Asymmetric hydrolysis of aryloxyacetaldehyde cyanohydrin acetates.

Abstract

Cyanohydrins are considered to be versatile synthons in organic synthesis because they can be readily converted to a-hydroxycarboxylic acids,1} oc-hydroxyaldehydes2) and ethanolamine derivatives,3) which include a number of physiologically active compounds. Lactic acid, tartaric acid, ephedrine and /?-adrenergic blocking agents are the representative examples of these classes of compounds. Thus, synthesis of chiral cyanohydrins is considered to be an interesting and useful problem, but only a very few reports have been known so far.4>5) Cyanohydrins are knownto be rather unstable compounds because of rapid equilibrium between aldehydes and hydrogen cyanide,6) and this equilibrium will inevitablly be accompanied by racemization of chiral cyanohydrins. Thus, based on the assumption that it would be desirable to prepare chiral

Asymmetric Hydrolysis of 1-Cyanoalkyl Acetates

“…6 ) We have investigated asymmetric hydrolysis of l-cyanoalkyl acetates, because it was supposed that esterases would show wide substrate specificities. 7 ) In the course of our studies, 8) Matsumoto and Ohno have demonstrated that a lipase produced by a Pseudomonas sp. selectively hydrolysed (R)-enantiomers of 2-aryloxy-I-cyanoethyl acetates.…”

Recent advances in the use of enzyme-catalysed reactions in organic synthesis

“…By localizing in a single plasmid the genes encoding the enzymes transketolase and 3-deoxy-~-arabinoheptulosonate synthase, biocatalysis previously exploited in the multi-step, immobilized enzyme synthesis of DAHP ( 107) is reconstructed in an intact microbial cell. In this reaction sequence, fructose-6-phosphate (1 14) is converted into erythrose-4-phosphate (1 15) under the action of transketolase, followed by coupling of (115) with phosphoenol pyruvate (116) in the presence of DAHP synthase to yield DAHP (107). This plasmid biocatalysis takes advantage of the long overlooked impact of transketolase activity on the flow of carbon into aromatic amino acid biosynthesis.…”

Formation of optically active aryloxyacetaldehyde cyanohydrin acetates with the aid of a microorganism.

“…After the reaction was complete, the organic materials were extracted with diethyl ether (100ml x 3). The combined organic layer waså .dried over anhydrous Na2SO4 and evaporated under reduced pressure to afford a mixture of the starting acetate (4) and the hydrolyzed cyanohydrin (3). The products were purified Preparation of l-aryloxy-2,3-epoxypropane.…”