Theoretical Exploration on Structural Stabilities and Detonation Properties of Nitrimino Substituted Derivatives of Cyclopropane

The packed density, detonation velocities, and detonation pressures of a series of cyclopropane derivatives were investigated to look for high energy density compounds. For exploring the possibility of synthesis, the bond order, heats of formation(HOF), bond dissociation energy(BDE), and characteristic height were calculated. Based on our results, A3 has the best detonation characters. Both A1 and A2 showed comparative detonation parameters and compact sensitivity with RDX, and could be regarded as the candidates of high energy density molecules.Both the heats of formation and explosive heats rose with the increase of nitrimino groups and the strain energy of three-membered ring. For A1 compound, pyrolysis mechanism might be a mix one(breakages of C–C and N–NO2 bonds). However, for A2 and A3 compounds, the N–NO2 is the trigger bond in explosive reactions. Our results may provide the basic information for further study of this kind of compounds.

Facile and Convenient One-pot Synthesis of 1,1-Disubstituted Cyclopropanes in Water

A facile and convenient one-pot synthesis method of substituted cyclopropanes in water has been developed. A series of 1,1-disubstituted cyclopropanes 3 were synthesized from the reaction of β-dicarbonyl compounds 1 with 1,2-dibromoethane 2, in very high yields catalyzed by tetrabutylammonium bromide（TBAB） at 50 ℃ in the presence of K2CO3 in water. The catalyst TBAB in the aqueous phase can be reused after the separation of organic products.

Synthesis and Unexpected Ring-opening Reaction of a New TADDOL Analogue with Chiral Cyclopropane Ring as Backbone

Synthesis and ring-opening reaction of TADDOL analogue with cyclopropane as chiral backbone were described. A plausible ring-opening and carbonium ion rearrangement mechanism have been proposed.

Synthesis and Structure of trans-1,2-Bisaromatic Heterocycle Substituted Cyclopropanes

Trans-1,2-bis(2 ' -(5 ' -phenyl-1 ' , 3 ' , 4 '-oxadiazolyl ) ) cyclopropane (BDCP) and its eleven substituted novel derivatives were synthesized. Besides four derivatives of l,2-bis(2'-(5'-phenyl-l ' , 3 ' , 4 ' -ox-adiazo1yl))ethane (BPDS) were also synthesized as model compounds. The crystal structure of ethyl BDCP was determined and the cyclopropane ring was found to be able to transmit conjugation between the aromatic groups directly bonding with it by studying the ultraviolet and fluorescent spectra of the above compounds.

Addition of Per(poly)fluoroalkyl Iodides to vinyl Cyclopropane Derivatives: Synthesis of Fluoroalkyl Substituted γ,δ-Unsaturated Carbonyl Compounds

In the presence of CrC13 /Fe bimetal couple,per(poly)fluoroalkyl iodides add to vinyl cyclopropane compounds giving addition-ring-opening products in good yields.

Stereoselective Synthesis of Polysubstituted Cyclopropanes from Poly(ethylene glycol) Supported Pyridinium Ylide

Polysubstituted cyclopropanes were efficiently prepared with poly（ethylene glycol）（PEG） as soluble support. The reaction of PEG-supported pyridinium ylide with arylidenemalononitrile（R=CN） or ethyl arylidenecyanoa-cetate（R=COOEt） in the presence of triethylamine（TEA） afforded PEG-supported cyclopropanecarboxylates, which were cleaved by 1% KCN/EtOH to obtain polysubstituted cyclopropanes with exclusive trans-selectivity and good yields.

Synthesis of Optically Active trans-2-Aminocyclopropane-carboxylic Esters

Two new optically active trans-2-atrfinocyclopropanecarboxylic esters （β-ACCs） of optical purity 91%-96% were concisely synthesized via ozonization, oxidation, Curtius rearrangement from commercial available optically active trans-chrysanthemate in total yield 36%.

Gas Chromatographic Enantiomer Separation of Cyclopropane Derivatives on Three 2, 6-Di-O-allyl-3-O-acylated-β- cyclodextrins Chiral Stationary Phases

Eight pairs of enantiomers of cyclopropane derivatives were resolved on capillary gas chromatographic columns using three new 2, 6-di-O-allyl-3-O-acylated-β-cyclodextrins as chiral stationary phases. It was found that the three β-CDs can separate some of the racemic cyclopropane derivatives well.

