2,2′-Bis(diphenylphosphino)biphenyl revisited

Article abstract of DOI:10.1016/0022-328X(95)05767-J

The reaction between 2,2′-dilithiobiphenyl and two equivalents of chlorodiphenylphosphine is confirmed to afford equal amounts of 9-phenyl-9-phosphafluorene (2) and triphenylphosphine. 2,2′-Bis(diphenylphosphino)biphenyl (1,1′-biphenyl-2,2′-diylbis(diphenylphosphine) (1)) can be conveniently prepared by Ullmann coupling of 2-iodophenyldiphenylphosphine oxide and subsequent reduction with trichlorosilane.