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1.
Peter Šafář Jozefína Žúžiová Eva Tóthová Štefan Marchalín Nadežda Prónayová Ľubomír Švorc Viktor Vrábel Sébastien Comesse Adam Daïch 《Tetrahedron: Asymmetry》2010,21(5):623-630
New homochiral 6-ethyl-7,8-indolizidinediol derivatives, related to the bioactive dihydroxylated indolizidine alkaloids, are reported to be easily accessible in four or five steps from enantiopure 9-hydroxy-octahydrofuro[3,2-f]indolizin-6(2H)-ones in good overall yields and high diastereomeric purities. The simple procedure used herein involves a regiospecific THF-ring opening as a key step, in addition to the C–Br linkage reduction, and the alcohol deprotection followed by lactam reduction. 相似文献
2.
Cristina Pesenti 《Tetrahedron letters》2004,45(26):5125-5129
A novel synthesis of enantiopure hydroxyethylamine isosteres 1 has been developed. Reaction of lithiated β-sulfinylethylamines 3 with N-Cbz-imines generated in situ from α-amino-sulfones 4 afforded in good to excellent yields and moderate stereocontrol the 2-sulfinyl-1,3-diamines 2. The latter were submitted to the nonoxidative Pummerer reaction (NOPR) in CH2Cl2, that produced the target compounds 1 in very good yields with inversion of configuration. In some cases, the use of acetonitrile as solvent resulted in a double-inversion pathway, leading for example to the oxazolidinone 5. The total synthesis of an epimer of Saquinavir has been achieved by this method. 相似文献
3.
Mihaela Gulea Małgorzata Kwiatkowska Piotr Łyżwa Remi Legay Annie-Claude Gaumont Piotr Kiełbasiński 《Tetrahedron: Asymmetry》2009,20(3):293-297
The Michael addition of selected sulfur and nitrogen nucleophiles to a chiral non-racemic 2-phosphono-2,3-didehydrothiolane S-oxide is fully diastereoselective. The enantiomeric excesses of the adducts obtained could be determined by 31P NMR spectroscopy using (R)-(+)-tert-butyl(phenyl)phosphinothioic acid as a chiral solvating agent. The addition of thiophenol was monitored by 31P NMR spectroscopy which made it possible to observe the formation and evolution of the kinetic and thermodynamic adducts in the reaction mixture. The structures of both enantiomeric thiophenol adducts have been determined by X-ray analysis. 相似文献
4.
Chiral non-racemic bicyclic lactams 2b,c, derived from (R)- and (S)-phenylglycinol, were used in the enantioselective synthesis of (−)-lupinine and 5-epitashiromine, respectively. The efficiency of the synthesis relied on the high diastereoselectivities of formation and reduction of compounds 2b,c. 相似文献
5.
Vania Bernardes Xavier Verdaguer Albert Moyano Miquel A. Perics Antoni Riera Andrew E. Greene 《Journal of organometallic chemistry》1994,470(1-2):C12-C14
The hexacarbonyldicobalt complexes of chiral (non-racemic) unsubstituted terminal alkoxyacetylenes have been synthesized for the first time by a novel procedure that involves one-pot transformation of a chiral alcohol to the corresponding trimethylsilylated alkoxy acetylene, followed by complexation and protodesilylation (also one-pot). The synthesis is efficient and amenable to the preparation of multigram quantities. 相似文献
6.
Steurer M Tiedl K Wang Y Weissensteiner W 《Chemical communications (Cambridge, England)》2005,(39):4929-4931
Chiral, non-racemic 1,2,3-trisubstituted ferrocene derivatives are accessible from monosubstituted ferrocenes through two sequential ortho-deprotonation reactions; removal of the central substituent gives 1,3-disubstituted ferrocenes. 相似文献
7.
A facile access to a wide range of original saturated N-heterocyclic ureas is described using, as a key step, a Michael-type reaction involving isocyanates or amines on a piperidine framework possessing an α,β-unsaturated ester functionality. 相似文献
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手性螺-环丙烷双内酯化合物的合成与结构 总被引:3,自引:0,他引:3
本文进一步研究了5-(l-孟氧基)-3-溴-2(5H)-呋喃酮(1)与氧的亲核试剂,如二苯甲醇、苯甲醇、α-甲基苯甲醇、薄荷醇、冰片醇发生新颖的串联不对称双Michael加成/分子内亲核取代反应,合成了一般方法难以合成的含有多个手性中心的螺[1-溴-4-l-孟氧基-5-氧杂-6-氧代双环[3.1.0]己烷-2,3'-(4'-亲核基-5'-孟氧基丁内酯)](4a-4e)。通过元素分析,IR,UV,^1HNMR,^1^3CNMR,MS,[α]~D^2^0波谱分析数据以及X四圆衍射确定了4a-4e的化学结构和绝对构型。 相似文献
11.
