UNS: New Approaches to Catalyst Screening and Development

主要研究者：Stephen G DiMagno提案编号：1500076催化剂是促进化学反应的材料，用于从各种原材料生产工业化学品、燃料、塑料和药品。 一个基本的科学挑战是设计催化剂，使其对特定类型的反应具有活性。 在自然界中，被称为酶的生物催化剂具有非常特定的催化功能。 该项目的总体目标是使用酶来帮助指导新催化剂材料的设计。 关键的新奇在于，酶筛选过程报告了催化剂候选物是否能够进行立体化学，这是制造许多有价值的化合物和药物的基础。 在这一持续的努力中，涉及立体化学的复杂化学反应将被开发和研究。 一个可能的目标是更有效的方法来合成商业药物，如普瑞巴林。 该项目的教育活动包括在生物学和化学的界面上培训研究生和博士后研究助理，以及通过化学日对高中生进行宣传。NSF支持的研究计划的继续重点是使用酶通过称为原位酶筛选（ISES）的过程来帮助识别合成有机化学的感兴趣的催化剂。 ISES中使用的报告酶是手性传感器，其提供催化剂候选物的相对速率、立体选择性和底物范围的信息。 该更新提案将使用ISES工具和ISES筛选结果的先前发现来推进三个目标。 第一个目的是扩展Rh和Pd介导的（假）卤代/碳环化转换各种环的大小，探索后环化/交叉复分解和闭环复分解之间的竞争，检查其他亲核试剂，并测试机械假设，特别是关于立体化学过程的碳环化步骤。 第二个目标是开发ISES方法的范围，特别关注通过三酶对开发磷酸二乙酯离去基团和乙酸酯离去基团的可行酶对。 为此，候选的二烷基磷酸酶报告酶将从大肠杆菌表达。产气菌，并且该酶将与醇脱氢酶串联用于筛选直接涉及磷酸二乙酯置换的金属-配体介导的烯丙基取代。 第三个目标是通过亲核开环确定3-取代氧杂环丁烷和N-保护氮杂环丁烷的去对称化的可行催化组合。 如果成功，这种化学方法将为β（2）-氨基酸（AAs）和γ（3）-AAs的不对称合成提供一个全新的入口。

PI: Stephen G DiMagnoProposal Number: 1500076Catalysts are materials that promote chemical reactions for production of industrial chemicals, fuels, plastics, and pharmaceuticals from a wide variety of raw materials. A fundamental scientific challenge is to design the catalyst to be active for a specific type of reaction. In Nature, biological catalysts called enzymes have very specific catalyst functions. The overall goal of this project is to use enzymes to help guide the design of new catalyst materials. The key novelty is that the enzyme screening process reports if the catalyst candidate is capable of performing stereochemistry, which is fundamental to making many valuable compounds and pharmaceuticals. In this continuing effort, complex chemical reactions involving stereochemistry will be developed and studied. One possible target is a more efficient approach to synthesis of commercial drugs like Pregabalin. The educational activities of the project include training of graduate students and post-doctoral research associates at the interface of biology and chemistry, as well as high school student outreach through Chemistry Day.This proposed continuation of NSF-supported research focuses on the use enzymes to help identify catalysts of interest for synthetic organic chemistry through a process called In Situ Enzymatic Screening (ISES). The reporting enzymes used in ISES are chiral sensors that provide information the relative rate, stereoselectivity, and substrate scope of catalyst candidates. This renewal proposal will use ISES tools and previous discoveries from ISES screening outcomes to advance three Aims. The first Aim is to extend both the Rh- and Pd-mediated (pseudo) halometalation/carbocyclization transformations various ring sizes, explore competition between post-cyclization/cross-metathesis and ring-closing metathesis, examine other nucleophiles, and test mechanistic postulates, particularly regarding the stereochemical course of the carbocyclization step. The second Aim is develop the scope of the ISES method, with specific focus on developing viable enzyme couples for both the diethyl phosphate leaving group and for the acetate leaving group through a three enzyme couple. Towards this end, candidate dialkyl phosphatase reporting enzymes will be expressed from E. aerogenes, and this enzyme will be used, in tandem with an alcohol dehydrogenase, to screen for metal-ligand mediated allylic substitution directly that involves displacement of the diethyl phosphate. The third Aim seeks to identify viable catalytic combinations for the desymmetrization of 3-substituted oxetanes and N-protected azetidines via nucleophilic-opening. If successful, this chemistry would provide a fundamentally new entry into the asymmetric synthesis of beta(2)-amino acids (AAs) and of gamma(3)-AAs.