Reaction Of Allyl Halides Research Articles

A Thioether-Catalyzed Cross-Coupling Reaction of Allyl Halides and Arylboronic Acids.

C(sp3 )-C(sp2 ) cross-coupling reactions are an indispensable tool for organic synthesis. In these reactions transition metals have been extensively employed to promote the formation of valuable carbon-carbon bonds. Herein, we report our recent discovery of a designer thioether as a highly active organocatalyst for reactions between an allyl bromide and an arylboronic acid. The cross-coupling event occurred readily under mild condition in the presence of a weak inorganic base. Preliminary mechanistic studies suggested a sulfonium ylide mechanism.

Formation of a new carbon-carbon bond in the reaction of allyl halides with tin(iv) bis-o-amidophenolate

A reaction of tin(IV) bis-o-amidophenolate complex based on redox-active 4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-o-aminophenol with various allyl halides was studied. This process includes the addition of 1 equiv. of allyl halide to the starting complex and is accompanied by the change in the redox state of one of the redox-active ligands. The reaction results in the formation of a new carbon—carbon bond between the allylic fragment and the carbon atom at position 5 of the ligand o-iminoquinone ring, as well as a tin—halogen bond. The structure and composition of compounds synthesized were confirmed by ESR, NMR, and IR spectroscopy and elemental analysis.

ChemInform Abstract: Short Synthesis of Chiral 4‐Substituted (S)‐Imidazolinium Salts Bearing Sulfonates and Their Use in γ‐Selective Reactions of Allylic Halides with Grignard Reagents.

AbstractNew NHC ligand precursors are synthesized, which serve as highly active catalysts (turnover number about 100) for γ‐selective additions to cinnamyl electrophiles without the need for metal salts.

Nano copper ferrite: A reusable catalyst for the synthesis of β, γ-unsaturated ketones

Copper ferrite nano material as reusable heterogeneous initiator in the synthesis of β, γ-unsaturated ketones and allylation to acid chlorides are presented. The reaction of allylichalides with various acid chlorides is achieved in the presence of copper ferrite nano powders at room temperature in tetrahydrofuran (THF). The present method is first of its kind in the synthesis of title compounds without any additive/ co-catalyst. The nano catalyst is easily recovered and its reusability is recorded.

Short Synthesis of Chiral 4‐Substituted (S)‐Imidazolinium Salts Bearing Sulfonates and Their Use in γ‐Selective Reactions of Allylic Halides with Grignard Reagents

AbstractA one‐pot reaction of Boc‐protected amino alcohols and 2‐sulfobenzoic anhydride followed by the addition of a wide variety of primary amines has allowed rapid access to diverse libraries of amidosulfonates 1,2‐C6H4(SO3–)(COCHR1CH2NH2+R2) (R1 = Bn, iPr, Ph; R2 = aryl, CHMePh, 1‐adamantyl), of which two examples have been characterised by X‐ray crystallography. These reactions proceed by SN2 opening of unisolated oxazoline intermediates. The amidosulfonates have been converted to imidazolinium sulfonate zwitterions (N‐heterocyclic carbene precursors) in a two‐step process, which involved reduction with BH3·SMe2 and cyclisation with HC(OEt)3. Two examples (R1 = Bn, R2 = 2,6‐iPrC6H3 and R1 = iPr, R2 = 3,5‐Me2C6H3) have been crystallographically characterised, the latter as a PF6 salt. The imidazolinium sulfonate zwitterions (1 mol‐%) catalysed additions of RMgBr (R = alkyl) to (E)‐ArC(R)=CHCH2Br (R = H, Me). Additions to cinnamyl bromides showed high γ (SN2′) selectivity (up to 18.4:1) and provided significantly enantiomerically enriched products (up to 82 % ee).

Measurement of Heterogeneous Reaction Rates: Three Strategies for Controlling Mass Transport and Their Application to Indium-Mediated Allylations

We describe three new strategies for determining heterogeneous reaction rates using photomicroscopy to measure the rate of retreat of metal surfaces: (i) spheres in a stirred solution, (ii) microscopic powder in an unstirred solution, and (iii) spheres on a rotating shaft. The strategies are applied to indium-mediated allylation (IMA), which is a powerful tool for synthetic chemists because of its stereoselectivity, broad applicability, and high yields. The rate-limiting step of IMA, reaction of allyl halides at indium metal surfaces, is shown to be fast, with a minimum value of the heterogeneous rate constant of 1 × 10(-2) cm/s, an order of magnitude faster than the previously determined minimum value. The strategies described here can be applied to any reaction in which the surface is retreating or advancing, thereby broadening the applicability of photomicroscopy to measuring heterogeneous reaction kinetics.

ChemInform Abstract: Palladium‐Catalyzed Reaction of Allyl Halides with α‐Diazocarbonyl Compounds.

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.

A Theoretical Study of SN2′ Reactions of Allylic Halides: Role of Ion Pairs

Various disparate experimental results are explained by the hypothesis that reactions of anionic nucleophiles with allylic halides are generally S(N)2. The S(N)2' reactions that do occur proceed generally with anti stereochemistry. Reactions with ion pair nucleophiles occur preferentially as S(N)2' reactions with syn stereochemistry. This hypothesis is consistent with a variety of computations at the HF, B3LYP, mPW1PW91 and MP2 levels with the 6-31+G(d) basis set of reactions of Li and Na fluoride and chloride with allyl halides and 4-halo-2-pentenes. Solvation is considered by a combination of coordination of dimethyl ether to the lithium and sodium cations and "dielectric solvation" with a polarized continuum model.

