Enantioselective synthesis of (S)-4-methyleneglutamic acid via tandem conjugate addition–elimination under phase-transfer catalytic conditions
摘要:
An efficient enantioselective synthetic method for (S)-4-methyleneglutamic acid is reported. Phase-transfer catalytic conjugate addition elimination of the benzophenone imine of glycine tert-butyl ester in the presence of chiral Cinchona-derived catalysts give the corresponding conjugated addition products (>99% ee), which could be hydrolyzed to chiral (S)-4-methyleneglutamic acid. (C) 2010 Elsevier Ltd. All rights reserved.
Facile 1,3-diaza-Claisen Rearrangements of Tertiary Allylic Amines Bearing an Electron-Deficient Alkene
作者:Rachel M. Aranha、Amy M. Bowser、Jose S. Madalengoitia
DOI:10.1021/ol802577z
日期:2009.2.5
Tertiary allylic amines with an electron-deficient alkene react with isocyanates and isothiocyanates to give highly substituted ureas and thioureas arising from formal1,3-diaza-Claisenrearrangements. Isocyanates and isothiocyanates with strong electron-withdrawing groups are more reactive. Similarly, the data suggest that a stronger electron-withdrawing substituent on the alkene favors a faster reaction
Enantioselective synthesis of (S)-4-methyleneglutamic acid via tandem conjugate addition–elimination under phase-transfer catalytic conditions
作者:Sukhoon Kang、Qinghua Shi、Min Woo Ha、Jin-Mo Ku、Maosheng Cheng、Byeong-Seon Jeong、Hyeung-geun Park、Sang-sup Jew
DOI:10.1016/j.tet.2010.04.034
日期:2010.6
An efficient enantioselective synthetic method for (S)-4-methyleneglutamic acid is reported. Phase-transfer catalytic conjugate addition elimination of the benzophenone imine of glycine tert-butyl ester in the presence of chiral Cinchona-derived catalysts give the corresponding conjugated addition products (>99% ee), which could be hydrolyzed to chiral (S)-4-methyleneglutamic acid. (C) 2010 Elsevier Ltd. All rights reserved.