ABSOLUTE ASYMMETRIC SYNTHESIS IN HOMOGENEOUS CONDITIONS USING THE CHIRAL CRYSTALLINE ENVIRONMENT AND TOTAL RESOLUTION VIA PHOTORACEMIZATION-CRYSTALLIZATION

从非手性试剂开始，在没有任何外部手性试剂的情况下实现不对称合成一直是化学家们的一个有趣的挑战，也是自然界旋光性起源问题的核心。由非手性材料形成的手性晶体的立体定向固体化学反应被定义为“绝对”不对称合成。这种对称合成涉及到利用手性结晶记忆的冻结手性进行绝对不对称合成的新概念。我们发现立体控制光化学反应可以在固体状态下发生。此外，还证明了利用手性晶体在均相条件下进行绝对不对称合成的新方法。我们发现氮原子上具有大体积取代基的非手性无环亚胺在手性空间基上结晶，并在低温四氢呋喃中溶解时保持手性构象。与正丁基锂在-80 ~ 20℃范围内反应得到了光学活性丁基加合物和氢化产物。这个反应提供了在均匀条件下使用手性晶体进行绝对不对称合成的第一个例子。

The achievement of an asymmetric synthesis starting from an achiral reagent and in the absence of any external chiral agent has long been an intriguing challenge to chemists and is also central to the problem of the origin of optically activity in nature. Stereospecific solid-state chemical reactions of chiral crystals formed by achiral materials are defined as "absolute" asymmetric synthesis. This symmetric synthesis involves new concept of absolute asymmetric synthesis using the frozen chirality memoried by chiral crystallization.We found that the stereo-controlled photochemical reaction could occur in the solid state. Furthermore, new absolute asymmetric synthesis in homogeneous conditions using chiral christals were also demonstrated. We found achiral acyclic imides with bulky substituents on the nitrogen atom crystallized in chiral space group, and maintain the chiral conformation when the crystals dissolved in THF at low-temperature. The reaction with n-butyllithium at a range of -80-20℃ gave optically active butyl adduct and hydrogenated product. This reaction provides the first example of absolute asymmetric synthesis using chiral crystals in homogeneous conditions.