Asymmetric Reactions with Dual-Functional Organocatalysis

描述（由申请人提供）：在过去的两个资助周期中，我们的研究项目在不对称碱催化的发展方面取得了重大进展，以及有机催化剂的酸碱和低碱双功能催化作为发展不对称反应的广泛适用概念。在我们之前的研究中，催化剂通过参与单一的立体化学过渡态而具有活性、对映选择性和非对映选择性。我们建议的研究重点是新的反应级联的发明和发展。基于金鸡纳生物碱作为有效的手性质子供体的初步研究结果，非对称双功能协同有机催化的发展成为我们提出的研究的共同主题。在这种催化模式中，有机催化剂作为双功能催化剂，通过激活和定向两种参与的反应物或中间体来促进反应级联中的两个不同的单独步骤。具体目的是：1)发展？？的对映选择性和非对映选择性共轭加成-质子化反应。用于不对称合成手性氨基化合物的-二取代硝基烯。2)对映选择性异构化的仿生质子转移催化研究进展-不饱和羰基变为手性？？-不饱和羰基化合物通过串联去质子-质子化反应。3)通过对映选择性和化学控制与氢过氧化物的共轭加成-质子化反应发展不对称过氧化物。通过建立广泛的合成重要的不对称转化，目前代表了现有催化剂的未满足的挑战，我们的研究将提供独特的入口，并实现有效的生物和治疗性手性分子的不对称合成，这些手性分子要么无法获得，要么难以用现有的合成方法以简洁和有用的方式制备。

DESCRIPTION (provided by applicant): During the last two funding cycles our research program has made significant progress in the development of asymmetric base catalysis, as well as acid-base and iminium-base bifunctional catalysis by organic catalysts as broadly applicable concepts for the development of asymmetric reactions. In our previous studies the catalysts afford activity, enantioselectivity and diastereoselectivity through their involvement in a single transition state of stereochemical consequences. Our proposed studies focus on the invention and development of new reaction cascades. Building on preliminary results revealing the ability of cinchona alkaloids to serve as efficient chiral proton donors, the development of asymmetric dual-functional cooperative organocatalysis becomes a common theme underlying our proposed studies. In this mode of catalysis the organic catalysts act as a bifunctional catalyst to promote two different individual steps in the reaction cascades by activating and orienting the two participating reactants or intermediates. The specific aims are: 1) Development of enantioselective and diastereoselective conjugate addition-protonation reactions of ???-disubstituted nitroalkenes for asymmetric synthesis of chiral amino compounds. 2) Development of biomimetic proton transfer catalysis for enantioselective isomerizations of ???-unsaturated carbonyl to chiral ???-unsaturated carbonyl compounds via tandem deprotonation-protonation reactions. 3) Development of asymmetric peroxidations via enantioselective and chemo-controlled conjugate addition-protonation reactions with hydroperoxides. By establishing a broad range of synthetically important asymmetric transformations that currently represent unmet challenges for existing catalysts, our studies will provide unique entries into and achieve efficient asymmetric syntheses of chiral molecules of biological and therapeutic interest that are either inaccessible or difficult to prepare in a concise and useful manner by existing synthetic methods. PUBLIC HEALTH RELEVANCE: Small molecules constitute one of the most important forms of therapeutic agents and play an increasingly important role in biomedical research. The goal of this work is to develop new and efficient synthetic methods that will greatly enhance our ability to rapidly create molecules of diverse structures with defined configuration, thereby providing biomedical researchers with powerful tools to accelerate the discovery of small molecules possessing biologically interesting and therapeutically desirable properties. These synthetic methods will also provide the foundation for the development of cost-effective processes for the sustainable manufacturing of therapeutic agents with significant implications to public health.