Hydrolysis of Phosphonothioates with a Binaphthyl Group: P‑Stereogenic O‑Binaphthyl Phosphonothioic Acids and Their Use as Optically Active Ligands and Chiral Discriminating Agents

The hydrolysis of phosphonothioates with a binaphthyl group afforded the first example of O-(2′-hydroxy)­binaphthyl phosphonothioic acids in good to high yields and >95:5 diastereoselectivity. The reaction proceeds via an axis-to-center chirality-transfer reaction. The ability of these acids to act as chiral molecular auxiliaries was demonstrated by using them as optically active ligands for the asymmetric ethylation of benzaldehyde and as a chiral discriminating agent for chiral aliphatic amines.