共查询到20条相似文献,搜索用时 265 毫秒
1.
利用手性双哑唑啉与三氟甲磺酸亚铜催化2-甲氧基苯乙烯与重氮乙酸二环己基甲酯的不对称环丙烷化反应合成了手性环丙烷羟酸酯,用氢化氧钠对其进行选择性水解得到全反式环丙烷羟酸,其ee值GC测定为88%。进一步经过Curtius重排、烷基化等反应及重结晶等步骤合成了光学纯的具有生理活性的环丙胺化合物Ia和Ib。 相似文献
2.
3.
4.
5.
6.
本文介绍了手性铁催化体系在酮及亚胺的不对称还原、烯烃及硫醚的不对称氧化、不对称环加成、不对称环丙烷化以及不对称Friedel-Crafts烷基化等反应中的应用. 相似文献
7.
新型手性双二茂铁希呋碱亚胺配体的合成及其在不对称环丙烷化反应中的应用 总被引:3,自引:1,他引:3
以手性二茂铁乙胺为手性前体分别与吡啶二醛和吡啶二酮进行希呋碱缩合反应,合成了两种二茂铁手性亚胺膦配体,并经元素分析,^1HNMR,^31PNMR等手段进行了表征,用这类化合物作为手性配体,研究了其金属Ru(Ⅱ)配合物对苯乙烯与重氮乙酸乙酯的不对称环丙烷反应的催化作用,结果表明该类化合物的Ru(Ⅱ)配合物具有很高的催化活性。 相似文献
8.
手性金属催化剂在不对称环丙烷化反应中的应用进展 总被引:1,自引:0,他引:1
手性金属催化剂在不对称环丙烷化反应中的应用一直是不对称合成领域的一个热点。对三十多年来的这一领域的手性金属催化剂的发展作了详细的归纳和评述。 相似文献
9.
多手性中心的螺-环丙烷类化合物的合成 总被引:4,自引:0,他引:4
研究了 5 (l 孟氧基 ) 3 溴 2 ( 5H) 呋喃酮新手性源 ( 1)与亲核性醇类化合物发生的串联不对称双Michael加成 /分子内亲核取代反应 ,通过此反应 ,一举生成了 4个新的手性中心 ,得到了一般方法难以合成的含有多个手性中心的丁内酯并螺 环丙烷类化合物 5a~ 5d .详细报道了 5a~ 5d的合成方法以及它们的 [α],IR ,UV ,1HNMR ,13 CNMR ,MS和元素分析等结构分析数据 .经X 四圆衍射确定了 5 (l 孟氧基 ) 3 溴代丁内酯并 [3,4,1″,2″] 螺 [4 .2 ] [环丙烷 3″,3′ ( 4′ 甲氧基 5′ 孟氧基丁内酯 ) ]( 5a)的立体化学结构 .此不对称串联反应为进一步设计某些光学活性的复杂结构的分子提供了重要的合成途径 相似文献
10.
综述了手性氮杂环丁烷衍生物的合成方法以及它们在不对称硼氢化反应、二乙基锌对醛的加成反应、Henry反应、Diels-Alder反应和环丙烷化反应中的应用研究进展. 相似文献
11.
Bunnage ME Chippindale AM Davies SG Parkin RM Smith AD Withey JM 《Organic & biomolecular chemistry》2003,1(21):3698-3707
Conjugate addition of lithium dibenzylamide to tert-butyl (+/-)-3-methylcyclopentene-1-carboxylate occurs with high levels of stereocontrol, with preferential addition of lithium dibenzylamide to the face of the cyclic alpha,beta-unsaturated acceptor anti- to the 3-methyl substituent. High levels of enantiorecognition are observed between tert-butyl (+/-)-3-methylcyclopentene-1-carboxylate and an excess of lithium (+/-)-N-benzyl-N-alpha-methylbenzylamide (10 eq.) (E > 140) in their mutual kinetic resolution, while the kinetic resolution of tert-butyl (+/-)-3-methylcyclopentene-1-carboxylate with lithium (S)-N-benzyl-N-alpha-methylbenzylamide proceeds to give, at 51% conversion, tert-butyl (1R,2S,3R,alphaS)-3-methyl-2-N-benzyl-N-alpha-methylbenzylaminocyclopentane-1-carboxylate consistent with E > 130, and in 39% yield and 99 +/- 0.5% de after purification. Subsequent deprotection by hydrogenolysis and ester hydrolysis gives (1R,2S,3R)-3-methylcispentacin in > 98% de and 98 +/- 1% ee. Selective epimerisation of tert-butyl (1R,2S,3R,alphaS)-3-methyl-2-N-benzyl-N-alpha-methylbenzylaminocyclopentane-1-carboxylate by treatment with KO'Bu in 'BuOH gives tert-butyl (1S,2S,3R,alphaS)-3-methyl-2-N-benzyl-N-alpha-methylbenzylaminocyclopentane-1-carboxylate in quantitative yield and in > 98% de, with subsequent deprotection by hydrogenolysis and ester hydrolysis giving (1S,2S,3R)-3-methyltranspentacin hydrochloride in > 98% de and 97 +/- 1% ee. 相似文献
12.
