Hydration Of Terminal Alkynes Catalyzed By Cobalt Corrole Complex

In organic synthesis,catalyzing the hydration reaction of carbon-carbon triple bonds is particularly important because it can provide important carbonyl compounds for the chemical industry.Markovnikov hydration of terminal alkynes is an ideal method for synthesizing methyl ketones because its atomic economy is 100%,which meets the development requirements of green chemistry.In order to avoid the use of precious metals and highy toxic metals,the development of cheap metal catalysts has always been a hot issue in the field of alkynes hydration.It is an important design idea to screen some nitrogen-containing ligands to form metal complexes with cheap metals to catalyzed the hydration of alkynes.The paper analyzes and summarizes the laws and characteristics of cheap metal-catalyzed hydration of alkynes,and uses these laws and characteristics as guiding principles to synthesize a cobalt corrole complex that can efficiently catalyze hydration of alkynes.The main contents are as follows:1.Synthesized 5,10,15-tri（pentafluorophenyl）corrole ligand and its metal cobalt complex5,10,15-tri（pentafluorophenyl）corrolato cobalt（III）-PPh₃,were characterized by NMR,HR-MS and Uv-Vis.2.The Markov hydration of terminal alkynes catalyzed by cobalt corrole complex was reported for the first time.Phenylacetylene was selected as the template substrate.By optimizing conditions such as the amount of catalyst,protic acid,solvent,temperature,amount of water,and reaction time,the best process conditions were obtained:0.3 mol%F₁₅-Co-PPh₃,2 mol%H₂SO₄,Me OH,80°C,4.4 equiv.and 12 h.Under these conditions,the GC yield of acetophenone is 100%,and the isolated yield is 95%.Secondly,in terms of substrate expansion,aromatic,aliphatic,electron-rich,electron-poor,and acid-sensitive group substrates could all be converted into corresponding methyl ketons with a high yield.In addition,a gram-level reaction experiment was carried out,and the isolated yield of acetophenone was 90%,and the TON was 300.At same time,the catalyst stability test was also carried out.The results showed that the cobalt complex was stable in the alkynes hydration.3.The mechanism of alkyne hydration reaction was studied by separating intermediates in anhydrous environment.Results The gem-diether hydration pathway was excluded and the possible enol ether hydration pathway was preliminarily obtained.