Synthetic Studies on 1-Amino-1-Cyclopropane-Carboxylic Acid( Ⅰ )——The Cyclopropanation via Addition-Elimination Reactions

Various addition-elimination approaches have been explored for diastereoselective construction of 1-amino- 1-cyclopropane-carboxylic acid (ACPC) derivatives, and the desired product was obtained from a reaction of cyclo(NAc-L-Val-NAc-Gly) and methyl α-bro-moacrylate under protonic solvent.

Nickel-Catalyzed Regio-and Stereoselective Defluorinative Arylation of gem-Difluorinated Cyclopropanes

Comprehensive Summary,Herein,we report nickel-catalyzed cross-coupling of gem-difluorinated cyclopropanes with boronic acids,providing the corresponding arylated 2-fluoroallylic scaffolds.This approach used commercially available phosphine ligand Xantphos to obtain monofluorinated alkenes with high regioselectivity and Z-stereoselectivity.Mechanistic studies proposed a Ni(II)-fluoroallyl pathway and excluded the radical pathway.

Controlled semi-Pinacol rearrangement on a strained ring:Efficient access to multi-substituted cyclopropanes by group migration strategy

We describe a versatile electrophile addition/SPR sequence of readily available cyclopropyl carbinols that affords multi-substituted carbonylated cyclopropanes with high stereo-fidelity.This approach tolerates various heteroatom electrophiles,migration of carbon moiety of all possible hybridization states,facile ring reorganization and natural compound valorization.The examples represent an unprecedented version of SPR wherein migration to a non-benzylic bulky tertiary carbo-cation is realized with promising enantiocontrol.

Asymmetric radical allylation of β-keto esters with vinyl cyclopropanes by dual photoredox/nickel catalysis

Radical-involved allylation reactions have emerged as a powerful platform for construction of carbon-carbon and carbonheteroatom bonds, facilitating the strategic incorporation of diverse allyl moieties. Nevertheless, this burgeoning field still faces ongoing challenges, including limitations of radical precursors and coupling partners, and difficulties in achieving enantiocontrol. Herein, we report for the first time a highly enantioselective radical allylation involving β-keto esters with vinyl cyclopropanes utilizing a synergistic dual photoredox/nickel catalysis under visible light irradiation. The mild and redox-neutral catalytic protocol demonstrates an extensive substrate compatibility and good functional tolerance, providing access to enantioenriched β-keto esters featuring quaternary α-stereocenter with good yields and high enantioselectivities. Preliminary mechanistic studies have uncovered that the success of the reaction hinges on the dual roles of nickel catalyst, including in situ formation of photoredox sensitive substrate/Ni complex and the ensuing asymmetric radical addition step.

Photocatalyzed[2+1]cyclization of alkenes and silylated trifluorodiazoethanes:facile entry into(difluoromethylene)cyclopropanes

Methylenecyclopropanes are among the most robust building blocks in synthetic chemistry,but the study on(difluoromethylene)-cyclopropanes is rather limited,because of the difficulty in the synthesis of these compounds.Herein,we report the invention of a novel carbene precursor,(1-diazo-2,2,2-trifluoroethyl)dimethyl(phenyl)silane(1a)and its application in the synthesis of(difluoromethylene)cyclopropanes.The reaction proceeds through photocatalyzed[2+1]cyclization of readily available alkenes and diazo compound 1a followed by the work-up of the reaction through the elimination of silyl fluoride.Both aromatic and aliphatic alkenes are tolerated by the mild reaction conditions,affording various(difluoromethylene)cyclopropanes in 44%–82%yield(>30 examples).Gram scale reaction and diversified downstream transformations highlight the synthetic potential of this methodology.The experimental and DFT calculations suggest the involvement of triplet carbene intermediate.

[3+2]Cycloaddition of Vinyl Cyclopropane and Hydroxylamines via Isocynate Intermediate toγ-Lactams

Comprehensive Summary A general and efficient strategy for the synthesis ofγ-lactams has been reported.The hydroxylamines form Lossen rearrangement products of electron-deficient group migration with base and then undergo[3+2]cycloaddition reaction with vinyl cyclopropane,which could be performed with broad substrate scope,excellent functional group tolerance and high efficiency to produce the desired products.It also allowed further modification to other derivatives of theseγ-lactams.

