REACTIVITY AND STRUCTURE OF CHIRAL CRYSTAL. Fumio Toda, Department of Applied Chemistry, Faculty of Engineering, Ehime University, Matsuyama, Ehime 790, Japan

We have been studied the relationship between reactivity and structure of inclusion chiral crystal prepared from chiral host and achiral guest. In this microsymposium, we present some interesting difference of selectivity of photoreaction in the chiral crystal prepared by recrystallization of chiral host and achiral guest compounds from solvent and that prepared by mixing of powdered both components in the solid state. In most cases, photoreaction of the host-guest inclusion crystal prepared by recrystallization of chiral host and achiral guest from solvent and that prepared by mixing powdered both components gave the optically active product of the same chirality. X-ray analysis of the inclusion crystal prepared by the recrystallization showed that achiral guest molecules are arranged in a chiral form in the inclusion crystal. In a special case, however, photoirradiation of the host-guest inclusion crystal prepared by recrystallization of an achiral guest and chiral host compound from solvent gave (+)-chiral photo-reaction product. On the other hand, the same reaction of the inclusion crystal prepared by mixing the both in the solid state gave (-)-chiral photoreaction product.

The very interesting difference of inclusion behavior by chiral host and racemic host was found. Chiral and racemic 7-bromo-1,4,8-triphenyl-2,3-benzo[3.3.0]octa-2,4,7-trien-6-one include 4-picoline and 2-icoline, respectively.