Reaction Of Alkyl Halides Research Articles

Ionic Liquid as Catalyst and Reaction Medium: A Simple, Convenient and Green Procedure for the Synthesis of Thioethers, Thioesters and Dithianes using an Inexpensive Ionic Liquid, [pmIm]Br

AbstractAn easily accessible and inexpensive room temperature ionic liquid, 1‐pentyl‐3‐methylimidazolium bromide, [pmIm]Br efficiently catalyzes the reaction of alkyl halides or acyl halides with thiols without any solvent at room temperature leading to the synthesis of thioethers and thioesters in high yields. This reaction has also been extended for the preparation of dithianes and transthioetherification. The ionic liquid is recovered and recycled for subsequent runs.

A Convenient Method for the Preparation of Primary Amines Using Tritylamine.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Cross‐Coupling Reaction of Alkyl Halides with Organometallic Reagents Using Transition‐Metal Catalysts

AbstractFor Abstract see ChemInform Abstract in Full Text.

Highly Enantioselective Phase-Transfer-Catalyzed Alkylation of Protected α-Amino Acid Amides toward Practical Asymmetric Synthesis of Vicinal Diamines, α-Amino Ketones, and α-Amino Alcohols

Highly enantioselective alkylation of protected glycine diphenylmethyl (Dpm) amide 1 and Weinreb amide 10 has been realized under phase-transfer conditions by the successful utilization of designer chiral quaternary ammonium salts of type 4 as catalyst. Particularly, remarkable reactivity of the chiral ammonium enolate derived from 1b and 4c allowed the reaction with less reactive simple secondary alkyl halides with high efficiency and enantioselectivity. An additional unique feature of this chiral ammonium enolate is its ability to recognize the chirality of beta-branched primary alkyl halides, which provides impressive levels of kinetic resolution and double stereodifferentiation during the alkylation, allowing for two alpha- and gamma-stereocenters to be controlled. Combined with the subsequent reduction using LiAlH4 in cyclopentyl methyl ether (CPME), this system offers a facile access to structurally diverse optically active vicinal diamines. Furthermore, the optically active alpha-amino acid Weinreb amide 11 can be efficiently converted to the corresponding amino ketone by a simple treatment with Grignard reagents. In addition, reduction and alkylation of the optically active alpha-amino ketone into both syn and anti alpha-amino alcohols with almost complete relative and absolute stereochemical control have been achieved. With (S,S)- and (R,R)-4 in hand, the present approach renders both enantiomers of alpha-amino amides including Weinreb amides readily available with enormous structural variation and also establishes a general and practical route to vicinal diamines, alpha-amino ketones, and alpha-amino alcohols with the desired stereochemistry.

Nickel‐Catalyzed Cross‐Coupling Reaction of Alkyl Halides with Organozinc and Grignard Reagents with 1,3,8,10‐Tetraenes as Additives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A convenient method for the preparation of primary amines using tritylamine

A simple method for the preparation of primary amines by treating N-tritylamines with trifluoroacetic acid has been established. The N-tritylamines were prepared by the reaction of alkyl halides or alkyl p-toluenesulfonates with tritylamine, or by the reaction of alkyl bromides with lithium tritylamide.

Iron-Catalyzed Chemoselective Cross-Coupling of Primary and Secondary Alkyl Halides with Arylzinc Reagents

Functional-group-compatible cross-coupling reaction of alkyl halides with arylzinc reagents takes place under iron catalysis in the presence of TMEDA, producing a variety of aromatic compounds in good to excellent yield. The pronounced effect of a magnesium salt was found to be the key to the promotion of the iron-catalyzed coupling reaction.

Zr-Catalyzed Coupling Reaction of Alkyl Halides, Tosylates, and Sulfates with β-Phenethyl Grignard Reagents via Styrene-Zirconate Intermediates

β-Phenethylmagnesium chlorides react with alkyl halides, tosylates, and sulfates in the presence of a catalytic amount of Cp 2 ZrCl 2 to afford 2-arylalkanes via alkylation of styrene-zirconate intermediates at the benzylic position. Competitive reaction using mixtures of alkyl halides (alkyl-X; X = F, Cl, Br) showed that the reactivities of the halides increase in the order of alkyl-Cl < alkyl-F < alkyl-Br with the relative rates of 1: ] 9:428.

Novel Route to N‐Alkyl‐ and N,N′‐Dialkylhydrazines by High‐Pressure Alkylation of Azines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Nickel‐Catalyzed Cross‐Coupling Reaction of Alkyl Halides with Organozinc and Grignard Reagents with 1,3,8,10‐Tetraenes as Additives

Essential additives: The addition of bis(1,3-butadienyl) compounds (tetraenes) was essential in the efficient Ni-catalyzed cross-coupling of organozinc reagents with alkyl bromides and a tosylate (see scheme, X=C(CO2Me)2 or NCH2Ph). The efficiency of the Ni-catalyzed cross-coupling of an alkyl fluoride with a Grignard reagent was also improved by using these tetraenes. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z460246_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Nickel‐Catalyzed Cross‐Coupling Reaction of Alkyl Halides with Organozinc and Grignard Reagents with 1,3,8,10‐Tetraenes as Additives

Die Additive bringen's: Die Zugabe von Bis(1,3-butadienyl)verbindungen (Tetraenen) war für die effiziente Ni-katalysierte Kupplung von Organozinkreagentien mit Alkylbromiden und einem Tosylat essenziell (siehe Schema, X=C(CO2Me)2 oder NCH2Ph). Auch die Effizienz der Ni-katalysierten Kupplung eines Alkylfluorids mit einem Grignard-Reagens wurde durch diese Tetraene verbessert.

