Diphenylphosphine Oxide

[4559-70-0]  · C12H11OP  · Diphenylphosphine Oxide  · (MW 202.20)

(preparation of triarylphosphine oxides,1 important as asymmetric catalysts; preparation of alkenyldiphenylphosphine oxides3,4 and Horner-Wittig reagents5)

Physical Data: mp 56-57 °C.

Form Supplied in: white solid; widely commercially available.

Handling, Storage, and Precautions: moisture sensitive; irritant.

Palladium-Catalyzed Coupling with Aryl Triflates.

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).

Preparation of Diphenylvinylphosphine Oxides.

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

Reaction with Chlorodifluoromethane.

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.

1. Alcock, N. W.; Brown, J. M.; Hulmes, D. I. TA 1993, 4, 743.
2. Kurz, L.; Lee, G.; Morgans, D., Jr.; Waldyke, M. J.; Ward, T. TL 1990, 31, 632.
3. Xu, Y.; Xia, J.; Guo, H. S 1986, 8, 691.
4. Yamashita, M.; Tsunekawa, K.; Sugiura, M.; Oshikawa, T. S 1985, 1, 65.
5. Edwards, M. L.; Stemerick, D. M.; Jarvi, E. T. Mattews, D. P.; McCarthy, J. R. TL 1990, 31, 5571.

Jeffrey O. Saunders

Vertex Pharmaceuticals, Cambridge, MA, USA

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