共查询到20条相似文献,搜索用时 15 毫秒
1.
Pingli Liu Liang Huang Yuelie Lu Mina Dilmeghani Jean Baum Tingjian Xiang Jeff Adams Andrew Tasker Rob Larsen Margaret M. Faul 《Tetrahedron letters》2007,48(13):2307-2310
Synthesis of five and six membered heterocycles, indolines, 2,3-dihydrobenzofurans, chromans, isochromans, 1,2,3,4-tetrahydroquinolines, and 1,2,3,4-tetrahydroisoquinolines, in 70-99% yield by a ligand-free palladium catalyzed reductive Heck cyclization of phenyl bromides and chlorides, under mild conditions, is reported. Water was found to be essential for these reactions. 相似文献
2.
Efficient synthesis of the 3-benzazepine framework via intramolecular Heck reductive cyclization 总被引:1,自引:0,他引:1
A microwave-assisted protocol based on reductive Heck reaction was developed for regio- and stereoselective construction of the 3-benzazepine core. 相似文献
3.
A novel reductive Heck cyclization approach was developed in order to construct a model DEF-benzoxocin ring system that is present in nogalamycin, menogaril, and related anthracycline antitumor antibiotics. 相似文献
4.
Hirano K Inaba Y Takahashi N Shimano M Oishi S Fujii N Ohno H 《The Journal of organic chemistry》2011,76(5):1212-1227
A direct, concise, and atom-economical synthetic method for the generation of fused indoles, using a gold-catalyzed cascade cyclization of diynes, has been developed. The reaction gave various fused indoles, such as aryl-annulated[a]carbazoles, dihydrobenzo[g]indoles, and azepino- or oxepinoindole derivatives in good to excellent yields, through an intramolecular cascade 5-endo-dig hydroamination followed by a 6- or 7-endo-dig cycloisomerization, without producing theoretical byproduct. Three of the resulting indoles exhibited potent antifungal activities against T. mentagrophytes and T. rubrum, demonstrating the practical application of the described cascade reaction for drug discovery. 相似文献
5.
R. Kh. Freidlina A. A. Kamyshova L. A. Zhuravleva E. Ts. Chukovskaya 《Russian Chemical Bulletin》1976,25(9):1897-1900
1. | Reductive cyclization of compounds with the CCl2 grouping, ClCH2CH2CCl2CH2CClXR (R=H, CH3; X=CN, CO2CH3) led to the formation of monosubstituted cyclopropanes, cyclo-C3H5CH2CHXR. Under the reaction conditions, the Cl atom in the position to CO2CH3 and CN groups is reduced without taking part in cyclization. |
2. | The presence of chloro-substituted C atoms in the direction to the CCl2CH2CHC1 fragment hinders the reductive cyclization of this fragment. |
3. | Cyclization by means of the two dichloromethyl groups in the compound CHC12CH2CHC12 does not take place. In this case, the principal reaction route is a stepwise reduction and alkoxylation. |
6.
Direct alkenylation of indoles at the 3-position with 1,3-dicarbonyl compounds under Brønsted acidic ionic liquid catalysis has been developed. The yields were excellent, and the catalyst can be reused at least six times without noticeable loss of catalytic activity. 相似文献
7.
[reaction: see text] Indolines and indoles are prepared for the first time by direct electrochemical reduction of arenediazonium salts. 相似文献
8.
Gang Wang Wenqi Li Tianxiang Liu Yonghong Zhang Bin Wang Fei Xue Weiwei Jin Caiyan Ma Yu Xia Chenjiang Liu 《Chemical science》2022,13(39):11594
A palladium-catalyzed dearomative reaction of indoles has been developed through a domino Heck/gem-difluorovinylation sequence. By taking advantage of a difluorocarbene precursor (ClCF2COONa), the palladium difluorocarbene ([Pd] CF2) species was formed smoothly. Then, a migratory insertion/β-H elimination process enabled access to polycyclic indolines containing 1,1-difluoroethylene units in acceptable yields with a broad substrate scope, which also showed dearomative gem-difluorovinylation for the first time. Remarkably, the superb diversified transformations allowed the product to install various functional groups.Dearomative gem-difluorovinylation was reported for the first time and provided a new way to construct complex organofluorine compounds rapidly. 相似文献
9.
