CHEM 250 Chapter Notes - Chapter 4: Substituent, Butane, Newman Projection
Document Summary
The chemistry of cycloalkanes is like that of open-chain alkanes: both are nonpolar and fairly inert. Cycloalkanes are less flexible and there is much less rotational freedom around single bonds in cycloalkanes. In cyclopropane, no bond rotation can take place around a cyclopropane carbon-carbon bond without breaking open the ring. Larger cycloalkanes have increasing rotational freedom, and very large rings are so floppy that they are nearly indistinguishable from open-chain alkanes. Cycloalkanes have a top face and a bottom face which allows isomerism in substituted cycloalkanes. ex: 1,2-dimethylcyclopropane has two isomers; one with two methyl groups on the same face, and one with methyl groups on opposite faces. Unlike constitutional isomers, the two isomers of 1,2-dimethylcyclopropane have the same order of connections but differ in the spatial orientation of the atoms. The isomers seen above are a subclass of stereoisomers called cis-trans isomers. The following prefixes are used to distinguish the two: cis-: on the same side, trans-: across.
