Regio- and Stereoselective Reduction of Diketones and Oxidation of Diols by Biocatalytic Hydrogen Transfer
作者:Klaus Edegger、Wolfgang Stampfer、Birgit Seisser、Kurt Faber、Sandra F. Mayer、Reinhold Oehrlein、Andreas Hafner、Wolfgang Kroutil
DOI:10.1002/ejoc.200500839
日期:2006.4
The asymmetric reduction of symmetrical and nonsymmetrical diketones as well as the stereoselectiveoxidation of various diols by biocatalytic hydrogen transfer was investigated by employing lyophilized cells of Rhodococcus ruber DSM 44541 containing alcohol dehydrogense ADH-‘A’. Symmetrical and nonsymmetrical diketones at the (ω-1)- and (ω-2)-positions are reduced to the Prelog product with high stereopreference
Chemoenzymatic synthesis of “α-bichiral” synthons. Application to the preparation of chiral epoxides
作者:Pascale Besse、Henri Veschambre
DOI:10.1016/s0957-4166(00)80239-6
日期:1993.6
Microbiological reduction of 3-bromo-2-octanone and 3-azido-2-octanone led to all the stereoisomers of 3-bromo-2-octanol and 3-azido-2-octanol. Chiral 2,3-epoxyoctanes were prepared from the 3-bromo-2-octanols.
Synthesis of chiral α-alkoxyketones via allene oxides
作者:Michael Shipman、Heidi R. Thorpe、Ian R. Clemens
DOI:10.1016/s0040-4039(96)02436-7
日期:1997.2
Treatment of enantiomerically enriched epoxy mesylates 7-9 with potassium alkoxides under carefully controlled reaction conditions (18-crown-6, THF, -78 degrees C) provide the corresponding alpha-alkoxyketones 10-13 without significant racemisation. The reactions are shown to proceed with net stereochemical inversion at the epoxide centre. (C) 1997, Elsevier Science Ltd.
Kinetic resolution of vic -diols by Bacillus stearothermophilus diacetyl reductase
The kinetic resolution of several racemic syn-and anti-1,2-diols by enzymatic oxidation with Bacillus stearothermophilus diacetyl reductase is described. The enantiomerically pure (R,R)- and (R,S)-diols are recovered in almost quantitative yield. (C) 1998 Elsevier Science Ltd. All rights reserved.
Generation and trapping of allene oxides: An approach to chiral, nonracemic α-alkoxyketones
作者:Michael Shipman、Heidi R Thorpe、Ian R Clemens
DOI:10.1016/s0040-4020(98)00878-3
日期:1998.11
Epoxy mesylates 5 react with a variety of sodium alkoxides to produce the corresponding alpha-alkoxyketones in good yields. Evidence is presented for the involvement of transient allene oxides in these reactions. Enantiomerically enriched epoxy mesylates (2R,3S)-5a-c were prepared using the Sharpless asymmetric epoxidation reaction as the key step. These precursors rearrange to alpha-alkoxyketones without significant racemisation under modified reaction conditions (ROK, 18-crown-6, THF, -78 degrees C). The reactions are shown to proceed with stereochemical inversion at the epoxide centre. (C) 1998 Elsevier Science Ltd. All rights reserved.