940280-80-8Relevant academic research and scientific papers
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 (2019/07/04)
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.
Chiral bicyclo[3.3.0]octa-2,5-dienes as steering ligands in substrate-dependent rhodium-catalyzed 1,4-addition of arylboronic acids to enones
Heibig, Sarah,Sauer, Sven,Cramer, Nicolai,Laschat, Sabine,Baro, Angelika,Frey, Wolfgang
, p. 2331 - 2337 (2008/09/19)
The synthesis of disubstituted chiral diene ligands (3aR,6aR)- and (3aS,6aS)-10 with a pentalene backbone from the corresponding bicyclo[3.3.0]octa1,4-diones 7 is described. The latter were accessible by enzymatic resolution of the racemic diol rac-5 and
Design of C2-symmetric tetrahydropentalenes as new chiral diene ligands for highly enantioselective Rh-catalyzed arylation of N-tosylarylimines with arylboronic acids
Wang, Zhi-Qian,Feng, Chen-Guo,Xu, Ming-Hua,Lin, Guo-Qiang
, p. 5336 - 5337 (2008/02/03)
A new type of C2-symmetric chiral diene ligand bearing a simple bicyclic [3.3.0] backbone was discovered. (3aS,6aS)-3,6-diphenyl-1,3a,4,6a-tetrahydropentalene was applied successfully in the Rh-catalyzed asymmetric arylation of N-tosylarylimine
Stereochemistry of the Addition of Phenylmetal Reagents to Bicyclooctanediones and -octadienediones. - Synthesis of Phenyl-Substituted Bicyclooctadienes.
Quast, Helmut,Carlsen, Juergen,Herkert, Thomas,Janiak, Rolf,Roeschert, Horst,et al.
, p. 495 - 512 (2007/10/02)
Conjugate addition of dilithium diphenylcyanocuprate is observed only on one side of the dienedione 4b, affording the enedione 5b, but on both sides in the presence of boron trifluoride yielding the diphenyldione 6b.Likewise, the latter reagent gives rise
