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The Taft's substituent constant of the pentafluorophenyl group is reestimated to be 1.50 by correlation between IR spectral data and sigma constants for a series of esters of 3-phenylpropanic acid and butanoic acid. The pentafluorophenyl group is found to possess the moderate electron-withdrawing ability between 3,5-dinitrophenyl and difluoromethyl groups.

Research has been conducted on zinc porphyrin and 5-[4-(1-hydroxyethyl)phenyl]-10,15,20-triphenylporphyrin. The validity of the transition-state model proposed for the lipase-catalyzed secondary alcohol kinetic resolution has been investigated via the synthesis of these porphyrin compounds and the results are reported.

The synthesis of optically pure and active 1,2-bis(pentafluorophenyl)ethane-1,2-diols (1R,2R) and (1S,2S) using lipase-catalyzed transesterification derived cyanohydrin intermediates (R)- and (S)- is described. X-ray structural data of the naproxen ester of the intermediates indicate that they exhibit well-ordered packing structure with pentafluorophenyl and the 6-methoxynaphthyl groups exhibiting face-to-face stacking interactions and end-to-end parallel contacts.

An NADPH-dependent reductase that exhibit reducing activity for 1-chloro-2-hexanone was isolated from bakers' yeast. Gel filtration and sodium dodecyl sulphate-polyacrylamide gel electrophoresis indicated that the reductase is a monomeric enzyme with a 37-kilodalton molecular weight. Moreover, the reductase exhibited low Michaelis values and high specificity constants for all the substrates investigated.

The acyl moiety of acylating agents enhances the enantioselectivity of Pseudomonas cepacia lipase-promoted acylations of racemic alcohols. This stereochemical controlling function, which arises from the transient attachment of the acyl group at the active site of the lipase, was evident in the kinetic resolution of 2-((N,N-dimethylcarbamoyl)-methyl)-3-cyclopenten-1-ol and 2-(2-(tert-butyldimethylsilyloxy)ethyl)-3-cyclopenten-1-ol using enol esters as acyl donors.

Host-guest combination influences the circular dichroism (CD) spectra of amino acid ester-porphyrin supramolecular systems. Observation of induced CD requires the presence of intermolecular hydrogen bonding to the carbonyl group of the guest molecule. Molecular orbital calculations show the influence of relative geometry or the carbonyl group and porphyrin plane on the induced CD of the system. Coupling of electric and magnetic transition dipole moments of the carbonyl group with the electric transition dipole moment of the porphyrin Soret bond influences the observed induced CD.

A chiral porphyrin and its reference porphyrins with features for binding of alpha-amino acid esters to hosts are synthesized. Three recognition groups, Zn, OH, and CH2CO2Me, are introduced into the porphyrin framework for binding experiments. Zn ion and the OH group stabilize the host-guest complex through coordination and hydrogen bonding interactions.

Three host porphyrins were prepared in order to investigate the relationship between the structure of the hosts and their recognition of amino acid esters. A host molecule bearing both coordination and hydrogen bonding recognition sites was constructed. Host-guest interactions were characterized by UV-vis titration, circular dichroism (CD) and 1H nuclear magnetic resonance spectroscopic studies. It was found that the fixation of the carbonyl group of the guest by two-point recognition caused marked enhancements in induced CD.

Research has been conducted on the enantioselectivity and substrate specificity of the chiral catalysts. The potential capabilities of the carbonyl reductase, a monomeric NADPH-dependent enzyme, as a chiral biocatalyst have been investigated and the results are reported.

Chiral macrocycles with the hydrogen bond donor/acceptor sites in the cavity are prepared and covalently bonded to silica gel to provide chiral stationary phases (CSPs), which has displayed excellent abilities to solve chiral compounds including ketones, esters, carboxylic acids, sulfoxides, amines amino acid derivatives and metal complexes. The MM calculations have shown that the chiral recognition of Co[(acac).sub.2] is obtained by a combination of steric interactions and hydrogen bonds between the carbonyl O atom coordinated to the Co atom and the macrocyclic amide NH groups.

The size and shape of the chiral cavity of a macrocyclic receptor are tuned by the alteration of the binaphthyl moiety in order to improve the chiral recognition/discrimination ability. The host with the 3,5-bis(trifluoromethyl)phenyl group at the 3,3'-positions has an excellent ability as an NMR chiral solvating agent.

Bifunctional macrocycles and diamide are designed and synthesized. The analysis has shown the importance of the relative orientation of the binaphthyl moiety and the orthogonal disposition of the binaphthyl moiety in bifunctional macrocycle has brought the differential ring-current effect on the chiral guest molecule bound.

Optically active aziridine derivatives have attracted considerable attention because of their versatile synthetic utilities, and a variety of methods for asymmetric syntheses are reported. Methods for the regio-and stereoselective ring cleavage of the aziridines are well studied, and are still under active investigation for the syntheses of chiral amines, amino alcohols, and amino acids.

The temperature effect on enantioselectvity (E) in lipase-catalyzed kinetic resolutions of 34-phenyl-2H-azirine-2-methanol was evaluated through the utilization of a lipase from Pseudomonas cepacia (PS) in a reaction with vinyl acetate in ether under -40 degrees Celsius. Lowering the temperature even as to as low as -40 degrees Celsius enhances the E value, favoring the (R)-enantiomer.