[3]Ferrocenophane-Based Chelate Bis(phosphane) Ligands for Asymmetric Copolymerization
FULL PAPER
(
(
11.3 mL, 182 mmol, 64 equiv.) was added to a solution of rac-3
800 mg, 2.82 mmol, 6.7:1 trans:cis mixture) in 15 mL of acetoni-
76%). Recrystallization from dichloromethane/diethyl ether at
+8 °C gave an enrichment of the (R,R,S,Rpl)-9 isomer (71% de) but
at the expense of a great loss of material. The analytical data were
obtained from this (R,R,S,Rpl)-9 enriched sample (m. p. 192 °C).
trile. The mixture was stirred for 1 h at room temperature and then
all volatiles removed in vacuo. The residue was taken up in acetoni-
trile (40 mL), potassium carbonate (780 mg, 5.64 mmol, 2 equiv.)
was added and then (S)-2-methoxymethylpyrrolidine (0.4 mL,
32
C H36FeNOP (537.5): calcd. C 71.51, H 6.75, N 2.61; found C
+
70.99, H 6.95, N 2.43. MS (EI, 70 eV): m/z (%) = 537.2 (33.1) [M ],
423.1 (100) [M+ – amine]. H NMR (599.9 MHz, CDCl
1
3
.1 mmol, 1.1 equiv.). The reaction mixture was refluxed for 18 h.
3
, 298 K):
The volatiles were then removed at room temperature in vacuo. The
solid residue was taken up in n-hexane and filtered through Celite.
Concentration of the clear filtrate in vacuo gave 980 mg (98%) of
a solid. Twofold recrystallization from diethyl ether at –18 °C gave
an enrichment of (S,S,R)-7 of 87% de, but only at the expense of
loosing the majority of the material. The physical characterization
was carried out using the obtained 74:26 mixture of (S,S,S)-7 and
δ = 0.53 (m, 1 H, 16/17-H), 1.10 (m, 1 H, 16/17-H), 1.25 (d, 3 H,
3
JH,H = 7.3 Hz, 7-H), 1.29 (m, 2 H, 16/17-H), 2.27 (m, 2 H, 15-H),
2.47 (m, 1 H, 8-Heq), 2.84 (m, 1 H, 6-H), 2.86 (m, 1 H, 19-H), 3.23
(s, 3 H, 20-H), 3.25 (m, 2 H, 18, 19-H), 3.31 (m, 2 H, 8-Hax, 9-H),
3.64, 3.84, 4.11, 4.41 (each m, each 1 H, Cp1–5), 3.69, 4.14, 4.18
(each m, each 1 H, Cp10–14), 7.26 (m, 6 H, Ph), 7.38 (m, 2 H, Ph),
7.43 (m, 2 H, Ph) ppm. The (R,R,S,Rpl)-9:(S,S,S,Spl)-9 ratio was
1
(R,R,S)-7, m.p. 90 °C. C20
H27FeNO (353.3): calcd. C 68.00, H 7.70,
determined by the H NMR Cp signals at δ = 4.41 [m, 1 H
N 3.96; found C 67.75, H 7.22, N 3.60. MS (EI, 70 eV): m/z (%) =
(R,R,S,Rpl)-9] ppm and δ = 4.45 [m, 1 H (S,S,S,Spl)-9] ppm.
