ABSTRACT
This chapter reviews solid-state asymmetric photoreactions by classification into supramolecular approaches and spontaneous chiral crystallization approaches since the beginning in the 1970s. Supramolecular approaches have led to advances in solid-state asymmetric photochemistry to a great extent. The development of intermolecular photoreactions leads to an extension of the scope of solid-state chiral photochemistry. Reactivity in a cocrystal is controlled by the crystal packing arrangement, so the key point is the preparation of photoreactive cocrystals. The host-guest and ionic chiral auxiliary approaches have been most intensively applied for solid-state asymmetric induction. Absolute asymmetric photoreactions using chiral crystals spontaneously formed from achiral molecules can be accomplished in the crystalline state without using any external chiral source. Such absolute asymmetric synthesis is a promising methodology for asymmetric synthesis even if spontaneous chiral crystallization cannot be predicted at present.
