查看更多>>摘要：Heteronuclear metal complexes have played an increasingly important role in both small molecules activation and catalytic transfor-mation due to the potential metal-metal synergies.In this work,we reported that the well-defined Mg-Ni-Mg complex[(LMg)2Ni(C2H4)2]{L=[(DippNCMe)2CH]-,Dipp=2,6-iPr2C6H3} was capable of catalyzing the conversion of a diverse array of terminal alkenes to hydrosilylated products in onti-Markovnikov fashion using PhSiH3 as the silicon source.The stoichiometric reaction of het-erometallic Mg-Ni-Mg complex with one equivalent PhSiH3 obtained a silyl-nickel-monohydride complex[(LMg)2NiH(C2H4)(SiHPhEt)]featuring a Ni-Si-H-Mg interaction.Moreover,treatment of heterometallic Mg-Ni-Mg complex with three equivalents PhSiH3 provided the silyl-nickel-trihydride complex[(LMg)2NiH3(SiHPhEt)]with three hydride-bridged at Mg-Ni-Mg fragment.Further reactions of the resultant silyl-nickel complexes with alkenes,e.g.,ethylene and styrene,yielded the corresponding alkene-coordinated Mg-Ni-Mg complexes[(LMg)2Ni(C2H4)2],[(LMg)2NiH2(C2H4)]and[(LMg)2NiH2(CH2CHPh)],respectively,with the elimination of PhEtSiH2.Based on the control experiments,both silyl-nickel-monohydride and silyl-nickel-trihydride complexes were considered as active intermediates in the catalytic hydrosilylation reaction.
查看更多>>摘要：Herein,we reported a precise de novo synthesis of chiral 3,4-dihydroquinazoline frameworks via a one-pot anionic stereogen-ic-at-cobalt(Ⅲ)complex-catalyzed enantioselective Ugi-azide/Pd-catalyzed cyclization sequence.This powerful protocol involves 5 components and 2 catalytic systems,delivering chiral 3,4-dihydroquinazolines with excellent enantioselectivities(up to 94％ee).The preliminary antifungal experiments suggest that both Ugi-adducts and 3,4-dihydroquinazolines have great potential in inhibiting plant pathogens such as Trichoderma viride and Fusarium graminearum.
查看更多>>摘要：The synthesis of N-glycosides has received significant attention due to their crucial role in carbohydrate chemistry.Despite considera-ble advancements developed in the construction of N-glycosides,methods for the stereoselective construction of 2-deoxy-a-N-glyco-sides αre still limited.Herein,we disclosed a nickel-catalyzed hydroamination of glycals under mild conditions.This transformation could allow for the stereoselective synthesis of an array of 2-deoxy-α-N-glycosides with excellent α-stereoselectivity.Nickel-catalyzed glycosylation reactions,particularly those involving anomeric C(sp3)-metal bond formation,have proven to be an effective and stere-oselective strategy for producing various N-glycosides.Additionally,with highlight of the application of this reaction,y-sugar amino acid derivatives were synthesized.
查看更多>>摘要：Side-chain engineering has emerged as a highly effective strategy for tailoring the aggregation behavior and charge transport proper-ties of non-fullerene small molecule acceptors(SMAs).In this study,we designed and synthesized two SMAs,namely BTPSi-Bu and BTPSi-Pr,respectively incorporating tributylsilyloxy and triisopropylsilyloxy groups in their outer positions.Notably,BTPSi-Bu exhibited better planarity,crystallization,and favorable phase separation when paired with PM6 donor polymer compared to its counterpart,BTPSi-Pr.The resulting organic solar cells,utilizing the PM6:BTPSi-Bu blend,demonstrated a remarkable power conversion efficiency of 17.41％and a high open-circuit voltage of 0.859 V.These findings underscore the significance of integrating trialkylsilyloxy side chains into SMAs as a rational design approach for enhancing the performance of photovoltaic systems.
查看更多>>摘要：Transition-metal-catalyzed asymmetric alkylation of aldehydes represents a straightforward strategy for the synthesis of chiral sec-ondary alcohols.However,efficient methods using organoborons as coupling reagents are rare.Herein,we report a highly enanti-oselective nickel-catalyzed alkylation reaction of aldehydes,using readily available alkylborons as nucleophiles.A wide variety of chiral secondary alcohols were prepared from commercially available aldehydes with high yields.The key to the excellent enantiose-lectivity and chemoselectivity was the employment of a bulky C2-symmetric chiral NHC ligand.This protocol features excellent enan-tiocontrol,mild conditions,and good functional group compatibility.
