Reaction Of Alkyl Halides Research Articles

Synthesis of the complex bridged 1,5-oxazabicycles via one-pot reactions of 4,5-diazafluoren-9-one, alkyl halides, and cyclic 1,3-diketone

An efficient and practical procedure for the preparation of the complex bridged 1,5-oxazabicycles was developed via a one-pot domino reaction of 4,5-diazafluoren-9-one, reactive alkyl halides, and cyclic 1,3-dicarbonyl compounds. Also published in Chemistry of Heterocyclic Compounds , 2012, 48 (4), pp 658-665 http://link.springer.com/article/10.1007/s10593-012-1040-0

Short oligo (ethylene glycol) functionalized imidazolium dicationic room temperature ionic liquids: Synthesis, properties, and catalytic activity in azidation

Imidazolium based dicationic room temperature ionic liquids (RTILs) were synthesized, characterized, and investigated their physicochemical properties along with catalytic activity in azidation reaction. In this method two N-methylimidazolium cations were bridged with different short oligo (ethylene glycol) chains as linkers and mesylate (CH3SO3-) or tosylate (CH3C6H4SO3-) moieties as anion containing RTILs were synthesized. These RTILs were showed interesting physicochemical properties such as high thermal stability, solubility in various organic solvents, high viscosity at different temperature and efficient catalytic activity in organic transformation by tuning their cation and anion components. Catalytic activities of these RTILs were investigated for a representative reaction of alkyl halide to their corresponding azide and RTILs were reused for five times without losing their catalytic activity. The present catalytic system dicationic RTILs in methanol were showed significant high yield in short reaction time compared to the traditional monocationic ILs in azidation reaction. Moreover, we also performed theoretical study of synthesized RTILs to correlate experimental results of catalytic activity with their molecular geometry. Geometrical study and experimental results reveals that simple structural modifications of synthesized RTILs were showed major influence on their physicochemical properties as well as catalytic activity. Hence, to utilize the tunability property of these RTILs may open exciting perspectives for use in various synthetic applications in “Green” synthesis.

ChemInform Abstract: Alkylboronic Esters from Copper‐Catalyzed Borylation of Primary and Secondary Alkyl Halides and Pseudohalides.

AbstractAlkylboronic esters are obtained by the present copper‐catalyzed reaction of alkyl halides with diboron reagent (II).

A Convenient Synthesis of 2‐Sulfanylbenzoselenazole Derivatives via the Reaction of 2‐Lithiophenyl Isothiocyanates with Selenium

AbstractThe title compounds have been prepared from 2‐bromophenyl isothiocyanates 1. Thus, 2‐lithiophenyl isothiocyanates 2, obtained from 1 and BuLi through Br/Li exchange, reacted with Se at −78° to form lithium benzoselenazole‐2‐thiolates 3, which, upon aqueous workup, afforded benzoselenazole‐2(3H)‐thiones 4. The thiolates 3 were alkylated with reactive alkyl halides and acylated with carboxylic acid chlorides to give 2‐(alkylsulfanyl)benzoselenazoles 5 and S‐(benzoselenazol‐2‐yl) thiocarboxylates 6, respectively.

Photocatalytic Arylation of Alkenes, Alkynes and Enones with Diazonium Salts

Teaching old dogs new tricks: Visible light photoredox catalysis improves the classic Meerwein arylation protocol significantly and allows the light-controlled arylation of alkenes, alkynes and enones by diazonium salts.

In Situ Dearomatisation/Alkylation of Arylphosphane Derivatives

AbstractThe dearomatisation of aryldialkylphosphane–boranes and aryldialkylphosphane oxides under Birch reduction conditions, followed by treatment with reactive alkyl halides, provides the corresponding α‐functionalised (cyclohexa‐1,4‐dien‐3‐yl)phosphane derivatives. This reaction offers a method of choice for the synthesis of bulky (cyclohexadienyl)phosphanes.

ChemInform Abstract: Pd‐Catalyzed Cross‐Coupling Reactions of Alkyl Halides

AbstractReview: 87 refs.

Silylboranes as New Sources of Silyl Radicals for Chain‐Transfer Reactions

Various silylboranes, which were outfitted with a catecholborane moiety at one end and a (Me(3)Si)(3)Si moiety at the other end of a carbon chain, were prepared through the hydroboration of the corresponding unsaturated silanes. The C-centered radical species generated from these silylboranes efficiently cyclized to provide, through a 5-exo intramolecular homolytic substitution at the silicon center, the corresponding silacycle and a Me(3)Si radical that was subsequently trapped by sulfonyl acceptors. These cyclizations proceeded at unprecedented rates, due, in part, to a strong gem-dialkyl effect that was attributable to the presence of bulky substituents on a quaternary center located on the chain. In parallel, we designed arylsilylboranes that produced silyl radicals through a 1,5-hydrogen transfer. Such silyl radicals may be valuable radical chain carriers, for instance, in oximation reactions of alkyl halides. Finally, computational studies allowed calculation of activation barriers of the homolytic substitution step and additionally illustrated that the overall reaction mechanism involved a transition state in which the attacking carbon center, the central silicon atom, and the Me(3)Si leaving group were collinear.

