Review of General Chemistry
Cyclohydrocarbons
Due to angle strain, the bonds in three- and four-membered carbon rings are weak. Because of these weak bonds, cyclopropane and cyclobutane undergo reactions that are atypical of alkanes. For example, cyclopropane reacts with halogens dissolved in carbon tetra-chloride to form dihaloalkanes.
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Under similar conditions, straight-chain propane does not react.
In general, cycloalkanes undergo the normal reactions of the aliphatic alkanes (the straight-chain and branched-chain alkanes). Thus, cyclopentane will react with halogens in ultraviolet light to form halosubstituted cycloalkanes.
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Cycloalkenes and cycloalkynes undergo the ordinary addition reactions of alkenes and alkynes. Cyclopropene, cyclopropyne, cyclobutene, and cyclobutyne also undergo ring-opening reactions.
