Design of Chiral Hydroxyalkyl‐ and Hydroxyarylazolinium Salts as New Chelating Diaminocarbene Ligand Precursors Devoted to Asymmetric Copper‐Catalyzed Conjugate Addition
The design and the synthesis of a set of new chiral hydroxyalkyl- and hydroxyaryl-chelating diaminocarbene ligands is reported. Comparative catalytic studies show the importance of the scaffold design around the NHC unit to obtain a high enantiocontrol in Cu-catalyzed asymmetricconjugateaddition (ACA). Whereas low selectivities are observed when the stereogenic centre is placed within the N-heterocyclic