Wurtz reaction intramolecular

In the case of an intramolecular Wurtz reaction less side-reactions are observed this variant is especially useful for the construction of strained carbon skeletons. For example bicyclobutane 5 has been prepared from l-bromo-3-chlorocyclobutane 4 in a yield of > 90% ... 

The procedure provides a good example of a high-yield intramolecular Wurtz reaction. Internjolecular Wurtz reactions normally do not give high yields of coupled products and are accompanied by formation of alkenes and alkanes corresponding to the alkyl halide.7 In contrast, intramolecular reactions of... 

Metals other than sodium may be considered for the reduction in intramolecular Wurtz reactions.11 One of the most common of these is zinc under various reaction conditions. Examples of use of this reagent that have resulted in high yields of cyclopropane and derivatives of cyclopropane include cyclopropane from... 

Butenyl)-, (2,3-dimethyl-3-butenyl)- and (4-pentenyl)-dimethylsilyl)]carbene have been generated by treatment of the corresponding chloromethylsilanes with sodium. Intramolecular [1 + 2] cycloaddition of the carbenic carbon atom to the double bond leads to l-silabicyclo[3.1.0]hexanes and l-silabicyclo[4.1.0]heptanes, respectively, usually in competition with intramolecular C,H insertion (equation 24)56. In contrast, no carbene-derived product could be obtained from (allyldimethylsilyl)carbene. Finally, reaction of chloromethyldimethylvinylsilane with sodium provided, besides the typical products of a Wurtz reaction (103 and 104), a small amount of cyclopropane 106 (equation 26)56. It has been suggested that (dimethylvinylsilyl)carbene (102) isomerizes to silabicyclo[1.1.0]butane 105 by intramolecular cyclopropanation, and nucleophilic ringopening finally leads to 106. 

Paracyclophane has been isolated from the pyrolysis of p-xylene and by dimerization of / -xylylene. Paracydophanes have been synthesized by intramolecular Wurtz reactions at high dilution. ... 

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. 

Then methylenecyclopropane was synthesized by reaction of potassium vapour with l-iodo-2-iodomethyl-2-propene in a form of intramolecular Wurtz reaction [3] ... 

Hence this chapter provides analogy between silylene and carbene chemistry as a useful approach for construction of small-ring monosilacycles. Furthermore, intramolecular Wurtz, Diyne coupling, Kipping and Gilman reactions have been shown to be useful tools for construction of medium-ring oligosilacycles. 

The Wurtz Coupling is one of the oldest organic reactions, and produces the simple dimer derived from two equivalents of alkyl halide. The intramolecular version of the reaction has also found application in the preparation of strained ring compounds ... 

The intramolecular Wurtz-type coupling of dihaloorganic compounds with use of metallic zinc is a classical synthetic route to cyclic compounds. For example, cyclopropane derivatives can be prepared from 1,3-dihalo-propanes (29, 189a, 248, 451), and cyclobutane derivatives from 1,4-dihalobutanes (71). These reactions presumably proceed via the intermediate formation of organozinc compounds. The reaction of diethylzinc with esters of a,a -dibrominated aliphatic dicarboxylic acids leads to the... 

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