Question

The correct IUPAC name of the compound is:

A.${\mathbf{3}},{\mathbf{3}} - {\mathbf{dimethyl}} - {\mathbf{3}} - {\mathbf{cyclopentyl}} - {\mathbf{propanal}}$
B.${\mathbf{3}} - {\mathbf{cyclopentyl}} - {\mathbf{3-methyl}} - {\mathbf{butanal}}$
C.${\mathbf{1}} - \left( {{\mathbf{1}} - {\mathbf{methyl}} - {\mathbf{1}} - {\mathbf{formyl}}} \right){\mathbf{methyl}} - {\mathbf{ethyl}} - {\mathbf{cyclopropane}}$
D.${\mathbf{3}},{\mathbf{3}} - {\mathbf{diethyl}} - {\mathbf{3}} - {\mathbf{cyclobutyl}} - {\mathbf{butanal}}$

Answer 1

The basic knowledge about our IUPAC Nomenclature is very important to answer this question. There are set rules in an IUPAC nomenclature to give the name of a compound. IUPAC stands for the international union of pure and applied chemistry.

Complete step by step solution:
IUPAC nomenclature is based on naming a molecule’s longest chain of carbons connected by single bonds, whether in a continuous chain or in a ring. All deviations, either multiple bonds or atoms other than carbon, hydrogen are indicated by prefixes or suffixes, according to a specific set of priorities.
Step 1: The parent chain of the compound contains 4 carbon atoms and an aldehyde group. Hence it is named as $\;butanal$ .
Step2: Two substituents are present at third carbon atoms, one is the $methyl$ group and the other is the $cyclopentyl$ group. So it will be named as $3 - cyclopentyl,3 - methyl$.(The priority of these two compounds is decided by its alphabetical order)

Step 3: Now from the above 2 steps we can write the name of the compound in the third step that is
In the names given in option A and C, the parent hydrocarbon chain contains 3 carbon atoms. This is not the longest chain. Hence these names are incorrect.
In the name given $3 - cyclopentyl - 3-methyl - butanal.$ in option D, two $ethyl$ and one $cyclobutyl$ groups are named but are not present in their given structure, hence the name is also not correct.

Hence, correct answer is option B.

Note: use the following steps in the series to get an IUPAC name of the compound. First, select the longest carbon chain. Then numbered the chain according to the preference given or priority is given to the functional group. Add the suffixes and prefixes according to the priority of that functional group.