+
+
13
1
3
53.2 (18) [M ], 239.0 (100) [M – amine], 120.9 (11). IR (KBr): ν˜
C{ H} NMR (150.8 MHz, CDCl
3
, 298 K): δ = 16.4 (C-7), 21.0
=
3098 cm–1 (w), 3065 (w), 2979 (m), 2940 (m), 2887 (m), 2815 (m), (C-16/17), 27.5 (C-6), 27.9 (C-16/17), 44.9 (d, JP,C = 10.9 Hz, C-8),
1
5
=
2
663 (w), 1617(w), 1466 (m), 1374 (m), 1196 (m), 1123 (s), 808 (s),
50.5 (C-15), 53.3 (C-9), 59.0 (C-20), 59.5 (C-18), 67.3, 68.6, 70.0,
–1 1
38 (m) cm . H NMR (599.9 MHz, CD
1.23 (d, JH,H = 7.1 Hz, 3 H, 7-H), 1.55 (m, 1 H, 17-H), 1.59 (m,
H, 16-H), 1.65 (m, 1 H, 17-H), 2.06 (m, 1 H, 8-Heq), 2.44 (m, 1
2
Cl
2
, 298 K, (S,S,S)-7): δ 72.3, 93.3 (d, JP,C = 5.7 Hz) (Cp1–5), 68.9, 73.9 (d, JP,C = 5.2 Hz),
3
1
2
74.2 (d, JP,C = 5.8 Hz), 74.1 (d, JP,C = 13.5 Hz), 92.0 (d, JP,C
18.3 Hz) (Cp10–14), 71.9 (C-19), 127.7 (Php, Php), 127.7 (d, JP,C
=
=
=
H, 8-Hax), 2.50 (m, 1 H, 15-H), 2.73 (m, 2 H, 6-H, 18-H), 2.82 (m, 15.1 Hz, Pho/m), 128.1 (d, JP,C = 19.3 Hz, Pho/m), 133.4 (d, JP,C
1
1 H, 15-H), 3.18 (m, 1 H, 19-H), 3.33 (s, 3 H, 20-H), 3.37 (m, 1 H,
9-H), 3.57 (dd, 3
1 H,H = 11.8 Hz, 1.9 Hz, 1 H, 9-H), 3.93, 4.04,
4.10, 4.17 (each m, each 1 H, Cp1–5), 4.00, 4.05, 4.08, 4.21 (each
21.0 Hz, Pho/m), 134.3 (d, JP,C = 20.1 Hz, Pho/m), 138.6 (d, JP,C
= 12.1 Hz, Phi), 138.9 (d, JP,C = 9.1 Hz, Phi) ppm. P{ H} NMR
(121.5 MHz, CDCl , 298 K): δ = –22.2 ppm.
1
31
1
J
3
m, each 1 H, Cp10–14) ppm. The (S,S,S)-7:(R,R,S)-7 ratio in the
sample was determined by the corresponding well-resolved
X-ray Crystal Structure Analysis of (R,R,S,Rpl)-9: Single crystals
were obtained by slow evaporation of a solution in dichlorometh-
1
6
(
00 MHz H NMR cyclopentadienyl resonances at δ = 3.89 [m, 1H
1
3
1
ane/diethyl ether: Formula C32
H36FeNOP, M = 537.44, yellow
R,R,S)-7] ppm and δ = 3.93 [m, 1 H (S,S,R)-7] ppm. C{ H}
NMR (150.8 MHz, CD Cl , 298 K): δ = 17.1 (C-7), 23.4 (C-16),
8.3 (C-6), 28.7 (C-17), 48.8 (C-8), 49.7 (C-15), 53.2 (C-9), 59.1 (C-
0), 60.1 (C-18), 67.1, 68.5, 68.6, 69.2, 93.2 (Cp1–5), 67.8, 68.1, 69.5,
2.2, 81.4 (Cp10–14), 77.0 (C-19) ppm.
crystal 0.50×0.30×0.15 mm, a = 7.200(1), b = 8.828(1), c =
2
2
3
–3
2
1.233(1) Å, β = 91.31(1)°, V = 1349.3(3) Å , ρcalcd. = 1.323 g·cm ,
2
2
7
–
1
μ = 6.44 cm , empirical absorption correction (0.739 Յ T Յ
.910), Z = 2, monoclinic, space group P2 (No. 4), λ = 0.71073 Å,
T = 198 K, ω and φ scans, 10520 reflections collected (±h, ±k,
0
1
X-ray Crystal Structure Analysis of (S,S,S)-7: Single crystals were
obtained from ether at –18 °C. formula C20 27FeNO, M = 353.28,
yellow crystal 0.35×0.25×0.03 mm, a = 8.936(1), b = 9.802(1), c =
–1
±
l), [(sinθ)/λ] = 0.66 Å , 5716 independent (Rint = 0.028) and 5488
H
observed reflections [I Ն 2 σ(I)], 327 refined parameters, R = 0.026,
–3
2
wR = 0.072, max. residual electron density 0.25 (–0.29) e·Å ,
3
–3
9
=
=
.977(1) Å, β = 104.46(1)°, V = 846.2(2) Å , ρcalcd. = 1.386 g cm , μ
Flack parameter –0.001(10), hydroge atoms calculated and refined
as riding atoms.
