Copper alkyl halides

This zinc-copper couple reacts with methanol, the mixture reducing an alkyl halide to an alkane ... 

A key step in the reaction mechanism appears to be nucleophilic attack on the alkyl halide by the negatively charged copper atom but the details of the mechanism are not well understood Indeed there is probably more than one mechanism by which cuprates react with organic halogen compounds Vinyl halides and aryl halides are known to be very unreactive toward nucleophilic attack yet react with lithium dialkylcuprates... 

The direct process is less flexible than the Grignard process and is restricted primarily to the production of the, nevertheless all-important, methyl- and phenyl-chlorosilanes. The main reason for this is that higher alkyl halides than methyl chloride decompose at the reaction temperature and give poor yields of the desired products and also the fact that the copper catalyst is only really effective with methyl chloride. 

Tnfluorometltylation of aryl, alkenyl, and alkyl halides can be accomplished by heating methyl fluorosulfonyldifluoroacetate and the appropriate halide precursor with copper(I) iodide at 60-80 °C in DMF [27 7] (equation 145). Similar trifluoromethylations of aryl, benzyl, and vinyl halides can be carried out with fluorosulfonyldifluoromethyl iodide and copper metal in DMF at 60-80 °C [2 75] (equation 146). 

M-C(t bonds can be formed by each of the metals. The simple alkyls and ai7ls of Ag are less stable than those of Cu while those of Au have not been isolated. Copper alkyls and ai7ls are prepared by the action of LiR or a Grignard reagent on a Cu halide ... 

The benzodithiepines 126 and 127 have been used as formyl and acyl anion equivalents, respectively, although the range of electrophiles was restricted to alkyl halides (75S720) and epifluorohydrin (72TL1837). The carbonyl products were formed by hydrolysis with either mercury or copper salts. 

A microwave-assisted three-component reaction has been used to prepare a series of 1,4-disubstituted-1,2,3-triazoles with complete control of regiose-lectivity by click chemistry , a fast and efficient approach to novel functionalized compounds using near perfect reactions [76]. In this user-friendly procedure for the copper(l) catalyzed 1,3-dipolar cycloaddition of azides and alkynes, irradiation of an alkyl halide, sodium azide, an alkyne and the Cu(l) catalyst, produced by the comproportionation of Cu(0) and Cu(ll), at 125 °C for 10-15 min, or at 75 °C for certain substrates, generated the organic azide in situ and gave the 1,4-disubstituted regioisomer 43 in 81-93% yield, with no contamination by the 1,5-regioisomer (Scheme 18). 

Primary, secondary, and tertiary aliphatic amines have been cleaved to give aldehydes, ketones, or carboxylic acids with aqueous bromine and with neutral permanganate. The other product of this reaction is the amine with one less alkyl group. In a different type of procedure, primary alkyl primary amines can be converted to ge/n-dihalides, RCH2NH2 —> RCHX2 (X =Br or Cl), by treatment with an alkyl nitrite and the anhydrous copper(I) halide. 

Li, D., Che, C.-M., Kwong, H.-L. and Yam, V.W.-W. (1992) Photoinduced C-C bond formation from alkyl halides catalysed by luminescent dinuclear gold(I) and copper(l) complexes. Journal of the Chemical Society, Dalton Transactions, 3325-3329. 

Scheme 5.7 illustrates these and other applications of the hydride donors. Entries 1 and 2 are examples of reduction of alkyl halides, whereas Entry 3 shows removal of an aromatic halogen. Entries 4 to 6 are sulfonate displacements, with the last example using a copper hydride reagent. Entry 7 is an epoxide ring opening. Entries 8 and 9 illustrate the difference in ease of reduction of alkynes with and without hydroxy participation. 

Luche reported that when a zinc-copper couple was used, alkyl halides reacted with conjugated carbonyl compounds and nitriles to give 1,4-addition products in good yields under sonication conditions (Eq. 10.26).57... 

