9. Glossary

catalyst; catalyseur

A substance that modifies the rate of a chemical reaction, and sometimes its selectivity, without entering into the balance equation. Catalysts are used in much smaller quantities than reaction substrates.

catalyse asymétrique; asymmetric catalysis

A reaction that uses a chiral catalyst and favors the formation of a particular stereoisomer. For example, a chiral carbon (stereogenic center) has four different substituents and two enantiomers that are mirror images of each other, but are not superimposable. The aim of asymmetric catalysis is to synthesize just one of these two enantiomers. There are many applications for this technique, not least in the pharmaceutical industry. For example, some drugs are active in only one of their two forms, and the other may even be harmful. In such cases, only...