Studies on the development of enzymatic and non-enzymatic asymmetric synthesis

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Asymmetric synthesis is of considerable current interest. Thus we investigated the following asymmetric reactions by enzymatic and non-enzymatic techniques.1. Asymmetric ring opening of cyclic acid anhydrides with lipase in organic slovents. A lipase (amano P) catalyzed the asymmetric ring opening of 3-substituted glutamic anhydride with 1- butanol to afford the half esters having 60 - 91 % ee. And also, the same lipase irreversibly catalyzed a ring opening of 2-substituted anhydrides preferentially at the less hindered carbonyl to give monoesters with high regioselectivity.2. Irreversible and highly enantioselective resolution of 2-holo-1-aryl-ethanols and fydroperoxides in organic solvents catalyzed by a lipase. Lipase was found to be an excellent catalyst for irreversible transesterification of alcohols with enol esters in organic solvent. By this enzyme reaction, stereoselective acylation of racemic halohydrines and hydropcroxide was successfully achieved.3. Stereoselective acylation of binaphtol and deacylation of its esters using a lipase. It was found that a lipase from pseudomanas sp. catalyzed a acylation of binaphtol with enol esters and deacylation or alcoholysis of its racemic monoesters. From both side of reaction, the monoesters and binaphtol were obtained in high optical yield respectively.4. Novel asymmetric synthesis of optically active lactones. The cyclic diamides containing naphthyl diamine or stilbendiamine as a C_2-chiral auxiliary in the ring structure were effectively converted to the lactones with trifluoro acetic acid in high d.e.