A facile and practical method for the preparation of thioacetates from alkyl halides and sodium thioacetate catalysed by PEG400

Thioacetates are conveniently prepared in high yields under mild conditions by the reaction of alkyl halides and sodium thioacetate, prepared in situ from thioacetic acid and sodium carbonate, catalysed by PEG400 at room temperature.

Cobalt-catalyzed cross-coupling reactions of alkyl halides with allylic and benzylic Grignard reagents and their application to tandem radical cyclization/cross-coupling reactions.

Details of cobalt-catalyzed cross-coupling reactions of alkyl halides with allylic Grignard reagents are disclosed. A combination of cobalt(II) chloride and 1,2-bis(diphenylphosphino)ethane (DPPE) or 1,3-bis(diphenylphosphino)propane (DPPP) is suitable as a precatalyst and allows secondary and tertiary alkyl halides--as well as primary ones--to be employed as coupling partners for allyl Grignard reagents. The reaction offers a facile synthesis of quaternary carbon centers, which has practically never been possible with palladium, nickel, and copper catalysts. Benzyl, methallyl, and crotyl Grignard reagents can all couple with alkyl halides. The benzylation definitely requires DPPE or DPPP as a ligand. The reaction mechanism should include the generation of an alkyl radical from the parent alkyl halide. The mechanism can be interpreted in terms of a tandem radical cyclization/cross-coupling reaction. In addition, serendipitous tandem radical cyclization/cyclopropanation/carbonyl allylation of 5-alkoxy-6-halo-4-oxa-1-hexene derivatives is also described. The intermediacy of a carbon-centered radical results in the loss of the original stereochemistry of the parent alkyl halides, creating the potential for asymmetric cross-coupling of racemic alkyl halides.

Kumada—Corriu Reactions of Alkyl Halides with Alkynyl Nucleophiles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Condensed Isoquinolines. 17. Enamine Properties of Benzimidazo[1,2-b]isoquinolin-11(5H)-one in Alkylation Reactions

The alkylation of benzimidazo[1,2-b]isoquinolin-11(5H)-one has been studied. This occurs at N(5) or C(6) depending on the type of alkylating agent and the reaction conditions. It was shown that C(6) alkylation is effected in reactions with reactive alkyl halides. A repeat alkylation occurs preferentially at the same position. Interaction with o-xylylidene dibromide leads to spiro[benzimidazo[1,2-b]-isoquinolin-6,2'-indan]-11-one and 1,6-dihydro-11H-6a,11b-diazobenzo[b]benzo[5,6]cyclohepta[1,2,3-l,m]fluoren-11-one, which are derivatives of new heterocyclic systems.

Radical Reactions Using Decacarbonyldimanganese under Biphasic Conditions.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Nickel‐Catalyzed Regioselective Three Component Coupling Reaction of Alkyl Halides, Butadienes, and Ar‐M (M=MgX, ZnX)

AbstractA new method for the regioselective three component cross‐coupling reaction of alkyl halides, 1,3‐butadienes, and aryl‐Grignard reagents has been developed by the use of a nickel catalyst. This reaction proceeds efficiently at 25 °C using (dppf)NiCl2 as a catalyst. Alkyl chlorides, bromides, and iodides can be used as suitable alkylating reagents. The reaction also proceeds when arylzinc halides are used instead of Grignard reagents. Competitive reactions of a mixture of primary, secondary, and tertiary alkyl bromides showed that the reactivities of the halides increase in the order primary&lt;secondary&lt;tertiary. A possible reaction pathway involving single electron transfer from a nickelate complex to alkyl halides is proposed.

Regioselectivity in Alkylation Reactions of 1,2‐O‐Stannylene Acetals of D‐Arabinofuranose.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Kumada-Corriu reactions of alkyl halides with alkynyl nucleophiles.

[reaction: see text] Pd(2)(dba)(3)-Ph(3)P-catalyzed Kumada-Corriu coupling reactions of unactivated alkyl bromides or iodides with an alkynyl nucleophile furnish C(sp)-C(sp)3 bond formation. Alkynyl nucleophiles can be alkynyllithiums or the corresponding Grignard reagents. The superior performance of Ph(3)P ligand over the trialkylphosphine ligands indicates that this cross-coupling reaction may be a reductive-elimination-controlled process.

Radical Reactions Using Decacarbonyldimanganese under Biphasic Conditions

AbstractRadical reactions of alkyl halides, initiated by photolysis in the presence of decacarbonyldimanganese, can be performed in biphasic media. Reactions in the presence of aqueous sodium hydroxide together with a phase‐transfer catalyst result in the efficient removal of manganese halide by‐products and also lead to the regeneration of decacarbonyldimanganese. A range of efficient radical couplings, cyclisations and intermolecular addition reactions were performed under these conditions. This included the development of a new tandem radical addition−ionic cyclisation sequence that was employed in a short approach to (±)‐coronamic acid. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2004)