H. Veschambre

Microbiological reduction of keto-sulfones. Application in a three-step synthesis of (S)-(+)-β-angelica lactone

Abstract Microbiological reductions of several keto-sulfones led to the corresponding hydroxy-sulfones in moderate to high enantiomeric excess. A three-step synthesis of (S)-(+)-β-angelica lactone from ethyl-4-oxo-3-(phenyl-sulfonyl)-pentanoate via the intermediate chiral alcohol is described.

Fructose‐1,6‐Bisphosphate Aldolase‐Mediated Synthesis of Aminocyclitols (Analogues of Valiolamine) and their Evaluation as Glycosidase Inhibitors

A highly stereoselective method for the preparation of nitro‐ and aminocyclitols, using fructose‐1,6‐bisphosphate aldolase, which catalyzes the aldol reaction of dihydroxyacetone phosphate (DHAP) on hydroxynitrobutanals, is reported. The key part of the synthesis is based on a one‐pot /two‐enzyme process whereby three reactions take place; rabbit muscle aldolase (RAMA) catalyzed aldolization, phytase‐catalyzed phosphate hydrolysis, and intramolecular spontaneous nitroaldolization. Two families of nitrocyclitols were obtained depending on the carbon configuration in the β position to the nitro group. Reduction of the latter afforded the aminocyclitols. Evaluation of the inhibition properties of the amines towards five commercially available glycosidases has shown selectivity for β‐glucosidase and β‐galactosidase.

Reduction microbiologique d'aldehydes α, β-ethyleniques par Beauveria sulfurescens

Abstract αβ-unsaturated aldehydes are reduced by Beauveria sulfurescens , giving a mixture of the corresponding ethylenic and saturated alcohols. Optically active saturated alcohols have the ( S )-configuration.

Deprotection of carbonyl croups by anodic oxidation of dithioacetals : A key step in the synthesis of α-diones, α-ketols and chiral synthons.

Abstract The anodic oxidation of α-keto and α-hydroxythloacetals provides an efficient way for the regeneration of α-diones and α-ketols, specially in the cases where chemical reactions are unsuccessful.

Microbial reduction of α,β-unsaturated carbonyl compounds: A general property?

Abstract The double bonds of cyclohexenone and methylcyclohexenone were reduced by a strain of Clostridium and by various strains of Streptomyces . These results and those observed previously show that this reduction is widespread among microorganisms.

Reduction of 1,1-dideuterio-2-methyl-2-penten-1-ol by beauveria sulfurescens. Mechanism of the microbiological reduction of α,β-unsaturated ald

Abstract Reduction of 1,1-dideuterio-2-methyl-2-penten-1-ol by Beauveria sulfurescens leads to the corresponding saturated mono-deuterated alcohol. This result allows the understanding of the mechanism of the microbiological reduction of α,β-unsaturated alcohols by B. sulfurescens. Thus, the stereochemical rule previously established for the reduction of α,β-unsaturated ketones can be carried out to the reduction of unsaturated aldehydes by B. sulfurescens.

Microbiological synthesis and circular dichroism of optically active 2-deuterio-cycloalkanones

Abstract Optically active 2-deuterio-cyclopentanone and 2-deuterio-cyclohexanone have been prepared by microbiological reduction of 2-deuterio α,β-unsaturated cyclic ketones by Beauveria sulfurescens .

Microbiological synthesis of optically active (2R,3S)-2,3-deuteriocyclohexan-1-ones and (2R,3S)-2-methyl-3-deuteriocyclohexan-1-one. Enantiospecificanti-addition of hydrogen to the double bond of cyclohex-2-en-1-ones.

Abstract Addition of hydrogen to the double bond of cyclohexenones during microbiological reduction by Beauveria sulfurescens gives the trans product in high yield (90%) resulting from anti -addition to the si face on C-2 and the re face on C-3.

Reduction of (αβ-Unsaturated Ketones by Various Fungi

αβ-Unsaturated ketones were reduced by selected fungi (which are known steroid hydroxylators) incubated under limited aerobic conditions.