ALKENES ALKYNES AND AROMATIC COMPOUNDS Alkenes contain at

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ALKENES, ALKYNES AND AROMATIC COMPOUNDS

ALKENES, ALKYNES AND AROMATIC COMPOUNDS

■ Alkenes – contain at least one double bond ■ Alkynes – contain at

■ Alkenes – contain at least one double bond ■ Alkynes – contain at least one triple bond ■ Aromatic compounds – based on a benzene ring ■ Note: alkenes and alkynes are sometimes referred to as “unsaturated” hydrocarbons ■ Alkanes are referred to as “saturated” hydrocarbons ■ Aromatic compounds are usually classified separately [even though they have double bonds, they behave very differently]

Naming Alkenes and Alkynes: ■ Key changes: Ø find the longest chain that includes

Naming Alkenes and Alkynes: ■ Key changes: Ø find the longest chain that includes the double or triple bond Ø the first carbon of the double or triple bond should have the lowest number possible Ø the suffix changes to –ene or –yne and has a number indicating its location in the name For example:

■ Go to powerpoint and video on skeletal formulas

■ Go to powerpoint and video on skeletal formulas

Alkenes: cis- and trans- isomers

Alkenes: cis- and trans- isomers

Aromatic Compounds:

Aromatic Compounds:

Naming aromatic compounds: 1. Number the carbons in the benzene ring. If more than

Naming aromatic compounds: 1. Number the carbons in the benzene ring. If more than one type of branch is attached, start numbering at the carbon with the most complex group attached. 2. Name any branches attached to the benzene ring. Give these branches position numbers. If only one group is attached, no numbers are needed. 3. Use the number and name of the branch as the prefix. Attach this to the root benzene. 4. Another common convention: – Substituents at the 1 and 2 position are referred to as ortho- (o-) – Substituents at the 1 and 3 position are referred to as meta- (m-) – Substituents at the 1 and 4 position are referred to as para- (p-) – no numbers are used if this convention is employed