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 ringshaped pure inorganic ligand composed of six Mo VI O 6 octahe-drons 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.

A recyclable Cu@C2N nano-catalyst applied in the transformation of alkynes: pH switchable access to ketones and 1,3-diynes

“…Performing the reaction at 90 °C gave the desired product with 14% yield. Then, concentrated sulfuric acid was used as the acid and an increase in the amount of concentrated sulfuric acid led to higher product yields (Table 1, entries [15][16][17][18].…”

Silver-mediated Room Temperature Reactions for the Synthesis of N-α-Ketoacyl Sulfoximines and N-α,β-Unsaturated Acyl Sulfoximines

“…When the reaction was conducted under a nitrogen atmosphere after performing freeze–thaw cycles of the solvent system, the reaction worked and provided product 3a , suggesting that the reaction does not have any role with the atmospheric oxygen (eq ii). In the literature, there are reports where phenylacetylenes get converted into glyoxal, − glyoxylic acid, − and acetophenone − under oxidative conditions; therefore, there must be a likely chance of their formation as intermediates and are likely responsible for the formation of coupled product 3a . To rule out the possibility, the reactions were performed with glyoxal/glyoxylic acid/acetophenone (eqs iii–v), but no coupling was observed, suggesting their noninvolvement in the present optimized reaction.…”

Hoogsteen triplexes stabilized through ethynyl-linked pyrene-indole synthesized by high-temperature Sonogashira coupling

“…In addition, it should also be mentioned that the Sonogashira reaction of aryl acetylenes in the presence of palladium can simultaneously proceed through the regioselective hydration of alkyne leading to the corresponding aryl ketones. 34,35 Previously, we have observed this type of undesired product as a result of our attempt to couple the C-3 indolyl atom. 27 However, there was no such observation in the present coupling to the C-5 indolyl atom and the product was isolated in a high yield of 84%.…”