(R)-(+)-2,2′-Bis­(di­phenyl­phosphinoyl)-1,1′-bi­naphthyl

The title compound, BINAP oxide, C(44)H(32)O(2)P(2), (I), was synthesized by direct oxidation of (R)-(+)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP) with tert-butyl hydroperoxide in toluene solution. The angle between the naphthyl planes of the binaphthyl group is 94.17 (3) degrees.