Phosphorane, triphenyl(phenylmethylene)-

Usually, Wittig reagents are prepared in situ from the appropriate phosphonium salt. As such, benzyltriphenylphosphonium chloride is available as a white powder or as a mixture with sodium amide, NaNH2. benzyltriphenylphosphonium chloride is a slightly hygroscopic solid. It can be dried efficiently under vacuum at elevated temperature (<10 Torr and 40 °C) overnight. Benzylidenetriphenylphosphorane is destroyed rapidly by exposure to oxygen or to moisture, and for this reason is usually prepared immediately before use. When protected from these materials, however, solutions of the ylide are stable for extended periods of time.