Merrifield resin-supported hydrocinchonidinium salts containing particular functional groups that can participate in hydrogen bonding were prepared and evaluated as chiral phase-transfer catalysts using the asymmetric benzylation of glycine imine ester. These electronically modified Merrifield resin-supported phase-transfer catalysts generally provided better enantioselectivities compared to the unmodified ones.
Enantioselective Total Synthesis of (−)-Maoecrystal V
作者:Changwu Zheng、Igor Dubovyk、Kiel E. Lazarski、Regan J. Thomson
DOI:10.1021/ja5109694
日期:2014.12.24
The enantioselectivesynthesis of maoecrystal V, a cytotoxic polycyclic diterpene, is described. Key reactions in the synthesis include an intramolecular Heck reaction, an oxidative cycloetherification, and an intermolecular Diels-Alder reaction to forge the carbocyclic core in a concise and stereoselective manner. Late-stage amine and C-H oxidation is used to install the final functional groups required