Alicyclics & Aromatics

Cyclic hydrocarbons, or alicyclics are ring-shaped structures that can act as either a parent chain of a side group.

• general formula = CNH2N
• more reactive as opposed to straight-chains
• numbering can start anywhere on the ring, but the #'s of the side chains must be the lowest possible numbers
• prefix "cyclo-" is added to the beginning of the parent chain

Naming

Cycloalkanes

1. count length of carbon chain
2. similar naming rules as straight-chains
3. if the numbers of the side groups are equal (ex. 2,4,6 either way you count) then you give the lower number to the side group that comes first in the alphabet

Cycloalkenes & Cycloalkynes

1. similar naming to cycloalkanes, except with different endings
2. more reactive than cycloalkanes
3. when numbering the double/triple bonds, they should always be located at the first and second carbons

Aromatics

Properties

• electrons are "delocalized" meaning they can move around the ring and are shared equally in the ring
• carbon-carbon bonds have same reactivity because of delocalization
• less reactive structures than cycloalkanes
• have a nice odour
• contains atleast one benzene ring

Naming

• can be a parent or side chain
• as a side chain, its given the name "phenyl"
• as a parent chain, "benzene" is added to the end of the whole name

Ex. Name the structures:
                                                 
                                                              cyclopentyne


                                       
                                                       4-chlorocyclohexene


All this organic chemistry is tough! It's a lot to memorize and there are a lot of rules to follow. But rest assured, it gets easier. Try these exercises. After all, practice makes perfect right? :)