﻿ Enynes
 Basic IUPAC Organic Nomenclature

### Enynes

The term enyne simply implies the presence of both an alkene and an alkyne.
Enynes are named in a similar manner to alkenes, alkynes and polyenes.
• The root name is based on the longest chain containing both ends of the alkene and alkyne units.
• The alkene suffix "ene" minus the last "e" is inserted after the root with its locant before the root.
• The alkyne suffix, "yne" is added at the end with its locant preceding it.
• Hence alkene +  alkyne = enyne.
• The chain is numbered in accord with the first point of difference rule to either the alkene or alkyne units the lowest possible locant.
• The locant for the lowest numbered carbon of the alkene or alkyne is used in the name.
• If there is a choice, then the C=C takes priority and is given the lowest locant.

 Functional groups : alkene and alkyne, therefore suffix = -en and  -yne The longest continuous chain is C6 therefore root = hex The first point of difference requires that we number from the left as drawn Locant for C=C is therefore 1- Locant for C≡C is therefore 4- hex-1-en-4-yne CH2=CHCH2C≡CCH3 Functional groups : alkene and alkyne, therefore suffix = -en and  -yne The longest continuous chain is C6 therefore root = hex The first point of difference requires that we number from the right as drawn Locant for C≡C is therefore 1- Locant for C=C is therefore 4- hex-4-en-1-yne CH3CH=CHCH2C≡CH Functional groups : alkene and alkyne, therefore suffix = -en and  -yne The longest continuous chain is C6 therefore root = pent The first point of difference fails since C=C and C≡C are equally distant from the ends. Therefore the C=C takes priority and requires that we number from the left as drawn Locant for C=C is therefore 1- Locant for C≡C is therefore 4- pent-1-en-4-yne CH2=CHCH2C≡CH

 ©Dr. Ian Hunt, Department of Chemistry