Wurtz reaction compounds

The Wurtz reaction, which reties on in situ formation of an active organosodium species, is also usefiil for preparing tetraorganotin compounds and is practiced commercially. Yields are usually only fair and a variety of by-products, including ditins, also form ... 

It seems likely that the mechanism of the Wurtz reaction consists of two basic steps. The first is halogen-metal exchange to give an organometallic compound (RX -(- M —+ RM), which in many cases can be isolated (12-36). Following this, the organometallic compound reacts with a second molecule of alkyl halide (RX + RM —> RR). This reaction and its mechanism are considered in the next section (10-94). 

Next to the formation of Grignard reagents, the most important application of this reaction is the conversion of alkyl and aryl halides to organolithium compounds, but it has also been carried out with many other metals, (e.g., Na, Be, Zn, Hg, As, Sb, and Sn). With sodium, the Wurtz reaction (10-93) is an important side reaction. In some cases, where the reaction between a halide and a metal is too slow, an alloy of the metal with potassium or sodium can be used instead. The most important example is the preparation of tetraethyl lead from ethyl bromide and a Pb—Na alloy. 

The Wurtz reaction between bromobenzene and 1-bromobutane, sodium being the metal, needs to be carried out between 15 and 30°C. It is difficult to start the reaction below 15°C starting compounds will accumulate and the delayed start in a halogen medium, which is too concentrated, will lead to a detonation. Above 30°C the reaction is too violent and cannot be controlled. 

The Grignard compounds react with varying ease with organic halides in the manner of the Wurtz reaction according to the equation ... 

Uses Solvent for oils, waxes, perfumes, alkaloids, fats, and gums organic synthesis (Grignard and Wurtz reactions) extractant manufacture of gun powder, ethylene, and other organic compounds analytical chemistry perfumery alcohol denaturant primer for gasoline engines anesthetic. 

Experience in the synthesis of 87 and 88 using Wurtz reactions of SiH-containing compounds with 1,2- and 1,1-dihalogenethenes suggested that they are of little use for the formation of 179 and 180. 

Which one of the given compounds cannot be produced by a Wurtz reaction ... 

The reaction of butyllithium with cellulose iodotosylate prepared by iodination of cellulose tosylate of high DS (1.65) has bwn studied. General considerations concerning the direction of the reactions proceeding in the system RX + R Li suggest that the interaction between iododeoxycellulose and organolithium compounds may involve the normal Wurtz reaction (7), the reaction of metallization (8), and the... 

The coupling of alkyl halides by treatment with sodium to give a symmetrical product is called the Wurtz reaction. Side reactions (elimination and rearrangement) are so common that the reaction is seldom used. Mixed Wurtz reactions of two alkyl halides are even less feasible because of the number of products obtained. A somewhat more useful reaction (though still not very good) takes place when a mixture of an alkyl and an aryl halide is treated with sodium to give an alkylated aromatic compound (the Wurtz-Fittig reaction)... 

J.W. Morzycki and co-workers described the synthesis of dimeric steroids to be used as components of artificial lipid bilayer membranes. The key coupling of two steroid derivatives was achieved by the Wurtz reaction. The steroid primary alkyl iodide was dissolved in anhydrous toluene and treated with an excess of sodium metal. After 20h of reflux, the desired homocoupled product was obtained in moderate yield along with a considerable amount (36%) of the reduced compound. 

Wurtz reaction The coupling of two alkyl halides, RX, with sodium metal to give the R-R compound. Usually of almost no synthetic value as there are many side reactions. However, the intramolecular reaction of l-bromo-3-chlorocyclobutane with sodium gives bicyclobutane in about 95% yield. 

In step A a carbanion is formed. In step B the carbanion reacts with a molecule of halide by one of three routes (o) a displacement reaction at a carbon atom, (6) an elimination process, or (c) a displacement reaction at a halogen atom. Each of the products shown in step B has been isolated from the reaction mixture and there is experimental evidence for each of the steps indicated. We can conclude, for example, that step A occurs in a Wurtz reaction and that rganosodium compounds do exist, since carbonation of a typical reaction mixture leads to considerable quantities of the corresponding carboxylic acid.8 Furthermore, the coupling reaction... 

Iodides, except methyl iodide, cannot be used because they undergo the Wurtz reaction too easily and thus give low yields of the organolithium compound. In the aliphatic series it is best to use chlorides, and in the aromatic series bromides. It is important that the halide be very pure. 

Carbon-linkage alkylation includes the Wurtz reaction for the preparation of aliphatic compounds ... 

In the above reaction there is both n-propylbromide and methylbromide in the mixture. According to the equation for the Wurtz reaction, these two compounds can couple to form n-butane. But, at the same time free methyl groups can combine with each other as can free propyl groups, forming ethane and hexane. This leads to a decrease in the production of n-butane. A more efficient reaction mixture would be just ethylbromide and Na. Here, the only coupled product would be n-butane... 

Closely related to the Wurtz reaction is the synthesis of organosodium compounds, such as amylsodium (25) and phenylsodium (13). These can be prepared from sodium and the organic halide by using an excess of sodium and keeping the temperature low in order to minimize the Wurtz reaction. The promising alfin catalyst for the polymerization of butadiene is prepared by a reaction of this type (24). The catalyst consists essentially of allylsodium, mixed with sodium chloride and a sodium alkoxide. 

Silica Si-OH groups can be converted to Si-Cl by chlorination, after which Grignard reaction, Wurtz reaction, or some other reaction typical of organo-halogen compounds yields chemically bonded species with Si-C linkages. 

The Wurtz reaction constitutes the direct coupling of the nucleophilic carbon of an alkylsodium compound and the electrophilic carbon in a haloalkane. It is an unselective reaction. There is no way to control it to prevent coupling of two like alkyl groups while attempting to couple two different ones. In other words, the reaction between chloroethane and 1-chloropropane gives a statistical mixture of butane (from two ethyls), pentane (from an ethyl and a propyl), and hexane (from two propyls). 

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