An asymmetric catalytic strategy in photocatalysis utilizing a chirality-induced approach through an organocatalytic/photoredox relay catalysis strategy is successfully achieved for the rapid construction of polycycli...An asymmetric catalytic strategy in photocatalysis utilizing a chirality-induced approach through an organocatalytic/photoredox relay catalysis strategy is successfully achieved for the rapid construction of polycyclic compounds containing vicinal amino alcohols in a one-pot protocol. This methodology facilitates the efficient synthesis of diverse substituted polycyclic tetrahydroquinoline and benzofuran-derived vicinal amino alcohols, each containing five consecutive chiral centers, with high yields,excellent diastereoselectivities and enantioselectivities(up to 95% yield, >20:1 dr and 98% ee), under mild reaction conditions driven by sequential bifunctional squaramide organocatalyst-catalyzed [4+2] annulation and photocatalyst-catalyzed ketyl radical addition cyclization reaction process. Furthermore, investigations into the stereoselectivity mechanism and high-resolution mass spectrometry(HRMS) experiments on free radical trapping have provided evidence for elucidating the detailed mechanism of chirality-induced processes and chiral intermediate conversions in this procedure.展开更多
Organocatalysis, defined as the use of small organic molecules for catalyzing chemical transformations, can be traced back more than a century and has become a thriving area over the past 20 years.
Triggered by environmental concerns and the rising demands for metal-free polymers in e.g. bio-related and microelectronic applications, studies on organocatalytic polymerization have been launched and developed unpre...Triggered by environmental concerns and the rising demands for metal-free polymers in e.g. bio-related and microelectronic applications, studies on organocatalytic polymerization have been launched and developed unprecedentedly during the last 15 years. A wide range of organic molecules are now available in polymer chemists＇ toolbox to choose from as catalysts for polymerization of （hetero）cyclic and polar vinyl monomers. Apart from the intrinsic merits such as lower toxicity and better solubility compared with （transition） metal catalysts/initiators, organocatalysts have also shown, in many cases, excellence to achieve high polymerization rates and/or good control （selectivity）. In addition, particular natures and catalytic/activating mechanisms of organocatalysts have led to new opportunities for rational design and efficient synthesis of macromolecular architectures, i.e. chain structures, topological structures and functionalities. This mini-review is specially themed on pathways to construct copolymer chain structures by organocatalytic copolymerization of mixed type monomers （comonomers bearing different polymerizing moieties） and will be sectioned by different comonomer combinations, including cyclic monoesters of different sizes, cyclic monoesters and lactides, cyclic esters and cyclic carbonates or epoxides, heterocycles and vinyl monomers.展开更多
The highly enantioselective cross-dehydrogenative coupling of aldehydes with benzylic compounds has been developed as an efficient and rapid protocol for synthesis of enantioriched a-alkylated aldehydes.
Highly potent ionic organocatalyst is developed for room-temperature controlled ring-opening polymerization(ROP)of lactones,includingδ-valerolactone,ε-caprolactone,andδ-hexalactone.The catalysts are prepared by sim...Highly potent ionic organocatalyst is developed for room-temperature controlled ring-opening polymerization(ROP)of lactones,includingδ-valerolactone,ε-caprolactone,andδ-hexalactone.The catalysts are prepared by simply mixing tetra-n-butyl ammonium hydroxide and a(thio)urea at elevated temperature under vacuum,and used in cooperation with an alcoholic initiator.The performance of the catalyst is readily adjusted and optimized through variation of the(thio)urea precursor,catalyst composition,and reaction condition.Urea-derived catalysts are generally superior to thiourea-derived ones.Provided with proper N-substituents,the catalyst affords both high polymerization efficiency and high selectivity for monomer enchainment over macromolecular transesterification,even at high monomer conversion and/or substantially extended reaction time.In addition to acidity,structural symmetry of the urea also proves decisive for the catalytic activity,which enables a catalyst-assisted proton transfer process for the ring-opening of lactone and thus provides a novel mechanistic insight for ROP catalyzed by hydrogen-bonding type bifunctional ionic organocatalysts.展开更多
An organocatalytic asymmetric trifluoromethylthiolation of 3-aryl or 3-alkyloxindoles employing a trifluoromethyl-substituted thioperoxide as the electrophilic trifluoromethylthiolating reagent was described.Reactions...An organocatalytic asymmetric trifluoromethylthiolation of 3-aryl or 3-alkyloxindoles employing a trifluoromethyl-substituted thioperoxide as the electrophilic trifluoromethylthiolating reagent was described.Reactions occurred in good to excellent enantioselectivities to generate oxindoles with a SCF_(3)-substituted quaternary chiral center.展开更多
An intramolecular organocatalytic enantioselective aza-Michael reaction of carbamates, sulfonamides and acetamides to a,b-unsaturated ketones was developed. This process is promoted by 9-amino-9-deoxy-epi-quinine and ...An intramolecular organocatalytic enantioselective aza-Michael reaction of carbamates, sulfonamides and acetamides to a,b-unsaturated ketones was developed. This process is promoted by 9-amino-9-deoxy-epi-quinine and diphenyl hydrogen phosphate to afford a straightforward and expeditious synthesis of several synthetically useful five-and six-membered heterocycles with excellent enantioselectivity（92%–97.5% ee） and very good yields（up to 99%）.展开更多
基金supported by the National Natural Science Foundation of China(21632003,21871116,22071085,U22A20390)the Fundamental Research Funds for the Central Universities(lzujbky-2023-stlt01)the 111 Program from the Ministry of Education of China。
文摘An asymmetric catalytic strategy in photocatalysis utilizing a chirality-induced approach through an organocatalytic/photoredox relay catalysis strategy is successfully achieved for the rapid construction of polycyclic compounds containing vicinal amino alcohols in a one-pot protocol. This methodology facilitates the efficient synthesis of diverse substituted polycyclic tetrahydroquinoline and benzofuran-derived vicinal amino alcohols, each containing five consecutive chiral centers, with high yields,excellent diastereoselectivities and enantioselectivities(up to 95% yield, >20:1 dr and 98% ee), under mild reaction conditions driven by sequential bifunctional squaramide organocatalyst-catalyzed [4+2] annulation and photocatalyst-catalyzed ketyl radical addition cyclization reaction process. Furthermore, investigations into the stereoselectivity mechanism and high-resolution mass spectrometry(HRMS) experiments on free radical trapping have provided evidence for elucidating the detailed mechanism of chirality-induced processes and chiral intermediate conversions in this procedure.
