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

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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.