Halogenation cycloalkanes

No, we will not attempt to discuss these halogenated cycloalkanes in the current chapter. Rather, we will discuss comparatively well-defined, and therefore relatively conceptually simple, species which gained prominence in our efforts simply because the desired thermochemical data are available. The initial post-introduction and technical section of this chapter relates to the energetics of mono-and di-halogenated derivatives of... 

The reactivities of primary, secondary and tertiary halides are largely dependent on the reagents employed. The ring size of halogenated cycloalkanes and the steric environment also influence the rate of reduction. In general, when the reduction proceeds through an 5n2 type of reaction, primary halides are most easily reduced. On the other hand, when the reduction proceeds through an 5n1 process or involves free radicals as intermediates, the order of reduction falls in the expected sequence tertiary > secondary > primary. 

Chiraldex B -TA Broad range, alkyl alcohols, halogen acid esters, amino alkanes, amino acids derivatives, halogenated cycloalkanes, certain lactones, diols, alkyl halides, furan and pyran derivatives. 

Komplexe Kupferhydride reduzieren ebenfalls prim., sek. und tert. Halogen-alkane und -cycloalkane mit guten Ausbeuten zu den entsprechenden Kohlenwasserstoffen3 (weiteres s. S. 400). 

Tab. 31 Alkane bzw. Cycloalkane durch selektive Reduktion von Halogen-Verbindungen...

Given the IUPAC name of an alkane or cycloalkane, or a halogen-substituted alkane or cycloalkane, draw its structural formula. 

Given the structural formula of an alkane or cycloalkane or a halogenated derivative, write the correct IUPAC name. 

In all there are about seventy different haloalkane species which have been detected in the atmosphere, together with more than twenty haloalkenes, nearly one-hundred halo-genated cycloalkane and aromatic compounds and about forty halogenated pesticides10. In view of their greater abundances, this review will focus upon the atmospheric chemistry of CFCs, HCFCs and HFCs. 

Reductive dehalogenation is an efficient method of synthesis of cyclopropanes spiroannulated to five- and higher-membered carbocycles (i.e. compounds in which spiroannulation does not result in accumulation of extra strain) . The required gem-(dihalomethyl)cycloalkanes are usually prepared by halogenation of the precursor diols (equation 1). The cyclization is most efficiently accomplished in the Zn-alcohol-water system . For example, spiro[2.5]octane 7 was prepared in 91% yield using this procedure. This method is useful even for a one-step preparation of bis-spirocyclopropyl compounds as exemplified in equation 2. However, the application of the reductive dehalogenation method to the synthesis of more strained SPC (i.e. spirohexane or spiropentane) often leads to rearranged products. For example, methylenecyclopentane was the only product obtained from bis(bromomethyl)cyclobutane (equation 3) ... 

It has been initially proposed that the electrochemical formation of cycloalkanes from a,co-dihaloalkanes involves a concerted mechanism in which a two-electron cleavage of one C-X bond to form a carbanion takes place simultaneously with the displacement of the second halogen. Later, Fry and Britton questioned this mechanism and suggested a... 

Furthermore when the effect of diluent on the extraction efficiency of TOPO for uranium(VI) is examined in the extraction of aqueous solutions containing 5 g/1 of uranyl salts in nitric and sulphuric acids, it is found from some representative data (Table 3) that hydrocarbons such as alkane or cycloalkane enhance the extraction efficiencies in all systems, while halogen-substituted hydrocarbon such as chloroform reduces them. 

Die Herstellung von Alkanen aus Hydroxy-alkanen durch Reduktion mit Alkalimetal-len ist prinzipiell durchfiihrbar, praktisch jedoch ohne Bedeutung, da man besser entweder den Alkohol in das Halogen-Derivat oder durch Wasser-Abspaltung in das Aiken iiber-fiihrt und dann zum Alkan bzw. Cycloalkan reduziert s.ds. Handb. V/1 a, S. 20ff., 281 ff. 

Alkanes and cycloalkanes can also react with a halogen (usually chlorine or bromine) in a reaction called halogenation. Halogenation is a substitution reaction, that is, a reaction that results in the replacement of one group for another. In... 

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