Towards Absolute Asymmetric Synthesis

这一奖项来自化学系化学合成计划，以支持威斯康星大学麦迪逊分校化学系的特赫希克·尹教授的研究。尹教授对有机小分子的“手性”或“手性”很感兴趣。许多重要的有机分子，包括药物分子和重要的生物分子，如氨基酸和糖，可以左手或右手形式存在，只有一种形式是生物所需的。这种不受欢迎的形式可能是有害的，因此几乎所有新的候选药物或诊断探针都必须只有一种“惯用手”。也可以用左旋或右旋圆偏振来产生光。这个项目的长期目标是利用圆偏振光的左旋性来决定有机小分子的左旋性。这是通过设计螺旋手性催化剂来实现的，这种催化剂首先可以被只用一只手的圆偏振光选择性地激活，然后将这种用手的手转移到化学反应及其产物上。这个项目需要一种结合了合成有机化学、有机金属化学、光化学和计算化学的跨学科方法来实现其目标，并以这种方式为学生提供出色的培训。尹教授也是努力增加从事科学职业的学生多样性的领导者，该项目包括继续这些重要努力的更广泛的影响。本课题所研究的手性光催化剂是八面体的Ir络合物，其配体排列在具有明确螺旋手性的金属周围。这类化合物是这些研究的一个有吸引力的起点，因为它们具有强大的和研究得很好的光化学，因为它们最近被证明是一系列有机转化的相当有效的光敏剂，因为它们可以很容易地以立体化学的纯形式合成。该项目的第一阶段表明，螺旋型手性Ir光催化剂的单一对映体的手性可以传递到新形成的有机光环加合物中。第二阶段寻求了解有效的对映选择性光催化所必需的结构-活性关系。第三个也是最具雄心的阶段试图确定能够选择性地激活具有圆偏振光的手性Ir光催化剂外消旋混合物的正交结构特征。该项目的广泛影响培养了一批与潜在的新药、材料和精细化学品的建设相关的尖端合成有机化学方面的研究生、本科生和博士后研究人员。

This award from the Chemical Synthesis Program of the Chemistry Division goes to support research by Professor Tehshik Yoon of the University of Wisconsin-Madison's Chemistry Department. Professor Yoon is interested in the "chirality", or "handedness", of small organic molecules. Many important organic molecules, including drug molecules and biologically important molecules like amino acids and sugars can exist in either left- or right-handed forms, with only one form being biologically desirable. The undesirable form can be harmful, so almost all new drug-candidates or diagnostic probes must be of only one "handedness". Light can also be produced with either left- or right-handed circular polarizations. The long-term goal of this project is to use the handedness of circularly polarized light to dictate the handedness of a small organic molecule. This is accomplished by designing helically chiral catalysts that can first be selectively activated by circularly polarized light with only one handedness and then transferring that handedness to a chemical reaction and its resultant product. This project requires an interdisciplinary approach that combines synthetic organic chemistry, organometallic chemistry, photochemistry, and computational chemistry to achieve its objectives, and in that way it provides outstanding training for students. Professor Yoon is also a leader in efforts to increase the diversity of students who undertake careers in science, and the project includes broader impacts that continue these important efforts. The chiral photocatalysts studied in this project are octahedral iridium complexes whose ligands are arranged about the metal with well-defined helical chirality. This class of compounds constitutes an attractive starting point for these studies because they possess a robust and well-studied photochemistry, because they have been recently shown to be quite effective photosensitizers for a range of organic transformations, and because they can easily be synthesized in stereochemically pure form. The first phase of this project shows that the chirality of a single enantiomer of a helically chiral iridium photocatalyst can be transmitted to a newly formed organic photocycloadduct. The second phase seeks understanding of the structure-activity relationships necessary for effective enantioselective photocatalysis. The third and most ambitious phase attempts to identify orthogonal structural features that enable selective activation of a racemic mixture of chiral Ir photocatalysts with circularly polarized light. The broader impacts of this project train a diverse set of graduate, undergraduate, and postdoctoral researchers in cutting-edge synthetic organic chemistry relevant to the construction of potential new drugs, materials, and fine chemicals.