–1
8.96 cm , empirical absorption correction (0.745 Յ T Յ 974), Z
2, monoclinic, space group P2 (No. 4), λ = 0.71073 Å, T =
1
Formation of the Enantiomeric Products (R,R,Rpl)-10 and (S,S,Spl)-
10. Directed Phosphorylation of (R,R)-3 and of (S,S)-3: tert-Butyl-
lithium (10.6 mL of a 1.5 m hexane solution, 15.9 mmol, 1.5 equiv.)
was added dropwise with stirring to a solution of the enantiomer-
ically pure complex (R,R)-3 (3.01 g, 10.6 mmol) in 20 mL of diethyl
ether at 0 °C. The reaction mixture was then stirred at room tem-
perature for 30 min. The dark orange-colored mixture was then
again cooled to 0 °C, and chlorodiphenylphosphane (3.53 g,
1
98 K, ω and φ scans, 5606 reflections collected (±h, ±k, ±l),
–1
[(sinθ)/λ] = 0.66 Å , 3525 independent (Rint = 0.045) and 3274 ob-
served reflections [I Ն 2 σ(I)], 210 refined parameters, R = 0.032,
wR = 0.069, max. residual electron density 0.26 (–0.28) e·Å ,
2
Flack parameter –0.010(15), hydrogen atoms calculated and refined
as riding atoms.
–
3
Formation of 9. Directed Phosphorylyation of 7: n-Butyllithium
(
1.7 mL of a 1.96 m solution in hexane, 3.3 mmol, 1.2 equiv.) was
added dropwise with stirring at 4 °C to a solution of 0.95 g
2.7 mmol) of the 1:1 mixture of the (R,R,S)-7 and (S,S,S)-7 dia-
2
.94 mL, 15.9 mmol, 1.5 equiv.) was added dropwise with stirring.
The mixture was then stirred at room temperature for 12 h. Satu-
rated aqueous NaHCO solution (60 mL) was added slowly to
(
3
stereoisomers. The cooling bath was then removed and the mixture
stirred for 3 h at room temperature. During this time an orange-
colored precipitate appeared. The mixture was then re-cooled to
quench the reaction. Workup analogously as described above gave
the crude product (4.74 g) as a red oil. Chromatography (silica gel,
cyclohexene/ethylacetate, 1:1) yielded the product (R,R,Rpl)-10
4
2
°C and ClPPh (0.74 g, 0.6 mL, 3.4 mmol, 1.3 equiv.) was added
(
3.62 g, 73%) as a yellow solid.
dropwise with stirring. The reaction mixture was then stirred at
room temperature for 12 h. The reaction was quenched by adding
saturated aqueous sodium hydrogencarbonate solution (20 mL).
The aqueous layer was extracted with diethyl ether (3×10 mL). The
combined original phases were washed with water (2×10 mL) and
brine (10 mL) and dried with magnesium sulfate. Filtration and
removal of the solvent in vacuo gave an orange-colored solid
Analogous treatment of (S,S)-3 (0.88 g, 3.1 mmol) in diethyl ether
(17 mL) with tert-butyllithium (2.4 mL of a 1.5 m solution in hex-
ane, 4.6 mmol) and subsequent reaction with chlorodiphenylphos-
phane (1.03 g, 0.85 mL, 4.6 mmol) gave 0.99 g (70%) of the enanti-
omer (S,S,Spl)-10, m.p. 156 °C. C28H30FeNP (467.4): calcd. C
71.96, H 6.47, N 3.00; found for (R,R,Rpl)-10: C 71.72, H 6.39, N
2.67; (S,S,Spl)-10: C 71.71, H 6.56, N 2.85. MS (EI, 70 eV): m/z
(
1.22 g). Chromatography (silica gel, CHCl
3
/CH
3 3
OH/NEt ,
+
+
20
400:50:1) gave a 1:1 mixture of the diastereomers of 9 (1.10 g,
(%) = 467.1 (100) [M ], 422.0 (46) [M – amine]. [α]
D
(R,R,Rpl)-
Eur. J. Org. Chem. 2005, 1909–1918
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© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 1915