Two vinyl‐functionalized chiral2,2'‐bis(diphenylphosphino)‐1,1'‐binaphthyl(BINAP)ligands,(S)‐4,4'‐divinyl‐BINAP and(S)‐5,5'‐divinyl‐BINAP,were successfully synthesized.Chiral BINAP‐based por...Two vinyl‐functionalized chiral2,2'‐bis(diphenylphosphino)‐1,1'‐binaphthyl(BINAP)ligands,(S)‐4,4'‐divinyl‐BINAP and(S)‐5,5'‐divinyl‐BINAP,were successfully synthesized.Chiral BINAP‐based porous organic polymers(POPs),denoted as4‐BINAP@POPs and5‐BINAP@POPs,were efficiently prepared via the copolymerization of vinyl‐functionalized BINAP with divinyl benzene under solvothermal conditions.Thorough characterization using nuclear magnetic resonance spectroscopy,thermogravimetric analysis,extended X‐ray absorption fine structure analysis,and high‐angle annular dark‐field scanning transmission electron microscopy,we confirmed that chiral BINAP groups were successfully incorporated into the structure of the materials considered to contain hierarchical pores.Ru was introduced as a catalytic species into the POPs using different synthetic routes.Systematic investigation of the resultant chiral Ru/POP catalysts for heterogeneous asymmetric hydrogenation ofβ‐keto esters revealed their excellent chiral inducibility as well as high activity and stability.Our work thereby paves a path towards the use of advanced hierarchical porous polymers as solid chiral platforms for heterogeneous asymmetric catalysis.展开更多
The asymmetric reduction of β-keto esters to their corresponding hydroxy alcohols can be performed by employing homogeneous and heterogeneous chemo- and bio-catalysis. This review covers the scope and limitations of ...The asymmetric reduction of β-keto esters to their corresponding hydroxy alcohols can be performed by employing homogeneous and heterogeneous chemo- and bio-catalysis. This review covers the scope and limitations of different catalysts and methodologies that were employed for the reaction and compare between them on the basis of catalytic performance, product separation and catalyst recycling procedure. In general, heterogeneous catalytic systems are advantageous from industrial point of views as they can be easily separated by filtration and re-used. Nickel modified with tartaric acid and sodium bromide was found to be suitable heterogeneous catalyst for the enantioselective hydrogenation, yet its performance is lower than this of homogeneous chiral metal catalysts such as Ru-BINAP. Heterogenization of the chiral complex via immobilization or entrapment using organic and inorganic supports was thus tested. However, though the resulted heterogeneous analogues were highly enantioselective and could be re-used, the activity of the system is often very low compared to homogeneous system due to mass transfer limitations. Alternatively, performing liquid phase hydrogenation under homogeneous conditions, using Ru-BINAP soluble derivatives, yielded high activit5＇ and enantioselectivity. Product separation and catalysts recycling were facilitated by either extraction of the product with solvent that does not dissolve the complex or by selective filtration of the product. Alternatively, precipitation of the complex at the end of the reaction was also reported.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020400)~~
文摘Two vinyl‐functionalized chiral2,2'‐bis(diphenylphosphino)‐1,1'‐binaphthyl(BINAP)ligands,(S)‐4,4'‐divinyl‐BINAP and(S)‐5,5'‐divinyl‐BINAP,were successfully synthesized.Chiral BINAP‐based porous organic polymers(POPs),denoted as4‐BINAP@POPs and5‐BINAP@POPs,were efficiently prepared via the copolymerization of vinyl‐functionalized BINAP with divinyl benzene under solvothermal conditions.Thorough characterization using nuclear magnetic resonance spectroscopy,thermogravimetric analysis,extended X‐ray absorption fine structure analysis,and high‐angle annular dark‐field scanning transmission electron microscopy,we confirmed that chiral BINAP groups were successfully incorporated into the structure of the materials considered to contain hierarchical pores.Ru was introduced as a catalytic species into the POPs using different synthetic routes.Systematic investigation of the resultant chiral Ru/POP catalysts for heterogeneous asymmetric hydrogenation ofβ‐keto esters revealed their excellent chiral inducibility as well as high activity and stability.Our work thereby paves a path towards the use of advanced hierarchical porous polymers as solid chiral platforms for heterogeneous asymmetric catalysis.
文摘The asymmetric reduction of β-keto esters to their corresponding hydroxy alcohols can be performed by employing homogeneous and heterogeneous chemo- and bio-catalysis. This review covers the scope and limitations of different catalysts and methodologies that were employed for the reaction and compare between them on the basis of catalytic performance, product separation and catalyst recycling procedure. In general, heterogeneous catalytic systems are advantageous from industrial point of views as they can be easily separated by filtration and re-used. Nickel modified with tartaric acid and sodium bromide was found to be suitable heterogeneous catalyst for the enantioselective hydrogenation, yet its performance is lower than this of homogeneous chiral metal catalysts such as Ru-BINAP. Heterogenization of the chiral complex via immobilization or entrapment using organic and inorganic supports was thus tested. However, though the resulted heterogeneous analogues were highly enantioselective and could be re-used, the activity of the system is often very low compared to homogeneous system due to mass transfer limitations. Alternatively, performing liquid phase hydrogenation under homogeneous conditions, using Ru-BINAP soluble derivatives, yielded high activit5＇ and enantioselectivity. Product separation and catalysts recycling were facilitated by either extraction of the product with solvent that does not dissolve the complex or by selective filtration of the product. Alternatively, precipitation of the complex at the end of the reaction was also reported.
