Comprehensive Summary Isochromanone is the core structure of many bioactive compounds.Direct oxidation of isochromans is one of leading methods for the construction of isochromanones,while most established processes r...Comprehensive Summary Isochromanone is the core structure of many bioactive compounds.Direct oxidation of isochromans is one of leading methods for the construction of isochromanones,while most established processes remain suffering from the use of environmentally unfriendly metal oxidants,harsh reaction conditions,and the difficulty in catalyst recycling and product separation.Herein,we report a convenient,cost-effective,and green method for the synthesis of high-value added isochromanones via isochroman oxidations with O_(2) by a novel heterogeneous vanadium cluster catalyst(Cat.1)under mild conditions.This reaction protocol demonstrates high catalytic activity with good catalyst recyclability and reusability for a wide scope of substrates.展开更多
Attaining the selective oxidation of isochroman into isochromanone in a molecular oxygen(O_(2))environment without any additives,via a heterogeneous oxidation process,is highly desirable and challenging work.Herein,we...Attaining the selective oxidation of isochroman into isochromanone in a molecular oxygen(O_(2))environment without any additives,via a heterogeneous oxidation process,is highly desirable and challenging work.Herein,we prepare two mixed-addendum polyoxometalate-based coordination polymers of the general formula[H_(x)M_(1-x)(i-PrIm)_(4)][H_(2)N(CH_(3))_(2)]_(4)[HPMo_(8)V_(6)O_(42)](M=Co 1,Ni,2;i-PrIm=1-isopropyl-1H-imidazole).Needing no additives,they can catalyze the selective oxidation of isochroman to isochromanone with O_(2)as an oxidant,with yields of 91.5%(1)and 46.8%(2),respectively.Mechanistic studies indicate that the excellent performance of catalyst 1 is attributed to the synergistic operation of[Co(i-Pr-Im)_(4))]complex and PMo_(8)V_(6)unit,and that the catalytic reaction is a radical pathway involving superoxide radicals.Additionally,the catalyst 1 can be recycled and reused at least four times with uncompromised performance.These results provide fundamental guidelines for designing efficient and multi-site heterogeneous catalysts for the selective oxidation of benzyl C(sp^(3))-H bonds by activating O_(2).展开更多
基金the National Natural Science Foundation of China(22171122)the Liaoning Revitalization Talents Program(XLYC2007130)Talent Scientific Research Fund of Liaoning Petrochemical University(2016XJL-019).
文摘Comprehensive Summary Isochromanone is the core structure of many bioactive compounds.Direct oxidation of isochromans is one of leading methods for the construction of isochromanones,while most established processes remain suffering from the use of environmentally unfriendly metal oxidants,harsh reaction conditions,and the difficulty in catalyst recycling and product separation.Herein,we report a convenient,cost-effective,and green method for the synthesis of high-value added isochromanones via isochroman oxidations with O_(2) by a novel heterogeneous vanadium cluster catalyst(Cat.1)under mild conditions.This reaction protocol demonstrates high catalytic activity with good catalyst recyclability and reusability for a wide scope of substrates.
基金financially supported by the National Natural Science Foundation of China(Nos.22171122 and 22201123)Liaoning Revitalization Talents Program(No.XLYC 2007130)+1 种基金Fundamental Research Project(No.LJ212410148038)of the Educational Department of Liaoning ProvinceTalent Scientific Research Fund of Liaoning Petrochemical University(No.2016XJJL–019)。
文摘Attaining the selective oxidation of isochroman into isochromanone in a molecular oxygen(O_(2))environment without any additives,via a heterogeneous oxidation process,is highly desirable and challenging work.Herein,we prepare two mixed-addendum polyoxometalate-based coordination polymers of the general formula[H_(x)M_(1-x)(i-PrIm)_(4)][H_(2)N(CH_(3))_(2)]_(4)[HPMo_(8)V_(6)O_(42)](M=Co 1,Ni,2;i-PrIm=1-isopropyl-1H-imidazole).Needing no additives,they can catalyze the selective oxidation of isochroman to isochromanone with O_(2)as an oxidant,with yields of 91.5%(1)and 46.8%(2),respectively.Mechanistic studies indicate that the excellent performance of catalyst 1 is attributed to the synergistic operation of[Co(i-Pr-Im)_(4))]complex and PMo_(8)V_(6)unit,and that the catalytic reaction is a radical pathway involving superoxide radicals.Additionally,the catalyst 1 can be recycled and reused at least four times with uncompromised performance.These results provide fundamental guidelines for designing efficient and multi-site heterogeneous catalysts for the selective oxidation of benzyl C(sp^(3))-H bonds by activating O_(2).
