Synthesis of Optically Active 2,2'-Dihalo-1,1'-binaphthyls via Stable Diazonium Salts

Article abstract of DOI:10.1021/jo00222a029

Optically pure 2,2'-dibromo-1,1'-binaphthyl (DBBN) (5) and optically pure 2,2'-diiodo-1,1'-binaphthyl (DIBN) (6) are synthesized in preparative quantities starting from 2-naphthol.These compounds are useful for the preparation of chiral, bidentate ligands based on the 1,1'-binaphthyl system.The synthesis proceeds through a common optically active precursor, 2,2'-diamino-1,1'-binaphthyl ((R)-(+)-DABN) (2), and involves the preparation and subsequent decomposition of stable diazonium metal complexes (3 and 4).The effects of several variables, including the nature of the metal M, on these reactions is discussed, and comparison to related procedures reported in the literature is made.