Cycloalkanes Worksheet - Answer Key
- In cycloalkanes with an attached alkyl substituent, the ring is the parent hydrocarbon, unless the substituent has more carbon atoms than in the ring. If there is only one substituent on a ring, do not give that substituent a number.
- Name: ethylcyclobutane
- If the ring has two substituents they are cited in alphabetical order and the number one position is given to the substituent cited first.
- Name: 1 – ethyl – 2 – methylcyclopentane
In this case the numbering is the same regardless of direction that you count the chain. So we have the flexibility to given the lower number preference to the substituents that is listed first.
- If there is more than two substituents, the substituent given the number one is the one that results in a second substituent getting as low a number as possible. If two substituents have the same low number, the ring is numbered in the direction that gives the third substituent the lowest number possible.
- Name: 4 – ethyl – 1,2 – dimethylcyclohexane
In this case we are more concerned with achieving lowest possible numbers. So the fact the ethyl is listed first does not factor into the numbering scheme.
- Give the systematic name for the following
- Name: 2 – cyclopropylpentane
- Name: 1 – ethyl – 3 – (2 – methylpropyl)cyclohexane