查看更多>>摘要：DNA 5-formylcytosine(5fC)is a prominent epigenetic modification within biological systems.Recent investigations have shed light on its pivotal role in governing cell fate,gene expression,and disease pathways.However,our comprehension of the precise control of the 5fC site structure to influence its functionality remains limited.In this study,we have successfully achieved precise control over 5fC activity by harnessing the interaction between streptavidin and biotin.This research underscores the potential application of interac-tions between biomacromolecules and small molecules in advancing the field of DNA epigenetic functional regulation.
查看更多>>摘要：The stability of organic radicals in ambient condition is important for their practical application.During the development of organic radical chemistry,the electron-withdrawing and steric hindrance groups are usually introduced to improve the stability of radicals via reducing the reactivity of radicals with oxygen in air.Herein,the electron-withdrawing carbonyl groups are introduced to construct a planar aromatic oxalic acid radical(IDF-O8)with two-dimensional electron spin pan structure.Interestingly,IDF-O8 exhibited a low op-tical bandgap of 0.91 eV in film,however,the multiple quinone resonance structures between electron-withdrawing ketone and phe-nol radicals contribute to the high stability of open-shell radical IDF-O8 without protection of large steric hindrance groups.Under the irradiation of 808 nm(1.2 W·cm-2),IDF-O8 reaches 147 ℃ in powder state.This work provides an efficient synthesis route for the open-shell electron spin pan system,which is different from the famous fullerene,carbon nanotube and graphene.The electron spin pan can be extended to spin tube or spin sphere system based on the design strategy of aromatic inorganic acid radicals in future.
查看更多>>摘要：Hyperlanins A(1)and B(2),two highly rearranged polycyclic polyprenylated acylphloroglucinol(PPAP)-related meroterpenoids based on different new carbon skeletons,were isolated from Hypericum lancasteri.Compound 1 incorporates an unprecedented 5/6/7/5 ring system featuring a 3,13-dioxatetracyclo[9.2.1.12,5.01.8]pentadecane core.Compound 2 possesses a unique compact 6/6/5/6/6/5/6 ring system with a caged tetracyclo[6.2.1.13,8.05,11]dodecane motif.Their structures were established by spectroscopic data,X-ray dif-fraction,and computational approaches.Both compounds showed anti-inflammatory activity in vitro.Compounds 1 and 2 could de-crease the lipopolysaccharide(LPS)-/nigericin-induced IL-1β release in THP-1 cells.Both compounds also showed inhibition in hypox-ia-inducible factor-1α(HIF-1α)pathway luciferase reporter assay.
查看更多>>摘要：Redox nanozymes offer an appealing reactive oxygen species(ROS)-based antibacterial strategy via disrupting intracellular homeosta-sis,however,they still face many obstacles such as low enzymic activity and irreversible loss of catalytic active center.Meanwhile,the antioxidant glutathione(GSH)overexpressed in infected sites would limit the therapy efficiency.Herein,we develop a multifunctional nanozyme based on copper(Ⅰ)(Cu+)ion doped MoO3-x(Cu+-MoO3-x)by a simple yet efficient oxygen vacancy-reduced strategy without any pretreatment or additional agents.The resultant Cu+-MoO3_x hybrid possesses enhanced peroxidase-like(POD-like)activity,rapid GSH-depleting function and biodegradable ability.It can achieve highly efficient elimination of Pseudomonas aeruginosa(P.aerugino-sa)via disrupting cellular redox balance.More intriguingly,GSH-depleting redox reaction between Cu+-MoO3-x and GSH could trans-late Mo6+into Mo5+,thereby leading to partial recovery of POD-like activity of Cu+-MoO3-x hybrid for continuous·OH generation.In vitro and in vivo experiments demonstrated that Cu+-MoO3_x hybrid had stronger antibacterial property compared to MoO3-x by rapid GSH consumption and plentiful OH generation without providing extra H2O2,as well as neglective toxicity to healthy organs.In view of its remarkable enzymic activity and good biosafety,the developed Cu+-MoO3-x redox nanozyme can be used as a promising antimicro-bial for P.aeruginosa infection.
查看更多>>摘要：An efficient and highly stereoselective synthetic method to access polycyclic chromanes has been achieved through organocatalyzed one-pot step-wise reactions involving 2-hydroxycinnamaldehydes,2-aminochalcones,and malononitrile as substrates.The reactions underwent a quintuple process by aza-Michael/Michael/Knoevenagel/oxa-Michael/aldol-type reaction in sequence to give products bearing 3 new generated rings and 5 chiral centers in moderate to quantitative yields with excellent stereoselectivities.A novel ret-ro-reaction mechanism was discovered in the synthetic transformations of products.
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