Combining Fluorous and Triazole Moieties for the Tagging of Chiral Azabis(oxazoline) Ligands
作者:Ramesh Rasappan、Tobias Olbrich、Oliver Reiser
DOI:10.1002/adsc.200900129
日期:——
New fluorous-tagged azabis(oxazoline) ligands were prepared using the copper-catalyzed azide-alkyne cycloaddition as ligation method. The resulting ligands were tested in copper-catalyzed asymmetric benzoylations (up to 99% ee), nitroaldol (up to 90% ee), and Michael reactions (up to 82% ee). The combination of unpolar fluorinated alkyl chains and polar triazolemoieties imposes properties that are
Polytopic Bis(oxazoline)-Based Ligands for the Development of Recoverable Catalytic Systems Applied to the Cyclopropanation Reaction
作者:José I. García、Jaime García、Clara I. Herrerías、José A. Mayoral、Ana C. Miñana、Carlos Sáenz
DOI:10.1002/ejoc.201301510
日期:2014.3
Financial support from the Spanish Ministerio de Economia y Competitividad (MINECO) (project number CTQ2011-28124-C02-01), the European Social Fund (ESF) and the Gobierno de Aragon (Grupo Consolidado E11) is gratefully acknowledged. ACM is indebted to the Consejo Superior de Investigaciones Cientificas for a grant (CSIC JAE-Pre program).
非常感谢西班牙经济与竞争部长 (MINECO)(项目编号 CTQ2011-28124-C02-01)、欧洲社会基金 (ESF) 和 Gobierno de Aragon (Grupo Consolidado E11) 的财政支持。ACM 向 Consejo Superior de Investigaciones Cientificas 提供资助(CSIC JAE-Pre 计划)。
Racemic 1,2-diols and a-hydroxy carbonyl compounds can be asymmetrically benzoylated in a kinetic resolution in the presence of various Cu(II)-aza(bisoxazoline) catalysts. A novel bisbenzyl-substituted aza(bisoxazoline) ligand proved to be especially effective when immobilized on MeOPEG(5000), giving from 91 to >= 99% ee in 37-49% yield for each of five sequential reactions.