bromide and allylic ether groups are effective handles for the elaboration of these useful synthetic intermediates. [ABSTRACT FROM AUTHOR]

The article discusses intramolecular coupling reactions between Vinyl Bromides, Aryl and Vinyl Halides, and Aryl Iodides by using Palladium (Pd) as catalyst in Indium medium. A homo-coupling reaction between aryl halides in copper medium is called Ullmann reaction. It started with vinyl bromide which was obtained from ethyl phenylsulfonylacetate and 2,3-dibromo-1-propene using Pd as catalyst. Preparation of Five- to Eight-membered Carbocycles and Heterocycles is also mentioned.

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Palladium-catalyzed cross-coupling reactions of 1,1-diboronates with vinyl bromides and dibromoalkenes were found to afford 1,4-dienes and allenes, respectively. These reactions utilize the high reactivities of both 1,1-diboronates and allylboron intermediates generated in the initial coupling. [ABSTRACT FROM AUTHOR]