共查询到20条相似文献,搜索用时 640 毫秒
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在鹰爪碱诱导下,2-氯甲基-4,4-二甲基噁唑啉与叔丁基苯基膦硼烷经络合反应,以43%的收率合成了光学纯度大于99%,手性中心在P上的新型手性噁唑啉氮膦配体(3); 3和铱配合物([Ir(cod)Cl]2)经络合反应以55%的收率制得两个新型手性膦噁唑啉铱络合物催化剂(1和2),其结构经1H NMR, 13C NMR, 31P NMR和元素分析表征。考察了1和2对烯烃的不对称氢化反应的催化性能。结果表明:1具有较好的催化能力,收率>92%,但催化剂的手性诱导能力较差(ee≤36%)。 相似文献
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Oligomers of leucine, methionine, phenylalanine, and tyrosine were prepared enzymatically (using papain) from the respective methyl esters, with yields ranging from 51–96%. The effect of pH, buffer and salt concentration, and addition of alcohol on the oligomerization of leucine methyl ester was examined. The limits and potentialities of the enzymatic reaction as a method for obtaining monodisperse oligomers are discussed. 相似文献
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以H8-BINOL衍生的手性磷酸硼为催化剂,频哪醇硼烷为还原剂,实现了α-亚氨基酯的不对称还原。经过对反应条件的优化,确定了在0 ℃、反应36 h,催化剂用量5%(以底物的物质的量为基准,下同),3Å分子筛添加量5 mg并以甲苯作为溶剂的条件下,生成的α-氨基酯可达到95%的产率和96%的对映选择性。底物及产物结构均经1H NMR,13C NMR和LC-MS(ESI)表征。该方法中生成的H8-BINOL衍生的手性磷酸硼是一种手性双功能催化剂,该催化剂催化的不对称反应具有条件温和、经济高效和绿色环保的特点。
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Enantioselective synthesis of optically active α-amino acids from glycine via Schiff base employing (+)-N,N-diisopropyl-10-camphorsulfonamide as a chiral template is described. 相似文献
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In recent years, β-amino acids and their derivatives have attracted considerable attention due to their occurrence in biologically active natural products, such as dolastatins,cyclohexylnorstatine and Taxol. β-Amino acids also find application in the synthesis of β-lactams,piperidines, indolizidines. Moreover, the peptides consisting of β-amino acids, the so-called β-peptides, have been extensively studied recently. Consequently, considerable efforts have been directed to the synthesis of β-amino acids and their derivatives1. In particular, stereoselective synthesis of β-amino acids has been a challenging project, and there are only limited methods available. In this presentation, we report our efforts in this area. 相似文献
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以天然氨基酸为手性原料合成了4种新型的手性方酰胺荧光探针分子(5~8), 该合成路线简短, 后处理简单, 无需柱层析纯化. 以荧光光谱为检测手段, 测试了此类探针分子对苯丙氨酸、 缬氨酸和脯氨酸的手性识别效果, 结果表明, 探针分子5可以有效识别苯丙氨酸的2个对映异构体. 当加入L-苯丙氨酸后, 探针分子5的荧光强度显著增强, 而加入D-苯丙氨酸后探针分子5的荧光强度显著减弱, 2种异构体的荧光强度比(IL/ID)可达2.4. 相似文献