Destito, PaoloVidal Vides, CristianLópez García, FernandoMascareñas Cid, José Luis2021-03-222021-09-292021Destito, P.; Vidal, C.; and López, F.; Mascareñas, J. L. (2021), Transition Metal- Promoted Reactions in Aqueous Media and Biological Settings. Chem. Eur. J., 27: 4789-4816. doi: 10.1002/chem.202003927http://hdl.handle.net/10347/24848This is the peer reviewed version of the following article: P. Destito, C. Vidal, F. López, J. L. Mascareñas, Chem. Eur. J. 2021, 27, 4789, which has been published in final form at https://doi.org/10.1002/chem.202003927. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsDuring the last decade, there has been a tremendous interest for developing non‐natural biocompatible transformations in biologically relevant media. Among the different encountered strategies, the use of transition metal complexes offers unique possibilities due to their high transformative power. However, translating the potential of metal catalysts to biological settings, including living cells or small‐animal models such as mice or zebrafish, poses numerous challenges associated to their biocompatibility, and their stability and reactivity in crowded aqueous environments. Herein, we describe the most relevant advances in this direction, with a particular emphasis on the systems’ structure, their mode of action and the mechanistic bases of each transformation. Thus, the key challenges from an organometallic perspective might be more easily identifiedeng© 2020 Wiley‐VCH GmbH. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archivingAqueous catalysisBiocatalysisBiological chemistryCellular chemistryOrganometallic catalysisjournal article10.1002/chem.2020039271521-3765open access