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

这项建议涉及基于阴离子四电子给体(“第一类”)的软环和铂环的发展。具体地说，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；以及(B)考察它们作为对映选择性催化剂在与芳基硼酸作为亲核试剂的加成反应中的应用，特别是现有催化剂体系对其有局限性的加成反应和那些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元的光学活性I型对映体环族，目的是确定能够产生最佳对映体选择性的手性二醇单元；(B)制备和评价具有平面手性金属结合芳香族部分和手性亚磷酸酯单元的光学活性I型对偶环和铂环，目的是确定具有最佳对映体选择性的光学活性I型配合物；(C)研究作为高活性和对映体选择性催化剂的I型对映体环类化合物，用于与芳基硼酸作为亲核剂的加成反应。将要研究的具体反应包括芳基硼酸与醛的加成反应(已报道的催化剂体系的对映选择性不佳)，以及芳基硼酸与2-甲酰基苯甲酸甲酯的加成反应生成手性3-取代邻苯二甲酸甲酯，以及与α-酮酸酯的加成反应生成具有季节型α-碳的α-羟基酯。凭借这一奖项，有机与高分子化学项目支持了斯塔滕岛纽约州立大学化学系胡乔生教授的工作。胡教授和他的学生正在探索含有钯或铂的化合物的合成，以及这些化合物随后催化新的有机化学反应的能力。与许多其他催化剂系统相比，目标化合物易于获得，对空气和湿度都稳定，使其易于制备和操作。这项拟议的研究有望揭示催化的新机会，使人们能够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系统，对光学活性有机化合物的制备和研究产生重大影响，光学活性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.