D. Sanhes et al. / Tetrahedron: Asymmetry 20 (2009) 1009–1014
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4.2. Synthesis of ligands and complexes
4.2.1. Synthesis of compound 1
described. The product was isolated as a white solid. Yield: 80%
(0.401 mmol, 651 mg) after purification by flash column chroma-
tography (toluene, Rf = 0.77). 1H NMR (400 MHz, CDCl3) d: 7.51–
6.95 (m, 21H, Haromatic), 5.33 (m, 1H, C*H–O), 4.77 (d, 1H,
J = 2.8 Hz, CHCO), 4.63 (d, 1H, J = 2.4 Hz, CHCO), 4.58 (dt, 1H,
J = 10.4 Hz, 3.6 Hz, C*H–N), 3.30 (m, 1H, CH2), 3.20 (m, 1H, CH2),
2.44 (m, 2H, CHanthracene), 1.68–1.13 (m, 72H, CH3). 13C NMR
(100.6 MHz, CDCl3) d: 176.9, 176.4 (2C, C@O), 146.5–122.5 (42C,
Caromatic), 71.6 (1C, C*H–O), 59.6 (1C, CH2), 57.6 (1C, C*H–N),
46.3, 45.9 (2C, CHCO), 45.5, 42.3 (2C, CHanthracene), 35.6–29.8
(24C, CH3). 31P{1H} NMR (161.97 MHz, CDCl3) d: 147.45, 133.78
(2P, PO). Anal. Calcd for C83H101NO8P2: C, 76.53; H, 7.82. Found:
C, 76.25; H, 8.01.
Synthesis of compound 4: The synthesis of diphosphite 4 was
completed according to the general procedure previously de-
scribed. The product was isolated as a white solid. Yield: 86%
(0.431 mmol, 737 mg) after purification by flash column chroma-
tography (toluene, Rf = 0.70). 1H NMR (400 MHz, CDCl3) d: 7.61–
6.82 (m, 21H, Haromatic), 5.17 (dd, 1H, J = 9.2 Hz, 5.2 Hz, C*H–O),
4.12 (m, 2H, CHCO), 3.89 (m, 1H, CH2), 3.48 (m, 1H, CH2), 3.05
(m, 1H, C*H–N), 2.99, 2.89 (m, 2H, NCH2), 2.61 (m, 2H, CHanthra-
cene), 2.02, 1.93 (m, 2H, NCH2), 1.83–1.30 (m, 72H, CH3). 13C
NMR (100.6 MHz, CDCl3) d: 150.0–122.5 (42C, Caromatic), 76.3
(1C, C*H–O), 66.2 (1C, C*H–N), 62.2(1C, CH2), 55.1, 52.8 (2C,
NCH2), 47.4, 47.3 (2C, CHCH2N), 44.3, 44.0 (2C, CHanthracene),
35.6–29.8 (24C, CH3). 31P{1H} NMR (161.97 MHz, CDCl3) d:
141.86, 136.86 (2P, PO). Anal. Calcd for C83H105NO6P2: C, 78.21;
H, 8.30. Found: C, 78.00; H, 8.45.
A
solution of 9,10-dihydroanthracene-9,10-a,b-succinic acid
anhydride (1.00 g, 3.6 mmol) and (1S,3S)-2-amino-1-phenyl-1,3-
propandiol (1.21 g, 7.2 mmol) in toluene (120 mL) was refluxed
for 12 h in the presence of molecular sieves 4 Å. The reaction mix-
ture was monitored by TLC (hexane/ethyl acetate = 3/2), then
cooled, filtered and the solvent removed under reduced pressure.
