Cyclopentane Hydrogen chloride

Other Cycloalkanes. Hydrogen chloride promoted monoethylation of other cycloparaffins (e.g., cyclopentane, methylcyclopentane and methylcyclohexane) and many paraffins (e.g., propane, isobutane, n -pentane, isopentane, 2,2-dimethylbutane, 2,3-dimethylbutane, n-heptane and 2,2,4-trimethylpentane). 

Diels-Alder reactions of, 386 reaction with hydrogen chloride, 379—380 Cyclopentadienide anion, 428, 436 Cyclopentane, 70... 

It may be prepared by the condensation of 1-phenyl-cyclopentane carbonyl chloride with 2-(diethylaminoethoxy) ethanol to yield carbetapentane base by the elimination of a mole of hydrogen chloride. The base is dissolved in ethanol and treated with a equimolar portion of citric acid to give the official compound. 

Chlorinations are important, particularly in industry, simply because chlorine is inexpensive. (It is prepared by electrolysis of hydrogen chloride, HCl.) The drawback to chlorination is low selectivity, so the process results in mixtures of isomers that are difficult to separate. To circumvent the problem, an alkane that contains a single type of hydrogen can be used as a substrate, thus giving (at least initially) a single product. Cyclopentane is one such alkane. We depict it using the bond-line notation (Section 1-9). 

DIBAL-H/n-butyllithium, in cyclic and acyclic systems with iron pentacarbonyl, in cyclodecanes with lithium dihydrodimethoxyaluminate(III)/copper(I) iodide, and in cyclohexane and cyclopentane systems with NaH/sodium r-butylpentyl/Ni(OAc)2. ° The monoreduction of 1,3-diketones can be carried out under similar conditions, as illustrated by the reaction of a substituted cyclohexane-1,3-dione with oxalyl chloride to give the corresponding 1-chlorocyclohexenone, which was subsequently reduced to the enone with zinc-silver couple (Scheme 45). Kropp et al. have reported the photolytic reduction of vinyl iodides in acyclic systems however, when an a-hydrogen is present, formation of the diene product is a limiting side reaction (Scheme 46). For a more extensive discussion of vinyl halide reductions, see the preceding chapter in this volume. 

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