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Abstract: We derived a novel equation capable of predicting the degree of enantioselectivity in a catalytic reaction without any knowledge of the reaction mechanism and/or the transition-state structure, and tested the validity of this equation by changing substrates systematically in the lipase or oxazaborolidine-catalyzed reactions. A good correlation was observed between the predicted and observed E values, and the stereochemistry of the products could be predicted correctly in most cases (28 out of 30). [Copyright &y& Elsevier]

Abstract: The gene encoding a versatile biocatalyst that shows high enantioselectivity for a variety of ketones, SCR (Saccharomyces cerevisiae carbonyl reductase), has been identified, cloned, and expressed in Escherichia coli. Two types of expression systems with high NADPH-regenerating capacities have been constructed. One is the tandem system, where the genes encoding SCR and GDH (glucose dehydrogenase) are located in the same plasmid, and the other is the two-plasmid system, where each of the SCR and GDH genes is located in separate plasmids that can coexist in one E. coli cell. Asymmetric reduction of ketones with the recombinant E. coli cells gave synthetically useful 20 alcohols, 11 of which were enantiomerically pure. The productivity of one of these products was as high as 41g/L. [Copyright &y& Elsevier]

Abstract: The gene encoding a versatile biocatalyst that shows high enantioselectivity for a variety of ketones, SCR (Saccharomyces cerevisiae carbonyl reductase), has been identified, cloned, and expressed in E. coli. Recombinant E. coli co-producing SCR and GDH (glucose dehydrogenase) is an easy-to-use, synthetically useful biocatalyst, and 8 out of the 16 alcohols obtained had enantiomeric purities of >98% ee. [Copyright &y& Elsevier]

Lipase-catalyzed kinetic resolutions of 1,1-diphenyl-2-propanol were performed at high temperatures up to 120°C. Burkholderia cepacia lipase immobilized on porous ceramic particles, lipase PS-C II (Amano Enzyme Inc.), gave an enantiopure product at 40–120°C, with the highest conversion (39%) at 80–90°C. The mechanism of high enantioselectivity retained even at 120°C is also described briefly. [Copyright &y& Elsevier]

It has been demonstrated that lipase is useful not only for kinetic resolution but also for the rapid determination of absolute configurations. We have previously proposed a mechanism represented by transition-state models to rationalize the enantioselectivity in the lipase- and subtilisin-catalyzed kinetic resolutions of secondary alcohols. The mechanism indicates that the enzyme-catalyzed reactions can be used as a tool for determining the absolute stereochemistry of secondary alcohols. In order to increase reliability, the enzymatic method was combined with Mosher''s method using MTPA, to give a protocol which is named the double-confirmation method. The absolute configurations of six 1-substituted ethanols were determined consistently by this new procedure. The enzymatic method is quick, easy, economical, and reliable. An interesting similarity in conformation between the transition-state models and MTPA esters is also described. [Copyright &y& Elsevier]

Abstract: Iron oxide produced by iron-oxidizing bacteria, Leptothrix ochracea, (biogenous iron oxide: BIO) was used as a support for immobilized palladium catalysts with organic cross-linkers. Palladium immobilized on BIO bearing imidazolium chloride delivered the desired biaryl products in sufficient yields in the Suzuki–Miyaura coupling reactions under solvent-free conditions and could be reused several times without significant loss of catalytic activity. It is shown that BIO can be exploited as a useful support for immobilization of palladium and the BIO-immobilized palladium catalyst effectively promotes the solvent-free Suzuki–Miyaura coupling reactions. [Copyright &y& Elsevier]

Abstract: Synthetically useful cyanohydrin acetates, ArCH(OAc)CN (Ar=C6H5, 3,4-methylenedioxyphenyl, 4-Me–C6H4, 4-Cl–C6H4, 4-F–C6H4, 4-CF3–C6H4), were successfully synthesized in high enantiomeric purities (79–93% ee) via the lipase-catalyzed dynamic kinetic resolution (DKR) of cyanohydrins synthesized in situ from the corresponding aldehydes and acetone cyanohydrin. The combined use of silica-supported BTAH (benzyltrimethylammonium hydroxide) and porous ceramic-immobilized lipase under the optimized reaction conditions enabled the remarkable acceleration of the enantioselective DKR reactions. [Copyright &y& Elsevier]

Abstract: A molecular tweezer bearing two pentafluorophenyl groups 2b and its o-methylated aryl homologue 2c were newly synthesized by the slight modification of the known procedure. The low yield in the introduction of pentafluorophenyl group to the precursor dibromide 6 was improved by application of the modified Suzuki–Miyaura coupling reaction using C6F5B(OH)2 with Pd2(dba)3/P(t-Bu)3/CsF/Ag2O catalytic system, which was recently developed by us. [Copyright &y& Elsevier]

Abstract: A significant enhancement of the enantioselectivity (E value=249) in the lipase-catalyzed resolution of a primary alcohol, racemic 5-(hydroxymethyl)-3-phenyl-2-isoxazoline (±)-1, was obtained by using the ‘low-temperature method’ (−60°C) with porous ceramic-immobilized lipase (Amano PS-C II) and vinyl acetate in acetone. [Copyright &y& Elsevier]

Lipase-catalyzed enantioface-selective protonation of the enol acetate of 2-methylcyclohexanone was performed by using Burkholderia cepacia lipase immobilized on porous ceramic particles, `Lipase PS-C II'' (Amano Enzyme Inc.), in i-Pr2O and ethanol, giving (R)-2-methylcyclohexanone with 77% ee at best with 82% conversion at 0 °C. The enantioselectivity (E-value) was found to be temperature dependent and significant in controlling the efficiency of the asymmetric protonation. [Copyright &y& Elsevier]