Asymmetric Synthesis Based on Chiral Heterobicyclo{2.2.1}heptanes

在有机合成项目的支持下，宾夕法尼亚州立大学化学系张旭木教授探索了手性杂双环（2.2.1）庚烷作为对映选择性有机转化的催化剂和助剂的使用。膦催化的（3+2）环加成反应在手性磷双环（2.2.1）庚烷介导下产生具有高度区域选择性和对映选择性的手性环戊烯。探讨了相关不对称催化剂在含吸电子基团的炔的亲核加成反应、Baylis-Hillman反应以及硫醚介导的醛的环氧化和氮化反应中的适用性。手性氮杂环（2.2.1）庚烷作为手性助剂用于不对称去质子化、烯胺烷基化和环加成反应。开发能够精确控制有机分子三维形态的合成方法已变得越来越重要，因为即使两个分子在结构上看似微小的差异，如镜像一样相互关联，也常常会导致化学性质的巨大差异。宾夕法尼亚州立大学化学系张旭木教授在有机合成计划的支持下，探索了实现这种高度受控的有机分子合成的方法。通过探索和发展由专门设计和定制的含磷或含氮分子介导的反应，张教授能够赋予这些反应的产物特定的三维形式。除了开发实用的合成方法外，张教授还探索了这些分子转化发生的机制，并针对重要的药物和医药中间体展示了它们的合成效用。

With the support of the Organic Synthesis Program, Professor Xumu Zhang, of the Department of Chemistry at the Pennsylvania State University, explores the use of chiral heterobicyclo(2.2.1) heptanes as catalysts and auxiliaries for enantioselective organic transformations. Phosphine-catalyzed (3+2) cycloaddition reactions afford chiral cyclopentenes with a high degree of regio- and enantioselectivity when mediated by chiral phosphabicyclo(2.2.1)heptanes. Related asymmetric catalysts are explored for their applicability in nucleophilic gamma addition reactions with alkynes bearing electron withdrawing groups, the Baylis-Hillman reaction, and thioether-mediated epoxidation and aziridination of aldehydes. Chiral azabicyclo(2.2.1)heptanes are employed as chiral auxiliaries for asymmetric deprotonation, enamine alkylation, and cycloaddition reactions. It has become increasingly important to develop synthetic methods which allow precise control over the three-dimensional form of organic molecules, since even the seemingly minor difference in structure displayed by two molecules related to one another as mirror images not infrequently leads to a dramatic difference in chemical properties. Professor Xumu Zhang, of the Department of Chemistry at the Pennsylvania State University, with the support of the Organic Synthesis Program, explores methods to effect such highly controlled syntheses of organic molecules. By exploring and developing reactions which are mediated by specifically designed and tailored phosphorus- or nitrogen-containing molecules, Professor Zhang is able to impart specific three-dimensional forms to the products of these reactions. In addition to developing practical synthetic methods, Professor Zhang explores the mechanisms by which these molecular transformations take place and targets important drugs and pharmaceutical intermediates to demonstrate their synthetic utility.