ABSTRACT
This chapter reviews the advances of supramolecular photochirogenesis in various confined media, excluding micelles, chiral solvents, liquid crystals, metal complexes, polymer matrices, clays, and crystals. A chiral cis-1,2-diphenylcyclopropane photoisomerizes to the chiral trans isomer upon singlet-or triplet-photosensitized irradiation. The most successful supramolecular photochirogenesis with chirally modified zeolites is the enantiodifferentiating photocyclization of tropolone derivatives in zeolites modified with ()-ephedrine or ()-norephedrine, giving bicyclo[3.2.0] heptadienes in high ees. Achieving efficient photochemical chiral induction within zeolite supercages requires a geometrical distribution of reactant and chiral inductor molecules in the same supercage. Photochemistry of nucleic acids has also been intensively investigated, particularly in connection with the causes of skin cancer. The use of sensitizing chiral hosts automatically fulfills the condition, as the complexation-photochirogenesis-the excited state, while the supramolecular asymmetric photoreactions employing the initial ground-state complexation may require some special device to excite selectively the bound species and to accelerate the decomplexation of photoproduct from the chiral host.
