Cycloalkane Nomenclature and Conformation

Rotation of the rear carbon of the staggered conformation by 60° gives the eclipsed conformation shown. 

PROBLEM 2.9 Draw Newman projections for two different staggered conformations of butane (looking end-on at the bond between carbon-2 and carbon-3), and predict which of the two conformations is more stable. (If you have a model kit, build a model of butane to help you visualize the Newman projections.) 

The most important thing to remember about conformers is that they are just different forms of a single molecule that can be interconverted by rotational motions about single (sigma) bonds. More often than not, there is sufficient thermal energy for this rotation at room temperature. Consequently, at room temperature, it is usually not possible to separate conformers from one another. 

Cycloalkanes are saturated hydrocarbons that have at least one ring of carbon atoms. A common example is cyclohexane. 

Cycloalkanes are named by placing the prefix cyclo- before the alkane name that corresponds to the number of carbon atoms in the ring. The structures and names of the first six unsubstituted cycloalkanes are as follows  

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