The IUPAC name of CH3COCH(CH3)2 is

Explanation:

The IUPAC name of this structure is 3-Methyl-2-butanone.
The longest chain is of four carbon. The functional group here is keto group.
The numbering will start from left carbon as the functional group should also have the lowest numbering.
The substituent methyl group will be at third carbon.

Final Answer:

Hence the IUPAC name of this structureCH3COCH(CH3)2 is 3-Methyl-2-butanone