N. V. Dubrovina, A. Börner et al.
FULL PAPER
liquor, enriched with the opposite enantiomeric phosphinic acid
2e, was used for another resolution step with (S)-(–)-N-benzyl-α-
methylbenzylamine to give (+)-2e.
yielded the product 1a as a colorless oil (two diastereomers in a
1
ratio of 1:1). Yield: 1.63 g (80%). H NMR (C6D6): δ = 0.94–2.28
1
(m, 18 H), 2.45 (m, 1 H, CH), 2.92 (m, 1 H, CH), 3.05 (dt, JP,H
=
2
1
183, JH,H = 12 Hz, 1 H, P-H of one diastereomer), 3.55 (dt, JP,H
(–)-(4aα,5aβ,9aβ,9bβ)-5-Oxododecahydro-5λ5-dibenzophosphol-5-ol
[(–)-2e]: An excess of aqueous NaOH (2 ) was added to a solution
of the diastereomerically pure salt (2.22 g, 4.9 mmol) in CHCl3
(20 mL). The solution was stirred at room temperature for 30 min.
The organic layer was then separated and washed with aqueous
NaOH solution (2 , 2×20 mL). The basic water layer was then
acidified with an excess of aqueous HCl solution (2 ) and the
compound extracted with CH2Cl2 (3×50 mL). The organic solvent
was removed under reduced pressure to give the pure product.
Yield: 0.93 g (58%); m.p. 173.5–174.5 °C. [α]2D5 = –21.0 (c = 0.6,
MeOH).
= 181, JH,H = 11 Hz,1 H, P-H of other diastereomer) ppm. 13C
2
NMR (C6D6): δ = 21.0, 22.2–22.4 (CH2), 24.6 (CH2), 25.3–25.5
(CH2), 26.8–26.9 (CH2), 28.2–29.0 (CH2), 32.1 (d, JC,P = 8 Hz,
CH), 32.6–33.3 (CH2), 35.3 (d, JC,P = 7 Hz, CH), 35.5 (d, JC,P
10 Hz, CH), 38.9 (d, JC,P = 8 Hz, CH), 45.7 (CH), 46.1 (d, JC,P
=
=
4 Hz, CH), 55.9 (CH), 56.7 (d, JC,P = 5 Hz; CH) ppm. 31P NMR
(C6D6): δ = –47.3 (s, one diastereomer), δ = –55.9 (s, other dia-
stereomer). Treatment of the phosphanes 1a with selenium in
CDCl3 at room temperature afforded the corresponding phosphane
selenides, which were characterized in the 31P NMR spectrum by
a triplet at δ = 12.4, (JP,Se = 704 Hz) and another at δ = 23.1 (JP,Se
= 710 Hz). The diastereomers were purified as their BH3 adducts,
which were prepared by addition of a small excess of a solution of
BH3-dimethylsulfide complex in toluene to the phosphanes.
(+)-(4aα,5aβ,9aβ,9bβ)-5-Oxododecahydro-5λ5-dibenzophosphol-5-ol
[(+)-2e]: Yield: 1.44 g (90%); m.p. 173–174 °C, [α]2D5 = 18.0 (c = 0.6,
MeOH).
Dimethyl-(4aβ,5aβ)-(5-oxo-2,3,4,4a,5,5a,6,7,8,9-decahydro-1H-5λ5-
dibenzophosphol-5-yl)amine (10): Me2NPCl2 (16.4 g, 0.113 mol) was
added to a suspension of AlCl3 (14.1 g, 0.106 mol) in CH2Cl2
(150 mL). After the addition the mixture was stirred for 40 min
until complete dissolution had occurred. A solution of dien 9
(16.7 g, 0.103 mol) in CH2Cl2 (100 mL) was added dropwise to this
solution in an ice bath. The resulting red solution was stirred at
0 °C for 8 h and at room temperature overnight. The mixture was
slowly poured into ice (200 mL) and stirred with ice/water for 1 h.
