Summaryof main observation and conclusion Herein,we developed an Ir/phase-transfer-catalysiscooperatively catalyzed asymmetric cascade allyla-tion/2-aza-Cope rearrangement of aldimine esters to prepare synthetically i...Summaryof main observation and conclusion Herein,we developed an Ir/phase-transfer-catalysiscooperatively catalyzed asymmetric cascade allyla-tion/2-aza-Cope rearrangement of aldimine esters to prepare synthetically important homoallylic amines in good yields with excellent enantioselectivi-ties.Compared with the bimetallic catalytic system to realize this transformation,the current cooperative Ir/tetrabutyl ammonium bromide catalytic system provides an alternative but more practical approach,which not only simplify the manipulation process but also increase the cost efficiency.展开更多
Li-rich manganese-based oxides (LRMO) with high capacities are attractive cathode materials for next-generation lithium-ion batteries.However,poor cycling stability is one of the key issues impeding their commercializ...Li-rich manganese-based oxides (LRMO) with high capacities are attractive cathode materials for next-generation lithium-ion batteries.However,poor cycling stability is one of the key issues impeding their commercialization.Here,for the first time,we employed trimethoxy(3,3,3-trifluoropropyl)silane (TMTFS) as a multifunctional electrolyte additive to stabilize the LRMO cathode interphase and elevate its cycling performance.The LRMO electrode delivered a high reversible capacity of 250.4 mAh·g^(-1) with a stable capacity retention of 91% after 200 cycles.展开更多
We report an unprecedented Pd-catalyzed asymmetric allylic alkylation of 1-(indol-2-yl)cyclobutanols followed by anα-iminol rearrangement.High yields with excellent chemo-,regio-,diastereo-,and enantioselectivities h...We report an unprecedented Pd-catalyzed asymmetric allylic alkylation of 1-(indol-2-yl)cyclobutanols followed by anα-iminol rearrangement.High yields with excellent chemo-,regio-,diastereo-,and enantioselectivities have been realized,affording a wide range of enantioenriched 2-spirocyclicindolines bearing two contiguous stereocenters.The facial selectivity of the ensuing rearrangement is controlled by the subtle difference of the substituents on the all-carbon quaternary stereogenic center formed in the allylic alkylation step.Nonactivated racemic terminal allylic alcohols are utilized as efficient electrophiles via kinetic resolution pathways for the first time in Pd-catalyzed asymmetric allylic alkylation.The role of Et3B additive is pivotal to activating allylic alcohols toward the formation of π-allylpalladium species and suppressing N/O allylic alkylation of indole with enhanced C3-nucleophilicity.Electrospray ionization high-resolution mass spectrometry(ESIHRMS)experiments provided strong evidence for the existence of the key nucleophilic boron anionic species,which fully accounts for the essential role of the Et_(3)B additive.The study of the mechanism indicates that the real catalytically active species is an electronic π-cinnamyl-palladium complex coordinated by two phosphoramidite ligands,which is consistent with the observed nonlinear effect and control experiments and is further confirmed by X-ray structure analysis.展开更多
Sequential Ir-catalyzed asymmetric allylation/2-aza-Cope rearrangement of arylidene aminomalonates with allylic carbonates was successfully developed,and a variety of enantioenriched homoallylic amine derivatives were...Sequential Ir-catalyzed asymmetric allylation/2-aza-Cope rearrangement of arylidene aminomalonates with allylic carbonates was successfully developed,and a variety of enantioenriched homoallylic amine derivatives were obtained in high yields with good chirality transfer and excellent E/Z-geometry control(up to 99%yield,96%ee).Compared with previous dual catalytic system established for this transformation,the current mono metal catalytic system provides a simpler and more practical protocol employing the readily available starting materials.展开更多
基金This work was supported by NSFC(Nos.21525207,21772147)China Postdoctoral Science Foundation funded project(No.2017M620331).The Program of Introducing Talents of Discipline to Universities of China(111 Program)is also appreciated.We thank Prof.Shu-Li You at Shanghai Institute of Organic Chemistry(SIOC)for generously providing ligand THQPhos.
