Provided herein are methods that utilize polyhydroxyalkanoates (PHAs) as a substrate for further conversion to C4 and C5 compounds. Polyhydroxyalkanoates can undergo esterification to yield alkyl hydroxyalkanoates and alkyl alkenoates, which may serve as useful precursors in the production of alkadienes and alkenedioic acids, including for example butadiene and butenedioic acid.