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《Tetrahedron: Asymmetry》2006,17(20):2876-2883
An efficient and a convenient enantioselective synthesis of (3R,4S)-3-methoxy-4-methylaminopyrrolidine has been carried out by a lipase-mediated resolution protocol. This method describes the preparation of (±)-1-Cbz-cis-3-azido-4-hydroxypyrrolidine starting from commercially available diallylamine followed by ring-closing metathesis (RCM) via SN2 displacement reactions. Pseudomonas cepacia lipase immobilized on diatomaceous earth (Amano PS-D) provides (3R,4S)-11 and (3S,4R)-12 in an excellent enantiomeric excess. 相似文献
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《Tetrahedron: Asymmetry》2000,11(19):3867-3871
A short, high yielding, enantioselective synthesis of the novel H3 agonist Sch 50971 1 is described. The key enantiodifferentiating step is the 1,4-addition of a chiral N-propionyloxazolidinone to a nitroolefin. 相似文献
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The title compound(C25H16Cl2N3O3S),as a thiopyran derivative,has been synthe-sized by the cyclization of an organic intermediate obtained from Baylis-Hillman adducts with a β-aroylthioamide using copper(I) salt as the catalyst.The crystal belongs to the monoclinic system,space group P21/c with a = 13.668(3),b = 8.4803(17) c = 21.999(4) ,β = 113.57(3)°,V = 2337.2(10) 3,Z = 4,Mr = 510.38,Dc = 1.451 g/cm3,μ = 0.401 mm-1,F(000) = 1048,the final R = 0.0487 and wR = 0.1079 for 3678 observed reflections with I > 2σ(I). 相似文献
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A convenient approach for the preparation of (2S,3R,4R,5S,6R)-2-(3-(4-ethylbenzyl)-4-chlorophenyl)-6-(hydroxymethyl)- tetrahydro-2H-pyran-3,4,5-triol I is developed. The target compound via four steps is synthesized from 4-bromo-2-(bromomethyl)- 1-chlorobenzene and the isomers of undesired ortho-products were avoided during the preparation. 相似文献
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《Tetrahedron: Asymmetry》2001,12(19):2657-2661
A short four-step synthesis of (3R,4R,5R)-4-hydroxyisoleucine lactone with total control of stereochemistry is reported, the key intermediate being the didehydroamino acid derivative arising from an aldol dehydration reaction between a glycine anion equivalent and butan-2,3-dione. 相似文献
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G. Yu. Ishmuratov A. V. Bannova E. R. Latypova R. R. Muslukhov A. A. Smol′nikov R. F. Talipov 《Chemistry of Natural Compounds》2012,48(5):789-790
A modified stereospecific synthesis of potentially biologically and pharmacologically active methyl (1R,2R,3E,5R)-3-(hydroxyimino)-5-methyl-2-(1-methylethyl)cyclohexanecarboxylate from (R)-4-menthen-3-one was developed using sequential 1,4-conjugate addition of Norman reagent catalyzed by CuI?CBF3?Et2O?CCuCl2 and ozonolysis?Creduction of the intermediate (R,R,R)-vinylmenthone by hydroxylamine hydrochloridein MeOH. 相似文献
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AbstractAn alternative and concise total synthesis of (3?R, 4S)-4-Hydroxylasiodiplodin has been reported from inexpensive and commercially available 6-heptenal and Orsellinic acid starting materials. The key steps involved in the synthesis are Wittig reaction, Sharpless epoxidation, Yamaguchi esterification and ring-closing metathesis (RCM). 相似文献
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Kharisov R. Ya. Gazetdinov R. R. Botsman O. V. Muslukhov R. R. Ishmuratov G. Yu. Tolstikov G. A. 《Russian Journal of Organic Chemistry》2002,38(7):1005-1008
Ozonolytic decyclization of (R)-4-menthen-3-one is accompanied by fragmentation of the isobutyl group, leading to -functionalized 3-methylpentanoic acid derivatives. 相似文献
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以1-磺丁基-3-甲基咪唑硫酸氢盐离子液体(b)为反应介质,7-氨基头孢烷酸(7-ACA,2)为原料,与4-甲基-5-甲酰基噻唑经缩合反应制得(6R,7R)-7-氨基-3-[2-(4-甲基-5-噻唑)乙烯基]-8-氧代-5-硫-1-氮杂双环[4.2.0]辛-2-烯-2-羧酸(7-ATCA,1),其结构经1H NMR,13C NMR和IR表征。考察了离子液体及其用量,原料摩尔比r[n(4-甲基-5-甲酰基噻唑)∶n(2)],反应温度和反应时间对1收率的影响。在最佳反应条件[b为反应介质,b用量为20 m L,r=1.3,于65℃反应5 h]下,1收率可达90%以上。 相似文献
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Marc Rolland Tarek Kassem Valérie Rolland Jean Martinez 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(12):1415-1417
We present the crystal and molecular structures of 2,3,6,7,8,8a-hexahydro-6,8-methano-7,7,8a-trimethyl-3-(1-methyl-2-oxopropylidene)-5H-1,4-benzoxazin-2-one, C16H21NO3, (III), and 2,3,6,7,8,8a-hexahydro-3-(2-hydroxy-1-methylpropyl)-6,8-methano-7,7,8a-trimethyl-5H-1,4-benzoxazin-2-one, C16H25NO3, (V). These compounds are two of the four key intermediates in our synthetic route to (2R,3R,4R)-4-hydroxyisoleucine. The two structures provide a full understanding of the stereochemistry in successive steps. This synthesis was based on a new optically pure chiral oxazinone auxiliary derived from (1R,2R,5R)-2-hydroxypinan-3-one. 相似文献
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1,4-苯并二氧六环木脂素类天然产物多数具有增加胆碱乙酰化酶和抗肝毒等活性 ,其活性主要源于 1 ,4-苯并二氧六环官能团 [1] . 1 ,4-苯并二氧六环木脂素的消旋全合成已有报道 [2 ] ,但其不对称合成还是空白[3] .我们发展了一条对映选择性合成 1 ,4-苯并二氧六环木脂素的简捷有效的路线 .基于前面的工作 [4 ] ,我们发现 1 ,4-苯并二氧六环醛类衍生物是合成此类天然产物的关键中间体 ,选择 2 - (4-羟基- 3-甲氧基 ) - 3-羟甲基 - 1 ,4-苯并二氧六环 - 6-醛 (1 )作为目标分子 ,其合成路线如下 :Reagents and conditions:( ) Me OH,H2 SO4,9… 相似文献