共查询到20条相似文献,搜索用时 31 毫秒
1.
Masafumi Tamura Hayato Ogata Yuu Ishida Yasunori Takahashi 《Tetrahedron letters》2017,58(40):3808-3813
Pd-catalyzed asymmetric 1,4-addition of phenylboronic acid to α,β-unsaturated carbonyl compounds was developed using chiral 1,10-phenanthroline derivative as ligand. Good yields (up to 97%), and high enantioselectivities (up to 97% ee) were achieved. 相似文献
2.
Yin YingZhuo Chai Hai-Feng WangPeng Li Chang-Wu ZhengGang Zhao Yue-Peng Cai 《Tetrahedron》2011,67(19):3337-3342
A highly enantioselective [4+2] cycloaddition reaction of β,γ-unsaturated α-keto esters with oxazolones was realized with readily available cinchona alkaloids as the catalysts. Using this reaction, a series of highly functionalized δ-lactones with adjacent α-quaternary-β-tertiary stereocenters were obtained in high yields (up to 97%) and with good-to-excellent enantioselectivities (up to 97% ee). 相似文献
3.
Sun ZW Peng FZ Li ZQ Zou LW Zhang SX Li X Shao ZH 《The Journal of organic chemistry》2012,77(8):4103-4110
A new class of chiral primary amine catalysts bearing multiple hydrogen-bonding donors have been designed and synthesized. The newly developed bifunctional organocatalysts efficiently catalyzed not only enantioselective conjugate addition of aromatic ketones to nitroolefins in good yields (up to 87%) with excellent enantioselectivities (97→99% ee) but also enantioselective conjugate addition of acetone to nitroolefins in excellent yields (90-96%) with high enantioselectivities (up to 97% ee). 相似文献
4.
Long Li Feng Han Xin Nie Yubiao Hong Sergei Ivlev Eric Meggers 《Angewandte Chemie (International ed. in English)》2020,59(30):12392-12395
A strategy for expanding the utility of chiral pyridine‐2,6‐bis(oxazoline) (pybox) ligands for asymmetric transition metal catalysis is introduced by adding a bidentate ligand to modulate the electronic properties and asymmetric induction. Specifically, a ruthenium(II) pybox fragment is combined with a cyclometalated N‐heterocyclic carbene (NHC) ligand to generate catalysts for enantioselective transition metal nitrenoid chemistry, including ring contraction to chiral 2H‐azirines (up to 97 % ee with 2000 TON) and enantioselective C(sp3)?H aminations (up to 97 % ee with 50 TON). 相似文献
5.
Bandini M Melucci M Piccinelli F Sinisi R Tommasi S Umani-Ronchi A 《Chemical communications (Cambridge, England)》2007,(43):4519-4521
Enantiomerically pure diamino-bis(tert-thiophene) proved to be a valuable and flexible chiral ligand for Pd- and Zn-catalyzed transformations, allowing for high levels of stereocontrol in asymmetric allylic alkylation (ee up to 99%) and hydrosilylations of prochiral carbonyls (ee up to 97%). 相似文献
6.
Yu-Hua Liao Hui Zhang Zhi-Jun Wu Lin-Feng Cun Xiao-Mei Zhang Wei-Cheng Yuan 《Tetrahedron: Asymmetry》2009,20(20):2397-2402
A highly bifunctional thiourea-tertiary amine-catalyzed enantioselective Michael addition reaction of anthrone to a wide variety of nitroalkenes has been developed, and the corresponding adducts were obtained smoothly in high yields (up to 97%) and good enantioselectivities (up to 94% ee). 相似文献
7.
GAO Jun-long ZHENG Liang-yu ZHANG Suo-qin ZHANG Xin-min SUN Guo-dong QIN Lin LI Yao-xian LIU Qing-wen LI Xiao-bo 《高等学校化学研究》2010,26(1):50-54
A series of proline-based amino pyridine dipeptide organocatalysts was synthesized and applied in direct asymmetric intermolecular aldol reaction. These catalysts showed good solubility in organic solvents, good yields (73%―97%) and enantioselectivitives(74%―94%). Among them, dipeptide organocatalyst(2) was found to be the most efficient one for the asymmetric aldol reaction between cyclohexanone and 4-nitrobeznaldehyde. After optimizing the catalytic reaction conditions, we found that the catalyst showed high yield(97%), enantioselectivity(e.e., up to 92%) and anti-diastereoselectivity(up to 95:5) at mild room temperature without any additives. 相似文献
8.
A rationally designed organocatalyst for direct asymmetric aldol reaction in the presence of water has been developed. High yield (up to 99%), diastereoselectivity (up to 99:1) and enantioselectivity (up to 97%) were obtained under optimal conditions. 相似文献
9.
T Zhou B Peters MF Maldonado T Govender PG Andersson 《Journal of the American Chemical Society》2012,134(33):13592-13595
A highly efficient and enantioselective Ir-catalyzed hydrogenation of unsaturated sulfones was developed. Chiral cyclic and acyclic sulfones were produced in excellent enantioselectivities (up to 98% ee). Coupled with the Ramberg-B?cklund rearrangement, this reaction offers a novel route to chiral allylic and homoallylic compounds in excellent enantioselectivities (up to 97% ee) and high yields (up to 94%). 相似文献
10.
