Chelating Hydroxyalkyl NHC as Efficient Chiral Ligands for Room-Temperature Copper-Catalyzed Asymmetric Allylic Alkylation
Résumé
The application of chiral chelating hydroxy NHC in copper-catalyzed asymmetric allylic alkylation (Cu-AAA) involving various dialkylzincs and allylic phosphate substrates is reported here. From a library of 11 chiral chelating hydroxyalkyl NHC, a fine-tuning has been done to identify the best architectural features enabling to produce the expected γ-adducts in total regioselectivity, good isolated yields, and excellent enantioselectivities (ranging from 93% to >98% ee).