An efficient synthesis of chiral benzannulated spiroketals via catalytic asymmetric[3+2]cycloaddition of exocyclic enol ethers with p-quinones was achieved.The transformation was enabled by a chiral N,N′-dioxides/Tm^...An efficient synthesis of chiral benzannulated spiroketals via catalytic asymmetric[3+2]cycloaddition of exocyclic enol ethers with p-quinones was achieved.The transformation was enabled by a chiral N,N′-dioxides/Tm^(Ⅲ)complex as the Lewis acid catalyst and afforded a series of enantiomerically enriched benzannulated spiroketal derivatives in good yields(up to 99%)and enantioselectivities(up to 98%ee).Topographic steric maps and distribution of the buried volumes of the catalysts via Cavallo’s SambVca 2 tool were used to elucidate the enantioinduction raised by the ligands and the metal ions.展开更多
Chiral organobases occupy a significant position in asymmetric organocatalysis. The general types of chiral organobases include tertiary amines, amidines, guanidines, cyclopropenimines, and iminophosphoranes, etc. The...Chiral organobases occupy a significant position in asymmetric organocatalysis. The general types of chiral organobases include tertiary amines, amidines, guanidines, cyclopropenimines, and iminophosphoranes, etc. These organobases are demonstrated to be effective organocatalysts to promote divers kinds of base-initiated reactions in excellent yields and stereoselectivities. In previous reports, several groups have summarized each kind of chiral organobases in different reviews. To the aim of understanding the whole of them in one review, herein, we provide a brief introduction of these chiral organobases in asymmetric catalysis.展开更多
Chiral Lewis acid-catalyzed enantioselective nitrooxylation of cyclic and acyclicβ-keto amides/esters with hypervalent iodine(III)reagents is reported.A number ofα-nitrooxy-β-keto amides/esters were obtained with g...Chiral Lewis acid-catalyzed enantioselective nitrooxylation of cyclic and acyclicβ-keto amides/esters with hypervalent iodine(III)reagents is reported.A number ofα-nitrooxy-β-keto amides/esters were obtained with good yields and high enantioselectivities by using bench-stable nitratobenziodoxole under mild conditions.展开更多
We report the first asymmetric three-component nucleophilic addition/dearomative[4+2]cycloaddition/isomerization cascade of transient dipoles generated from N-heteroarenes and allenoates with methyleneindolinones in t...We report the first asymmetric three-component nucleophilic addition/dearomative[4+2]cycloaddition/isomerization cascade of transient dipoles generated from N-heteroarenes and allenoates with methyleneindolinones in the presence of chiral N,N′-dioxide/metal complexes.This tandem reaction enabled rapid access to versatile chiral polycyclic N-heterocycles with good to excellent enantioselectivities under mild reaction conditions in spite of the strong background reaction,including 1,2-dihydroisoquinoline,1,2-dihydropyridine derivatives,and others.Meanwhile,a series of control experiments were conducted to elucidate the reaction mechanism and the roles of additives.展开更多
Ligand-accelerated catalysis(LAC),a term originally coined by Sharpless,has been a pivotal guiding principle in the advancement of asymmetric catalysis.The discovery and understanding of LAC have not only energized th...Ligand-accelerated catalysis(LAC),a term originally coined by Sharpless,has been a pivotal guiding principle in the advancement of asymmetric catalysis.The discovery and understanding of LAC have not only energized the enhancement of established catalytic asymmetric transformations but also ignited the creation of novel ones.In this review,we have curated a selection of illustrative examples,delving into the profound influence that chiral ligands exert on the acceleration of Lewis acid-promoted reactions,encompassing both thermally induced and photochemical processes.The impact of a chiral ligand on various facets,including solubility,aggregation state,geometry,Lewis acidity,and photophysical properties of metal salts,has been identified as crucial determinants.Moreover,the covalent and noncovalent interactions between ligands and substrates,the creation of chiral pockets by chiral ligands and metals,as well as the alterations in the physical and chemical properties of substrates induced by Lewis acid coordination,also play significant roles.Notably,the utilization of ligandaccelerated asymmetric Lewis acid catalysis in photoreactions presents an efficient approach for addressing the challenges associated with stereocontrol.We anticipate that this review will inspire researchers to pay more attention to the role of ligands and aid in the development of new efficient ligands and asymmetric reactions.展开更多
基金the National Natural Science Foundation of China(Nos.21890723 and 21921002)the Science and Technology Department of Sichuan Province(Nos.2021YJ0561)for financial support.
