Esters

Basic IUPAC Organic Nomenclature

Nomenclature	Formula	3D structure
Functional class name = alkyl alkanoate Substituent suffix = -oate

Esters are alkyl derivatives of carboxylic acids.
The easiest way to deal with naming esters is to recognise the carboxylic acid and the alcohol that they can be prepared from.
The general ester, RCO₂R' can be derived from the carboxylic acid RCO₂H and the alcohol R'OH.
The first component of an ester name, the alkyl is derived from the alcohol, R'OH portion of the structure.
The second component of an ester name, the -oate is derived from the carboxylic acid, RCO₂H portion of the structure.
Alcohol component

The root name is based on the longest chain including the carbonyl group.
Since the carboxylic acid group is at the end of the chain, it must be C1.
The ester suffix for the acid component is appended after the hydrocarbon suffix minus the "e" : e.g. -ane + -oate = -anoate etc.

Functional group is an ester, therefore suffix = -oate The alcohol component here is methanol, so the alkyl = methyl The acid component here is propanoic acid, so propanoate methyl propanoate
Functional group is an ester, therefore suffix = -oate The alcohol component here is 2-propanol (or isopropanol), so the alkyl = 2-propyl or isopropyl The acid component here is propanoic acid, so propanoate 2-propyl propanoate or isopropyl propanoate
Functional group is an ester, therefore suffix = -oate The alcohol component here is methanol, so the alkyl = methyl The acid component has a longest continuous chain that is C3 so the root = prop With the acid group at C1, there is a methyl group at C2 = 2-methyl methyl 2-methylpropanoate
Functional group is an ester, therefore suffix = -oate The alcohol component here is 2-propanol (or isopropanol), so the alkyl = 2-propyl or isopropyl The acid component has a longest continuous chain that is C4 so the root = but With the acid group at C1, there is a methyl group at C2 = 2-methyl 2-propyl 2-methylbutanoate or isopropyl 2-methylbutanoate