《Tetrahedron: Asymmetry》2003,14(12):1637-1644
Chiral α-amidophosphine boranes 7a–b can be diastereoselectively alkylated, using a phenylglycinol derivative as a chiral inducer, to furnish α-substituted α-amidophosphine boranes 8–12 with up to 99% diastereoisomeric excess. Selective reduction of the amidophosphine boranes afforded optically pure β-boranatophosphine-alcohol 13. The latter one can then be oxidized in boronatophosphine acid 14. 相似文献
12.
Tandem asymmetric double Michael addition/internal nucleophilic substitution of the novel chiral source, 5-(l-menthyloxy)-3-bromo-2(5H)-furanone with nucleophilic alcohol compounds has been investigated. The tandem asymmetric reaction can afford four new stereogenic centers with one reaction and give optically pure spiro-cyclopropane derivatives 5a--5d which are difficult to obtain by routine methods. The synthetic method for 5a--5d was studied in detail and the new compounds were identified on the basis of their analytical data and spectroscopic data, such as [α]~(20),IR,~1H NMR,~(13)C NMR, MS and elementary analysis. The absolute configuration of the sprio [5-l-menthyloxy-3-bromo butyrolactocyclopropane-3″, 3′(4′-methyloxy-5′-menthyloxybutyrolactone)] (5a) was established by X-ray crystallography. The work can provide important synthetic strategy in synthesis of some new optically active spiro-cyclopropane analogues and some biologically active molecules with complex structure. 相似文献
13.
Subhash P. Chavan Dushant A. Khobragade Ashok B. Pathak U.R. Kalkote 《Tetrahedron letters》2004,45(27):5263-5265
A simple and efficient synthesis of (±)-mesembrine 1 is described employing double Michael addition and as the key step in 18% overall yield. 相似文献
14.
Ryukichi Takagi 《Tetrahedron letters》2004,45(40):7401-7405
Construction of the bicyclo[3.3.1]nonenone core was achieved by stepwise annulation of 2-cyclohexenone derivatives and acrylates via successive Michael reactions. The process could also be effected by a one-pot procedure. 相似文献
15.
L. A. Sviridova G. A. Golubeva S. V. Shorunov 《Chemistry of Heterocyclic Compounds》2006,42(9):1185-1189
3-Nitromethylpyrazolidine reacts with derivatives of unsaturated acids and reducing agents with the formation of polyfunctional
compounds of the pyrazolidine nucleus.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1365–1369, September, 2006. 相似文献
16.
Moraleda D Gatineau D Martin D Giordano L Buono G 《Chemical communications (Cambridge, England)》2008,(26):3031-3033
We report a simple one-pot synthesis of enantiomerically enriched alkyl- and arylphenylphosphinous acid-borane starting from readily available (R(P))-(-)-menthylhydrogenophenylphosphinate and organolithium reagents. 相似文献
17.
Shi-Guang Li 《Tetrahedron》2010,66(44):8557-8561
A novel synthetic method for polysubstituted naphthalene derivatives via a pyrrolidine-mediated cascade Michael/Henry reaction was developed, in which easily prepared 2-(2-oxoethyl)benzaldehydes and nitroalkenes were employed as the starting materials. The reaction consists of four consecutive reactions that include a cascade Michael/Henry reaction, a dehydration reaction, and an aromatization reaction in one pot to afford synthetically important naphthalene derivatives with moderate yields. 相似文献
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Gibson SE Mainolfi N Kalindjian SB Wright PT White AJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,11(1):69-80
Amino alcohols have been used to introduce non-racemic chirality into macrocycles using a modular approach that relies on a Heck macrocyclisation reaction. A wide variety of macrocycles have been synthesised, and their structures studied using X-ray crystallography and molecular modelling. A fragmentation reaction encountered during the use of (S)-1,1-dimethylvalinol revealed that carboxylic acids generate acylals under reaction conditions often used for Heck reactions. 相似文献
20.
Mingxiu Lv Mengwei Wang Kui Lu Lu Peng Yufen Zhao 《Phosphorus, sulfur, and silicon and the related elements》2018,193(3):149-154
A facile, rapid and cheap synthetic strategy towards a wide range of novel 2-aminoethylidene-1,1-bisphosphonate derivatives was developed through the Michael addition reaction of various aromatic amines, aromatic amides as well as nucleoside analogues with tetraethyl ethenylidene-1,1-bisphosphonate. All the newly obtained compounds were characterized by 1H, 31P, 13C NMR spectroscopy, IR and HR MS. 相似文献