摘要：

We studied the ability of different biomaterials to enantioselectively catalyze oxidation or reduction reactions with the help of substrate rac -1- m or p -ArCH(OH)Me and the 1- o -ArC(O)Me derivatives. Apoenzyme (NAD(P)+-dependent secondary alcohol dehydrogenase(NAD(P)-E)) and cofactor (NAD(P)+) were activated by preincubating immobilized aqueous plant leaf (e.g., young wheat leaves), cereal tissue (wheat bran), vegetable (e.g., carrot), and seaweed (e.g., wakame seaweed) solutions, and the NAD(P)-E oxidized only ( R )-isomers highly enantioselectively. Thus, greater than 99% ee(s) of ( S )-isomers ( 1m - 5m and 1p - 5p ) can be obtained from corresponding rac -1- m or p -ArCH(OH)Me. Further, immobilized chlorella cells and immobilized bakerapos;s yeast can reduce highly stereoselectively; greater than 99% ee(s) of ( S )-isomers ( 1o - 5o ) can be obtained from corresponding 1- o -ArC(O)Me. Specific use of each isomer (( S )- 6 and ( R )- 6 ) with greater than 99% ee(s) of racemic -1-2-NpCH(OH)Me becomes possible through selective use of NAD(P)-E eluted from artemisia vulgaris indica leaves and young wheat leaves. We suggest that the pH of the reaction media can determine not only the direction of NAD(P)-E, toward enantioselectively catalyzed oxidation (pH > 7.0) or reduction reaction (pH < 7.0), but also the regioselective reactivity of NAD(P)-E to the substrate o - (pH < 7.0), m -, and p -substituted groups (pH > 7.0). Thus, in comparison to current biocatalysts, several biomaterials can serve as asymmetric reagent bases, providing easily obtained, low-cost natural catalysts with stereoselectivity, regioselectivity, and substrate specificity that work under mild conditions for asymmetric synthesis of organic compounds.

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