NSF Award
8960705
Chiral pesticides generally exhibit enantioselective action, where only one enantiomer is active and exhibits the desired biological activity. Despite mounting evidence that chiral pesticides should optimally be developed and marketed as single enantiomers, more than 90% of synthetic chiral pesticides are marketed as racemic mixtures. The principal reason for this is the high cost and technical difficulty of preparing chiral pesticides. Modern synthetic pyrethroid insecticides are among the most potent and selective pesticides known. a-Cyano-3-phenoxybenzyl alcohol, a cyanohydrin produced by the reaction of hydrogen cyanide and 3-phenoxybenzaldehyde, is chiral and is a major component of several commercially important pesticides. This project is directed at testing the feasibility of a novel membrane-based enzyme-reactor system for the production of enantiomerically pure (S)-a-cyano-3-phenoxybenzyl alcohol. The proposed system is readily amendable to scaleup and promises to produce enantiomerically pure (S)-a-cyano-3- phenoxybenzyl alcohol at low cost. The technical objectives of the Phase I project are 1) establish a knowledge base on the membrane-based process and the enzyme-catalyzed reaction, 2) design and construct a laboratory-scale system on the basis of the knowledge base, and 3) measure the system's performance. The proposed process is applicable to the synthesis of a wide range of valuable cyanohydrin enantiomers, which could be used as intermediates for the preparation of chiral a-amino alcohols, a-hydroxy acids, imidazoles, and heterocycles.