The residue obtained was dissolved in dichloromethane (20 mL)
and washed with ammonium chloride saturated aqueous solution
(3 ꢁ 20 mL). The combined organic layers were dried on anhydrous
Na2SO4, filtered and the solvent evaporated under vacuum leading
to a white powder recrystallized in ethyl acetate. Yield: 87%
(3.15 mmol, 1.34 g). 1H NMR (300 MHz, CDCl3) d: 7.37–7.16 (m,
13H, Haromatic), 5.03 (d, 1H, J = 9 Hz, CH-Ph), 4.78 (dd, 2H, HC–
CO, J = 3 Hz, J = 5 Hz), 4.19 (m, 1H, CHN), 3.16 (m, 2H, HC–CH–
CO), 3.05 (m, 2H, CH2).13C NMR (75.5 MHz, CDCl3) d: 179.4, 176.9
(2C, C@O), 141.1–138.9 (Caromatic), 129.1–124.3 (CHaromatic),
70.8 (CH-Ph), 59.8 (CH2), 59.6 (CH–N), 46.8 (CH–CO), 46.1 (CH–
CO), 45.5 (CH–CH–CO), 45.4 (CH–CH–CO). IR (KBr,
m
cmꢀ1): 3512
(OH), 3026 (@C–H), 2961 (C–H), 1770 (C@O), 1702 (C@O), 1465–
1458 (C@C), 535 (Pd–P). Mass spectrometry (ESI, m/z): 448.4
[M+Na], 426.4 [M+H]. Anal. Calcd for C27H23NO4 (M = 425.48): C,
76.22; H, 5.45; N, 3.29. Found: C, 76.20; H, 5.24; N, 3.32. Melting
point: 200 °C.
4.2.2. Synthesis of compound 2
To a solution of freshly distilled THF (10 mL), 1 was added
(100 mg; 0.24 mmol) and stirred until total dissolution. The solu-
tion was cooled at 0 °C and LiAlH4 (178 mg, 4.80 mmol) was slowly
added, giving a white suspension. The mixture was heated at reflux
for 24 h, then cooled at 0 °C. Diethylether, 10 mL, and a saturated
aqueous solution of Na2SO4 were added. The addition of the aque-
ous solution was slowly performed and was stopped when effer-
vescence was no longer observed in the reaction mixture. The
white product was then filtered over Celite and the solution ob-
tained was washed several times with a mixture CH2Cl2/MeOH
(9:1). The organic phase was washed with water (3 ꢁ 20 mL), dried
with anhydrous Na2SO4, filtered and concentrated at reduced pres-
sure, yielding the corresponding amine as a white powder. Yield:
99% (0.23 mmol, 0.09 g). 1H NMR (300 MHz, CDCl3) d: 7.35–7.11
4.2.4. Synthesis of [PdCl2(j
2-P,P-3)]
To a solution of 3 (0.1 g, 0.077 mmol) dissolved in 20 mL of dis-
tilled toluene, [PdCl2(COD)] (0.027 g, 0.077 mmol) was added. The
solution was heated at 50 °C for 2 h. Then the solvent was removed
under reduced pressure and the solid washed three times with
diethylether. Yield: 80% (0.062 mmol, 0.09 g). 1H NMR (500 MHz,
CDCl3) d: 7.57–6.59 (m, 21H, Haromatic); 5.65 (dd, 1H, J = 10 Hz,
J = 5 Hz, C*H–O); 5.12 (dd, 1H, J = 20 Hz, J = 10 Hz, CH2); 4.57 (d,
1H, J = 2 Hz, CHCO); 4.49 (d, 1H, J = 2 Hz, CHCO); 4.27 (m, 1H,
C*H–N); 2.62, 2.63 (m, 2H, CHanthracene)), 2.46 (dd, 1H,
J = 10 Hz, J = 5 Hz, CH2); 1.30–1.82 (s, 72H, CH3). 13C NMR
(125.8 MHz, CDCl3) d: 175.3, 175.1 (2C, C@O); 148.2-129.6 (21C,
Caromatic), 128.2–124.1 (21C, HCaromatic), 77.8 (1C, C*H–O),
62.0 (1C, CH2); 52.0 (1C, C*H–N); 46.3, 45.5 (2C, CHCO), 45.4, 45.2
(2C, CHanthracene), 32.5-29.6 (24C, CH3). 31P{1H} NMR (202 MHz,
CDCl3) d: 101.01 (d, 1P, J = 67 Hz, Pd–P), 98.97 (d, 1P, J = 67 Hz,
3
(m, 13H, Harom), 4.31 (d, J = 8 Hz, 1H, C*H–O), 4.22 (m, 2H, CH–
CH–CH2), 3.33 (m, 2H, CH2–OH), 2.99 (m, 2H, CH2–N), 2.71 (m,
2H, CH–CH2–N), 2.65 (m, 1H, CH2–N), 2.57 (m, 1H, C*H–N), 2.51
(m, 1H, CH2–N). 13C NMR (100.6 MHz, CDCl3) d: 143.7–141.7 (Caro-
matic), 128.5–123.6 (CHaromatic), 72.2 (1C, C*H–O), 67.0 (C*H–N),
59.3 (CH2–OH), 53.8, 51.9 (2C, CH2–N), 48.5 (CH–CH–CH2), 43.5,
Pd–P). IR (KBr,
m
cmꢀ1): 2962 (–C–H), 1781 (C@O), 1718 (C@O),
1467 (C@C), 1260 (C–O). Anal. Calcd for C83H101NO8P2 Cl2Rh: C,
67.3; H, 6.9; N, 0.9. Found: C, 65.7; H, 7.2; N, 0.8. SM (CI, NH3):
m/z = 1479 [M]+.
