1992 Volume 68 Issue 2 Pages 9-13
Stereo- and enantio-selective topochemical photoreactions are described in relation with crystallographic results of starting compounds. It was confirmed that ethyl 4-[2-(4-pyridyl)ethenyl]cinnamate crystallized into the chiral form without any external chiral reagents and that the chiral crystal, obtained from each recrystallization batch without seeding, always gave one or the other enantiomeric dimer in a large excess. The result was presumed to be a model of the generation of chiral homogeneity in nature. Topochemical reaction of achiral crystals of achiral molecules, ethyl α-cyano-4-[2-(2-pyridyl)ethenyl]cinnamate, proceeded stereo-specifically through the topochemical induction due to steric hindrance in the crystal cavity, and resulted in a syndiotactic compound.