There are several guidelines that should be followed in order to increase the chemoselectivity of the monoadduct. Firstly, radical concentration must be low in order to suppress radical termination reactions (rate constant of activation [fcal and fca2] < < rate constant of deactivation kd t andfcd2]). Secondly, further activation of the monoadduct should be avoided ( al> >kd2). Lastly, formation of oligomers should be suppressed, indicating that the rate of deactivation (kd 2[Cu"LmX]) should be much larger than the rate of propagation ( [alkene]). Alkyl halides for copper-catalyzed ATRA are typically chosen such that if addition occurs, then the newly... 

TMC ATRA reactions can also be conducted intramolecularly when alkyl halide and alkene functionalities are part of the same molecule. Intramolecular TMC ATRA or atom transfer radical cyclization (ATRC) is a very attractive synthetic tool because it enables the synthesis of functionalized ring systems that can be used as starting materials for the preparation of complex organic molecules [10,11], Furthermore, halide functionality in the resulting product can be very beneficial because it can be easily reduced, eliminated, displaced, converted to a Grignard reagent, or if desired serve as a further radical precursor. The use of copper-mediated ATRC in organic synthesis has been reviewed recently and some illustrative examples are shown in Scheme 3 [10,11,31,32,33],... 

Scheme 5 Examples of vinyl monomers (a) and alkyl halide initiators (b) that are used in copper-mediated ATRP...

ATRP, other factors, such as solvent and temperature, must also be taken into consideration. Typical monomers and alkyl halide initiators that are used in ATRP are shown in Scheme 5 [47], The copper complex is perhaps the most important component of this catalytic system because it regulates the dynamic equilibrium between dormant and active species. In this article, structural and mechanistic aspects of copper-catalyzed ATRP are discussed. 

Activation rate constants (k) in ATRP/ATRA are typically determined from model studies in which copper complex is reacted with alkyl halide in the presence of radical trapping agents such as TEMPO [127,128,129], Rates are determined by monitoring the rate of disappearance of alkyl halide in the presence of large excess of the activator (Cu X/L) and TEMPO. Under such pseudo-first order conditions, the activation rate constant can be calculated ln([RX]0/[RX]() vs.t plots (slope =-k) Cu C/... 

ARGET ATRP has been successfully applied for polymerization of methyl methacrylate, ft-butyl acrylate and styrene in the presence of Sn(EH)2 (10 mol% vs. alkyl halide initiator or 0.07 mol% vs. monomer) [164,165]. For all monomers, polymerizations were well controlled using between 10 and 50 ppm of copper complexes with highly active TPMA and Me6TREN ligands. ARGET ATRP has also been utilized in the synthesis of block copolymers (poly(n-butyl acrylate)— -polystyrene and polystyrene-Z -poly(n-butyl acrylate) [164,165] and grafting... 

The action of alkyl halides on elemental germanium in the presence of a copper/gallium catalyst leads to the simultaneous preparation of several or all of the above-mentioned organogermanium halides248 ... 

A mixture of (triisopropyl phosphito)copper(I) bromide (17.6 g, 0.05 mol) and l-bromo-2,2-diphenylethylene (9.1 g, 0.035 mol) was heated at 200°C for 1 h under a nitrogen atmosphere in a flask equipped with a Vigreaux column topped by a Dean-Stark trap. The alkyl halide produced in the reaction was collected in the trap. After cooling, the reaction mixture was poured into toluene (60 ml), and ethylenedi-amine was added (5 ml). After filtering and washing the precipitate with toluene, the combined toluene solutions were washed with 10% hydrochloric acid (10 ml) and water (10 ml), dried over magnesium... 

Reactions with cyclopropene.11 Lithium organocuprates react with the cyclo-propenone ketal 1 (12, 152-154) to form a copper species (a) that behaves as an enolate of a cyclopropanone. Thus it reacts with alkyl halides to form cis-2,3-disubstituted derivatives of 1. 

The C-H bond in CBnHi2 and related anions can be metallated by butyllithium and then converted into C-substituted anions with aldehydes, alkyl halides, Ph3SiCl, and Ph2PCl.322-329 C-halogenated (F,Cl,Br, or I) derivatives are made from the C-copper derivative with (PhS02)2NF or the corresponding N-halosuccinimide.330 The l-Me-2,3>4,5,6,7,8,9,10,ll>12-Fu-CBii- anion is made from the reaction of the corresponding Fn anion with... 

---