The crude product was obtained by extraction with dichlorometh-
ane and evaporation of the organic solvent. This oily material was
hydrolyzed to give the phospholanic acid 1a. Yield: 23.07 g (99%).
1
First Diastereomer: H NMR (CDCl3): δ = 0.05–0.82 (br. m, 3 H,
BH3), 0.88–2.21 (m, 17 H), 2.25 (m, 2 H), 4.29 (m, 1 H, CH), 5.16
(m, 1 H, CH) ppm. 13C NMR (CDCl3): δ = 22.0 (CH2), 23.8 (CH2),
24.0 (CH2), 24.9 (CH2), 26.3 (CH2), 27.0–27.4 (CH2), 29.0 (CH2)
1
1
31.1 (d, JC,P = 33 Hz, CH), 38.7 (d, JC,P = 35 Hz, CH), 44.1
(CH), 51.5 (CH) ppm. 31P NMR (CDCl3): δ = –7.7 (br. m) ppm.
Second Diastereomer: 1H NMR (CDCl3): δ = 0.05–0.82 (br. m, 3
H, BH3), 0.88–2.26 (m, 17 H), 2.67 (m, 2 H), 3.93 (m, 1 H, CH),
4.81 (m, 1 H, CH) ppm. 13C NMR (CDCl3): δ = 23.4 (CH2), 24.5–
24.8 (CH2), 26.5 (CH2), 27.3 (CH2), 28.6 (CH2), 29.7 (m, CH2),
1
1
33.2 (d, JC,P = 35 Hz, CH), 37.7 (d, JC,P = 35 Hz, CH), 43.7
1H NMR (CDCl3): δ = 1.03–2.18 (m, 20 H), 2.73 (d, J = 8 Hz, 6 (CH), 51.3 (CH) ppm. 31P NMR (CDCl3): δ = 11.8 (br. m) ppm.
H, CH3) ppm. 13C NMR (CDCl3): δ = 24.0 (d, JP,C = 6 Hz, CH2), MS (70 eV, EI): m/z (%) 209 (6) [M+ – H], 208 (8) [M+ – 2H], 196
25.5 (s, CH2), 25.8 (d, JP,C = 12 Hz, CH2), 26.7 (d, JP,C = 10 Hz, (100) [M+ – BH3], 154 (14). C12H24BP (210.10): calcd. C 68.60, H
CH2), 37.9 (d, JP,C = 2 Hz, CH3), 42.1 (d, JC,P = 82 Hz, CH), 131.2
(d, JC,P = 15 Hz, C=) ppm. 31P NMR (CDCl3): δ = 69.5 (s) ppm.
MS (70 eV, EI): m/z (%) 253 (20) [M+], 163 (65) [M+ – HOPNMe2],
94 (100), 92 (46), 91 (73).
11.51, P 14.74; found C 68.21, H 11.18, P 14.43.
Liberation of the phosphanes from their BH3 adducts was carried
out by treatment with DABCO in THF at room temperature and
subsequent chromatography on a short column of celite.
(4aβ,5aβ)-5-Oxo-2,3,4,4a,5,5a,6,7,8,9-decahydro-1H-5λ5-dibenzo-
phosphol-5-ol (11): An aqueous solution of HCl (6 ) was added to
a solution of the amide 10 (6.5 g, 25.8 mol) in EtOH (50 mL) and
the mixture was stirred overnight. The mixture was then made alka-
line by careful addition of an aqueous NaOH solution (4 ) and
extracted with CH2Cl2 (2×40 mL). The aqueous layer was acidified
with concentrated HCl. The crude product was obtained by extrac-
tion with dichloromethane (5×70 mL) and evaporation of the or-
ganic solvent. An analytically pure sample was obtained by
recrystallization from EtOH. Yield: 5.70 g (86 %); m.p. 172.5–
173.5 °C. 1H NMR (CDCl3): δ = 1.10–2.72 (m, 18 H), 9.17 (s, 1 H,
OH) ppm. 13C NMR (CDCl3): δ = 26.2 (d, JC,P = 13 Hz, CH2),
26.7 (s, CH2), 27.0 (d, JC,P = 5 Hz, CH2), 27.3 (d, JC,P = 10 Hz,
CH2), 41.9 (d, JC,P = 95 Hz, CH), 131.2 (d, JC,P = 15 Hz, C=) ppm.
