Carbon enhanced nucleophilicity of Na_(3)V_(2)(PO_(4))_(3):A general approach for dendrite-free zinc metal anodes

Zincophilic property and high electrical conductivity are both very important parameters to design novel Zn anode for aqueous Zn-ion batteries(AZIBs).However,single material is difficult to exhibit zincophilic property and high electrical conductivity at the same time.Herein,originating from theoretical calculation,a zincophilic particle regulation strategy is proposed to address these limitations and carbon coated Na_(3)V_(2)(PO_(4))_(3)is taken as an example to be a protective layer on zinc metal(NVPC@Zn).Na_(3)V_(2)(PO_(4))_(3)(NVP)is a common cathode material for Zn-ion batteries,which is zincophilic.Carbon materials not only offer an electron pathway to help Zn deposition onto NVPC surface,but also enhance the zinc nucleophilicity of Na_(3)V_(2)(PO_(4))_(3).Hence,this hybrid coating layer can tune zinc deposition and resist side reactions such as hydrogen generation and Zn metal corrosion.Experimentally,a symmetrical battery with NVPC@Zn electrode displays highly reversible plating/stripping behavior with a long cycle lifespan over 1800 h at2 mA cm^(-2),much better than carbon and Na_(3)V_(2)(PO_(4))_(3)solely modified Zn electrodes.When the Na_(3)V_(2)(PO_(4))_(3)is replaced with zincophobic Al2O3or zincophilic V2O3,the stability of the modified zinc anodes is also prolonged.This strategy expands the option of zincophilic materials and provides a general and effective way to stabilize the Zn electrode.

A New Asymmetric Synthesis of (+)-(3R, 4S, 5R, 7S)-Neoclausenamide via Intramolecular Nucleophilic Attack of Carbon Anion onto Cyclic Sulfate

An intramolecular nucleophilic substitution of carbon anion to cyclic sulfate was first employed in asymmetric synthesis of (+)-(3R, 4S, 5R, 7S)-neoclausenamide 1 which is a novel hepatoprotective lactam isolated from the dry leaves of Chinese folk medicine Clausena lansium (Lour) Skeel. The regioselectivity of beta-attack to this cyclic sulfate, just like its epoxide counterpart was attributed to the increased reactivity of beta-position by the phenyl group.

Synthesis and comparative study of reactivities of δ-lactone,estor group and oxazinone ring in coumarin derivatives towards carbon or nitrogen nucleophiles

Condensation of methyl 7-methylcoumarin-4-acetate(2)with primary amines and with an- thranilic acid gave 7-methyl-2-oxo-N-aryl-2H-[1]-benzopyran-4--acetamide(4a—d)and(7),respectively. Compound 7 underwent cyclization to give 2-(7-methyl-2-oxo-2H-[1]-benzopyran-4-yl)-methyl-4H-3,1- benzoxazin-4-one(3).The reaction of 3 with aromatic amines gave the corresponding quinazolone derivatives 5 which tautomerises to the thermodynamically more stable isomer 6,whereas its reaction with Grignard reagents and aromatic aldehydes gave 8a,8b,and 9a,9b,respectively.

Catalytic C-N Bond Alkynylation of N-Benzylic Sulfonamides with Terminal Alkynes

A new cross-coupling reaction of N-benzylic sulfonamides with terminal alkynes for the synthesis of internal alkynes is reported.In the presence of 5 mol%of(Tf)_(2)NH/Bi(OTf)_(3)(1∶1),a broad range of N-benzylic sulfona-mides react smoothly with arylacetylenes to afford structurally diverse internal alkynes in moderate to excellent yields.We reasoned that vinyl cations could be formed by the regioselective attack of terminal alkynes with benzyl cations generated in situ from N-benzylic sulfonamides under acidic conditions,which then eliminated to form a carbon-carbon triple bond.