Biocatalytic transformations are becoming increasingly important, attractive, and accessible for the synthesis of pharmaceuticals or fine chemicals. Recently, enzymatic synthesis routes to chemicals such as 1,4-butanediol, branched chain higher alcohols or complex natural products such as the investigational HIV treatment islatravir, or the investigational antiviral agent molnupravir were developed. This interest is largely owed to the high chemo-, stereo-and regioselectivity of enzymes, their applicability in mild reaction conditions and aqueous media, as well as their compatibility making the combination of several reaction steps in a single reaction vessel possible. Since enzymes can exhibit both substrate and reaction promiscuity, i.e. can act on non-native substrates or catalyze new reactions, the toolbox of possible biocatalytic transformations extends well beyond reactions seen in nature. Low catalytic activity may be increased by directed evolution. Furthermore, computer-aided de novo design of enzymes has been reported for selected transformations, opening up the possibility to design an enzyme for a given task. Enzymatic reactions and cascades thus provide a promising eco-friendly alternative to conventional synthesis pathways for a large range of compounds.