796966-21-7Relevant articles and documents
Asymmetric Catalysis in Liquid Confinement: Probing the Performance of Novel Chiral Rhodium–Diene Complexes in Microemulsions and Conventional Solvents
Deimling, Max,Kirchhof, Manuel,Schwager, Barbara,Qawasmi, Yaseen,Savin, Alex,Mühlh?user, Tina,Frey, Wolfgang,Claasen, Birgit,Baro, Angelika,Sottmann, Thomas,Laschat, Sabine
, p. 9464 - 9476 (2019)
The role of liquid confinement on the asymmetric Rh catalysis was studied using the 1,2-addition of phenylboroxine (2) to N-tosylimine 1 in the presence of [RhCl(C2H4)2]2 and chiral diene ligands as benchmark reaction. To get access to Rh complexes of different polarity, enantiomerically pure C2-symmetric p-substituted 3,6-diphenylbicyclo[3.3.0]octadienes 4 and diastereomerically enriched unsymmetric norbornadienes 5 and 6 carrying either the Evans or the SuperQuat auxiliary were synthesized. A microemulsion containing the equal amounts of H2O/KOH and toluene/reactants was formulated using the hydrophilic sugar surfactant n-octyl β-d-glucopyranoside (C8G1) to mediate the miscibility between the nonpolar reactants and KOH, needed to activate the Rh–diene complex. Prominent features of this organized reaction medium are its temperature insensitivity as well as the presence of water and toluene-rich compartments with a domain size of 55 ? confirmed by small-angle X-ray scattering (SAXS). Although bicyclooctadiene ligands 4 a,b,e performed equally well under homogeneous and microemulsion conditions, ligands 4 c,d gave a different chemoselectivity. For norbornadienes 5, 6, however, microemulsions markedly improved conversion and enantioselectivity as well as reaction rate, as was confirmed by kinetic studies using ligand 5 b.
Interplay of Polarity and Confinement in Asymmetric Catalysis with Chiral Rh Diene Complexes in Microemulsions
Abitaev, Karina,Abouhaileh, Abdulwahab,Frey, Wolfgang,Gugeler, Katrin,K?stner, Johannes,Kirchhof, Manuel,Laschat, Sabine,Sottmann, Thomas,Zens, Anna
supporting information, p. 16853 - 16870 (2021/11/30)
Microemulsions provide a unique opportunity to tailor the polarity and liquid confinement in asymmetric catalysis via nanoscale polar and nonpolar domains separated by a surfactant film. For chiral diene Rh complexes, the influence of counterion and surfa
Experimental and Theoretical Study on the Role of Monomeric vs Dimeric Rhodium Oxazolidinone Norbornadiene Complexes in Catalytic Asymmetric 1,2- And 1,4-Additions
Abitaev, Karina,Alvarez-Barcia, Sonia,Baro, Angelika,Bauer, Alina,Bauer, Matthias,Estes, Deven P.,Fischer, Felix Richard,Frey, Wolfgang,Gugeler, Katrin,K?stner, Johannes,Kirchhof, Manuel,Laschat, Sabine,Nowakowski, Michal,Plietker, Bernd,Qawasmi, Yaseen,Ringenberg, Mark R.,Schnierle, Marc,Sottmann, Thomas
supporting information, p. 3131 - 3145 (2020/10/02)
The influence of nuclearity and charge of chiral Rh diene complexes on the activity and enantioselectivity in catalytic asymmetric 1,2-additions of organoboron reagents to N-tosylimines and 1,4-additions to enones was investigated. For this purpose, catio