100939-27-3Relevant academic research and scientific papers
Design of α-Alkyl β-Hydroxy Esters Suitable for Providing Optical Resolution by Lipase Hydrolysis
Itoh, Toshiyuki,Kuroda, Keiko,Tomosada, Miki,Takagi, Yumiko
, p. 797 - 804 (2007/10/02)
A study of the lipase-catalyzed hydrolyses of various α-substituted β-acetoxy esters revealed that a sulfur functional group in the ester, which could play an important role in the stereorecognition by lipase A6 (Aspergillus sp.) and an anti conformation
Enantioselective Diastereospecific Synthesis of anti-α-Alkyl-β-hydroxy Esters through Cuprate Opening of Glycidic Esters
Mulzer, Johann,Lammer, Ortrud
, p. 2178 - 2190 (2007/10/02)
A diastereospecific chain elongation of the aldehydes 1 to anti-αalkyl-β-hydroxy esters 2 via the intermediates 4 - 7 is described.By means of the Sharpless epoxidation, 2 may be obtained with >90percent ee in either enantiomer.
Dehydrative Decarboxylation of 2,3-Disubstituted 3-Hydroxycarboxylic Acids with Dimethylformamide Acetals - Mechanistic Studies and Preparative Applicability
Mulzer, Johann,Bruentrup, Gisela
, p. 2057 - 2075 (2007/10/02)
Dimethylformamide dimethylacetal (2a) converts the threo-3-hydroxycarboxylic acids 4 smoothly into the (E)/(Z)-olefins 7/6 only if R2 is an aryl or vinyl substituent.Althougt the reaction exhibits a distinct (E)-selectivity it cannot be considered as a stereo-controlled olefin synthesis.If R2 is alkyl, 2a generates the methyl esters 10 from 4.The erythro-acids 5 react with 2a to give 43 - 95percent of >98percent sterically pure 7.As the key tranformation on the multistep way from 4/5 to 6/7 the fragmentation of the zwitterionic intermediate 11/20 is postulated.
Stereochemistry of the Addition of Carboxylic Acid Dianions to Aldehydes under Kinetic and Thermodynamic Control - Synthesis and Configurational Assignment of 2,3-Disubstituted threo- and erythro-3-Hydroxycarboxylic Acids
Mulzer, Johann,Zippel, Matthias,Bruentrup, Gisela,Segner, Johannes,Finke, Juergen
, p. 1108 - 1134 (2007/10/02)
Under kinetically controlled conditions (-50 deg C, 10 min) the carboxylic dianions 2 add to aldehydes 3 to give the threo/erythro-adducts 4/5 (Scheme 1); the threo-selectivity markedly increases with the bulkiness of the substituents of 2 or 3 and decreases with the charge/radius ratio of the counter-ions of 2.From these results a syn-transition state with a HOMO-LUMO ineraction between 2 and 3 is derived (Scheme 3).For appropriate substituents a far higher threo-selectivity is observed under thermodynamically (22-50 deg C, 1-3 days) than under kinetically controlled conditions.We describe the isolation of the hydroxy acids 6 and 7, which are formed from 4 and 5 on acidic hydrolysis, and show how their configurations can be unambiguously assigned on the basis of 1H-NMR data.
