By the Wurtz reaction

Cyclopropanes undergo a ready reaction with bromine to give 1,3-dibromopropane, and can in turn be formed from 1,3-dibromopropane by the Wurtz reaction. A variation... 

Note. (1) All hydrocarbons prepared by the Wurtz reaction contain small quantities of unsaturated hydrocarbons. These may be removed by shaking repeatedly with 10 per cent of the volume of concentrated sulphuric acid until the acid is no longer coloured (or is at most extremely pale yellow) each shaking should be of about 5 minutes duration. The hydrocarbon is washed with water, 10 per cent sodium carbonate solution, water (twice), and dried with magnesium sulphate or anhydrous calcium sulphate. It is then distilled from sodium two distillations are usually necessary. 

Diphenyl-methylphenyl polysilane copolymer films synthesized by the Wurtz reaction were spin casted on silicon substrates.78 The copolymer shows a narrow PL at room temperature in the NUV region, which can be used for LEDs. PL shows a sharp peak at 368 nm with a FWHM of 24 nm. The potential of the high-purity material as a source of blue or NUV emitter is necessary to obtain a low value for the FWHM. Although all emissions are at 369 nm, the PL intensity is a function of the concentration of the polymer in the solvent related to the thickness of the film. 

This is exactly analogous to the preparation of paraffin homologues by the Wurtz 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. 

The Wittig reaction is employed industrially as in the BASF syntheses for Vitamin A and jS-carotene. Laboratory methods have to be modified for industrial practice. Triphenylphosphine is obtained by the Wurtz reaction (p. 126). The triphenylphosphine oxide recovered after reaction is reconverted into Ph3P by treatment first with phosgene and then with phosphorus. 

This reaction is precisely parallel to the Wurtz Reaction in the aliphatic series, by which, for instance, n-butane can be obtained by the action of sodium on ethyl bromide. 

Aliphatic hydrocarbons can be prepared by the reduction of the readily accessible ketones with amalgamated zinc and concentrated hydrochloric acid (Clemmensen method of reduction). This procedure is particularly valuable for the prep>aration of hydrocarbons wdth an odd number of carbon atoms where the Wurtz reaction cannot be applied with the higher hydrocarbons some secondary alcohol is produced, which must be removed by repeated distillation from sodium. 

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 ... 

Dehydrochlorination to Epoxides. The most useful chemical reaction of chlorohydrins is dehydrochlotination to form epoxides (oxkanes). This reaction was first described by Wurtz in 1859 (12) in which ethylene chlorohydria and propylene chlorohydria were treated with aqueous potassium hydroxide [1310-58-3] to form ethylene oxide and propylene oxide, respectively. For many years both of these epoxides were produced industrially by the dehydrochlotination reaction. In the past 40 years, the ethylene oxide process based on chlorohydria has been replaced by the dkect oxidation of ethylene over silver catalysts. However, such epoxides as propylene oxide (qv) and epichl orohydrin are stiU manufactured by processes that involve chlorohydria intermediates. 

The coupling of alkyl halides 1 upon treatment with a metal, e.g. elemental sodium, to yield symmetrical alkanes 2, is called the Wurtz reaction. Aryl alkanes can be prepared by the Wurtz-Fittig reaction, i.e. the coupling of aryl halides with alkyl halides. 

The mechanism is not known with certainty. It seems likely that it is basically a two-step process, similar to that of the Wurtz reaction (10-93), which can be represented schematically by... 

This is, of course, the Wurtz reaction, and support for such a mechanism involving carbanions (radicals may be involved under some conditions, however) is provided by the observation that in some cases it is possible, with optically active halides, to demonstrate inversion of configuration at the carbon atom undergoing nucleophilic attack. The carbanion, e.g. (61), can also act as a base and promote elimination ... 

Most polysilanes are synthesized by the Wurtz-type coupling reaction, which is non-stereospecific, and hence the configuration is usually undefined, although in a few cases, stereochemically defined polysilanes have been synthesized (ROP of all-anti l,2,3,4-tetramethyl-l,2,3,4-tetraphenylcyclotetrasilane99 101 and masked disilene polymerization).61... 

Many reducing agents are capable of severing a carbon-halogen bond. Cathodic cleavage provides perhaps the most versatile method, and has been put to excellent use. The electrochemical variation of the Wurtz reaction constitutes a powerful method for the construction of a variety of rings, particularly strained systems. Dramatic examples are provided by the assembly of bicyclobutane (308) [89], bicyclohexene (310) [90-92], [2.2.2]propellane (312) [93], spiropentane (316) [94], j -lactams 318 [95], and a variety of small-ring heterocycles (320) [96,97]. 

A senes of cyclopolyarsines is known. They may be prepared by a generally useful reaction that is reminiscent of the Wurtz reaction of orgunomctallic chemistry ... 

H. Rose found the syrupy liquid crystallized when kept in vacuo. C. A. Wurtz said the salt can be dried at 280° without decomposition. P. L. Dulong said that the salt is deliquescent in air, and insoluble in alcohol. According to A. Gutmann, a cold or boiling soln. of sodium thiosulphate does not act on sodium or potassium phosphite—vide the arsenites. N. N. Mittra and N. R. Dhar found that the reaction with mercuric chloride and sodium phosphite as primary reactions is hastened by the simultaneous reaction of mercuric chloride with sodium arsenite or arsenious acid. 

While method A furnished only dimethyl(vinyl)silane (see Section IILC.l.a), the Wurtz reaction (method B) in an inert solvent gave a mixture of products which stem either from the a-elimination generating 3a or from the C,C coupling process leading to 158 (equation 38)55. It is assumed that 3a forms 1,1-dimethylsilirane by 1,3-C,H insertion (cf equation 23) and that C,C and Si,C cleavage of this sensitive ring system by (trimethylsi-lyl)methyl sodium is responsible for the formation of 159-161 (combined yield 32%). It is obvious that, due to the complexity of this reaction, method B cannot serve as a versatile entry into the chemistry of 3a. 

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