ChemInform Abstract: Simple and Efficient Method for the Synthesis of Azides in Water‐THF Solvent System.

AbstractA novel and efficient method for the synthesis of azides is developed using nucleophilic substitution reactions of alkyl halides, alkoxy esters or acid chlorides with sodium azide in a H2O/THF system.

Nonconventional versus conventional application of pseudo‐first‐order kinetics to fundamental organic reactions

AbstractThree new analysis procedures for pseudo‐first‐order kinetics are introduced and applied to eight different fundamental organic reactions. The reactions belong to the following classes: nitroalkane proton transfer, formal hydride ion transfers from NADH model compounds, and SN2 reactions of alkyl halides with ionic and neutral nucleophiles. The three methods consist of (1) half‐life dependence of kapp, (2) sequential linear pseudo‐first‐order correlation, and (3) revised instantaneous rate constant analysis. Each of the three procedures is capable of distinguishing between one‐ and multistep mechanisms, and the combination of the three procedures provides a powerful strategy for differentiating between the two mechanistic possibilities. The data from the eight reactions chosen as examples clearly show how the procedures work in practice. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 44: 2–12, 2012

Carbon Halide Bond Activation of Benzyl Chloride and Benzyl Bromide Using An NHC‐Stabilized Nickel(0) Complex

AbstractA first example of the application of an NHC‐stabilized nickel complex as a catalyst in Suzuki–Miyaura cross‐coupling reactions of alkyl halides is reported. The complexes trans‐[Ni(iPr2Im)2(X)(CH2Ph)] (X = Cl 2 and Br 3) were prepared from the reactions of benzyl chloride and benzyl bromide and the dinuclear complex [Ni2(iPr2Im)4(COD)] (1). These compounds were fully characterized by elemental analysis, IR spectroscopy, multinuclear NMR spectroscopy, and X‐ray crystallography. Based on these stoichiometric oxidative addition reactions catalytic Suzuki–Miyaura cross‐coupling reactions have been performed. Complex 1 is an effective catalyst for the Suzuki–Miyaura cross‐coupling reaction of benzyl chloride and phenylboronic acid. Quantitative conversion of benzyl chloride with a high selectivity to the cross‐coupling product diphenylmethane was achieved after two hours reaction time using three equivalents phenylboronic acid, three equivalents cesium fluoride and 1.22 mol‐% [Ni2(iPr2Im)4(COD)] (1) as a catalyst.

Insights into Supported Copper(II)‐Catalyzed Azide‐Alkyne Cycloaddition in Water

AbstractCross‐linked polymeric ionic liquid material‐supported copper (Cu‐CPSIL), imidazolium‐loaded Merrifield resin‐supported copper (Cu‐PSIL) and silica dispersed CuO (CuO/SiO2), were prepared and proved to be efficient catalysts for the one‐pot synthesis of 1,4‐disubsituted‐1,2,3‐triazoles by the reaction of alkyl halides with sodium azide and terminal alkynes in water at room temperature. Moreover, these supported copper catalysts were recovered quantitatively from the reaction mixture by simple filtration and reused for five consecutive recycles without significant loss of catalytic activity. Among the three immobilized copper catalysts, Cu‐CPSIL exhibited excellent catalytic activity for the reaction of aliphatic bromides, sodium azide and terminal alkynes. The differences in the catalytic performances of the catalysts could be ascribed to the copper dispersion and the interaction between copper and the supports. In addition, water was used as the reaction media and the proton provider, the latter was found to be very important for the reaction. The XPS results suggested that the supported Cu(II) catalysts were reduced to catalytic Cu(I) species via alkynes homocoupling reaction. By means of IR and ESI‐MS studies, a possible mechanism of cycloaddition based on the reduction of Cu(II) to Cu(I) species was proposed.

Cross-coupling Reaction of Grignard Reagents with Alkyl Halides Catalyzed by Green, Economical Copper Bromide Catalyst

For the first time a systematic research on the catalytic activity of CuXn(X=Cl, Br, I; x=1,2) for the cross-coupling reaction of alkyl halides with Grignard reagents was carried out and environmentally friendly, economical CuBr2showed highest catalytic activity among the catalyst. The conditions of the cross-coupling reaction were studied. The suitable amount of catalyst, reaction temperature and time are 0.3% mol (based on alkyl halide), 67°C (reflux), 6 h, respectively. Under the optimal conditions, the yields of the cross-coupling could reach up to 93%. Moreover, Grignard reagent with an electron-rich group reacted rapidly and with an electron-withdrawing group reacted sluggishly.

