查询词典 asymmetric

The electron transfer mediated asymmetric radical allylation reactions were investigated in details.

中文摘要本论文对电子转移引发的不对称自由基烯丙基化反应进行了研究。

The asymmetric allylation of aldehydes is one of the most important methods for preparation of chiral homoallylic alcohol, which is the building block in organic synthesis of fine chemistry and drugs.

手性烯丙基醇是一类重要医药中间体，合成手性烯丙基醇的常见方法是醛的不对称烯丙基化反应。

It was found that the asymmetric induction level of H〓-MAP was exclusively higher than that of corresponding MAP. Under the optimized reaction conditions, the allylation product could be obtained in up to 90.9% ee with H〓-MAP having 3, 5-xylyls as chiral inducer.

发现H〓-MAPs比MAPs类配体取得了更好的不对称诱导效果，在优化的反应条件下，可以得到90.9％ee值的产物，大大高于文献中报道的MAPs配体的最好结果（73％ee）。

It was found that the binaphthyl backbone of S configuration was matched to the S, S pyrrolidino group. In this case, the asymmetric allylation product could be obtained in 85. 6% ee.

轴手性是S构型时，和中心手性S，S构型相匹配，它和钯形成的络合物在催化烯丙基取代反应时，取得了比不含中心手性因素的吡咯烷基氮膦配体高得多的对映选择性，可以得到85.6％ee值的产物。

E. value of productions were detected by high performance liquid chromatography. Results The chiral aminoalcohol ligand compound Ⅰ can promote the asymmetric allylation of acylhydrazones and the yield was 57%; The highest values of e. e. obtained for this reaction was 22%.

结果 手性氨基醇配体化合物Ⅰ能够促进烯丙基三氯硅烷和酰腙的烯丙基化加成反应，在它的辅助作用下，烯丙基化加成产物的产率可达到57%，对映体过量值最高达到22%。

The asymmetric ring-opening aminolysis of meso-epoxides represents one of the most important reactions in organic synthesis,giving rise to enantio-enriched aminoalcohol products with two chiral centers.

中文摘要：胺类对内消旋环氧化合物的不对称开环是一类重要的反应，反应生成两个手性中心的氨基醇化合物在有机合成中有着重要的应用。

Results: The differentiated neuron appeared different patterns of amitotic figures such as transverse sever, longitudinal split, etc. The proliferating neurons divided in an asymmetric way morphologically and chemically. The differentiated neuron appeared an obvious movement of cell migration and neurite extension.

结果：培养分化的神经细胞呈现横裂、纵裂等不同方式的无丝分裂像；分裂中的神经细胞可呈现形态及化学不对称性；分化的神经细胞有明显的细胞迁徙运动和突起延伸。

Results: PC12 cells exhibited amitotic figures including circular shrink, sideways concave, etc.The figures of asymmetric division in shape, size and the cell chemical properties by staining and the cell enucleation were observed.

结果：PC12细胞呈现横缢型和侧凹型等无丝分裂像，并且观察到其形态、大小和化学性质的不对称性分裂及细胞脱颖现象。

Stipules fully amplexicaul; leaf blade entire, symmetric or asymmetric, margin often toothed; wax glands in axils of main basal veins, often also in other vein axils or on nodes.

托叶完全抱茎；全缘的叶片，对称或不对称的，边缘通常齿；蜡腺体在基出主脉腋处，通常也在其他脉腋内或在节上。

During continual growth, the fetal part is constricted, resulting in asymmetric amputational defects.

在不断的生长过程中，胎儿局部受限，引起非对称性的截断缺损。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失