Esters are prepared from a carboyxlic acid and an alcohol (Fischer esterification).
So the problem becomes, "how can you prepare this ester from an alochol and a carboxylic acid, each containing three carbons? (propene)"
The "pair" of carboxylic acid and alcohol to make this ester is propanoic acid and propanol.
From propene, to make propanol, just do an anti-Markovnikov H2O addition using borane (BH3 or B2H6) then hydrogen peroxide (H2O2).
To make propanoic acid, oxidize propanol to propanoic acid using Jones reagent (aqueous chromium).
You can also convert propanoic acid to its acid chloride using SOCl2, and then add propanol.
