| Abstract: | In this dissertation, we propose a test statistic for testing goodness of fit of m Lipase catalyzed kinetic resolutions have been utilized in the preparation of optically active compounds with enantiomeric excess up to 98%. These optically active compounds can subsequently be used as substrates for enzymatic aldol condensations. An extention of this lipase technology has been applied to achieve double resolution of a mixture of stereoisomers with two chiral centers, i.e. a pair of enantiomers and a meso compound, with modest to high optical purity. Dilithium tetrabromonicklate and dilithium dimethylcyanocuprate have been used to open the epoxide ring of glycidaldehyde diethyl acetal with high regioselectivity. New applications of fructose 1,6-diphosphate (FDP) aldolase (EC 4.1.2.13) catalyzed reactions have been developed for the synthesis of potentially biologically active thiosugars, glycolipid precursors, and sulfur-linked pseudodisaccharides. The enzymatic synthesis of pseudodisaccharides utilizes a dialdehyde as an acceptor substrate to condense with two equivalent of dihydroxyacetone phosphate (DHAP) and represents a novel methodology to construct this type of compound. This methodology should be generally applicable to the synthesis of a variety of symmetric as well as asymmetric pseudodisaccharides as potential glycosidase inhibitors. The substrate specificity and synthetic utility of deoxyribose 5-phosphate aldolase (DERA, EC 4.1.2.4) have been explored. It was shown that this enzyme tolerates a variety of different functionalities on acceptors, thus allowing synthesis of deoxyaldoses, deoxyketoses, deoxyhalosugars, azidodeoxysugars, azadeoxysugars, deoxythiosugars, glycolipid precursors, and glycoamino acids. In addition to acetaldehyde, propanal, acetone, and fluoroacetone have been used as nucleophilic components to condense with a number of acceptor aldehydes. A new stereogenic center with (3S) configuration is formed when acetaldehyde, fluoroacetone, or acetone are used as donor substrates. With propanal, two new stereogenic centers are formed with (2R, 35) configurations. A byproduct, 7-azido-(2R,4S)-dimethyl-2,4,7-trideoxy-D-glycero-D-allo-heptopyranose, has been identified from double aldol condensation by reaction of D -3-azido-2- hydroxypropanal with two equivalent of propanal... |
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