Practical Synthesis of (R)- or (S)-2,2'-Bis(diarylphosphino)-1,1'-binaphthyls (BINAPs)

Article abstract of DOI:10.1021/jo00355a012

Practical methods for the synthesis of (R)- or (S)-2,2'bis(diarylphosphino)-1,1'-binaphthyls (BINAPs), useful ligands for transition-metal-catalyzed asymmetric reactions, have been developed. (+/-)-2,2'-Bis(diphenylphosphinyl)1,1'-binaphthyl <(+/-)-BINAPO>, prepared from 2,2'-dibromo-1,1'-binaphthyl and diphenylphosphinyl chloride, can be resolved into optical antipodes by the use of camphorsulfonic acid or 2,3-di-O-benzoyltartaric acid.Reduction of resolved BINAPO with trichlorosilane in the presence of triethylamine affords optically pure 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP).In a similar manner, several BINAP analogues have been prepared in optically pure form.The present procedures are suitable for obtaining these axially dissymmetric diphosphines in a large scale.The molecular structure of the 1:1:1 complex of (S)-(-)-BINAPO, (1R)-(-)-camphorsulfonic acid, and acetic acid has been studied by single-crystal X-ray analysis.