Hydration of Alkynes to Ketones with an Efficient and Practical Polyoxomolybdate‐based Cobalt Catalyst

Abstract Hydration of alkynes to ketones is one of the most atom economical and universal methods for the synthesis of carbonyl compounds. However, the basic reaction usually requires organic ligand catalysts or harsh reaction conditions to insert oxygen into the C≡C bond. Here, we report an inorganic ligand supported cobalt (III) catalyst, (NH 4 ) 3 [CoMo 6 O 18 (OH) 6 ], which is supported by a central cobalt (III) mononucleus and a ring‐shaped pure inorganic ligand composed of six Mo VI O 6 octahedrons to avoid the disadvantages of expensive and unrecyclable organic ligand catalysts or noble metal catalysts. Under mild conditions, the cobalt (III) catalyst can be used for the hydration of alkynes to ketones. The catalyst is non‐toxic, green, and environment friendly. The catalyst can be recycled at least six times with high activity. According to control experiments, a reasonable mechanism is provided.