The role of the support properties in the catalytic performance of an anchored copper(ii) aza-bis(oxazoline) in mesoporous silicas and their carbon replicas
A straightforward synthesis of chiral aza-bis(oxazoline) (Azabox) ligands from commercially available amino alcohols is described. The new protocol allows access to previously reported Azabox ligands in considerably improved yields but also to new derivatives, including non-C2-symmetrical ones.
C1-Symmetric VersusC2-Symmetric Ligands in Enantioselective Copper–Bis(oxazoline)-Catalyzed Cyclopropanation Reactions
作者:José M Fraile、José I. García、Anja Gissibl、José A. Mayoral、Elísabet Pires、Oliver Reiser、Marta Roldán、Isabel Villalba
DOI:10.1002/chem.200700681
日期:2007.10.26
A thorough experimental and theoretical study of the enantioselective cyclopropanation of alkenes catalyzed by chiralbis(oxazoline)- and azabis(oxazoline)-copper complexes, which comprise a new family of ligands that lack C2 symmetry, has been conducted. Surprisingly high enantioselectivities were observed with some of these ligands, which were rationalized on the basis of molecular modeling studies
Unlocking the Asymmetric Hydrogenation of Tetrasubstituted Acyclic Enones
作者:Jorge Faiges、Maria Biosca、Miquel A. Pericàs、Maria Besora、Oscar Pàmies、Montserrat Diéguez
DOI:10.1002/anie.202315872
日期:2024.2.26
Fast and highly selective Ir-catalysts have been developed for the asymmetric hydrogenation of challenging tetrasubstituted acyclicenones. The mechanism and the effects of the catalyst and reaction parameters on selectivity have been unraveled by means of deuterogenation experiments and DFT calculations.
Development of Bifunctional Aza-Bis(oxazoline) Copper Catalysts for Enantioselective Henry Reaction
作者:Kai Lang、Jongwoo Park、Sukwon Hong
DOI:10.1021/jo1009867
日期:2010.10.1
Base-functionalized aza-bis(oxazoline) ligands were prepared to explore the concept of dual activation through the Lewis acid and a tethered tertiary amine base, The catalytic activity of the Cu complex was evaluated for the asymmetric Henry reaction. Compared with a corresponding unfunctionalized copper complex with external 1-benzyl-4-ethylpiperazine base, the ethylpiperazine-functionalized aza-bis(oxazoline) copper catalyst resulted in rate acceleration (2.5 times) as well as improved enantioselectivity (72% ee vs 92% ee).