Oxidation chemistry using enzymes is approaching maturity and practical applicability in organic synthesis. Oxidoreductases (enzymes catalysing redox reactions) enable chemists to perform highly selective and efficient transformations ranging from simple alcohol oxidations to stereoselective halogenations of non‐activated C−H bonds. For many of these reactions, no “classical” chemical counterpart is known. Hence oxidoreductases open up shorter synthesis routes based on a more direct access to the target products. The generally very mild reaction conditions may also reduce the environmental impact of biocatalytic reactions compared to classical counterparts. In this Review, we critically summarise the most important recent developments in the field of biocatalytic oxidation chemistry and identify the most pressing bottlenecks as well as promising solutions.

Biocatalysis is an enabling technology adding to organic oxidation chemistry. Especially the high selectivity of enzymatic oxidation coevally operating under mild conditions and not necessitating problematic solvents makes it a very valuable tool for (green) chemistry. The present state of the art in the use of enzymes and microorganisms for catalytic oxidation and oxyfunctionalization chemistry is reviewed.

When challenged by a difficult reduction reaction, a chemist should always also consider biocatalysis in synthesis planning. The inherent selectivity of enzymes has been known for many decades now and the practical applicability of biocatalysis has undergone dramatic improvements rendering it a true alternative to established chemocatalysis. In this contribution recent developments in the field of enzymatic reduction using whole cells and isolated enzymes are reviewed.

Peroxygenases offer an attractive means to address challenges in selective oxyfunctionalization chemistry. Despite this, their application in synthetic chemistry remains challenging due to their facile inactivation by the stoichiometric oxidant H₂O₂. Often atom-inefficient peroxide generation systems are required, which show little potential for large-scale implementation. Here, we show that visible-light-driven, catalytic water oxidation can be used for in situ generation of H₂O₂ from water, rendering the peroxygenase catalytically active. In this way, the stereoselective oxyfunctionalization of hydrocarbons can be achieved by simply using the catalytic system, water and visible light.