HYDROGEN TRANSFER REACTIONS IN ORGANIC SYNTHESIS

在与健康相关的研究中， 研究有机分子的立体控制制备 结构/反应性关系（最终目标是开发 新药）、用于生物探针和传感器以及用于其它应用 推动有机合成领域的基础和应用研究。 这 格兰特建议在开发新的策略和试剂方面进行基础研究 基于自由基反应合成有机分子。 这些战略的实施将增进对重要的 新类型的有机反应，并将提供新的选择， 生物医学科学家的立体控制制备有机 分子。 双分子自由基反应最常使用试剂进行 例如氢化三丁基锡和三（三甲基甲硅烷基）硅烷。 一个案子是 这些试剂本身是有限的，因为它们的反应发生在 通过双分子链转移步骤。 单分子链的概念 转移（UMCT）反应的介绍，实验证据是 条件是某些硅微球将通过 UMCT机制。 几种双分子自由基加成反应具有 已经成功了，这些都强烈暗示了 UMCT方法。 在下一个授予期间，一系列合乎逻辑的机械和 合成实验将平行进行。 机械论 实验将旨在了解的范围和限制， 分子内氢转移反应 确定硅上的最佳取代基。 “正交链”还将 被研究。 早期的合成实验有一个目标， 用于双分子自由基加成反应的新型UMCT试剂。 以后的实验将集中在控制立体化学， 开发UMCT试剂的串联反应。 从长远来看， 设想了一种新的策略来进行双分子自由基加成 反应就会出现。

In the health-related research, the ever-increasing demand for stereocontrolled preparation of organic molecules for study of structure/reactivity relationships (with the ultimate goal of developing new drugs), for biological probes and sensors, and for other applications fuels basic and applied research in the field of organic synthesis. This grant proposes basic research in developing new strategies and reagents based on free radical reactions for the synthesis of organic molecules. Implementation of these strategies will increase understanding of important new classes of organic reactions, and will provide new options to biomedical scientists for the stereocontrolled preparation of organic molecules. Bimolecular radical reactions are most commonly conducted by using reagents such as tributyltin hydride and tris(trimethylsilyl)silane. A case is made that these reagents are inherently limited because their reactions occur with bimolecular chain transfer steps. The concept of unimolecular chain transfer (UMCT) reactions is introduced, and experimental evidence is provided that certain silicon hydrides will propagate radical chains by a UMCT mechanism. Several bimolecular radical addition reactions have already been successful, and these strongly hint at the advantages of the UMCT method. During the next granting period, a logical series of mechanistic and synthetic experiments will be conducted in parallel. Mechanistic experiments will be directed at understanding the scope and limitations of intramolecular hydrogen transfer reactions of silicon hydrides and at identifying optimal substituents on silicon. "Orthogonal chains" will also be studied. Early synthetic experiments have as a goal the introduction on new classes of UMCT reagents for bimolecular radical addition reactions. Later experiments will focus on control of stereochemistry, and on development of tandem reactions of UMCT reagents. In the long range, it is envisioned that a new strategy to conduct bimolecular radical addition reactions will emerge.