Enantioselective Photoreactions in the Solid State
Because molecules are packed at close positions regularly in crystals, selective photoreactions occur effectively by photoirradiation in the solid state. When enan tioselective reactions are required, achiral molecules should be arranged in a chi ral form in crystals. In some cases, achiral molecules are arranged in a chiral form in their own crystals. Photoreaction of the chiral crystal gives an optically active reaction product. When an achiral compound is oily material or does not form a chiral crystal, the achiral molecules can be arranged in a chiral form by inclusion complex formation with a chiral host compound. Photoirradiation of the inclusion complex crystals gives optically active product and the chiral host can be used again. These enantioselective photoreactions do not need an organic solvent and a chemical reagent and can be a typical example of a green and sustainable chem ical process.