Question

Provide an IUPAC name for each of the compounds shown. (Specify (E)/(Z) stereochemistry, if relevant, for straight chain alkenes only. Pay attention to commas, dashes, etc.)

1,2.

3,4.

Answer 1

Concepts and reason

The systematic naming of an organic compound is given by the IUPAC nomenclature. The naming of an organic compound is done such that the structure of an organic compound is correctly interpreted from the name.

The IUPAC nomenclature is a systematic way of naming organic compounds; one that is provided by the Union of Pure and Applied Chemistry. It provides the rules through which the naming of the compound is done.

The ${\rm{E - Z}}$ configuration is used to provide the absolute stereochemistry of double bonds. If the groups of high priority are on the same side of the double bond, the bond is assigned with Z configuration, and if they are on the opposite sides of the double bond, the bond is assigned as E.

Fundamentals

The rules for naming the organic compounds with functional groups are given below:

Identify the principal functional group. The group with the highest priority is the principal functional group.

Select the longest chain that is having the high priority functional group.

The priority order is carboxylic acids>acid anhydrides>esters>acyl halides> amides>nitriles>aldehydes>ketones>alcohols>thiols>amines>ethers>sulphides>alkenes>alkynes>alkyl halides>nitro>alkanes.

Give the root name by counting the carbon atoms that are present in the parent chain.

Give the numbering to the parent chain such that the functional group is at the lowest possible number.

If a functional group is present more than once, then it is prefixed with di, tri, tetra, and so on, depending on the number of the functional groups. Locate the position of the lowest priority groups with their positions.

To find the E/Z-configuration of an alkene, follow this rule:

For Z-configuration, the higher priority of functional group should be present in the same side.

For E-configuration, the higher priority of functional group should be opposite to each other.

(1)

The IUPAC name of the given compound is 3-isopropyl-5, 5-dimethylhex-2-ene.

(2)

The IUPAC name of the given compound is 3-isopropylhex-2-ene.

(3)

The IUPAC name of the given compound is 1,4,4-trimethylcyclobut-1-ene.

(4)

The IUPAC name of the given compound is 1,4,4-trimethylcyclopent-1-ene.

Ans: Part 1

The IUPAC naming of the given compound is (Z)-3-isopropyl-5, 5-dimethylhex-2-en.

Part 2

The IUPAC naming of the given compound is (E)-3-isopropylhex-2-en.

Part 3

The IUPAC naming of the given compound is 1, 4, 4-trimethylcyclobut-1-ene.

Part 4

The IUPAC naming of the given compound is 1,4,4-trimethylcyclopent-1-ene.