Step 1: Esterification: Butyric Acid is treatet with ethanol in the presence of Acid. The corresponding intermediate formed is Keto Ester (Ethyl Butyrate) and serves as a synthetic intermediate. (Highlighted RED in scheme).
Step 2: Nucleophilic Substitution Reaction: The corresponding Ester formed is treated with Methyl Magnesium Bromide. And after hydrolysis 2- Pentanone is synthesized. The r2 step reaction is shoen belo.