biostudies-literatureUnknown13(2)Blanco COWater is ubiquitous in olefin metathesis, at levels ranging from contaminant to cosolvent. It is also non-benign. Water-promoted catalyst decomposition competes with metathesis, even for "robust" ruthenium catalysts. Metathesis is hence typically noncatalytic for demanding reactions in water-rich environments (e.g., chemical biology), a challenge as the Ru decomposition products promote unwanted reactions such as DNA degradation. To date, only the first step of the decomposition cascade is understood: catalyst aquation. Here we demonstrate that the aqua species dramatically accelerate both β-elimination of the metallacyclobutane intermediate and bimolecular decomposition of four-coordinate [RuCl(H₂O)_n(L)(=CHR)]Cl. Decomposition can be inhibited by blocking aquation and β-elimination.ACS catalysis1097-1102https://www.ebi.ac.uk/biostudies/studies/S-EPMC9872090biostudies-literatureWater-Accelerated Decomposition of Olefin Metathesis Catalysts.PMC9872090Fogg DEBlanco COfalseWater-Accelerated Decomposition of Olefin Metathesis Catalysts.Water is ubiquitous in olefin metathesis, at levels ranging from contaminant to cosolvent. It is also non-benign. Water-promoted catalyst decomposition competes with metathesis, even for "robust" ruthenium catalysts. Metathesis is hence typically noncatalytic for demanding reactions in water-rich environments (e.g., chemical biology), a challenge as the Ru decomposition products promote unwanted reactions such as DNA degradation. To date, only the first step of the decomposition cascade is understood: catalyst aquation. Here we demonstrate that the aqua species dramatically accelerate both β-elimination of the metallacyclobutane intermediate and bimolecular decomposition of four-coordinate [RuCl(H₂O)_n(L)(=CHR)]Cl. Decomposition can be inhibited by blocking aquation and β-elimination.2023-01-01T00:00:00Z2023 Jan2025-04-26T13:17:20.981Z2025-04-06T14:12:56.023ZS-EPMC98720903671405410.1021/acscatal.2c05573