Synthesis of chiral ligands derived from the Betti base and their use in the enantioselective addition of diethylzinc to aromatic aldehydes

A novel procedure for selective direct N,N-alkylation of the chiral Betti base was developed, and a new family of chiral ligands, (S)-1-(α-cycloaminobenzyl)-2-naphthols, were prepared. The ligands with five- and six-membered cyclic amines showed highly efficient asymmetric induction in the addition of diethylzinc to aromatic aldehydes in 93–96% yields and 91–99% ee.