Syntheses and Structures of Binaphthyl-bridged Schiff Bases

The reaction of dinaphthofuran with lithium in anhydrous diethyl ether led to a solution of the corresponding C,O-dilithiated intermediate which, upon treatment with DMF at −78°C, afforded, after hydrolysis, 2′-hydroxy-1,1′-binaphthyl-2-carbaldehyde in a good yield. Then binaphthyl-bridged Schiff bases were prepared by the condensation of 2′-hydroxy-1,1′-binaphthyl-2-carbaldehyde with the corresponding aromatic amines.