Highly Enantioselective Conjugate Addition of Diethylzinc to Acyclic Enones with Fine-Tunable Phosphite−Pyridine Ligands

A new series of fine-tunable phosphite−pyridine (P,N) ligands derived from (S)-2-amino-2‘-hydroxy-6,6‘-dimethyl-1,1‘-biphenyl and (S)-2-amino-2‘-hydroxy-4,4‘,6,6‘-tetramethyl-1,1‘-biphenyl was employed in Cu(I)-catalyzed conjugate addition of diethylzinc to acyclic enones. Excellent enantioselectivities (up to 98% ee) and highly catalytic activities were achieved for a variety of acyclic enones.