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以钛酸四乙酯为催化剂, 芳基乙酮酸乙酯与天然L-薄荷醇进行酯交换, 合成了8个含手性基团的芳基乙酮酸薄荷醇酯; 在手性基团的立体选择性控制下, 芳基乙酮酸薄荷醇酯与硝基甲烷进行不对称Henry反应, 合成了7个(2R)-2-羟基-2-芳基-3-硝基丙酸薄荷醇酯新化合物, 用IR, 1H NMR, 13C NMR, MS和元素分析表征了化合物结构. 用高效液相色谱经手性柱分析了不对称反应效果, 缩合反应的非对映体过量在46.5%~64.2%之间, 表明可以通过立体选择性控制产物构型. 相似文献
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以4-溴儿茶酚和丙烯酸苯乙酯为原料,经过邻二酚羟基的保护、Heck偶联和脱保护3步反应合成了咖啡酸苯乙酯.其中,以乙酰基保护的4-溴儿茶酚在优化的Heck反应条件下,可获得40%收率的咖啡酸苯乙酯.确定的最佳Heck反应条件为:混合溶剂甲苯/二甲基甲酰胺的体积比为4∶1,醋酸钯(0.05 mmol),三苯基膦(0.15 mmol),三乙胺(2 mmol),反应温度90℃,反应时间24 h.该方法具有通用性好、原料易得和操作相对简单的优点. 相似文献
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以(S)-2-氨甲基-1-乙基吡咯烷为原料,合成了新型手性双功能有机催化剂(S)-1-[3,5-二(三氟甲基)苯基]-3-(1-乙基吡咯烷基-2-甲基)硫脲(2,产率82.2%).用2催化对甲氧基苯甲醛与硝基甲烷的不对称Henry反应,制得(R)-1-(4-甲氧基苯基)-2-硝基乙醇(3, 84%ee);3经Pd/C催化氢化得到(R)-2-氨基-1-(4-甲氧基苯基)乙醇(4);4与反式肉桂酰氯反应合成了(R)-aegeline,总产率37.6%(以对甲氧基苯甲醛计).化合物的结构经1H NMR, 13C NMR和MS表征. 相似文献
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以(R)-BINOL为原料合成NNN三齿钳形手性配体,研究了其与各种金属盐形成金属络合物在室温下原位催化芳香醛与硝基甲烷的不对称Henry反应.考察了不同金属盐、溶剂、碱对反应的影响,优化得到最佳反应条件为:CuOTf/NNN三齿配体(1∶1)催化体系,催化剂用量为10 mol%,甲醇作溶剂,室温反应5 d,收率57%,对映选择性80%ee;加入10 mol%有机碱(Me3Si)2MeN后反应速度加快,对映选择性略有降低,室温反应17 h,收率37%,ee值67%.此催化体系适用于大部分的芳香醛,收率中等,对映选择性可达75%ee. 相似文献
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不对称Henry反应的研究进展 总被引:1,自引:1,他引:1
总结了各种能有效催化不对称Henry反应的新方法、新条件和新催化剂,讨论了一类拓展的不对称催化Henry反应。对立体选择性催化Henry反应的催化剂的发展提出了作者的一些看法。参考文献26篇。 相似文献
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以D-酒石酸为原料,经环合,开环和酯交换反应合成了4个不对称酒石酸二酰胺化合物,其结构经1H NMR,13C NMR和HR-MS确证。 相似文献
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《Tetrahedron: Asymmetry》2006,17(24):3315-3326
The classical Henry reaction, the coupling of a nitroalkane with a carbonyl compound in the presence of a base, is an important C–C bond forming reaction in organic chemistry giving β-nitroalcohols, which are useful synthons in organic synthesis. However, an asymmetric version of the reaction, that has been developed recently, gives a new dimension to the classical Henry reaction whereby the control of stereochemistry of two newly generated carbon centres has become possible. In this review, the various catalytic methods for this purpose are discussed. 相似文献
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Henry reaction is one of the most classical reactions to construct synthetically useful product nitro alcohol, which as a privileged skeleton is widely distributed in various pharmaceuticals. This review summarizes the recent progress of copper-catalyzed asymmetric Henry reaction from 2011 to 2016. The significant progress that has been made in this area will be highlighted and some of challenges that the author believes may be hindering further progress will be revealed. 相似文献
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Synthesis of novel thiophene‐based chiral ligands and their application in asymmetric Henry reaction
A. Ebru Aydin 《应用有机金属化学》2013,27(5):283-289
Novel chiral thiolated amino alcohols were synthesized from norephedrine and thiophene carbaldehydes (methyl‐ or ethyl‐substituted) and applied to the catalytic asymmetric Henry reaction of various aldehydes with nitromethane to provide β‐hydroxy nitroalkanols in high conversion (92%). The reaction was optimized in terms of the metal, solvent, temperature and amount of chiral ligand. The corresponding catalyst with Cu(OTf)2 and 2‐propanol as the solvent provided the best enantioselectivities (up to 96% ee) of the corresponding nitroalcohols for aliphatic aldehydes. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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《Tetrahedron: Asymmetry》2007,18(9):1129-1133
Chiral Schiff-bases prepared from chiral amino alcohols catalyze the enantioselective Henry (nitro aldol) reaction between nitromethane and p-nitrobenzaldehyde in the presence of Cu(OTf)2 and Zn(OTf)2. Zn(OTf)2 promoted the reaction yield, while Cu(OTf)2 promoted the enantiomeric excess. The highest enantioselectivities were observed with ligand 3 (44% ee) and ligand 5 (47% ee). 相似文献
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Ferrocenyl-substituted aziridinylmethanol (Fam-1) was used as a catalyst with zinc for the asymmetric nitroaldol (Henry) reaction. This catalyst worked with a variety of aldehydes (aromatic, aliphatic, alpha,beta-unsaturated, and heteroaromatic) and alpha-ketoesters to give the nitroaldol product in up to 97% yield and 91% ee. The chiral ligand can be recovered and recycled without losing its activity. 相似文献
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A series of new planar and central chiral ligands based on [2.2]paracyclophane backbones were designed and prepared from enantiomerically pure 4-amino-13-bromo[2.2]paracyclophane and commercially available chiral amino alcohols. Their application in a copper-catalyzed asymmetric Henry reaction resulted in secondary alcohols with high yield and excellent selectivity for active aldehydes (up to 94% ee). This is a successful example of employing planar chiral [2.2]paracyclophane ligands in copper-catalyzed reaction. 相似文献
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The catalytic asymmetric Henry reaction of nitromethane to various aldehydes has been developed using a chiral binaphthylazepine derived amino alcohol and Cu(OAc)2·H2O as the catalyst. High yields and good enantioselectivities (up to 97% ee) were obtained for both aromatic and aliphatic aldehydes. Moreover, this catalytic system also works well for the diastereoselective Henry reaction to afford the corresponding adducts in up to 95:5 syn/anti selectivity and 95% enantioselectivity. 相似文献