基金supported by the National Natural Science Foundation of China(21774108)the Distinguished Young Investigator Fund of Zhejiang Province(LR16B040001)
文摘Organocatalysis, defined as the use of small organic molecules for catalyzing chemical transformations, can be traced back more than a century and has become a thriving area over the past 20 years.
基金supported by the National Natural Science Foundation of China(Nos.21504024 and 21674038)Fundamental Research Funds for Central Universities
文摘Triggered by environmental concerns and the rising demands for metal-free polymers in e.g. bio-related and microelectronic applications, studies on organocatalytic polymerization have been launched and developed unprecedentedly during the last 15 years. A wide range of organic molecules are now available in polymer chemists＇ toolbox to choose from as catalysts for polymerization of （hetero）cyclic and polar vinyl monomers. Apart from the intrinsic merits such as lower toxicity and better solubility compared with （transition） metal catalysts/initiators, organocatalysts have also shown, in many cases, excellence to achieve high polymerization rates and/or good control （selectivity）. In addition, particular natures and catalytic/activating mechanisms of organocatalysts have led to new opportunities for rational design and efficient synthesis of macromolecular architectures, i.e. chain structures, topological structures and functionalities. This mini-review is specially themed on pathways to construct copolymer chain structures by organocatalytic copolymerization of mixed type monomers （comonomers bearing different polymerizing moieties） and will be sectioned by different comonomer combinations, including cyclic monoesters of different sizes, cyclic monoesters and lactides, cyclic esters and cyclic carbonates or epoxides, heterocycles and vinyl monomers.
文摘The highly enantioselective cross-dehydrogenative coupling of aldehydes with benzylic compounds has been developed as an efficient and rapid protocol for synthesis of enantioriched a-alkylated aldehydes.
基金financially supported by the National Natural Science Foundation of China (Nos. 21734004 and 21674038)
文摘Highly potent ionic organocatalyst is developed for room-temperature controlled ring-opening polymerization(ROP)of lactones,includingδ-valerolactone,ε-caprolactone,andδ-hexalactone.The catalysts are prepared by simply mixing tetra-n-butyl ammonium hydroxide and a(thio)urea at elevated temperature under vacuum,and used in cooperation with an alcoholic initiator.The performance of the catalyst is readily adjusted and optimized through variation of the(thio)urea precursor,catalyst composition,and reaction condition.Urea-derived catalysts are generally superior to thiourea-derived ones.Provided with proper N-substituents,the catalyst affords both high polymerization efficiency and high selectivity for monomer enchainment over macromolecular transesterification,even at high monomer conversion and/or substantially extended reaction time.In addition to acidity,structural symmetry of the urea also proves decisive for the catalytic activity,which enables a catalyst-assisted proton transfer process for the ring-opening of lactone and thus provides a novel mechanistic insight for ROP catalyzed by hydrogen-bonding type bifunctional ionic organocatalysts.
基金The authors gratefully acknowledge the financial support from National Basic Research Program of China(2012CB821600)the Key Program of Natural Science Foundation of China(21032006)National Natural Science Foundation of China(21172245/21172244/21372247)and 100-talent program of SIOC.
文摘An organocatalytic asymmetric trifluoromethylthiolation of 3-aryl or 3-alkyloxindoles employing a trifluoromethyl-substituted thioperoxide as the electrophilic trifluoromethylthiolating reagent was described.Reactions occurred in good to excellent enantioselectivities to generate oxindoles with a SCF_(3)-substituted quaternary chiral center.
基金financial support from the National Natural Science Foundation of China (No. 21262022)
文摘An intramolecular organocatalytic enantioselective aza-Michael reaction of carbamates, sulfonamides and acetamides to a,b-unsaturated ketones was developed. This process is promoted by 9-amino-9-deoxy-epi-quinine and diphenyl hydrogen phosphate to afford a straightforward and expeditious synthesis of several synthetically useful five-and six-membered heterocycles with excellent enantioselectivity（92%–97.5% ee） and very good yields（up to 99%）.
