Multicyclic alkanes26.3 Multicyclic alkanes.
Multicyclic alkanesare hydrocarbons that havemore than one bonded cyclic ring. These
abound in biology as all kinds of hormones, steroids, cholesterol,carbohydrates, etc.
They are named as bicycloalkanes, tricycloalkanes, etc.
They are named slightly differently than singularly cyclic alkanes.
Figure 70
Bicyclo[2.1.0]pentane
Multicyclic alkanes are found frequently in living beings:
Figure 71
Part of Cholesterol
We will get to some of the most interesting multicyclic rings later on when we study benzene
and aromaticity.
26.4 Stereochemistry
BecausetheC-Cbondsincyclescannotrotatethrough360degrees, substitutedcycloalkanes
and similar compounds can exhibit diastereomerism^1. This is comparable to alkenes which
show cis/trans (or E/Z) isomerism. The isomers can be named using cis/trans notation^2 ,
or more rigorously using R-S notation^3.
1 Chapter 36 on page 151
2 Chapter37.1on page 153
3 Chapter 41 on page 163