Phosphorus trichloride → Phosphine, tert-butylbis(dimethylamino)-

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Reaktionsschritte

Tertiarybutylbis(dimethylamino)phosphine was prepared according to Reaction Scheme #2 by reaction of tertiarybutyllithium with bis(dimethylamino)phosphoruschloride which had been prepared from the reaction of neat trisdimethylaminophosphine and phosphorustrichlioride. Trisdimethylaminophosphine was prepared from the reaction of phosphorus trichloride with three equivalents of lithium dimethylamide in diethylether at 0° C. A solution of 88.4 g (0.64 mol) PCl3 in 50 ml diethylether was added dropwise to a stirred suspension of 105 g (2.06 mol) LiNMe2 in 1.5 liters diethylether at 0° C. The resulting mixture was filtered and the P(NMe2)3 product, 0.444 mol, 72.5 g (69% yield based on PCl3), was fractionally distilled from the filtrate at 45° C./9.5 torr. PCl3 0.222 mol (30.5 g) was added slowly to the purified P(NMe2)3 with stirring at 0° C. The resulting P(NMe2)2Cl compound was heated to 35° C. for one hour then diluted with 1 liter of hexane and cooled to -78° C. A 400 ml aliquot (0.68 mol) of tertiarybutyl lithium, ((CH3)3C)Li, in hexane was added dropwise over a two hour period with stirring. The mixture was allowed to warm, filtered and the tertiarybutyl-bis(dimethylamino)phosphine, ((CH3)3C)P(NMe2)2, product, 55 g, 0.31 mol (45% yield based on P(NMe2)2Cl), was purified by repeated fractional distillation of the filtrate.

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