Enantioselective photodeconjugation of conjugated esters and lactones

Abstract

The photodeconjugation of conjugated esters and lactones in the presence of small amounts of chiral catalysts is enantioselective. The enantio-meric excess is very sensitive to the conditions of the reaction. When chiral amino alcohols are used as chiral catalysts a synergism is observed between the effect of the amino and hydroxyl groups on the optical purity of the deconjugated molecules. The chiral discrimination between the two diastereoiso-meric transitions states leading to the R and S configuration of the product is caracterized by its Δ ΔH # and Δ ΔS #. A model which explains the results is proposed and some examples of generalisation of these studies are described. © 1986 IUPAC