Studies on New Additions to 5-Methoxy-2 (5H)-Furanone: 1, 4-Addition of Grignard Reagents, and 1,3-Dipolar Cycloaddition of Silyl Nitronates

1,4-Addition reaction of Grignard's reagent to 5-methoxy-2(5H)-furanone 1 was accomplished. which provided a new possible route for synthesizing beta -alkyl-Y-alkyloxy-Y-butyrolactone. A novel concise method of preparing fused heterocyclic compounds was offered by 1,3-dipolar cycloaddition reaction of silyl nitronates to 1.

Synthesis of Novel Discotic C_(60)-triphenylene Derivative by 1,3-Dipolar Cycloaddition

1 Introduction Fullerene has received considerable attention and a great researching interest due to its unique structure and interesting properties[1―3]. Many functional groups have been introduced, often region- or stereo-selectively, for tuning the physical properties of C60and for constructing supramoleculararchitectures^[4-6].

1,3-Dipolar Cycloaddition Reaction between Vinyl Acetate and N-Alkyl Hydroxypyridinium Halide

1, 3 Dipolar cycloaddition reaction between vinyl acetate and 3-hydroxypyridiniun betaine was performed under solid-liquid phase transfer catalytic condition, This reaction has been successfully used on the synthesis of an analogue of Bao-Gong-Teng A.

Asymmetric 1,3-Dipolar Cycloaddition of the Chiral Nitronic Esters with Acrylate

Asymmetric 1,3-dipolar cycloaddihon of the chiral nitronic esters with acrylate giving the enantiomerically pure novel chiral bisheterocyclic compounds is describcd

An expeditious synthesis of isoxazoline using cetyltrimethylammonium cerium nitrate:A phase transferring oxidative 1,3-dipolar cycloaddition

An expeditious and effective method for synthesis of isoxazoline from aldoximes and activated alkenes using cetyltrimethylammonium cerium nitrate at room temperature is described.Reaction was completed within short time period in high yields at room temperature.

Copper-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides withβ-trifluoromethyl-substituted alkenyl heteroarenes

Copper-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides andβ-trifluoromethyl-substituted alkenyl heteroarenes was developed for the first time.A wide range of enantioenriched pyrrolidines containing both heteroarenes and trifluoromethyl group with multiple stereogenic centers could be readily accessible by this method with good to high yields and excellent levels of both stereo-and regioselectivity(up to 99%yield,>20:1 rr,>20:1 dr,and up to 95%ee).Notably,substratecontrolled umpolung-type dipolar cycloaddition was also disclosed in this protocol to achieve regiodivergent synthesis withα-aryl substituted aldimine esters as the dipole precursors.Systematic DFT studies were conducted to explore the origin of the stereo-and regioselectivity of this 1,3-dipolar cycloaddition,and suggest that copper(Ⅱ)salt utilized in this catalytic system could be reduced in-situ to the active copper(Ⅰ)species and might be responsible for the observed high stereo-and regioselectivity.

Synthesis and thermal properties of novel calix[4]arene derivatives containing 1,2,3-triazole moiety via K_2CO_3-catalyzed 1,3-dipolar cycloaddition reaction

Two calix[4]arene derivatives containing 1,2,3-triazole moiety were synthesized via K2CO3-catalyzed1,3-dipolar cycloaddition reaction between calix[4]arene-based azide and active methylene compounds in good yields.The structures of the two compounds synthesized herein were fully confirmed by 1HNMR,,（13）C NMR,and MS（ESI）.The thermal analysis showed that the mass losses of the synthesized compounds 4 and 5 containing 1,2,3-triazole groups are similar to each other.

The Chemistry of Tetrafluoroallene:One-pot Synthesis of Trifluoromethylindolizines from 1,3-Diiodo-1,1,3,3-tetrafluoropropane by 1,3-Dipolar Cycloaddition

Heating a mixture of 1, 3-diiodo-1 ,1,3, 3-tetrafluoropropane (2), K2CO3, pyridinium bromides (3) in CH3CN at 65℃ for 10 h gives the corresponding trifluoromethylindolizines.

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.

Synthesis of Novel Fuctionalized Glycosides Based on 1,3-Dipolar Cycloaddition

1 Results 1,3-Dipolar cycloaddition reaction is one of the most common methods for preparing various five membered heterocycles,and provides a conveniet protocols for constructing C-C bond with functional groups.The reaction has also been successfully used in the syntheses of C-glycosides and other sacharride derivatives.We wish to present herein our recent approaches on the synthesis of novel C-amino-glycosides,C-aminodisaccharides,spiro heterocyclic glycosides and heterocycle linked C-disaccharides,et...

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.

