Enantioselective addition of diethylzinc to aldehydes catalyzed by monosubstituted [2.2]paracyclophane-based N,O-ligands: remarkable cooperative effects of planar and central chiralities

Diastereomeric monosubstituted [2.2]paracyclophane-based N,O-ligands, which unite the planar and central chiral elements, were optimized for the enantioselective diethylzinc addition to aldehydes. (S)-1-{(Sp)-[2.2]Paracyclophan-4-yl}methyl-2-pyrrolidine-α,α-diphenylmethanol (Sp,S)-3 catalyzed the addition to give (R)-1-phenyl-1-propanol in a high yield and with a good enantioselectivity (91% ee).