ABSTRACT
Numerous photoreactions are known to produce new stereogenic centers by either isomerization or addition processes. In asymmetric photoreactions, usually one of the possible isomers, which corresponds to the energetically more favorable transition state, predominates. This chapter aims to examine the progress in the field of asymmetric photoreactions involving a chiral reactant, and discusses the factors that control the diastereodifferentiation. The facial diastereoselectivity of the reaction was also completely controlled, when a diether was used as chiral auxiliary. The control of the diastereoselectivity of the allylic ene reaction could be extended to alkenes 205 substituted by a removable chiral auxiliary. A good control of the configuration of the newly created stereogenic centers is essential in synthesis. A better understanding of the factors gearing the diastereodifferentiation in photochemical reactions has led to more and more synthetic applications.
