ABSTRACT
This chapter focuses on the biosynthetic methods and highlights the principal ideas from single-step conversions to cascade reactions. Enzymes are often associated with the term “green chemistry” because they are natural, and biological degradable. However, it must be considered that enzymes are usually used in aqueous solutions causing downstream challenges: energy consuming evaporation or salt/solvent contaminated wastewater. The sequence yields very good diastereomeric and enantiomeric excesses suitable for the final drug and the process is favorable in terms of atom efficiency, because all atoms are included within the product and ostensibly there are no process inherent side-products. The use of native biosynthesis is the oldest and easiest way to produce natural products and has been used for thousands of years in the production and use of pharmaceutical products. The production of natural products in heterologous organisms requires the transfer of genetic information for the corresponding enzymes.
