...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Catalysis science & technology >Selectivity via catalyst or substrate control in catalytic asymmetric transformations of bifunctional symmetrical substrates
【24h】

Selectivity via catalyst or substrate control in catalytic asymmetric transformations of bifunctional symmetrical substrates

机译：双功能对称底物的催化不对称转化中通过催化剂或底物控制的选择性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Catalytic asymmetric transformations of bifunctional symmetrical substrates pose interesting problems in selectivity. In one extreme, catalyst control leads to identical selectivity at both sites, and amplification of chirality in the product. This improved enantiopurity comes at the expense of reduced yield; the undesired meso byproduct must be separated. Alternatively, substrate control may modify the inherent selectivity of the catalyst. The first transformation may change the substrate to make the second transformation less selective (negative cooperativity), while positive cooperativity can result in selectivity greater than that afforded by simple catalyst control. Similar behavior may occur in polyfunctional substrates with three or more identical reactive sites. Substrate vs. catalyst control and positive vs. negative cooperativity plausibly depends upon the structure of the substrate and the linker between the active sites, but has rarely been investigated systematically. This perspective presents several examples of structure-selectivity relationships with the eventual goal of designing substrates for positive cooperativity and enhanced selectivity in asymmetric catalysis.
机译：双功能对称底物的催化不对称转化在选择性中提出了有趣的问题。在一个极端情况下，催化剂的控制在两个地点都可以相同的选择性，并在产品中的手性扩增。这种改善的对映射是以降低产量为代价的。不需要的中间副产品必须分开。或者，底物控制可能会改变催化剂的固有选择性。第一个转换可能会改变底物，从而使第二个变换降低选择性（负合作性），而正合作性可能会导致选择性大于简单催化剂控制所提供的选择性。在具有三个或更多相同反应性位点的多功能底物中可能发生相似的行为。底物与催化剂的控制和正面合作性和阴性合作性合理地取决于底物的结构和活动位点之间的接头，但很少有系统地研究。该观点列出了结构选择关系的几个例子，该示例与设计基材的最终目标是为正合作，并提高了不对称催化的选择性。

著录项

相似文献

  • 外文文献
  • 中文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号