A Facile Synthesis of Indolizines by 1，3－Dipolar Cycloaddition of Pyridinium and Related Heteroaromatic Ylides with Alkenes in the Presence of TPCD，Py_4Co（HCrO_4）_2

facile one-step method is presented for the synthesis of indolizines in moder-ate to high yields by reaction of pyridinium, quinolinium and isoquinolinium ylideswith acrylonitrile, methyl acrylate and diethyl maleate respectively in the presenceof tetrakis-pyridino-cobalt(Ⅱ)dichromate (TPCD) in DMF.

An Improved Synthesis of α-Phenylseleno Arsonium Ylides

α-Seleno arsonium ylides 5 have been synthesized through the reaetion of α- unfunctionalized arsonium ylides 4 with almost equimolar phenylselenenyl iodide 2.

Chemistry and Application of Phosphonium and Arsonium Ylides (XV——A Facile Synthesis of Dimethyl 3,7-Diperfluoroalkyl-2,4,7-Nonatriendioates

We reported the stereoselectlve synthesis of fluorine-containing trisubstituted ethylenes(4) by hydrolysis of the adducts(3) which are the products of the reactions of some stable phosphonium or arsonium ylides with methyl 2-perfluoroalkynoates(2).

Studies on the Aromatic Dihalocarbonyl Ylides and Their Deoxygenation

The deoxygenation reaction of heptanones, cycloheptanone, cycloheptatrienone or substituted cycloheptatrienone with dihalo-carbene results in carbon monoxide and corresponding halides. The yield of CO produced by 2 , 4 , 6-triphenylcycloheptatrienone is 2.6-3.5 times as high as that produced by the saturated heptanones. The structures, energies, charge distributions, bond orders, and other relative parameters of the dihalocarbonyl glides were calculated by using the SCF-MNDO method. The obtained data reveal that the ylides from cycloheptatrienone have aromatic structure and are different from those produced from saturated cycloheptanone. The reactivities of the dihalocarbonyl ylides are discussed. It is proposed that this aromatic structure should be responsible for the high yield of CO from the reaction of cycloheptatrienone with dihalocarbene.

1,3-Dipolar Cycloaddition of Polycyclic Aromatic Azomethine Ylides and Alkynylbenziodoxoles for Synthesis of Functional Dibenzoullazines

A new family of dibenzoullazine derivatives was synthesized through 1,3-dipolar cycloaddition of polycyclic aromatic azomethine ylides with alkynylbenziodoxoles followed by oxidation.The benziodoxole moiety in the resulting products was used as a versatile linchpin for the synthesis of structurally diverse functional dibenzoullazines that are difficult to access by other synthetic methods.

Rhodium-catalyzed Doyle-Kirmse rearrangement reactions of sulfoxoniun ylides

Doyle-Kirmse rearrangement reactions have received continuous attention as an important method for constructing complex chemical structures. Herein, we disclosed an efficient rhodium-catalyzed DoyleKirmse rearrangement reaction, which can simultaneously construct C–C bonds and C–X(X = S/Se) bonds using sulfoxonium ylides as starting materials to obtain sulfur-or selenium-containing compounds. This strategy is characterized by the safer and greener carbene precursor, high yields and broad substrate scope, possessing a wide range of application.

Synthesis of 2-Trifluoromethyl-4-aminoquinolines via Heating-Promoted Multi-component Reaction of CF_(3)-Imidoyl Sulfoxonium Ylides and Amines with Difluorocarbene as a C1 Synthon

A thermally-induced multi-component reaction of CF_(3)-substituted imidoyl sulfoxonium ylides(TFISYs),amines and(triphenylphosphonio)difluoroacetate(PDFA)has been developed,allowing a facile access to 2-trifluoromethyl-4-aminoquinolines in high yields.The reaction proceeds smoothly with or without the addition of sulfur and utilizes difluorocarbene as a C1 synthon under simply heating conditions.Mechanistic study reveals that in-situ generated thiocarbonyl fluoride,isothiocyanate or gem-difluoroalkene might act as the key reaction intermediates.

Synergistic Catalysis with Azomethine Ylides

Azomethine ylides are useful intermediates for the rapid construction of chiral N-containing compounds.However,its synthetic potential has not been fully developed due to the limited reaction models.In combination with synergistic catalysis and azomethine ylide chemistry,we have developed several types of novel catalytic system including Cu/Pd,Cu/Ir and PTC/Ir catalysis;which can convert readily-available azomethine ylides to various high-valued molecules such as unnatural a-amino acids,homoallylic amines and N-heterocycles.Compared with the traditional mono-catalysis,the synergistic catalyst system exhibits enhanced catalytic efficiency and chiral induction ability in many cases.In addition,we have demonstrated that these strategies could be applied in the construction of bioactive compounds and natural products.

Synthesis of 2-aminothiazoles via rhodium-catalyzed carbenoid insertion/annulation of sulfoxonium ylides with thioureas

Sulfoxonium ylides as carbene precursors couple smoothly with thioureas in the presence of 5 mol% of rhodium(Ⅱ) acetate dimmer via carbenoid insertion to afford the corresponding 2-aminothiazoles with high chemoselectivity,providing a facile and efficient approach to access a variety of 2-aminothiazole derivatives with good functional groups tolerance.

Access to multi-functionalized oxazolines via silver-catalyzed heteroannulation of enamides with sulfoxonium ylides

Disclosed herein is an efficient Ag-catalyzed 4+1 heteroannulation reaction of enamides withα-carbonyl sulfoxonium ylides.The diastereoselective transformation provides a practical access to a diverse range of multi-functionalized oxazoline derivatives.The synthetic utility of the resultant tetrasubstituted oxazolines is further demonstrated by a series of useful manipulations into valuable building blocks of pharmaceutical relevance.