Sweet Strain Release:Donor-Acceptor Cyclopropane Mediated Glycosylation

Chemical glycosylation methodologies for the preparation of the bioactive oligosaccharides and glycoconjugates promise reliable access to these compounds as homogeneous materials with welldefined structures in sufficient amounts.Here we report a novel activation method of thio(seleno)glycosides employing donor-acceptor cyclopropane(DAC)agents and Sc(OTf)_(3).The Lewis acid catalyst converts DAC into a formal 1,3-zwitterionic species that in turn activates thioglycosides to furnish a glycosyl 1,4-zwitterionic intermediate,interconverting with reactive glycosyl oxocarbenium in the solution with reversible leaving-group dissociation.This activation method effectively promotes glycosylation reactions between both armed and disarmed thioglycosides and structurally diverse acceptors,affording oligosaccharides with satisfactory yields.The usefulness of our activation method has been demonstrated by the mechanism-inspired 2,4-dinitrobenzenesulfonyl(DNs)group directed S_(N)2-like glycosylation and the facile preparation of both linear and branched trisaccharides in one pot via controlled sequential activation of thioglycoside donors.

光响应基因BcCfaS通过脂质代谢调控灰葡萄孢菌的光形态建成及致病力

Light is a fundamental environmental factor for living organisms on earth—not only as a primary energy source but also as an informational signal.In fungi,light can be used as an indicator for both time and space to control important physiological and morphological responses.Botrytis cinerea(B.cinerea)is a devastating phytopathogenic fungus that exploits light cues to optimize virulence and the balance between conidiation and sclerotia development,thereby improving its dispersal and survival in ecosystems.However,the components and mechanisms underlying these processes remain obscure.Here,we identify a novel light-signaling component in B.cinerea,BcCfaS,which encodes a putative cyclopropane fatty-acyl-phospholipid synthase.BcCfaS is strongly induced by light at the transcriptional level and plays a crucial role in regulating photomorphogenesis.Deletion of BcCfaS results in reduced vegetative growth,altered colony morphology,impaired sclerotial development,and enhanced conidiation in a lightdependent manner.Moreover,the mutant exhibits serious defects in stress response and virulence on the host.Based on a lipidomics analysis,a number of previously unknown fungal lipids and many BcCfaS-regulated lipids are identified in B.cinerea,including several novel phospholipids and fatty acids.Importantly,we find that BcCfaS controls conidiation and sclerotial development by positively regulating methyl jasmonate(MeJA)synthesis to activate the transcription of light-signaling components,revealing for the first time the metabolic base of photomorphogenesis in fungi.Thus,we propose that BcCfaS serves as an integration node for light and lipid metabolism,thereby providing a regulatory mechanism by which fungi adapt their development to a changing light environment.These new findings provide an important target for antifungal design to prevent and control fungal disease.

Aminated Cyclopropylmethylphosphonates as Potent Prostate Cancer Inhibitors

Inspired by the anti-pancreatic promising results of our novel aminated cyclopropylmethylphosphonate compounds, an in vitro anti-prostate cancer activity exploration of these compounds was carried out on human prostate cancer cell line PC-3, and showed potent inhibiting activity at low micromolar concentrations (with an IC50 of approximately 45 μM).

Sidearm as a Control in the Asymmetric Ring Opening Reaction of Donor-Acceptor Cyclopropane

A new type of trisoxazoline and bisthiazoline based ligands have been developed,which are absent of chiral motif on the parent skeleton and containa chiral backbone on sidearm.The ligands promote the amine nucleophilic ring opening reaction of 1,1-cyclopropane diesters smoothly,furnishing the γ-amino acid derivatives in high yield with moderate to good enantioselectivity.

Synthesis of Functionalized 2-Aminopyrroles by Lewis Acid Catalyzed Ring-opening of 1,1,2,3-Tetrasubstituted Cyclopropanes with Arylamines

Under the catalysis of Lewis acid Co（CIO4）2 the reaction of the sterically hindered 1,1,2,3-tetrasubstituted cyclopropanes with arylamines in refluxing THF gave the functionalized 2-aminopyrroles with sequential ring-opening of cyclopropane, nucleophilic substitution, nucleophilic addition of cyano group and recyclization processes.

A Convenient Synthesis of Fluorine-Containing trans-1,2-Cyclopropane Derivatives from Semistabilized Arsonium Ylides

The fluorine-containing trans-l,2-cyclopropane derivatives 4ba--4dd were synthesized from the fluorine-containing electron-deficient alkenes 3a--3d with semistabilized arsonium ylides 2b--2d, in biphasic system of dichloromethane-50% aqueous sodium hydroxide, generated in situ from the corresponding arsonium salts 1b-1d at room temperature in good yields with high stereoselectivity. The structure of fluorine-containing trans-1,2-cyclopropane derivatives were also studied.