ASYMMETRIC THERMAL ADDITION AND CYCLOADDITION REACTIONS

这项提案是与原提案背道而驰的竞争性延续。 研究主题(环加成物路线到羟醛加合物) 方向。相对和绝对立体化学的控制是一种 现代有机合成的中心焦点。已经取得了长足的进步 在传统的重要转变的立体化学控制中 如Aldol反应、Diels-Alder环加成反应和烯醇化反应 烷基化反应。相对立体化学和绝对立体化学的控制 由热进行的重要的加成和环化反应 (而不是由金属推动的)途径鲜为人知，而这些 因此，反应被利用的频率较低。这有两个目标 提案将得到同样的重视：1)开发新的、 立体控制的热加成和环化反应，以及2) 了解控制立体化学的潜在因素。 研究对象分为两大类：1)偶极反应 循环添加--已经有了可以建立的基础， 和2)自由基反应，其中立体控制反应的匮乏 而自由基在合成中日益增长的重要性要求立即 学习。在这个早期阶段，该项目的目标非常明确 基础(新反应的发展和理解)。然而， 令人振奋的初步结果表明，这些目标是现实的， 以及对重要问题的独创性和强大的解决方案 生物医学活性化合物的合成即将到来。

This proposal is a competing continuation that departs from the original research theme (cycloadditive route to aldol adducts) in significant new directions. The control of relative and absolute stereochemistry is a central focus in modern organic synthesis. Great strides have been made in stereochemical control of traditionally important transformations like aldol reactions, Diels-Alder cycloadditions, and enolate alkylations. The control of relative and absolute stereochemistry in important addition and cyclization reactions that proceed by thermal (rather than metal-promoted) pathways is less understood, and these reactions are therefore exploited less frequently. Two goals of this proposal will receive equal emphasis: 1) the development of new, stereocontrolled thermal addition and cyclization reactions, and 2) the understanding of the underlying factors that control stereochemistry. Two broad classes of reactions are targeted for study: 1) dipolar cycloadditions-where there is already a foundation on which to build, and 2) radical reactionswhere the paucity of stereocontrolled reactions and the growing importance of radicals in synthesis demand immediate study. At this early stage, the goals of the project are very fundamental (development and understanding of new reactions). However, exciting preliminary results indicate that these goals are realistic, and that original and powerful solutions to important problems in the synthesis of biomedically active compounds will be forthcoming.