Functionalized N-Heterocyclic Carbene Ligands for Dual Enantioselective Control in the Cu-Catalyzed Conjugate Addition of Dialkylzinc Compounds to Acyclic Enones
A series of highly tunable, functionalized azolium compounds have been synthesized from chiral α-amino acid derivatives such as β-amino alcohols or α-amino esters. The combination of a Cu salt and a chiral azolium efficiently facilitated the asymmetric conjugate addition (ACA) reactions of acyclic enones with dialkylzinc under ambient conditions without temperature control. Of the (hydroxy amide)-functionalized