Allylcyanocuprates from Butylallyltellurides

Lithium diallylcyanocuprates generated by reaction of allyl halides with lithium n-butyltellurolate followed by transmetalation with lithium dibutylcyanocuprate react with vinyl triflates leading to highly unsaturated hydrocarbons.

Palladium-Catalyzed Allylic Substitution Using in Situ Generated Allylindium Reagents

It was found that in situ generated allylindium reagent from the reaction of allyl halides with indium is the efficient nucleophile for Pd-catalyzed allylic substitution to produce 1,5-dienes in good yield.

ChemInform Abstract: Nickel‐Catalyzed Cross‐Coupling Reaction of Allyl Halides with Alkynyltins.

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.

Synthesis, reactions and catalytic activities of σ- and η3-allyl-bis(triphenylstibine)rhodium(III) complexes

Reaction of [RhCl(CO)(SbPh3)2]1 with CH2CHCH2Br 2a gives the σ-allylrhodium(III) complex [Rh(σ-CH2CHCH2)Cl(Br)(CO)(SbPh3)2]3, while reactions of 1 with allyl halides and AgClO4 give η3-allylrhodium(III) complexes [Rh(η3-allyl)X(CO)(SbPh3)2]ClO44[allyl = CH2CHCH2, CH2CHCHMe (X = Br or Cl), CH2CMeCH2, or CH2CHCHPh (X = Cl)]. The complex [Rh(η3-CH2CHCH2)Br(CO)(SbPh3)2]ClO4 can also be prepared by the reaction of 3 with AgClO4. The complex [Rh(η3-CH2CHCH2)Cl(CO)(SbPh3)2]ClO4 reacts with alcohols, amines and triphenylphosphine to give 1 and allyl ethers, diallylamines and allylphosphonium perchlorate, respectively. Reactions of allyl halides with alcohols and amines are catalysed by the η3-allyl complexes 4 in the presence of ClO4–.

Selective allylation of carbonyl compounds in aqueous media

The use of aqueous neutral media leads to excellent yields of homoallylic alcohols from reaction sof allyl halides with carbonyl compounds in the presence of tin or zinc. The stereochemical course and range of application of this reaction have been investigated.

Organometallic synthesis in aqueous media. Synthesis of vinylallylcarbinols

A method has been proposed for the synthesisof vinylallylcarbinols by the reaction of allyl halides with α,β-unsaturated aldehydes with zinc in aqueous acetic acids.

A palladium-catalyzed cyclocarbonylation reaction leading to synthons for cyclopentanoid chemistry

Tricyclic compounds, containing a cyclopentanone ring and an alkylidene group α to the carbonylic function, have been obtained by reaction of allylic halides with bicyclo[2.2.1]hept-2-ene or bicyclo[2.2.1]hepta-2,5-diene and carbon monoxide in the presence of a triarylphosphine palladium as complex catalyst. Retro Diels-Alder type reactions, which in part occur during the carbonylation, lead to alkyliden- cyclopentenones.

Synthesis of Allyl Silanes Using Trimethylsilyllithium in the Presence of Copper(I) Iodide

Abstract Allyl silanes have been prepared by reaction of allylic halides with trimethylsilyllithium in the presence of copper(I) iodide.

Zinc (0)-Mediated Formation of Carbon-Carbon Bond from γ-Bromo Crotonate

Abstract The coupling reaction of allylic halides with diffferent organometallic reagents has been widely utilized for synthetic purpose.1 Unfortunately, with the exception of primary halides which give mostly α attack and of hindered substrates which prefer γ attack, the lack of regioselectivity is a great handicap for the generalization of the method.

Evidence for the intermediacy of π-allylic metal complexes in the reaction of allylic halides with grignard reagent in the presence of transition metal halides

The reactions of allyl bromide and crotyl chloride with Grignard reagent catalyzed by π-allyl and crotyl metal complexes of nickel, cobalt, and iron, and the stoichiometric reaction of the complexes with the Grignard reagent have been examined. The similarity in catalytic behaviour of the complex and the corresponding metallic halide affords further evidence in support of the previous proposal that the π-allylic metal intermediate plays an important role in the catalytic reaction. The stoichiometric reaction suggests that the dependence of distribution of product in the catalytic process on the type of both allylic halide and metal is attributable to the facility of ligand exchange between the π-allylic complex and Grignard reagent.

The Kharasch type reaction of allylic halides with Grignard reagent in the presence of transition metal halides

The reaction of allylic halide with Grignard reagent in the presence of transition metal chloride has been investigated. Three reactions of allylic halide occurred competitively; (i) reduction to olefin, (ii) coupling with Grignard reagent to olefin (cross-coupling) and (iii) coupling with itself to 1,5-diene (homo-coupling). The relative importance of these reactions depends on both the structures of allylic halide and Grignard reagent, as well as on the transition metal salt utilized. The mechanism was discussed in terms of the allylic transition metal intermediate.

Nucleophilic substitution reactions of allylic halides carrying electron-withdrawing substituents in the γ-position. Formation of cyclopropanes from dimethyl 2-bromo-2-methylpropylidenemalonate

Reaction of dimethyl 2-bromo-2-methylpropylidenemalonate with sodium methoxide or potassium cyanide in methanol produces cyclopropane derivatives in high yields, thus indicating an overall substitution with nucleophilic attack occurring at the β-position of the allylic halide.