文摘Summaryof main observation and conclusion Herein,we developed an Ir/phase-transfer-catalysiscooperatively catalyzed asymmetric cascade allyla-tion/2-aza-Cope rearrangement of aldimine esters to prepare synthetically important homoallylic amines in good yields with excellent enantioselectivi-ties.Compared with the bimetallic catalytic system to realize this transformation,the current cooperative Ir/tetrabutyl ammonium bromide catalytic system provides an alternative but more practical approach,which not only simplify the manipulation process but also increase the cost efficiency.
基金financially supported by the National Natural Science Foundation of China (Nos.22172116 and 21773176)。
文摘Li-rich manganese-based oxides (LRMO) with high capacities are attractive cathode materials for next-generation lithium-ion batteries.However,poor cycling stability is one of the key issues impeding their commercialization.Here,for the first time,we employed trimethoxy(3,3,3-trifluoropropyl)silane (TMTFS) as a multifunctional electrolyte additive to stabilize the LRMO cathode interphase and elevate its cycling performance.The LRMO electrode delivered a high reversible capacity of 250.4 mAh·g^(-1) with a stable capacity retention of 91% after 200 cycles.
基金supported by the NSFC(nos.21525207,21772147,and 220711186)the Huibei Province Natural Science Foundation(no.2020CFA036)+1 种基金Support by the Fundamental Research Funds for the Central Universitiesthe Program of Introducing Talents of Discipline to Universities of China(111 Program)is also appreciated.
文摘We report an unprecedented Pd-catalyzed asymmetric allylic alkylation of 1-(indol-2-yl)cyclobutanols followed by anα-iminol rearrangement.High yields with excellent chemo-,regio-,diastereo-,and enantioselectivities have been realized,affording a wide range of enantioenriched 2-spirocyclicindolines bearing two contiguous stereocenters.The facial selectivity of the ensuing rearrangement is controlled by the subtle difference of the substituents on the all-carbon quaternary stereogenic center formed in the allylic alkylation step.Nonactivated racemic terminal allylic alcohols are utilized as efficient electrophiles via kinetic resolution pathways for the first time in Pd-catalyzed asymmetric allylic alkylation.The role of Et3B additive is pivotal to activating allylic alcohols toward the formation of π-allylpalladium species and suppressing N/O allylic alkylation of indole with enhanced C3-nucleophilicity.Electrospray ionization high-resolution mass spectrometry(ESIHRMS)experiments provided strong evidence for the existence of the key nucleophilic boron anionic species,which fully accounts for the essential role of the Et_(3)B additive.The study of the mechanism indicates that the real catalytically active species is an electronic π-cinnamyl-palladium complex coordinated by two phosphoramidite ligands,which is consistent with the observed nonlinear effect and control experiments and is further confirmed by X-ray structure analysis.
基金We are grateful for financial support from the National Natural Science Foundation of China(Grant Nos.21525207,21772147to C.J.W.)Natural Science Foundation of Jiangsu Province(Grant No.SKB2019041078 to X.Q.D.)+2 种基金Wuhan Morning Light Plan ofYouth Science and Technology(Grant No.2017050304010307 to X.Q.D.)Postdoctoral Innovative Talent Support Program of china(BX20190253 to C.s.).We thank Prof.Shu-Li You at SloC forgenerously providing(R,R)-THQ-PhosThe Program of Introducing Talents of Discipline to Universities of China(111 Project)is alsoappreciated.
文摘Sequential Ir-catalyzed asymmetric allylation/2-aza-Cope rearrangement of arylidene aminomalonates with allylic carbonates was successfully developed,and a variety of enantioenriched homoallylic amine derivatives were obtained in high yields with good chirality transfer and excellent E/Z-geometry control(up to 99%yield,96%ee).Compared with previous dual catalytic system established for this transformation,the current mono metal catalytic system provides a simpler and more practical protocol employing the readily available starting materials.