An unprecedented organocatalytic asymmetric Michael/Hemiketalization/retro-aldol cascade sequence catalyzed by bifunctional amino-squaramides is described. The corresponding adducts were generally obtained in high yields (up to 97%) with moderate diastereo- (up to 79:21 dr) and good enantioselectivities (up to 90% ee). 相似文献
11.
Both ketone C-pyranosides (in up to 97% yields) and C-furanosides (in 83–97% yields) could be prepared, respectively, from the condensations of pentane-2,4-dione and various unprotected sugars in sodium carbonate aqueous media by adjusting the reaction conditions. 相似文献
12.
Jean-Thomas Issenhuth Samuel Dagorne Stéphane Bellemin-Laponnaz 《Comptes Rendus Chimie》2010,13(3):353-357
The CuCl/NaOt-Bu/BINAP system was found to efficiently catalyze the hydrosilylation of aryl alkyl ketones with excellent enantioselectivities by using phenyl methyl silane as a stoichiometric hydride source. High enantiomeric excesses (up to 97%) and excellent yields (up to 99%) were obtained. 相似文献
13.
Lucas Bacheley Ricardo Molina Betancourt Rathies Ravindra Dr. Gérard Guillamot Dr. Phannarath Phansavath Dr. Virginie Ratovelomanana-Vidal 《European journal of organic chemistry》2023,26(25):e202300383
A straightforward method to access novel families of enantioenriched cis-monofluorinated carbocyclic alcohols has been developed through ATH/DKR in up to 97 % yield, up to 99 : 1 dr and enantioinductions up to 97 % ee. Trans-difluorinated indans, tetrahydronaphthalenes, tetrahydroquinolines and chromans have been synthesized as well by deoxofluorination of the corresponding cis-fluoro alcohols. The reaction was performed on a series of variously substituted 3-fluorochromanols, 3-fluorotetrahydroquinolinols, 2-fluoro inden-1-ols and 2-fluoro 1,2,3,4-tetrahydronaphthalen-1-ols in up to 86 % yields, with diastereoselectivities up to 97 : 3 and enantioselectivities up to >99 % ee. 相似文献
14.
Chen JR Dong WR Candy M Pan FF Jörres M Bolm C 《Journal of the American Chemical Society》2012,134(16):6924-6927
An unprecedented strategy to access highly enantioenriched dihydropyrazoles is described. It involves formal [4+1] cycloadditions of in situ-derived azoalkenes and sulfur ylides catalyzed by a chiral copper/Tol-BINAP complex. A variety of synthetically and biologically important dihydropyrazoles have been obtained with high enantioselectivities (up to 97:3 er) in good yields (83-97%). 相似文献
15.
Wang J Zhang Q Zhang H Feng Y Yuan W Zhang X 《Organic & biomolecular chemistry》2012,10(15):2950-2954
By employing a chiral bifunctional thiourea-tertiary amine as catalyst, enantioselective Michael addition of a kojic acid derivative to nitro olefins was realised. The reactions afforded the products with good yields (up to 99%) in good enantioselectivities (up to 97% ee). In addition, the absolute configuration of one product was determined. 相似文献
16.
The catalytic enantioselective Friedel-Crafts reaction of indoles with 2-enoylpyridine 1-oxides has been studied in the presence of chiral pyridine 2,6-bis(5',5'-diphenyloxazoline)-Cu(II) complexes. The reaction furnished alkylated indoles in excellent yields (up to 97%) and enantioselectivities (up to 99% ee). 相似文献
17.
Chiral ruthenium(II)-salen complexes [RuII(salen)(PPh3)2] catalyse asymmetric aziridination of alkenes with up to 83% ees, asymmetric amidation of silyl enol ethers with up to 97% ees, and allylic amidation of cholesteryl acetates with good regioselectivity. 相似文献
18.
A C(2)-symmetric diethyl (i)Pr-bis(oxazoline)-Cu(OAc)(2).H(2)O was found to be an efficient catalyst for catalyzing an enantioselective Henry reaction between nitromethane and various aldehydes to provide beta-hydroxy nitroalkanes with high chemical yields (up to 95%) and enantiomeric excesses (up to 97%). 相似文献
19.
Ren-Qiang Mei Xiao-Ying XuYan-Chun Li Ji-Ya Fu Qing-Chun HuangLi-Xin Wang 《Tetrahedron letters》2011,52(14):1566-1568
Highly asymmetric Michael addition of 4-hydroxycoumarin to α,β-unsaturated ketones promoted by chiral primary amine thiourea bifunctional catalysts was developed and a series of Michael adducts were obtained in excellent yields (up to 97%) and enantioselectivities (up to 95% ee). Optically pure S-warfarin was easily obtained in 99% ee after single recrystallization. 相似文献
20.
Chiral bis(sulfonamide)-diamine served as new type of ligand for a Cu(OTf)(2)-catalyzed asymmetric Friedel-Crafts alkylation reaction of indoles with nitroalkenes. The desired products were obtained with up to 99% yield and 97% ee. 相似文献