Alkyl bromides nitrile

Carboxylic acid Ketone Aldehyde Amide 1° amine 2° amine 3° amine Alkyl chloride Alkyl bromide Nitrile... 

Alkyl-bromide und -jodide reagieren mit dem am meisten gebrauchten Tributyl-zinn-hydrid spontan, wahrend Chlor-alkane nur in der Hitze oder durch Kettenstarter wie Azo-bis-isobutansaure-nitril bzw. Belichtung initiiert reduziert werden. Fluor-alkane werden nicht angegriffen. 

A new route to nitrile oxides based on the reaction of primary alkyl bromides with NaN02 in the presence of acetic acid, is also reported (Eq. 6.35).60 This reaction is used for the direct... 

Alkynes are usually alkylated under strongly basic conditions. Gregory Fu of MIT recently reported (J. Am. Chem. Soc. 125 13642, 2003) a much milder Pd and Cu mediated coupling, illustrated by the reaction of the terminal alkyne 7 with the alkyl iodide 8 to give 9. Alkyl bromides work equally well. It is exciting that ketones, esters, alkyl chlorides, alkenes, nitriles and acetals are compatible with the procedure. The key to the reaction is the use of the supporting carbene ligand 10. 

In the presence of AgBF4, JV-alkyl derivatives of nitriles have been prepared by reaction with alkyl bromides. The first step was believed to involve the formation of species such as [Ag(RCN)4]BF4.159... 

Fiirstner reported in parallel coupling reactions using 5 mol% of the isolated ferrate(-II) catalyst [Li(TMEDA)]2[Fe(C2H4)4] 4 in THF (Fig. 2) (entry 2) [45, 46], Primary and secondary alkyl bromides and iodides and allylic halides worked well, while alkyl chlorides and tertiary alkyl iodides were inert. Many sensitive functionalities like ester, nitrile, isocyanate, epoxide, and amine groups are tolerated. 

Giese and coworkers determined on the basis of experimental results obtained by Scheffold et al. [268, 299] that addition reactions of alkyl bromides 249 to a,p-unsaturated nitriles or esters 248 catalyzed by cobalamine 247 are free radical reactions (Fig. 61) [300], This conclusion was based on the similar cis/trans-selectivities in addition reactions of the 4-tert-butylcyclohexyl radical to different electron-poor alkenes 248 using 247 as a catalyst on one hand and classical tributyltin hydride conditions on the other. The kinetics of the radical addition was determined. 

Li2CuCl4 in THF-NMP efficiently catalyzes the reaction of alkenyl Grignard reagents with primary alkyl bromides. Functional groups (ketone, ester, nitrile, sulfonate) are tolerated in this reaction (Scheme 34).91... 

You saw in Chapter 21 how carbonyls form enolates when they are treated with base. On p. 528, you met nitriles doing something very similar, and the first step of the grandisol synthesis is the reaction of the enolate of a nitrile with an electrophile—an alkyl bromide. 

The alkylation of nitriles has been developed as a general method for the preparation of substituted acetonitriles. An excellent discussion of the literature to 1937 has been given. The procedure consists in treating a nitrile in an inert solvent with finely divided sodium amide and the halogenated compound, followed by careful hydrolysis with water. Common solvents are ether, benzene, toluene, or liquid ammonia. Mono-, di-, and tri-alkylated products are possible, as shown by the alkylation of acetonitrile with ethyl bromide however, the mixtures can often be separated by fractional distillation. 

From 94, several compounds were generated such as the 3-thioalkyl compounds 96 (40-67%) by reaction with alkyl bromides. Intermediate 94 was also treated with HCl, iodine, 1,3-dibromopropane or with ethyl chlorocar-bonate affording the mercaptane 97 (68%), the disulfide 98 (45%, n = 0), compound 99 (37%, = 3) and the thiocarbonate 100 (67%), respectively. By a partial hydrolysis of the nitrile group with H2SO4 at reflux, carboxamides lOla-b (92%) were prepared from 96. The same reagents 96 can be transformed into methyl esters 102 (Scheme 26). 

The reaction employed was the substitution of the bromine of 1-bromohexane by nitrile anion. The alkyl bromide composed one phase and a concentrated aqueous solution of either KCN or NaCN made up the other phase. The crown ethers functioned as soluble PTC s while polymer 2 suspended at the interface served as an insoluble catalyst. A reaction temperature of 85° was employed to give reasonable conversion times. The reactions were followed with NMR by monitoring the integrated intensities of the hydrogens adjacent to the halide and nitrile groups. The two triplets associated with these peaks are well separated at 3.236 and 2.156 allowing direct comparison of their relative ratios in the reaction mixtures. While this method has limited accuracy, it does allow rapid initial evaluations. Figure 3 shows the relative rates of conversion of 1-bromohexane to the nitrile with KCN. 

It has also been shown that Ni complexes can successfully carry out intramolecular or intermolecular electroreductive addition of alkyl radicals to activated olefins. Thus bicyelic ketones 78 and 80 are conveniently prepared in good yields from 2-bromoalkyl-2-cyclohexenone 77 and 3-bromoalkyl-2-cyclohexenone 79, respectively [25]. Alkyl bromides also react with a,) -unsaturated esters and nitriles to give 1,4-addition products in moderate yields [26]. 

Reduction of the nitro group and halides. Amines are obtained in good yields. The reduction can also be performed by a reagent generated from borohydride resin. The latter reagent converts alkyl bromides and iodides to the hydrocarbons, whereas chlorides, tosylates, esters, and nitriles are not affected. 

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