43.4 (2C, CH–CH2–N). IR (KBr,
m
cmꢀ1): 3409 (OH), 3064–3018
(@C–H), 2935–2788 (C–H), 1477–1456 (C@C), 1093 (C–N), 1060–
1020 (C–O). HRMS (ES+): m/z (100%) calcd for C27H28NO2
398.2120, found 398.2113. Melting point: 124 °C.
4.2.5. Synthesis of [Rh(l-Cl)(j
2-P,P-3)]2
To a solution of 3 (0.25 g, 0.192 mmol) dissolved in 10 mL of
distilled toluene, [RhCl(COD)]2 (0.09 g, 0.180 mmol) was added.
The solution was heated at 50 °C for 4 h. Then the solvent was re-
moved under reduced pressure and the solid washed three times
with diethylether. Recrystallization from CH2Cl2/Et2O (4:1). Yield:
80% (0.144 mmol, 0.41 g). 1H NMR (500 MHz, CDCl3) d: 1H NMR
(500 MHz, CDCl3) d: 7.36–6.43 (m, 21H, Haromatic); 5.46 (m, 1H,
C*H–O); 4.68 (m, 1H, CH2); 4.55 (dl, 1H, J = 6 Hz, CHCO); 4.35 (d,
1H, J = 6 Hz, CHCO); 3.92 (m, 1H, C*H–N); 2.46, 2.29 (m, 2H,
CHanthracene)), 1.91 (m, 1H, CH2); 1.99–0.80 (s, 72H, CH3). 13C
NMR (125.8 MHz, CDCl3) d: 175.6, 174.9 (2C, C@O); 146.3–136.9
(21C, Caromatic), 131.6–122.9 (21C, HCaromatic), 75.2 (1C, C*H–
O), 59.4 (1C, CH2); 53.2 (1C, C*H–N); 45.9 (1C, CHCO), 45.3 (1C,
CHCO), 45.2 (1C, CHanthracene), 44.9 (1C, CHanthracene), 32.9–
15.3 (24C, CH3). 31P{1H} NMR (202 MHz, CDCl3) d: 134.50 (dt, 1P,
4.2.3. Synthesis of diphosphite ligands 3 and 4
General procedure. A solution of diols 1 and 2 (0.5 mmol), previ-
ously dried azeotropically with toluene (3 ꢁ 1 mL), in dry and de-
gassed toluene (5 mL) and cooled to 0 °C, was slowly added to a
solution of phosphorochloridite a (1.1 mmol), synthesized in situ
by standard procedures, in dry and degassed pyridine (0.75 mL).
The mixture was allowed to rise to room temperature and stirred
overnight. The mixture was then filtered to eliminate the pyridine
salts, and the filtrate was concentrated to dryness. The white foam
obtained was purified by flash chromatographic techniques over
nitrogen.
Synthesis of compound 3: The synthesis of diphosphite 3 was
completed according to the general procedure previously