A chemoselective oxidation of monosubstituted ethylene glycol: facile synthesis of optically active α-hydroxy acids
作者:Kiran Chinthapally、Sundarababu Baskaran
DOI:10.1039/c4ob00601a
日期:——
A mild and efficient method for the synthesis of optically active α-hydroxy acids through chemoselective oxidation of monosubstitutedethylene glycols using the TEMPO–NaOCl reagent system is described. It is evident from our studies that the solvent, pH and reaction temperature are very crucial for the success of this oxidation. The versatility of this method has been demonstrated with a variety of
Biocatalytic racemization of α-hydroxycarboxylic acids using a stereo-complementary pair of α-hydroxycarboxylic acid dehydrogenases
作者:Anne Bodlenner、Silvia M. Glueck、Bettina M. Nestl、Christian C. Gruber、Nina Baudendistel、Bernhard Hauer、Wolfgang Kroutil、Kurt Faber
DOI:10.1016/j.tet.2009.06.051
日期:2009.9
Biocatalyticracemization of aliphatic, (aryl)aliphatic and aromatic α-hydroxycarboxylicacids was achieved via a reversible oxidation-reductionsequence using a pair of stereo-complementary Prelog- and anti-Prelog d- and l-α-hydroxyisocaproate dehydrogenases from Lactobacillus confusus DSM 20196 and Lactobacillus paracasei DSM 20008, resp., overexpressed in Escherichia coli. The mild reaction conditions
bond insertion reactions between water and α-alkyl- and α-alkenyl-α-diazoesters as carbene precursors, with catalysis by a combination of achiral dirhodium complexes and chiral phosphoric acids or chiral phosphoramides. Participation of the phosphoric acids or phosphoramides in the carbene transfer reaction markedly suppressed competing side reactions, such as β-H migration, carbene dimerization, and olefin
KO, KWANG-YOUN;FRAZEE, W. J.;ELIEL, E. L., TETRAHEDRON, 1984, 40, N 8, 1333-1343
作者:KO, KWANG-YOUN、FRAZEE, W. J.、ELIEL, E. L.
DOI:——
日期:——
Asymmetric reactions based on 1,3-oxathianes3̄
作者:Kwang-Youn Ko、William J. Frazee、Ernest L. Eliel
DOI:10.1016/s0040-4020(01)82419-4
日期:1984.1
prepared1 chiral 2-acyl-l,3-oxathianes derived from (+)-pulegone with various metal hydride combinations proceeds stereoselectively, with diastereomer excess (d.e.) of as much as 97% in the case of reduction of phenylketones with lithium tri-sec.butylborohydride. Lesser selectivity (maximum 82% d.e.) is achieved with primary or tertiary alkyl ketones: the predominant diastereomer is readily purified