Biocatalysis is gaining increasing attention in the academic and industrial sector due to the possibility of developing highly stereoselective transformations in a sustainable manner. The creation of stereogenic centers in organic synthesis is not trivial and multiple approaches have been disclosed based on 2 organometallic and organocatalytic methods with the use of day by day more complex catalysts to induce asymmetry in selected transformations. The intrinsic chirality of enzymes makes them powerful tools for the development of stereoselective transformations, catalysing a wide range of chemical reactions due to the high abundance and diversity of enzymes in nature. In addition, the enormous advances in rational design and molecular biology methods have opened up the possibility to create more robust and versatile biocatalysts, which have improved the initial activities displayed by wild-type enzymes. Therefore, their applicability has been widely increased in terms of reaction conditions, substrate specificity, activity and selectivity among others. All these properties have attracted the industrial sector, which has taken advantage of the enzyme selectivities in multiple scenarios. Herein, the focus has been put in recent developments of stereoselective transformations for the synthesis of valuable building blocks towards the production of pharmaceuticals and biologically active natural products.

A sequential two‐step chemoenzymatic methodology for the stereoselective synthesis of (3E)‐4‐(het)arylbut‐3‐en‐2‐amines in a highly selective manner and under mild reaction conditions is described. The approach consists of oxidation of the corresponding racemic alcohol precursors by the use of a catalytic system made up of the laccase from Trametes versicolor and the oxy‐radical TEMPO, followed by the asymmetric reductive bio‐transamination of the corresponding ketone intermediates. Optimisation of the oxidation reaction, exhaustive amine transaminase screening for the bio‐transaminations and the compatibility of the two enzymatic reactions were studied in depth in search of a design of a compatible sequential cascade. This synthetic strategy was successful and the combinations of enzymes displayed a broad substrate scope, with 16 chiral amines being obtained in moderate to good isolated yields (29–75 %) and with excellent enantiomeric excess values (94 to >99 %). Interestingly, both amine enantiomers can be achieved, depending on the selectivity of the amine transaminase employed in the system.

The Wacker‐Tsuji aerobic oxidation of various allyl(hetero)arenes under photocatalytic conditions to form the corresponding methyl ketones is presented. By using a palladium complex [PdCl2(MeCN)2] and the photosensitizer [Acr‐Mes]ClO4 in aqueous medium and at room temperature, and by simple irradiation with blue led light, the desired carbonyl compounds were synthesized with high conversions (>80%) and excellent selectivities (>90%). The key process was the transient formation of Pd nanoparticles that can activate oxygen, thus recycling the Pd(II) species necessary in the Wacker oxidative reaction. While light irradiation was strictly mandatory, the addition of the photocatalyst improved the reaction selectivity, due to the formation of the starting allyl(hetero)arene from some of the obtained by‐products, thus entering back in the Wacker‐Tsuji catalytic cycle. Once optimized, the oxidation reaction was combined in a one‐pot two‐step sequential protocol with an enzymatic transformation. Depending on the biocatalyst employed, i. e. an amine transaminase or an alcohol dehydrogenase, the corresponding (R)‐ and (S)‐1‐arylpropan‐2‐amines or 1‐arylpropan‐2‐ols, respectively, could be synthesized in most cases with high yields (>70%) and in enantiopure form. Finally, an application of this photo‐metal‐biocatalytic strategy has been demonstrated in order to get access in a straightforward manner to selegiline, an anti‐Parkinson drug.

3-nitro-2H-chromenes and derivatives are compounds with diverse biological activity, among them, new 2-glyco-3-nitro-2H-chromenes have been prepared by one-pot oxa-Michael-Henrydehydration reactions between carbohydrate-derived nitroalkenes and several salicylaldehydes, using a minimal amount of solvent and DBU as catalyst. The antiproliferative activity of these new compounds has been evaluated against a panel of six human solid tumor cell lines, and compared to pharmacological reference compounds, finding that their activities are in the low micromolar range and that some of them are more effective than the standards.

The combination of metal-, photo-, enzyme-, and/or organocatalysis provides multiple synthetic solutions, especially when the creation of chiral centers is involved. Historically, enzymes and transition metal species have been exploited simultaneously through dynamic kinetic resolutions of racemates. However, more recently, linear cascades have appeared as elegant solutions for the preparation of valuable organic molecules combining multiple bioprocesses and metal-catalyzed transformations. Many advantages are derived from this symbiosis, although there are still bottlenecks to be addressed including the successful coexistence of both catalyst types, the need for compatible reaction media and mild conditions, or the minimization of cross-reactivities. Therefore, solutions are here also provided by means of catalyst coimmobilization, compartmentalization strategies, flow chemistry, etc. A comprehensive review is presented focusing on the period 2015 to early 2022, which has been divided into two main sections that comprise first the use of metals and enzymes as independent catalysts but working in an orchestral or sequential manner, and later their application as bionanohybrid materials through their coimmobilization in adequate supports. Each part has been classified into different subheadings, the first part based on the reaction catalyzed by the metal catalyst, while the development of nonasymmetric or stereoselective processes was considered for the bionanohybrid section.