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Enantioselective synthesis and (bio)catalysis : routes to enantiomerically pure alcohols and thiols

(1995) Hof, Robert Patrick

A unifying topic in this thesis is the development of routes to optically active compounds. The importance today of chiral -- optically pure -- compounds is evident. The phenomena of optical activity and chirality were discovered about one and a half century ago by pioneering work of Pasteur, van 't Hoff' and Le Bell. Once the impact of chiral compounds on living organisms was realized, major efforts were undertaken to find effective routes to optically pure compounds. The best (or worst) known example in this respect is thalidomide (sold as Softenon), of which only one of the enantiomers proved to have the desired sedative effect, whereas the other enantiomer caused severe fetal damage. This has had a major effect on developments in pharmaceutical, agrochemical, and flavour and fragance industry. Whereas only some years ago most synthetic drugs were sold as racemates, nowadays more and more are sold as single enantiomers. Also FDA regulation on the marketing of new drugs has become much more strict in recent years with respect to chiral compounds. Nowadays, there are several well established routes to optically pure compounds, of which three were followed during this research.
The first part of this thesis is dedicated to the synthesis of new chiral compounds (thiols) starting from naturally occuring enantiomerically pure compounds (the so-called chiral pool). The products of these reactions have possible applications in catalysis and synthesis. The second part deals with the use of these chiral molecules in asymmetric catalysis. Special attention has been devoted to this topic during the last decades.