[4559-70-0] · C12H11OP · Diphenylphosphine Oxide · (MW 202.20)
Physical Data: mp 56-57 °C.
Form Supplied in: white solid; widely commercially available.
Handling, Storage, and Precautions: moisture sensitive; irritant.
In the synthesis of P-N chelating ligands for asymmetric catalysis,1 aryl triflates are coupled with Ph2P(O)H under Pd catalysis, with subsequent reduction of the resulting phosphine oxides to the aryldiphenylphosphines (eq 1). (R)-(-)-1,1´-Binaphthol triflate provides the monophosphorylation product2 in good yield with maintainance of enantiomeric purity (eq 2).
Treatment of a-keto tosylates with diphenylphosphine oxide gives epoxyphosphine oxides, which provide vinylphosphine oxides via deoxygenation with Diphosphorus Tetraiodide (eq 3).3 Alternatively, alkenyl bromides react with diphenylphosphine oxide under palladium catalysis to yield vinylphosphine oxides (eq 4).4
Difluoromethyldiphenylphosphine oxide, synthesized from diphenylphosphine oxide and chlorodifluoromethane, reacts with aldehydes and ketones to yield 1,1-difluoroalkenes (eq 5).5 Alkenation proceeds in increasing (12-81%) yields over a range of more to less electron-deficient carbonyl compounds.
Jeffrey O. Saunders
Vertex Pharmaceuticals, Cambridge, MA, USA