Direct synthesis of benzoxazinones via Cp*Co(Ⅲ)-catalyzed C-H activation and annulation of sulfoxonium ylides with dioxazolones

A highly novel and direct synthesis of benzoxazinones was developed via Cp*Co(Ⅲ)-catalyzed C-H activation and[3+3]annulation between sulfoxonium ylides and dioxazolones.The reaction is conducted under base-free conditions and tolerates various functional groups.Starting from diverse readily available sulfoxonium ylides and dioxazolones,a variety of benzoxazinones could be synthesized in one step in 32%-75%yields.

Visible Light-Promoted Sulfoxonium Ylides Synthesis from Aryl Diazoacetates and Sulfoxides

A visible light-promoted reaction of donor/acceptor diazoalkanes with sulfoxides towards the synthesis of synthetically useful sulfoxonium ylides was reported.The reaction occurred under sole visible light irradiation without the need of any transition-metals or additives,affording the corresponding sulfoxonium ylides in moderate to good yields.The success of late-stage modification of natural isolates or drug candidates,scale-up reaction and transformation of sulfoxonium ylides to other useful molecules further rendered the approach valuable.

Cu-catalyzed endo-selective asymmetric 1,3-dipolar cycloaddition of azomethine ylides with ethenesulfonyl fluorides: Efficient access to chiral pyrrolidine-3-sulfonyl fluorides

Cu-catalyzed endo-selective asymmetric 1,3-dipolar cycloaddition of azomethine ylides with ethenesulfonyl fluorides(ESFs) was successfully developed, this protocol provided an efficient and facile method to a wide range of chiral pyrrolidine-3-sulfonyl fluorides with good to excellent results(up to 87% yield,>20:1 dr, 94% ee). Some other chiral sulfonyl derivatives, such as sulfonamide and sulfonate, were easily accessible through simple transformations with high yields, which demonstrated that the cycloaddition products could be synthetically useful in the sulfur(VI) fluoride exchange(Su FEx) chemistry.

Lending a hand to asymmetric trifluoromethylthiolation:enantioselective[2,3]-sigmatropic rearrangement of sulfonium ylides

The introduction of a trifluoromethanesulfenyl group(SCF3)into organic molecules can,in principle,significantly enhance the cell-membrane permeability,metabolic stability and bioavailability because of its high lipophilicity and intrinsic electron-withdrawing properties.As a consequence,tremendous efforts have been made to develop diverse trifluoromethylthiolation protocols by using either

Highly Enantioselective Trapping of Carboxylic Oxonium Ylides with Imines for Direct Assembly of Enantioenriched γ-Butenolides

Enantioenrichedγ-butenolides are valuable structural cores in many pharmaceuticals and natural products,but their direct and catalytically asymmetric assembly remains rare.Here,we report an efficient,atom-economic synthetic strategy for enantioenrichedγ-butenolides via a unique enantioselective reaction of cyclopropene carboxylic acids with imines under the synergistic catalysis of Rh2(esp)2/chiral Brønsted acid system.The reaction involved trapping of carboxylic oxonium ylides,generated from cyclopropene carboxylic acids,which presented as the first asymmetric trapping reactive intermediate in the process.

Transition-metal-free [3+3] annulation reaction of sulfoxonium ylides with cyclopropenones for the synthesis of 2-pyrones

An efficient and practical synthetic approach was developed for the tandem synthesis of trisubstituted 2-pyrone derivatives from sulfoxonium ylides and cyclopropenones.This[3+3]annulation reaction was carried out under transition-metal-free conditions.A broad range of functional groups were tolerant under mild conditions,and a variety of 2-pyrones were obtained in moderate to good yields.

Phosphonium and arsonium ylides(?)——ⅩⅦ.A facile synthesis of methyl 2,6-bisperfluoroalkylbenzoates via acyclic precursors

The title compounds 6a—6f were prepared with high yield via intramolecular Wittig reaction of methyl 3-perfluoroalkyl-6-perfluoroacyl-2-triphenylphosphoranylidenehex-3,5-dienoates (5a—5i)which were obtained from the reaciton of 3-perfluoroacylprop-2-enylidenetriphenylphos- phoranes(3a—3c)with methyl perfluoroalkynoates(4a—4c).

A Facile Access to Fluorinated Pyrrolidines via Catalytic Asymmetric 1,3-Dipolar Cycloaddition of Azomethine Ylides with Methyl a-Fluoroacrylate

Asymmetric 1,3-dipolar cycloaddition of methyl a-fluoroacrylate with azomethine ylides for the construction of optically active fluorinated pyrrolidines bearing one unique fluorinated quaternary and two tertiary stereogenic cen- ters has been achieved with Cu（CH3CN）4BF4/TF-BiphamPhos complexes for the first time. This catalytic system performs well over a broad scope of substrates, providing the synthetically useful adducts in good yields and excel- lent diastereoselectivities and good to high enantioselectivities.

Rhodium(Ⅲ)-catalyzed intermolecular cyclization of anilines with sulfoxonium ylides toward indoles

Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides. Notably, this transformation could smoothly proceed with high yields, good regioselectivity, and feature broad group tolerance and under redox-neutral condition to avoid external oxidant. The titled products are potentially important building blocks in the organic synthesis through various chemical transformations.

Catalytic Asymmetric[2,3]-Sigmatropic Rearrangement of Sulfur Ylides Generated from Carbenoids and Allenic 2-Methylphenyl Sulfide

The first investigation on catalytic asymmetric [2,3]-sigmatrop-ic rearrangement of sulfur ylides generated from carbenoids and allenic phenyl sulfide was carried out. Up to 55% ee value was obtained.