146329-67-1Relevant articles and documents
Synthesis of chiral α-Alkoxyketones via allene oxides
Shipman, Michael,Thorpe, Heidi R.,Clemens, Ian R.
, p. 897 - 900 (1997)
Treatment of enantiemerically enriched epoxy mesylates 7-9 with potassium alkoxides under carefully controlled reaction conditions (18-crown-6, THF, -78°C) provide the coresponding α-alkoxyketones 10-13 without significant racemisation. The reactions are shown to proceed with net stereochemicaI inversion at the epoxide centre.
Chemoenzymatic synthesis of 'α-bichiral' synthons. Application to the preparation of chiral epoxides
Besse,Veschambre
, p. 1271 - 1285 (1993)
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.
Generation of odorous acyloins by yeast pyruvate decarboxylases and their occurrence in sherry and soy sauce
Neuser, Frauke,Zorn, Holger,Berger, Ralf G.
, p. 6191 - 6195 (2000)
Volatile acyloins (α-hydroxy ketones) were obtained by condensing either aldehydes with pyruvate or 2-keto acids with acetaldehyde in a reaction catalyzed by yeast pyruvate decarboxylases (EC 4.1.1.1). Odor qualities and threshold values of 34 acyloins were evaluated, and 23 of them possessed distinct flavor properties. Sherry and soy sauce flavors were analyzed: 2-hydroxy-3-pentanone and 3-hydroxy-2-pentanone were identified in soy sauce for the first time; these and 2-hydroxy-5-methyl-3-hexanone and 3-hydroxy-1-phenyl-2-butanone were isolated from sherry for the first time. The biocatalytic efficiencies of crude pyruvate decarboxylase preparations from Zygosaccharomyces bisporus, Saccharomyces cerevisiae, Kluyveromyces lactis, and Kluyveromyces marxianus were compared. Product yields comparable to those of conversions with purified pyruvate decarboxylase demonstrated the suitability of crude enzyme extracts as cost-effective biocatalysts in acyloin formation. Conversion rates of >50% showed that the potential of this type of enzyme to catalyze the formation of aliphatic acyloins has been underestimated before.
Engineering transketolase to accept both unnatural donor and acceptor substrates and produce α-hydroxyketones
Yu, Haoran,Hernández López, Roberto Icken,Steadman, David,Méndez-Sánchez, Daniel,Higson, Sally,Cázares-K?rner, Armando,Sheppard, Tom D.,Ward, John M.,Hailes, Helen C.,Dalby, Paul A.
, p. 1758 - 1776 (2019/11/16)
A narrow substrate range is a major limitation in exploiting enzymes more widely as catalysts in synthetic organic chemistry. For enzymes using two substrates, the simultaneous optimisation of both substrate specificities is also required for the rapid expansion of accepted substrates. Transketolase (TK) catalyses the reversible transfer of a C2-ketol unit from a donor substrate to an aldehyde acceptor and suffers the limitation of narrow substrate scope for industrial applications. Herein, TK from Escherichia?coli was engineered to accept both pyruvate, as a novel donor substrate, and unnatural acceptor aldehydes, including propanal, pentanal, hexanal and 3-formylbenzoic acid (FBA). Twenty single-mutant variants were first designed and characterised experimentally. Beneficial mutations were then recombined to construct a small library. Screening of this library identified the best variant with a 9.2-fold improvement in the yield towards pyruvate and propionaldehyde, relative to wild-type (WT). Pentanal and hexanal were used as acceptors to determine stereoselectivities of the reactions, which were found to be higher than 98% enantiomeric excess (ee) for the S configuration. Three variants were identified to be active for the reaction between pyruvate and 3-FBA. The best variant was able to convert 47% of substrate into product within 24?h, whereas no conversion was observed for WT. Docking experiments suggested a cooperation between the mutations responsible for donor and acceptor recognition, which would promote the activity towards both the acceptor and donor. The variants obtained have the potential to be used for developing catalytic pathways to a diverse range of high-value products.
Selective Synthesis of Unsymmetrical Aliphatic Acyloins through Oxidation of Iridium Enolates
Sanz-Marco, Amparo,Martinez-Erro, Samuel,Martín-Matute, Belén
supporting information, p. 11564 - 11567 (2018/07/31)
The first method to access unsymmetrical aliphatic acyloins is presented. The method relies on a fast 1,3-hydride shift mediated by an IrIII complex in allylic alcohols followed by oxidation with TEMPO+. The direct conversion of allylic alcohols into acyloins is achieved in a one-pot procedure. Further functionalization of the Cα′ of the α-amino-oxylated ketone products gives access to highly functionalized unsymmetrical aliphatic ketones, which further highlights the utility of this transformation.
