Chemical synthesis of β-hydroxythioesters with different carbon chain length as well as different functionalities in an inexpensive way. The main points of the synthesis plan called for protection of the alcohol at C3 and the proper protection of the carboxylate terminus. The first two synthetic routes that were attempted failed at protecting the carboxylate terminus. The first path used a mono-substituted amine which ended in cyclization of the starting material after oxidation of the primary alcohol. In the second synthesis the main problem was removal of the benzyl group of the amide by hydrogenolysis. The failure of these syntheses lead to the idea of using selective and temporary protecting groups for the amide nitrogen and the primary hydroxyl group. Unfortunately, after several futile attempts to protect the carboxylate terminus, it was clear that this protection proved to be more difficult than expected and development of a new route was needed. Therefore, the final approach was based on the work done by Braun and coworkers on chiral acetate enolates, even though the final product was not enantiomerically pure. Nevertheless, we succeeded in the synthesis of a natural product obtaining good yields since Braun's chiral auxiliary can be easily recovered. Consequently, an in vitro system using purified synthases and chemically synthesized thioesters, as proposed in this thesis, can be used to study the specificity requirements of different kinds of type II synthases, beyond that obtainable from living systems.