Supraphos: a supramolecular strategy to prepare bidentate ligands.
We report a new strategy for the preparation of chelating bidentate ligands, which involves just the mixing of two monodentate ligands functionalized with complementary binding sites. In the current example, the assembly process is based on selective metal-ligand interactions, using phosphite zinc(II) porphyrins 1-6 and the nitrogen donor ligands b-i. From only 16 monodentate ligands, a library of 60 palladium catalysts based on 48 bidentate ligand assemblies has been prepared. The relatively small catalyst library gave a large variety in the selectivity of the alkylation of rac-1,3-diphenyl-2-propenyl acetate. Importantly, small variations in the building blocks lead to large differences in the enantioselectivity imposed by the catalyst (up to 97% ee).
Slagt
Vincent F
VF
Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
Röder
Marc
M
Kamer
Paul C J
PC
Van Leeuwen
Piet W N M
PW
Reek
Joost N H
JN