Asymmetric 1,3-dipolar cycloaddition of nitrile oxides to chiral acryloyl esters bearing glucofuranose as auxiliary

Asymmetric 1,3-dipolar cycloaddition of nitrite oxides to an acryloyl ester (1) derived from 1, 2:5, 6-di-O-isopropylidene glucose (6) was studied. Solvent and temperature effect was discussed. The single diastereoisomer was isolated with high diastereoselective excess.

1,3-Dipolar cycloaddition reaction for diastereoselective synthesis of functionalized dihydrospiro[indoline-3,2'-pyrroles]

The BF_3OEt_2 catalyzed one-pot 1,3-dipolar cycloaddition reaction of benzylamines,isatins and dimethyl acetylenedicarboxylate in dry methylene dichloride afforded the functionalized dihydrospiro[indoline-3,2＇-pyrroles]in moderate to good yields and with high diastereoselectivity.The reaction was accomplished by the tandem 1,3-dioplar cycloaddition of in situ generated azomethine ylide with acetylenedicarboxylate and the nucleophilic addition of pyrrole ring to second molecular acetylenedicarboxylate.

含氮Ylide对C_(60)的1,3-偶极环加成反应法合成含吡咯环C_(60)衍生物

利用肌氨酸与对位含不同取代基的苯甲醛、共轭烯烃醛类及酮类反应生成的含氮Ylide对C60的加成反应，合成并分离、纯化制得了一系列含不同取代基的C60吡咯环纯衍生物，并用1HNMR、13CNMR、FDMS、FT－IR、UV－Vis等光谱手段确定了它们的分子结构．

反式2,3-二芳基取代-1-氨基环丙烷羧酸的合成及其结构研究

芳香醛与马尿酸在Erlenmeyer反应条件下缩合得到 (Z) 2 苯基 4 芳亚甲基 5 ( 4H) 唑酮 ,然后在室温下与芳基重氮甲烷通过非对映高立体选择性 1,3 偶极环加成反应得到螺环化合物 ,再经醇解开环、水解去保护合成出反式 2 ,3 二芳基 1 氨基取代环丙烷羧酸 .通过元素分析 ,IR ,1HNMR ,13 CNMR ,MS和X射线晶体测定 ,确认了它们的化学结构和立体构型 .实验结果表明 ,通过选择适当的芳香醛和芳基重氮甲烷 ,可以得到不同立体构型的反式 2 ,3 二芳基取代 1 氨基环丙烷羧酸 .

1,3-偶极环加成合成新型含2-苯基-1,2,3-三唑基的1,2,4-噁二唑啉衍生物

Schiff碱 3和肟或氯代肟在三乙胺作用下通过 1,3 偶极环加成生成一系列含 2 苯基 1,2 ,3 三唑基的 1,2 ,4 二唑啉类化合物 4a～ 4g ,5a～ 5g和 6a～ 6g .2 1个新化合物的结构经元素分析 ,1 HNMR ,IR和MS谱确证 .

微波促进1,3-偶极环加成反应合成氮杂糖苷衍生物

利用微波促进氮杂糖硝酮(2)与丙烯酸类衍生物(3)发生1,3-偶极环加成反应,立体选择性地得到了一系列新的含异噁唑烷的氮杂糖衍生物(4),反应效率显著提高,反应时间由95h缩短为5～15min,收率由67%提高到78%～88%.利用NMR和HRMS等方法结合化合物(4d-1)的单晶结构确定了产物的结构和相对构型.

1-取代苄基-4-乙酰基-5-甲基-1,2,3-三唑的合成

以取代溴苄为原料,经取代和1,3-偶极环加成反应,得到1-取代苄基-4-乙酰基-5-甲基-1,2,3-三唑。实验表明,以无水碳酸钾为碱催化剂,乙腈和乙醇等体积混合为反应溶剂,物料配比n(取代苄基叠氮)∶n(乙酰丙酮)=1∶1.2,反应时间约为2 h,产品收率92%。目标化合物的结构得到1H NMR、MS和IR证实。

铜粉催化叠氮与端炔1,3-偶极环加成反应研究

该文探讨了普通铜粉高效催化的叠氮化物与端炔的1,3-偶极环加成反应。研究结果表明,以铜粉为催化剂,盐酸三乙胺(Et3N·HCl)为助催化剂,体积比为1∶1的水/叔丁醇(H2O/t-Bu OH)为溶剂,将叠氮化物与端炔于室温常压下反应2 h,高收率合成1,4-二取代-1,2,3-三唑化合物,收率可达93.05%。该方法所用催化剂廉价易得,且用量少,反应条件温和,耗时短,收率高,后处理操作简单。