Photochemistry of-chiral

Photochemical reactions—asymmetric as well as nonasymmetric ones—take their outset from electronically excited states of the reactant. In this chapter, direct cpl excitation is covered, sensitized reactions are discussed in Chap. 4. Asymmetric photochemistry produces new chirality in a reaction system. The cpl-induced reactions are often called absolute asymmetric, as there is no net chirality in the reactants. This discriminates asymmetric photochemistry from the photochemistry of chiral molecules, which can be induced by nonpolarized light. The newly created chirality in cpl-induced reactions becomes apparent in an excess of the amount of one reactant or product enantiomer over the other. This enantiomeric excess (ee) in a mixture of R and S enantiomers is defined as... 

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