Sheng-Yan Zhang Shan-Gang Sun Yu-Shuang Guo Xiao-Fan Lu Dian-Shun Guo 《Tetrahedron letters》2018,59(41):3719-3723
A highly efficient method for the synthesis of indoles has been successfully developed via a CuMgAl-LDH-catalyzed intramolecular annulation reaction of 2-alkynylsulfonanilides. This CuMgAl-LDH catalyst features facile preparation, recovery, and reuse at least seven times without a marked loss in the catalytic activity, as well as the unique dual activation. Moreover, the crystal structures and Hirshfeld surface analysis of typical indole compounds were also presented. 相似文献
10.
Mild and efficient cyclization reaction of 2-ethynylaniline derivatives to indoles in aqueous medium
Results of the optimized cyclization reaction of 2-ethynylaniline derivatives to indoles catalyzed by copper(II) salts are described. The reactions can be carried out in a mixture of H2O and MeOH in the presence of 1-ethylpiperidine at room temperature. These conditions can be applied to a bulky substrate, which is difficult to be cyclized efficiently by existing reaction conditions. Furthermore, this reaction condition was applied to a catalyst recycling reaction system. 相似文献
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12.
An efficient synthesis of o-nitrobenzylcarbonyl compounds is demonstrated through the Swern-type oxidation of readily accessible phenethanol analogues. Reductive cyclization of o-nitrobenzylcarbonyl 3 using catalytic Raney nickel gives 1H-indol-2-yl-1H-quinoline 2 in 95% yield. Hydrolysis of 2 affords the KDR kinase inhibitor 1 in quantitative yield. The examination of the reductive cyclization reaction and optimization of conditions is described. 相似文献
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14.
The reductive phenylation of nitroarenes was improved by using iron pentacarbonyl (IPC) as a reducing reagent. The method was applied to the synthesis of ellipticine and dibenzazocine derivatives. 相似文献
15.
A modified method is reported for the conversion of unsaturated sulfonamides into their cyclic saturated counterparts. This method utilises a single palladium catalyst for an intramolecular Heck reaction and subsequent transfer hydrogenation, which is achieved in one-pot following the addition of ammonium formate. Accordingly, a range of fourteen structural variations are reported and under optimal conditions the adducts were generated in typically good to excellent yields. Notably, discrimination of differentially substituted dienes can be accomplished in the case of compounds 28 and 29 and the process was only observed to fail with the more sterically hindered precursor 32. 相似文献
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17.
Deoxygenation of nitroaromatics is a classic synthetic method for the construction of nitrogen heterocycles. The generally accepted mechanism involves exhaustive deoxygenation to a singlet nitrene. We present theoretical evidence for an alternative, 6pi-electron 5-atom electrocyclization of nitroso-styrenes, -stilbenes, and -biphenyls to nitronates. A downstream 1,5-H shift and tautomerization leads to N-hydroxy heterocycles. [reaction: see text] 相似文献
18.
The reductive cyclization (electrohydrocyclization reaction) of tethered cyclic enones has been investigated under electrochemical, metal-mediated, and photochemical conditions. The tricyclic products are generally formed with excellent stereoselectivity, particularly if at least one of the enones is β,β-disubstituted. 相似文献
19.
Xia Z Wang K Zheng J Ma Z Jiang Z Wang X Lv X 《Organic & biomolecular chemistry》2012,10(8):1602-1611
A mild and efficient Cu(2)O-catalyzed domino intramolecular C-N coupling/C-Y (Y = O, S, N) bond formation was successfully achieved. Thus oxazino[3,2-a]indole, thiazino[3,2-a]indole and indolo[2,1-b]quinazoline derivatives were facilely assembled from readily accessible gem-dibromovinyl systems. The protocol is general and practical, affording a variety of the indole-incorporated products in good to excellent yields even under air atmosphere. 相似文献
20.
A synthetic strategy featuring efficient ruthenium-catalyzed asymmetric hydrogenation of racemic α-aryloxy cyclic ketone via dynamic kinetic resolution and palladium-catalyzed intramolecular reductive Heck cyclization has been developed for the asymmetric total synthesis of (-)-galanthamine (20.1%, 12 steps) and (-)-lycoramine (40.2%, 10 steps). 相似文献