Fluorous Phase-Based Fluorescent Chiral Discrimination

弗吉尼亚大学化学系林普教授在化学系化学结构、动力学和机理B项目资助下，开发了一种新的对映选择性荧光传感器，用于识别全氟碳溶剂（氟相）中的手性胺。这些传感器用于促进手性催化剂的高通量筛选，用于手性胺的不对称合成，这些手性胺在合成具有药物和生物重要性的有机化合物中很有用。该项目为研究生和本科生在有机合成、光谱研究和催化剂开发等领域提供广泛的教育和培训。该小组还参与了一项外展计划，为小学生和教师开展基于化学的示范。这个拓展项目致力于在小学阶段提供探究式的化学教学。含有全氟烷基链的对映选择性荧光传感器预计在含氟溶剂中比在普通有机溶剂中更容易溶解。它们用于在含氟溶剂中对功能性手性胺（如二胺、氨基醇和氨基酸）进行对映选择性荧光识别。制备了这种传感器的假对映体对。在每一对中，有两个传感器在与手性胺底物的两个对映体相互作用时具有相反的对映选择性荧光响应，具有两种明显不同的发射波长。这些传感器应用于手性催化剂的筛选。利用假对映体传感器对的含氟溶液，将在普通有机溶剂或水溶液中进行的手性催化剂筛选实验产生的产物提取到含氟相中。由于只有传感器及其带有手性产物的加合物可以溶解在含氟相中，因此其他物质如试剂、催化剂和起始物质的干扰最小。通过荧光法测定手性产物的产率和对映体组成。该传感器的结构被修改，以进行非功能化胺的对映选择性荧光识别。本项目基于氟相的荧光检测具有自动化进行高通量催化剂筛选的潜力。在PI的指导下，招收不同背景的研究生和本科生，从事有机合成、光谱研究和催化剂开发等方面的研究。学生将学到许多对他们未来就业有用的实验室技能，并使他们对社会做出贡献。

In this project funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Lin Pu of the Department of Chemistry at University of Virginia is developing new enantioselective fluorescent sensors for the recognition of chiral amines in perfluorocarbon solvents (fluorous phase). These sensors are used to facilitate the high throughput screening of chiral catalysts for the asymmetric synthesis of chiral amines that are useful in the synthesis of organic compounds of pharmaceutical and biological importance. This project provides extensive education and training for graduate and undergraduate students in areas such as organic synthesis, spectroscopic study, and catalyst development. This group also participates in an outreach program to carry out chemistry-based demonstrations for elementary school students and teachers. This outreach program is dedicated to providing inquiry-based chemistry instruction at the elementary school level.Enantioselective fluorescent sensors containing perfluoroalkyl chains are expected to be more soluble in fluorous solvents than in common organic solvents. They are used to conduct the enantioselective fluorescent recognition of functional chiral amines such as diamines, amino alcohols and amino acids in fluorous solvents. Pseudoenantiomeric pairs of such sensors are prepared. In each pair there are two sensors having the opposite enantioselective fluorescent response with two distinctively different emission wavelengths upon interaction with the two enantiomers of a chiral amine substrate. These sensors are applied to chiral catalyst screening. A fluorous solution of a pseudoenantiomeric sensor pair are used to extract the products, generated from the chiral catalyst screening experiments conducted in common organic solvents or aqueous solution, into the fluorous phase. Because only the sensors and their adducts with the chiral products could be dissolved in the fluorous phase, the interference of other species such as reagents, catalysts and starting materials is minimized. Through fluorescent measurement, both the yield and enantiomeric composition of the chiral products is simultaneously determined. The structure of the sensors is modified in order to conduct the enantioselective fluorescent recognition of un-functionalized amines. The fluorous phase-based fluorescent detection of this project has potential to be automated to conduct high throughput catalyst screening. Under the direction of PI, graduate students and undergraduate students of diverse backgrounds are recruited to conduct research in organic synthesis, spectroscopic studies, and catalyst development. Students will learn many laboratory skills that are useful for their future employment and allow them to make contributions to the society.