SELECTIVE REACTIONS OF THIOLATE ANIONS WITH 4-HYDROXY-<i>E</i>-2-ALKENOIC ESTERS OR 4-METHANESULFONYLOXY-<i>E</i>-2-ALKENOIC ESTERS. SYNTHESIS OF 2-ALKEN-4-OLIDES (Δ<sup>α,β</sup>-BUTENOLIDES) AND<i>E</i>,<i>E</i>-2,4-ALKADIENOIC ESTERS
Methyl 4-hydroxy-E-2-alkenoates prepared from aldehydes in one step, undergo the Michael reactions with thiolate anions to give 4-alkanolide derivatives, which are converted into 2-alken-4-olides. Methyl 4-methanesulfonyloxy-E-2-alkenoates undergo the substitution reactions, and subsequent treatments give methyl E,E-2,4-alkadienoates.
Cross metathesis of allyl alcohols: how to suppress and how to promote double bond isomerization
作者:Bernd Schmidt、Sylvia Hauke
DOI:10.1039/c3ob40167g
日期:——
formation of ketones, resulting from uncontrolled and undesired doublebondisomerization. By conducting the CM in the presence of phenol, the catalyst loading and the reaction time required for quantiative conversion can be reduced, and isomerization can be suppressed. On the other hand, consecutive isomerization can be deliberately promoted by evaporating excess methyl acrylate after completing cross
Allyl benzenesulfenates containing an electron-withdrawing group at the conjugated position were prepared in isomericforms which would be stabilized by partial bonding between the C=C bond and two lone pairs of electrons on the sulfur atom.
Preparation of (R)- and (S)-(E)-4-hydroxy-2-unsaturated acids by asymmetric hydrolysis of their racemic esters
作者:Pietro Alevi、Mario Anastasia、Pierangela Ciuffreda、Anna Maria Sanvito
DOI:10.1016/s0957-4166(00)80324-9
日期:1993.7
Several optically active (R)- and (S)-(E)-4-hydroxyalk-2-enoic acids, metabolites of bioactive compounds of lipid peroxidation, were prepared from the corresponding racemic methyl esters by enantioselective hydrolysis mediated by porcine pancreas lipase and porcine liver esterase.