Pd-catalyzed cross-coupling reactions of alkyl halides

Cross-coupling reactions have become indispensable tools for creating carbon-carbon (or heteroatom) bonds in organic synthesis. Like in other important transition metal catalyzed reactions, such as metathesis, addition, and polymerization, unsaturated compounds are usually employed as substrates for cross-coupling reactions. However during the past decade, a great deal of effort has been devoted to the use of alkyl halides as saturated compounds in cross-coupling reactions, which has resulted in significant progress in this undeveloped area by introducing new effective ligands. Many useful catalytic systems are now available for synthetic transformations based on C(sp(3))-C(sp(3)), C(sp(3))-C(sp(2)) and C(sp(3))-C(sp) bond formation as complementary methods to conventional C(sp(2))-C(sp(2)), C(sp(2))-C(sp) and C(sp)-C(sp) coupling. This tutorial review summarizes recent advances in cross-coupling reactions of alkyl halides and pseudohalides catalyzed by a palladium complex.

ChemInform Abstract: Silver‐Catalyzed Coupling Reactions of Alkyl Halides with Indenyllithiums.

AbstractThe reaction, catalyzed by AgBr, is applied to a wide range of secondary and tertiary alkyl halides to afford the corresponding indene or fluorene [cf.

ChemInform Abstract: Radical-Based Annulations of Iodo Lactams.

Abstract N-Alkylation of iodo lactams with reactive alkyl halides, or of the derived selenide lactams with less reactive alkyl halides, leads to substrates for free radical initiated cyclization to pyrrolizidinones and indolizidinones, e. g. 2 → 3. The first examples of iodide / vinyl bromide, selenide / aldehyde, and selenide / vinyl chloride radical cyclizations are described.

Silver-catalyzed coupling reactions of alkyl halides with indenyllithiums

Coupling reactions of tertiary and secondary alkyl halides with indenyllithiums proceeded effectively in the presence of a catalytic amount of silver bromide to provide tertiary- and secondary-alkyl-substituted indene derivatives in good yields.

ChemInform Abstract: Stereoselective Reactions. Part 31. Catalytic Asymmetric Alkylation of Achiral Lithium Enolates Using a Chiral Tetradentate Amine in the Presence of an Achiral Bidentate Amine.

Abstract Catalytic asymmetric alkylation of achiral lithium enolates of 1-tetralone and cyclohexanone with reactive alkyl halides was realized by using a combination of a chiral tetradentate amine (∼0.05 equiv.) and an achiral bidentate amine (2 equiv.).

Topic Sequence and Emphasis Variability of Selected Organic Chemistry Textbooks

Textbook choice has a significant effect upon course success. Among the factors that influence this decision, two of the most important are material organization and emphasis. This paper examines the sequencing of 19 organic chemistry topics, 21 concepts and skills, and 7 biological topics within nine of the currently available organic textbooks. The emphases of the textbooks were also examined through analysis of questions, reactions, and mechanisms presented for aromatics, aldehydes, and ketones. The most significant difference in organization among the books was whether the first type of reactivity discussed was addition reactions of alkenes (Brown et al.; Bruice; McMurry) or substitution−elimination reactions of alkyl halides (Carey; Hornback; Smith; Solomons and Fryhle; Wade; Vollhardt and Schore). Textbooks also vary in the order by which carbonyl compounds and their reactivity is introduced, though all do so after covering the reactivity of aromatic compounds. Most textbooks contain ∼250−300 questions covering aromatics and 150−250 questions covering aldehydes and ketones and their reactions at the carbonyl carbon, although one textbook (Smith) contains 441 carbonyl questions. All textbooks place a heavy emphasis on predict-the-product, provide-the-reagent, and multistep synthesis questions. Most of the texts examined introduce the same reactions with at least some mechanistic detail. Wade and Smith, however, provide the most complete mechanisms in the topics examined.

A green and highly efficient alkylation of thiols in water

An environmentally benign and efficient process for the preparation of thioethers was developed by simple and practical reactions of alkyl halides and thiols in water in the presence of K2CO3 or Et3N in very high yields. The reaction of aryl, alkyl, aliphatic and hindered thiols with various alkyl halides gave the corresponding products with significant advantages such as high conversions, short reaction time, mild reaction conditions, and low cost, simple workup with good to quantitative yields.