Development of Highly Enantioselective Type I Palladacycles and Platinacycles for Asymmetric Catalysis

本提案涉及阴离子四电子供体基（“I型”）钯环和铂环的发展。具体来说，本研究的重点是：(a)开发高活性和对映选择性的I型钯环和铂环，用于与芳基硼酸作为亲核试剂的加成反应；(b)研究它们作为对映选择性催化剂的应用，用于与芳基硼酸作为亲核试剂的加成反应，特别是现有催化剂体系有局限性的加成反应，以及尚未探索或实现的加成反应。这些目标将通过三个相关步骤来实现：(a)制备和评价具有手性亚磷酸酯单位的旋光性I型半环族，目的是确定可以产生最佳对映选择性的手性二醇单位；(b)具有平面手性金属键合芳香族部分和手性亚磷酸盐单元的I型光活性钯环和铂环的制备和评价，旨在鉴定具有最佳对映选择性的I型光活性配合物；(c)研究光学活性I型钯环和铂环作为与芳基硼酸作为亲核试剂加成反应的高活性和对映选择性催化剂。要研究的特定反应包括芳基硼酸与醛的加成反应，在这种反应中，已报道的催化剂体系的对映选择性不令人满意，芳基硼酸与2-甲酰苯甲酸甲酯的加成反应形成手性3取代的邻苯酞，与α -酮酯的加成反应与季α -碳形成α -羟基酯。通过这个奖项，有机和大分子化学项目支持了纽约市立大学史坦顿岛学院化学系胡乔生教授的工作。胡教授和他的学生正在探索含钯或铂化合物的合成，以及这些化合物催化新的有机化学反应的后续能力。与许多其他催化剂系统相比，目标化合物易于获得，对空气和水分都很稳定，使其易于制备和处理。这项提议的研究有望揭示催化的新机会，允许从异常简单的前体中获得各种合成有用的有机化合物。最终，这些研究将为合成界提供强大的催化剂体系，对光学活性有机化合物的制备和研究具有重要影响，这些有机化合物是合成生物活性化合物的重要中间体。

This proposal addresses the development of anionic four-electron donor-based ("Type I") palladacycles and platinacycles. Specifically, this study focuses on: (a) the development of highly active and enantioselective Type I palladacycles and platinacycles for addition reactions with arylboronic acids as nucleophiles; and (b) the investigation of their application as enantioselective catalysts for addition reactions with arylboronic acids as nucleophiles, particularly addition reactions for which existing catalyst systems have limitations and for those that have not yet been explored or realized. These aims will be approached through three related steps: (a) preparation and evaluation of families of optically active Type I palladacycles with chiral phosphite units, with the aim to identify chiral diol units that could produce the best enantioselectivity; (b) preparation and evaluation of optically active Type I palladacycles and platinacycles with planar chiral metal-bound aromatic parts and chiral phosphite units, with the aim to identify optically active Type I complexes with the best enantioselectivity; and (c) investigation of optically active Type I palladacycles and platinacycles as highly active and enantioselective catalysts for addition reactions with arylboronic acids as nucleophiles. Specific reactions to be examined include addition reactions of arylboronic acids with aldehydes, in which unsatisfactory enantioselectivities have been obtained for reported catalyst systems, and addition reactions of arylboronic acids with methyl 2-formylbenzoates to form chiral 3-substituted phthalides and with alpha-ketoesters to form alpha-hydroxy esters with a quaternary alpha-carbon.With this award, the Organic and Macromolecular Chemistry Program is supporting the work of Professor Qiao-Sheng Hu, of the Department of Chemistry at CUNY College of Staten Island. Professor Hu and his students are exploring the synthesis of compounds containing palladium or platinum and the subsequent ability of these compounds to catalyze new organic chemical reactions. Compared with many other catalyst systems, the targeted compounds are readily available and stable to both air and moisture, making them easy to prepare and handle. The proposed research is expected to reveal new opportunities for catalysis, allowing access to a variety of synthetically useful organic compounds from unusually simple precursors. Ultimately, these studies will provide the synthetic community with robust catalyst systems having great impact on the preparation and study of optically active organic compounds that are important intermediates in the synthesis of biologically active compounds.