My PhD dissertation - Institut Fresnel

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3.1.1 Dialkyl-N,N-diethylaminophosphines
Dichloro-N,N-diethylaminophosphine (23): Diethylamine (0.20 L, 0.15 kg, 2.0 mol) was
added dropwise to a solution of phosphorus trichloride (88 mL, 0.14 kg, 1.0 mol) in diethyl
ether (0.60 L) at -75 °C. After the end of addition, the mixture was allowed to reach 25 °C and
the salts were removed by filtration through a pad of celite (0.20 kg). The solvent was
stripped off and the residue distilled under vacuum to afford a colorless liquid; b.p. 41 –
42 °C/4.6 Torr (ref. [147] 20
b.p. 73 - 74 °C/13 Torr); n D = 1,4939 ; yield: 147 g (85%).
General procedure: The appropriate organolithium or Grignard reagent (0.20 mol) was
added dropwise to a solution of dichloro-N,N-diethylaminophosphine (23; 0.10 mol) in
tetrahydrofuran (0.20 L) at -75 °C. The reaction mixture was then allowed to warm up to
25 °C and solvents were removed at atmospheric pressure to be replaced by hexanes (0.10 L).
The salts were removed by filtration under inert atmosphere and the filtrate transferred via a
canula, to the addition funnel of the distillation apparatus described above. The solution was
then continuously added during distillation of the solvent at atmospheric pressure, and the
residual yellowish liquid was distilled under high reduced pressure.
Di-tert-butyl-N,N-diethylaminophosphine (24a): Prepared by addition of tert-butyllithium
in pentane (0.13 L); colorless liquid; b.p. 52 - 53 °C/0.77 Torr (ref. [148] b.p. 74 -75 °C/1 Torr);
20 n = 1,4806 (ref.
D
[148] 20 n D = 1,4885); yield: 19.8 g (89%).
1 H NMR: δ = 3.13 (qd, J = 8.7, 7.0 Hz, 4 H), 1.19 (d, J = 12.1 Hz, 18 H), 1.04 (t,
J = 7.0 Hz, 6 H) ppm.
13 C NMR: δ = 43.7 (d, J = 13.5 Hz), 27.6 (d, J = 17.0 Hz), 16.4 (d, J = 2.9 Hz)
31 P NMR: δ = 99.7 ppm.
Dibutyl-N,N-diethylaminophosphine (24b): Prepared by addition of butyllithium in hexane
(0.13 L); colorless liquid; b.p. 51 - 53 °C/0.73 Torr (ref. [147] b.p. 121 °C/16 Torr);
20 n D = 1,4576; yield: 19.4 g (88%).
1 H NMR: δ = 2.91 (dq, J = 8.6, 7.0 Hz, 4 H), 1.5 (m, 2 H), 1.4 (m, 8 H), 1.2 (m,
2 H), 1.01 (t, J = 7.0 Hz, 6 H), 0.90 (t broad, J = 7.0 Hz, 6 H) ppm.