Question

Name the following ketones and aldehydes. When possible, give both a common name and an IUPAC name.

$\mathbf{\left(}\mathbf{a}\mathbf{\right)}\mathbf{}{\mathbf{CH}}_{\mathbf{3}}\mathbf{CO}{\mathbf{\left(}{\mathbf{CH}}_{\mathbf{2}}\mathbf{\right)}}_{\mathbf{4}}{\mathbf{CH}}_{\mathbf{3}}$ $\mathbf{\left(}\mathbf{b}\mathbf{\right)}\mathbf{}{\mathbf{CH}}_{\mathbf{3}}{\mathbf{\left(}{\mathbf{CH}}_{\mathbf{2}}\mathbf{\right)}}_{\mathbf{2}}\mathbf{CO}{\mathbf{\left(}{\mathbf{CH}}_{\mathbf{2}}\mathbf{\right)}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{3}}$ $\mathbf{\left(}\mathbf{c}\mathbf{\right)}\mathbf{}{\mathbf{CH}}_{\mathbf{3}}\mathbf{\left(}{\mathbf{CH}}_{\mathbf{2}}\mathbf{\right)}\mathbf{CO}{\mathbf{\left(}{\mathbf{CH}}_{\mathbf{2}}\mathbf{\right)}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{3}}$

$\mathbf{\left(}\mathbf{d}\mathbf{\right)}\mathbf{}\mathbf{PhCOPh}$ $\mathbf{\left(}\mathbf{e}\mathbf{\right)}{\mathbf{CH}}_{\mathbf{3}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}\mathbf{CHO}$ $\mathbf{\left(}\mathbf{f}\mathbf{\right)}\mathbf{}{\mathbf{CH}}_{\mathbf{3}}{\mathbf{COCH}}_{\mathbf{3}}$

$\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{}\mathit{C}{\mathit{H}}_{\mathbf{3}}\mathit{C}{\mathit{H}}_{\mathbf{2}}\mathit{C}\mathit{H}\mathit{B}\mathit{r}\mathit{C}{\mathit{H}}_{\mathbf{2}}\mathit{C}\mathit{H}\mathbf{\left(}\mathbf{C}{\mathbf{H}}_{\mathbf{3}}\mathbf{\right)}\mathit{C}\mathit{H}\mathit{O}$ $\mathbf{\left(}\mathbf{h}\mathbf{\right)}\mathbf{}\mathit{P}\mathit{h}\mathbf{-}\mathbf{CH}\mathbf{=}\mathbf{CH}\mathbf{-}\mathbf{CHO}$

$\mathbf{\left(}\mathbf{i}\mathbf{\right)}\mathbf{}\mathit{C}{\mathit{H}}_{\mathbf{3}}\mathit{C}\mathit{H}\mathbf{=}\mathbf{CH}\mathbf{-}\mathbf{CH}\mathbf{=}\mathbf{CH}\mathbf{-}\mathbf{CHO}$

(j) (k) (l)

Short answer

(a) $\mathrm{heptan}-2-\mathrm{one}$

(b)$\mathrm{heptan}-4-\mathrm{one}$

(c) heptanal

(d) benzophenone

(e)butanal

(f) $\mathrm{propan}-2-\mathrm{one}$

(g) $4-\mathrm{bromo}-2-\mathrm{methylhexanal}$$3-\mathrm{phenylprop}-2-\mathrm{enal}$

(h) $3-\mathrm{phenylprop}-2-\mathrm{enal}$

(i) $\left(2\mathrm{E},4\mathrm{E}\right)-\mathrm{hexa}-2,4-\mathrm{dienal}$

(j) $2-\mathrm{hydroxycyclohexane}-1,3-\mathrm{dione}$

(k)$3-\mathrm{oxocyclopentane}-1-\mathrm{carbaldehyde}$

(l)$\left(2\mathrm{S},4\mathrm{R}\right)-2,4-\mathrm{dimethylcyclopentan}$

Step-by-step solution

Systematic Naming of Organic Compounds

A systematic way of naming organic compounds based on their chemical composition and structure is given by the IUPAC nomenclature. IUPAC nomenclature consists of three main parts which are root name, suffix, and prefix. Suffix denote the functional group present whereas the number and name of the substituents are denoted by the prefix. In general, IUPAC name for an organic compound can be written in the form as shown below.

$\mathrm{substitute}\mathrm{number}-\left(\mathrm{name}\mathrm{of}\mathrm{substituent}\right)\left(\mathrm{root}\mathrm{name}\right)\left(\mathrm{suffix}\right)$

Naming of ketones and aldehydes from their structures

(a) The structure of the compound can be drawn as:

$\mathrm{heptan}-2-\mathrm{one}$

In this organic compound, ketone functional group is attached to the second carbon atom. Therefore, the IUPAC name of the compound is $\mathrm{heptan}-2-\mathrm{one}$and the common name is methyl pentyl ketone.

(b) The structure of the compound can be drawn as:

$\mathrm{heptan}-4-\mathrm{one}$

(c) The structure of the compound can be drawn as:

$\mathrm{Heptanal}$

In this organic compound, aldehyde functional group is attached to the first carbon atom. Therefore, the IUPAC name of the compound is heptanal and the common name is $\mathrm{N}-\mathrm{heptaldehyde}$.

(d) The structure of the compound can be drawn as:

benzophenone

The IUPAC name of the compound is benzophenone and the common name is diphenyl ketone.

(e) The structure of the compound can be drawn as:

butanal

In this organic compound, aldehyde functional group is attached to the first carbon atom. Therefore, the IUPAC name of the compound is butanal and the common name is butyraldehyde.

(f) The structure of the compound can be drawn as:

propan-2-one

In this organic compound, ketone functional group is attached to the second carbon atom. Therefore, the IUPAC name of the compound is and the common name is acetone or dimethyl ketone.

(g) The structure of the compound can be drawn as:

4-bromo-2-methylhexanal

In this organic compound, aldehyde functional group is attached to the first carbon atom and a bromine atom is attached to the fourth carbon atom. Therefore, the IUPAC name of the compound is 4-bromo-2-methylhexanal.

(h) The structure of the compound can be drawn as:

3-phenylprop-2-enal

In this organic compound, aldehyde functional group is attached to the first carbon atom and a phenyl group is attached to third carbon atom. Therefore, the IUPAC name of the compound is 3-phenylprop-2-enal and the common name is cinnamaldehyde.

(i) The structure of the compound can be drawn as:

(2E,4E)-hexa-2,4-dienal

The IUPAC name of the compound is (2E,4E)-hexa-2,4-dienal.

(j)The structure of the compound is given as:

2-hydroxyxyclohexane-1,3-dione

In this organic compound, one hydroxy group (-OH) is present at the second carbon atom and the ketone functional group is attached to the first and third carbon atom. Therefore, the IUPAC name of the compound is 2-hydroxyxyclohexane-1,3-dione.

(k)The structure of the compound is given as:

3-oxocyclopentane-1-carbaldehyde

The IUPAC name of the compound is 3-oxocyclopentane-1-carbaldehyde.

(l) The structure of the compound is given as:

(2S,4R)-2,4-dimethylcyclopentan-1-one

The IUPAC name of the compound is (2S,4R)-2,4-dimethylcyclopentan-1-one.