Absolute asymmetric synthesis from achiral molecules in the chiral crystalline environment

The current status of absolute asymmetric synthesis in a chiral crystalline environment has been reviewed. A number of topochemically controlled four-center type photocycloadditions are described for a series of unsymmetrically substituted diolefin crystals and CT crystals. This concept has been applied to intramolecular photoreactions, and several successful absolute asymmetric syntheses have been achieved, involving Norrish Type II reaction, di-pi-methane rearrangement, electrocyclization, thietane formation, oxetane formation, hydrogen abstraction by thiocarbonyl and alkenyl groups, and radical-pair intermediates.