Synthesis of novel chiral biphenylamine ligand 6, 6′-dimethoxy-2, 2′-diaminobiphenyl

A new chiral ligand 6, 6′-dimethoxy-2, 2′-diaminobiphenyl was successfully prepared from 3-nitrophenol via iodination, Ullmann coupling, and reduction. The resolving reagent (2R, 3R)- or (2S, 3S)-2, 3-di(phenylaminoearbonyl)tartaric acid was prepared from commercially available tartaric acid in large scale and was used to resolve the racemic 6, 6′-dimethoxy-2, 2′-diaminobiphenyl. The chiral 6, 6′-dimethoxy-2, 2′-diaminobiphenyl obtained was proved to be enantiomerically pure.