31P NMR (CDCl3): δ = 73.8 (s) ppm. MS (70 eV, EI): m/z (%) 226
(20) [M+], 162 (100) [M+ – HPO2]. C12H19O2P (226.25) calcd. C
63.70, H 8.46, P 13.69; found C 63.13, H 8.57, P 14.03.
(4aα,5R/S,5aβ,9aβ,9bβ)-Dodecahydrodibenzophosphole 5-Oxide
(1b): Phospholane 1a (0.39 g, 2.0 mmol) was dissolved in iPrOH
(10 mL) and stirred for 1 h in air. Evaporation of the solvent
yielded the product 1b as a colorless oil (two diastereomers in a
ratio of 1:1). Yield: 0.42 g (100%).
First Diastereomer: 1H NMR (CDCl3): δ = 1.12–2.41 (m, 20 H),
1
7.02 (d, JH,P = 445 Hz, PH) ppm. 13C NMR (CDCl3): δ = 23.2
(m, CH2), 24.5–25.0 (m, CH2), 24.4 (m, CH2), 27.9 (m, CH2), 29.1
1
1
(CH2), 36.9 (d, JC,P = 66 Hz, CH), 38.5 (d, JC,P = 67 Hz, CH),
40.9 (d, JC,P = 8 Hz, CH), 41.8 (d, JC,P = 5 Hz, CH) ppm. 31P
2
2
NMR (CDCl3): δ = 48.0 (s) ppm.
Second Diastereomer: 1H NMR (CDCl3): δ = 1.12–2.41 (m, 20 H),
7.53 (d, JP,H = 445 Hz, PH) ppm. 13C NMR (CDCl3): δ = 23.2 (m,
CH2), 24.5–25.0 (m, CH2), 24.4 (m, CH2), 27.9 (m, CH2), 29.1
1
1
(CH2), 42.6 (d, JC,P = 62 Hz, CH), 43.3 (d, JC,P = 63 Hz, CH),
44.8 (d, JC,P = 11 Hz, CH), 48.8 (d, JC,P = 6 Hz, CH) ppm. 31P
NMR (CDCl3): δ = 55.1 (s) ppm. MS (70 eV, EI): m/z (%) 212
(100) [M+], 211 (32) [M+ – H].
2
2
(4aα,5R/S,5aβ,9aβ,9bβ)-Dodecahydrodibenzophosphole (1a): SOCl2
(6.19 g, 5.2 mmol) was added dropwise to a solution of optically
pure 2e (2.37 g, 10.4 mmol) in CHCl3 (25 mL) and the mixture was
refluxed for 1 h. The solvent was removed under reduced pressure
and the residue was dissolved in THF (20 mL). LiAlH4 (0.79 g,
20.8 mmol) was added carefully to the resulting solution at –20 °C
and the mixture was stirred for 1 h at the same temperature. Aque-
ous NaOH (7%, 5 mL) was then added to the mixture. Extraction
with n-hexane and filtration, followed by concentration in vacuo,
Preparation of [Rh(COD)(ligand)2]BF4: A solution of the ligand
(1.20 mmol) in CH2Cl2 (5 mL) was added slowly to a solution of
[Rh(COD)2]BF4 (0.24 g, 0.60 mmol) in CH2Cl2 (5 mL) at –40 °C.
The mixture was stirred overnight, while warming up to room tem-
perature. The clear reddish brown solution was used directly for
the hydrogenation.
3418
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Eur. J. Org. Chem. 2006, 3412–3420