Dichloromethylene triphenylphosphorane

Shriver, The Manipulation of Air-Sensitive Compounds, McGraw-Hill, New York, 1%9. 

Inorganic Syntheses, Volume 24 Edited by Jeaa ne M. Shreeve ) 1986 by Inorganic Syntheses, Inc. 

[PHENYL(TRIMETHYLSILYL)METHYLENE]-PHOSPHINOUS CHLORIDE [CHLORO-[PHENYL(TRIMETHYLSILYL)METHYLENE]PHOSPHINE] 

A solution of 100 g (0.61 mole) of trimethyl(phenylmethyl)silane [Pfalz and Bauer] and 87.5 mL (0.61 mole) of AI,yV,yV, (V -tetramethyl-l,2-ethanediamine (TMEDA) [Aldrich] dissolved in 150 mL of diethyl ether is placed in a 1-L three-necked flask provided with a dropping funnel, a mercury relief valve, and a magnetic stirrer. This solution is cooled to — 20°, and 364.3 mL (0.61 mole) of a. f M solution of butyllithium in hexane is added over a 90-min period. After being warmed to room temperature, the reaction mixture is stirred for at least 6.5 hr while the orange-yellow lithium complex salt precipitates. The mixture is cooled to -20°, and a solution of 92.7 g (0.61 mole) of N,N,N, N -tetramethylphosphorodiamidous chloride [Alfa Products] in 80 mL of diethyl ether is added over a period of 90 min. This mixture is allowed to warm to ambient temperature and is stirred for 1 hr. Then the LiCl is Altered and washed 

To a stirred solution of 105 g (0.396 mole) of [phenyl(tri-methylsilyl)methyl]phosphonous dichloride in 2-2.5 L of diethyl ether in a 4-L flask, 178 g (1.584 moles) of l,4-diazabicyclo[2.2.2]octane (DBO) is added. The mixture is stirred overnight at ambient temperature and then filtered. The solid is washed three times with 100-mL portions of pentane. The collected filtrates are concentrated to 1.5 L at ambient temperature under reduced pressure, and the base and its hydrochloride are separated by filtration. The solid is washed three times with 50-mL portions of pentane. This procedure (concentration and 

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The reaction of perchlorotoluene with triphenylphosphine has been studied (Diaz-Alzamora, 1968). It is noted that the reaction with carbon tetrachloride gives a mixture of (dichloromethylene)triphenylphosphorane and triphenylphosphine dichloride (Appel et al., 1976 Burn and Cadogan, 1963 Rabinowitz and Marcus, 1962). (The resulting reaction mixture was usually treated with water.) The sequence (49), involving a nucleophilic attack on chlorine, has been proposed. 

The method of preparation described here is based on the dechlorination of triphenyl(trichloromethyl)phosphonium chloride in benzene, which makes the isolation of the (dichloromethylene)triphenylphosphorane possible without decomposition."... 

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