Anthony KERMAGORET - THESES ET MEMOIRES DE L'UDS

Chapitre V
A n-BuLi solution (64.0 mmol, 1.6 M in hexane) was added drop wise to a degassed solution
of 2,5,5-trimethyl-2-oxazoline (7.24 g, 64.0 mmol) in 100 mL of THF at a constant
temperature of -78 °C. After the pale yellow mixture was stirred for 1 h at -78 °C, degassed
chlorotrimethylsilane (6.95 g, 64.0 mmol) was added drop wise and stirring for 2 h. Liquid
PPhCl2 (5.73 g, 32.0 mmol) was added to the colourless solution at -78 °C. The liquid was
allowed to reach room temperature overnight and a mixture of diethylether and toluene was
added to the yellow solution to precipitate the LiCl which was removed by filtration. Solvents
were evaporated and the remaining yellow oil was dried for several hours under vacuum at 40
°C. This afforded the pure ligand as a yellow oil (yield: 4.4 g, 13.25 mmol, 41 %).
1 H NMR (300 MHz, CDCl3): δ 1.12 and 1.13 (6H, 2s, CH3), ABX spin system (A = B = H, X
= P) 2.80 (2H, dd, JAB = 14.1 Hz, 2 JXB = 0.9 Hz, P-CH2) 2.92 (2H, dd, JAB = 14.1 Hz, 2 JXA =
4.6 Hz, P-CH2), 3.78 (4H, s, O-CH2), 7.31 – 7.35 (3H, m, aromatic H) and 7.48 – 7.53 (2H,
m, aromatic H); 13 C{ 1 H} NMR (75.5 MHz, CDCl3): δ 26.9 (d, 1 JPC = 22.0 Hz, P-CH2), 28.32
(s, CH3), 28.41 (s, CH3), 67.1 (s, O-CH2), 79.2 (s, C-CH3), 128.35 (d, 3 JPC = 6.9 Hz, m-CH of
aryl), 129.4 (s, p-CH of aryl), 132.2 (d, 2 JPC = 20.2 Hz, o-CH of aryl), 135.2 (d, JPC = 20.2 Hz,
C-P of aryl), 162.4 (d, 2 JPC = 4.7 Hz, C=N); 31 P{ 1 H} NMR (121.5 MHz, CDCl3): δ -24.83.
HRMS : Mass Calcd for C18H26N2O2P : 333.1732. Found. 333.1656 [(N,P,N)+H] + .
Synthesis of bis((pyridin-2-yl)methyl)phenylphosphonite 4
Liquid (pyridin-2-yl)methanol (1.39 g, 12.7 mmol) was dissolved in 30 ml of THF and cooled
at -78 °C. 1 equiv of n-BuLi (12.7 mmol in solution in 8 ml of hexane) was added drop wise
and the solution was stirred for 1h. After reaction 0.5 equiv of PPhCl2 (0.87 ml, 6.35 mmol)
was added drop wise at -78 °C and stirred overnight to room temperature. The solvent was
removed under reduced pressure and 20 ml of a mixture diethylether/CH2Cl2 was added to
precipitate LiCl. The yellow solution was filtered with a canula and the solvents were
removed under reduced pressure. The resulting yellow oil was dried under vacuum at 60 °C
overnight (Yield: 1.75 g, 5.4 mmol, , 86%).
1 H NMR (300 MHz, CDCl3): δ ABX spin system (A = B = H, X = P) 4.90 (2H, dd, JAB =
13.8 Hz, 2 JXB = 7.2 Hz) 5.07 (2H, dd, JAB = 13.8 Hz, 2 JXA = 8.4 Hz), 7.15 – 7.17 (2H, m,
aromatic H), 7.44 – 7.46 (5H, m, aromatic H), 7.62 – 7.67 (2H, m, aromatic H), 7.71 – 7.76
(2H, m, aromatic H) 8.50 – 8.52 (2H, m, aromatic H); 13 C{ 1 H} NMR (75.5 MHz, CDCl3): δ
69.3 (d, 2 JPC = 9.7 Hz, OCH2), 121.1 (s, C of Py), 122.4 (s, C of Py) 128.45 (d, 3 JPC = 5.5 Hz,
m-CH of aryl), 129.8 (s, p-CH of aryl), 130.2 (d, 2 JPC = 23.9 Hz, o-CH of aryl), 136.7 (s,
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