Enantioselective reactions circularly polarized light

The process by which a stereochemically inactive center is converted to a specific stereoisomeric form. In most cases, the reacting center is prochiral. Such processes can occur with reactions involving an optically active reagent, solvent, or catalyst (eg., an enzyme). The reaction produced by such a process is referred to as an enantioselective reaction. In principle, use of circularly polarized light in photochemical reactions of achiral reactants might also exhibit asymmetric induction. However, reported enantioselectivities in these cases have been very small. 

Absolute asymmetric synthesis A synthesis in which achiral reactants are converted to nonracemic, chiral products, and where the enantioselectivity is induced only by an external force such as circularly polarized light in a photochemical reaction [65]. 

In extreme cases, many enantiotopic- and enantioselective differentiating reactions of flexible achiral molecules proceed via differentiation of equilibrating enantiomeric conformers. Particularly noteworthy is the photochemical cycliza-tion of (Z)-l,2-diarylethenes to hexahelicenes using circularly polarized light... 

---