13.
Bunnage ME Burke AJ Davies SG Millican NL Nicholson RL Roberts PM Smith AD 《Organic & biomolecular chemistry》2003,1(21):3708-3715
Conjugate addition of homochiral lithium N-benzyl-N-alpha-methylbenzylamide to tert-butyl (E)-cinnamate or tert-butyl (E)-crotonate and in situ amination with trisyl azide results in the exclusive formation of the corresponding 2-diazo-3-amino esters in > 95% de. Amination of the lithium (E)-enolates of tert-butyl (3S,alphaR)-3-N-benzyl-N-alpha-methylbenzylamino-3-phenylpropanoate or tert-butyl (3S,alphaS)-3-N-benzyl-N-alpha-methylbenzylaminobutanoate with trisyl azide gives the (2R,3R,alphaR)- and (2S,3S,alphaS )-anti-2-azido-3-amino esters in good yields and in 85% de and > 95% de respectively. Alternatively, tert-butyl anti-(2S,3S,alphaS)-2-hydroxy-3-N-benzyl-N-alpha-methylbenzylaminobutanoate may be converted selectively to tert-butyl anti-(2S,3S,alphaS)-2-azido-3-N-benzyl-N-alpha-methylbenzylaminobutanoate by aziridinium ion formation and regioselective opening with azide. Deprotection of tert-butyl (2S,3S,alphaS)-2-azido-3-aminobutanoate via Staudinger reduction, hydrogenolysis and ester hydrolysis furnishes anti-(2S,3S)-diaminobutanoic acid in 98%, de and 98% ee. The asymmetric synthesis of the diastereomeric syn-(2R,3S)-diaminobutanoic acid (98% de and 98% ee) was accomplished via functional group manipulation of tert-butyl anti-(2S,3S,alphaS)-2-hydroxy-3-N-benzyl-N-alpha-methylbenzylaminobutanoate in a protocol involving azide inversion of tert-butyl (2S,3S)-2-mesyloxy-3-N-Boc-butanoate and subsequent deprotection. 相似文献
14.
15.
Kedrowski BL 《The Journal of organic chemistry》2003,68(13):5403-5406
A synthesis of differentially protected (R)- and (S)-2-methylcysteines is described. Monomethylation of dimethylmalonate followed by alkylation with tert-butylchloromethyl sulfide gave an achiral diester. Desymmeterization by selective hydrolysis of one ester with pig-liver esterase gave the acid in 97% chemical yield and 91% enantiomeric excess. Heating this acid with diphenylphosphoryl azide followed by 4-methoxybenzyl alcohol gave protected (R)-2-methylcysteine. Alternately, the acid and ester groups were interchanged and heated with diphenylphosphoryl azide followed by 4-methoxybenzyl alcohol, giving protected (S)-2-methylcysteine. 相似文献
16.
报道了天然产物(-)-肉豆蔻木脂素的全合成. 以香草醛为起始原料, 经Wittig反应、LiAlH4还原和Sharplass不对称双羟化等反应构建了苏式结构的中间体; 以焦性没食子酸为原料, 经Claisen重排反应制得另一种苯丙素片段; 2个中间体通过Mitsunobu反应, 缩合并使构型翻转, 得到赤式-(-)-肉豆蔻木脂素. 为赤式8-O-4′新木脂素的合成提供了一种新方法. 相似文献
17.
Ono S Ogawa K Yamashita K Yamamoto T Kazuta Y Matsuda A Shuto S 《Chemical & pharmaceutical bulletin》2002,50(7):966-968
(1S,2R)-1-phenyl-2-[(S)-1-aminopropyl]-N,N-diethylcyclopropanecarboxamide (2b, PPDC), a new class of potent N-methyl-D-aspartic acid (NMDA) receptor antagonist, was designed based on a new method for restricting the conformation of compounds having a cyclopropane ring. The three-dimensional structures of PPDC obtained by the three different methods of X-ray crystallographic analysis, usual MM2-calculations in vacuum, and MM2 calculations based on the nuclear Overhauser effect (NOE) data in D2O are similar, which are in accord with that hypothesized. These results suggest that this conformational restriction method is particularly effective in designing novel biologically active molecules. 相似文献
18.
(2S,3S)-[3-(2)H1]-4-Methyleneglutamic acid 1a and (2S,3R)-[2,3-(2)H2]-4-methyleneglutamic acid 1b have been synthesised for use in biosynthetic and metabolic studies. 相似文献
19.
20.
The reduction of prochiral ketones with a chiral reducing reagent, prepared from lithium aluminum hydride and (1R,2S,3S,5R)-(-)-10-methoxypinanediol (2), produced secondary chiral alcohols in good chemical yields (57–98%) and moderate enantiomeric excess (8–72%). 相似文献