ASYMMETRIC THERMAL ADDITION AND CYCLOADDITION REACTIONS

这一建议是一个竞争性的延续，偏离了原来的 研究主题（环加成路线羟醛加合物）在重大新 方向 相对和绝对立体化学的控制是一个关键因素。 现代有机合成的中心焦点。 方面取得了很大的进步 在传统上重要的转化的立体化学控制中， 如羟醛缩合反应、Diels-Alder环加成反应和烯醇化反应 烷基化相对和绝对立体化学的控制 重要加成和环化反应通过热 （而不是金属促进的）途径是不太了解，这些 因此，不太频繁地利用反应。 这两个目标 建议将得到同等重视：1）开发新的， 立体控制的热加成和环化反应，和2） 了解控制立体化学的潜在因素。 研究的目标是两大类反应：1）偶极 环加成--在已有基础的情况下， 和2）自由基反应，其中缺乏立体控制反应 自由基在合成中日益重要， study. 在这个早期阶段，该项目的目标非常 基础（开发和理解新反应）。 然而，在这方面， 令人兴奋的初步结果表明，这些目标是现实的， 以及解决世界上重要问题的原创而有力的解决方案， 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.