CHIROTECHNOLOGY - DESIGNING ECONOMIC CHIRAL SYNTHESES

The increasing awareness of the importance of chirality in the context of biological activity has stimulated a growing demand for efficient methods for the industrial synthesis of pure enantiomers. Various meth odologies for the synthesis of pure enantiomers, viz. use of the chira l pool, separation of racemates via crystallization techniques or enzy matic kinetic resolution and catalytic asymmetric synthesis are review ed and compared. Factors which influence the process economics and, he nce, route selection are discussed. In particular the merits and limit ations of catalytic asymmetric synthesis versus kinetic resolution are delineated. General guidelines are elaborated regarding the design of economic chiral syntheses and are illustrated by reference to the man ufacture of commercially important chiral drugs, e.g. ampicillin and a moxycillin side-chains, naproxen and ibuprofen, captopril and diltiaze m. Given the rapidly growing repertoire of cost-effective technologies , the industrial synthesis of chiral pharmaceuticals in enantiomerical ly pure form is clearly an economically viable proposition. Moreover, as understanding of the general principles involved provides a sound b asis for identifying the most attractive process.