文摘An efficient synthesis of chiral benzannulated spiroketals via catalytic asymmetric[3+2]cycloaddition of exocyclic enol ethers with p-quinones was achieved.The transformation was enabled by a chiral N,N′-dioxides/Tm^(Ⅲ)complex as the Lewis acid catalyst and afforded a series of enantiomerically enriched benzannulated spiroketal derivatives in good yields(up to 99%)and enantioselectivities(up to 98%ee).Topographic steric maps and distribution of the buried volumes of the catalysts via Cavallo’s SambVca 2 tool were used to elucidate the enantioinduction raised by the ligands and the metal ions.
基金the National Natural Science Foundation of China (Nos. 21625205 and 21332003)the National Program for Support of Top-Notch Young Professionals for financial support
文摘Chiral organobases occupy a significant position in asymmetric organocatalysis. The general types of chiral organobases include tertiary amines, amidines, guanidines, cyclopropenimines, and iminophosphoranes, etc. These organobases are demonstrated to be effective organocatalysts to promote divers kinds of base-initiated reactions in excellent yields and stereoselectivities. In previous reports, several groups have summarized each kind of chiral organobases in different reviews. To the aim of understanding the whole of them in one review, herein, we provide a brief introduction of these chiral organobases in asymmetric catalysis.
基金We appreciate the National Natural Science Foundation of China(22071160)for financial support.
文摘Chiral Lewis acid-catalyzed enantioselective nitrooxylation of cyclic and acyclicβ-keto amides/esters with hypervalent iodine(III)reagents is reported.A number ofα-nitrooxy-β-keto amides/esters were obtained with good yields and high enantioselectivities by using bench-stable nitratobenziodoxole under mild conditions.
基金the National Natural Science Foundation of China(grant no.21772127).
文摘We report the first asymmetric three-component nucleophilic addition/dearomative[4+2]cycloaddition/isomerization cascade of transient dipoles generated from N-heteroarenes and allenoates with methyleneindolinones in the presence of chiral N,N′-dioxide/metal complexes.This tandem reaction enabled rapid access to versatile chiral polycyclic N-heterocycles with good to excellent enantioselectivities under mild reaction conditions in spite of the strong background reaction,including 1,2-dihydroisoquinoline,1,2-dihydropyridine derivatives,and others.Meanwhile,a series of control experiments were conducted to elucidate the reaction mechanism and the roles of additives.
基金the National Natural Science Foundation of China(grant nos.22188101 and 21890723)Sichuan University(grant no.2020SCUNL204)for financial support。
文摘Ligand-accelerated catalysis(LAC),a term originally coined by Sharpless,has been a pivotal guiding principle in the advancement of asymmetric catalysis.The discovery and understanding of LAC have not only energized the enhancement of established catalytic asymmetric transformations but also ignited the creation of novel ones.In this review,we have curated a selection of illustrative examples,delving into the profound influence that chiral ligands exert on the acceleration of Lewis acid-promoted reactions,encompassing both thermally induced and photochemical processes.The impact of a chiral ligand on various facets,including solubility,aggregation state,geometry,Lewis acidity,and photophysical properties of metal salts,has been identified as crucial determinants.Moreover,the covalent and noncovalent interactions between ligands and substrates,the creation of chiral pockets by chiral ligands and metals,as well as the alterations in the physical and chemical properties of substrates induced by Lewis acid coordination,also play significant roles.Notably,the utilization of ligandaccelerated asymmetric Lewis acid catalysis in photoreactions presents an efficient approach for addressing the challenges associated with stereocontrol.We anticipate that this review will inspire researchers to pay more attention to the role of ligands and aid in the development of new efficient ligands and asymmetric reactions.