The development of catalytic aerobic epoxidation by numerous metal complexes in the presence of aldehyde as a sacrificial reduct-ant (Mukaiyama epoxidation) has been reported,however,comprehensive examination of oxygen atom transfer mechanism involv-ing free radical and highly reactive intermediates has yet to be presented.Herein,meso-tetrakis(pentafluorophenyl) porphyrina-tooxidovanadium(Ⅳ) (VOTPFPP) was prepared and proved to be efficient toward aerobic olefin epoxidation in the presence of iso-butyraldehyde.In situ electron paramagnetic resonance spectroscopy (in situ EPR) showed the generation,transfer pathways and ascription of free radicals in the epoxidation.According to the spectral and computational studies,the side-on vanadium-peroxo complexes are considered as the active intermediate species in the reaction process.In the cyclohexene epoxidation catalyzed by VOTPFPP,the kinetic isotope effect value of 1.0 was obtained,indicating that epoxidation occurred via oxygen atom transfer mecha-nism.The mechanism was further elucidated using isotopically labeled dioxygen experiments and density functional theory (DFT)calculations.

Fine Chemical Industry Research Institute,School of Chemical Engineering and Technology,Sun Yat-sen University,Zhuhai,Guangdong 519082,China;Fine Chemical Industry Research Institute,School of Chemistry,Sun Yat-sen University,Guangzhou,Guangdong 510275,China;School of Chemical Engineering,Guangdong University of Petrochemical Technology,Maoming,Guangdong 525000,China

[1]Xiao-Hui Liu;Jia-Ying Huang;Lei-Ming Tao;Hai-Yang Yu;Xian-Tai Zhou;Can Xue;Qi Han;Wen Zou;Hong-Bing Ji-.Oxygen Atom Transfer Mechanism for Vanadium-Oxo Porphyrin Complexes Mediated Aerobic Olefin Epoxidation)[J].中国化学（英文版）,2022(01):115-122

reduct,Mukaiyama,involv,porphyrina,tooxidovanadium,VOTPFPP,butyraldehyde,ascription,peroxo

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