Synthesis of pseudo-geminal-, pseudo-ortho-, and ortho-phosphinyl-oxazolinyl-[2.2]paracyclophanes for use as ligands in asymmetric catalysis.
Syntheses of three regioisomers of aromatic-substituted phosphinyl-oxazolinyl-[2.2]paracyclophanes, pseudo-geminal, pseudo-ortho, and ortho, have been carried out or, in the latter two cases, newly developed. It has, therefore, been demonstrated that all aromatic-substituted isomers relevant for use as chelating ligands for asymmetric catalysis are accessible. These P,N-ligands, along with their diastereoisomers, were shown to exhibit widely differing activity and enantioselectivity (up to 89% ee) in the Pd-catalyzed asymmetric allylic alkylation reaction.
Whelligan
Daniel K
DK
Institut für Organische Chemie der RWTH Aachen, Landoltweg 1, D-52074 Aachen, Germany.
Bolm
Carsten
C