Asymmetric Epoxidation of α-Substituted Acroleins Catalyzed by Diphenylprolinol Silyl Ether
作者:Bojan P. Bondzic、Tatsuya Urushima、Hayato Ishikawa、Yujiro Hayashi
DOI:10.1021/ol102269s
日期:2010.12.3
Asymmetric epoxidation of α-substituted acroleins with hydrogen peroxide has been catalyzed by diphenylprolinol diphenylmethylsilyl ether to afford α-substituted-β,β-unsubstituted-α,β-epoxy aldehyde with excellent enantioselectivity and the generation of a chiral quaternary carbon center. The method was applied to a short synthesis of (R)-methyl palmoxirate.
Lipase-Catalyzed Enantioselective Synthesis of Methyl (<i>R</i>)- and (<i>S</i>)-2-Tetradecyloxiranecarboxylate through Sequential Kinetic Resolution
作者:Oscar Jiménez、M. P. Bosch、Angel Guerrero
DOI:10.1021/jo970109y
日期:1997.5.1
Among a variety of lipases tested, Pseudomonas fluorescens lipase has been found to induce enantioselective acylation of methyl (R,S)-2-hydroxy-2-(hydroxymethyl)hexadecanoate (3), affording, through sequential kinetic resolution, both enantiomers in good optical yields. Efficiency of the process has been compared to the Sharpless asymmetric dihydroxylation of alkene 2 using (DHQD)(2)PHAL and (DHQ)(2)PHAL as chiral ligands. The (R)- and (S)-3 enantiomers have been cyclized to afford both enantiomers of methyl 2-tetradecyloxiranecarboxylate (1), a potent hypoglycemic agent and inhibitor of long-chain fatty acid oxidation.
A new general method to obtain chiral 2-alkylglycidic acid derivatives: synthesis of methyl (R)-(+)-palmoxirate
作者:Jose L. Garcia Ruano、Ana M. Martin Castro、Jesus H. Rodriguez