ˇ
R. Sebesta et al.
FULL PAPER
5.7, 11.4 Hz, 1 H, CH), 4.97 (m, 1 H, Fc), 4.55 (m, 1 H, Fc), 4.40
(m, 1 H, Fc), 4.15 (m, 1 H, Fc), 4.13 (m, 1 H, Fc), 3.77 (m, 1 H,
CHPh), 128.07 (d, J = 7.4 Hz, CHPh), 128.0 (CHPh), 124.6 (d, J =
6.2 Hz, CH), 87.5 (d, J = 22.2 Hz, CqFc), 85.1 (CqFc), 75.4 (d, J =
Fc), 3.67–3.74 (m, 1 H, CH2), 3.72 (m, 1 H, Fc), 2.77–2.82 (m, 1 4.5 Hz, CqFc), 75.2 (d, J = 3.6 Hz, CHFc), 72.6 (d, J = 5.4 Hz,
H, CH2), 2.26 (m, 1 H, CH2), 1.70–1.79 (m, 1 H, CH2), 1.58 (m, 1 CHFc), 70.2 (CHFc), 69.9 (d, J = 3.8 Hz, CHFc), 68.2 (CHFc), 67.3
H, CH2) ppm. 13C NMR (CDCl3): δ = 134.6, 134.3, 133.9, 133.6 (CHFc), 67.0 (CHFc), 24.8 (CH2), 22.3 (CH2), 21.2 (CH2) ppm. 31P
(2 d, CqPh), 131.7 (d, J = 9.8 Hz, CHPh), 131.5 (d, J = 9.8 Hz, NMR (CDCl ): δ = –20.9 ppm. IR (ATR): ν = 3083, 3073, 3004,
˜
3
CHPh), 131.5 (d, J = 3.0 Hz, CHPh), 131.3 (d, J = 3.0 Hz, CHPh), 2920, 2854, 1474, 1430 cm–1. C27H25PFe (436.3): calcd. C 74.33, H
130.5 (CH), 128.4 (d, J = 12.0 Hz, CHPh), 128.0 (d, J = 12.0 Hz, 5.78; found C 74.35, H 5.65. HPLC (OD-H, hexane/propan-2-ol,
CHPh), 124.1 (CH), 86.6 (CqFc), 86.4 (d, J = 10.1 Hz, CqFc), 76.4
(d, J = 9.8 Hz, CHFc), 73.3 (d, J = 15.2 Hz, CH), 72.4 (d, J =
113 Hz, CqFc), 71.4 (CHFc), 70.9 (d, J = 11.6 Hz, CHFc), 69.3
(CHFc), 68.5 (CHFc), 67.2 (CHFc), 24.6 (CH2), 22.6 (CH2), 20.9
90:10, 0.7 mL/min): tR(minor) = 6.05 min, tR(major) = 6.45 min;
er = 98:2.
(S)-1,5-[2-(Dicyclohexylphosphanyl)ferrocene-1,1Ј-diyl]pent-1-ene
(4b): Yield 77%; m.p. 136–140 °C. [α]D = +241 (c = 0.3, CH2Cl2).
1H NMR (CDCl3): δ = 6.37 (d, J = 11.2 Hz, 1 H, CH), 5.70 (dt, J
= 6.3, 11.1 Hz, 1 H, CH), 4.39 (m, 1 H, Fc), 4.37 (dd, J = 4.9,
7.2 Hz, 1 H, Fc), 4.16 (m, 1 H, Fc), 4.06 (m, 2 H, Fc), 3.94 (m, 1
H, Fc), 3.89 (m, 1 H, Fc), 3.51 (m, 1 H, CH2), 2.48 (ddd, J = 3.7,
12.7, 16.4 Hz, 1 H, CH2), 2.30 (m, 1 H, CH2), 2.21 (td, J = 4.0,
16.4 Hz, 1 H), 2.0 (m, 2 H, CH2 and CH), 1.87 (dd, J = 7.3,
17.1 Hz, 2 H, CH2), 1.65 (m, 8 H, CH2 and CH), 1.28 (m, 12 H,
CH2) ppm. 13C NMR (CDCl3): δ = 129.6 (CH), 125.7 (d, J =
7.2 Hz, CH), 88.1 (d, J = 21.6 Hz, CqFc), 85.4 (CHFc), 77.5 (d, J =
17.8 Hz, CqFc), 73.5 (d, J = 2.8 Hz, CqFc), 71.0 (d, J = 2.3 Hz,
CHFc), 69.7 (CHFc), 68.5 (d, J = 4.2 Hz, CHFc), 68.2 (CHFc), 67.6
(CHFc), 67.2 (CHFc), 35.9 (d, J = 12.9 Hz, CH), 34.3 (d, J = 9.9 Hz,
CH), 33.5 (d, J = 23.4 Hz, CH2), 31.5 (d, J = 17.1 Hz, CH2), 30.0
(d, J = 5.2 Hz, CH2), 29.7 (d, J = 7.1 Hz, CH2), 28.1 (d, J =
14.7 Hz, CH2), 27.7 (d, J = 6.3 Hz, CH2), 27.4 (d, J = 7.4 Hz,
CH2), 27.3 (d, J = 12.0 Hz, CH2), 26.5 (d, J = 1.0 Hz, CH2), 26.4
(d, J = 1.0 Hz, CH2), 25.0 (d, J = 2.2 Hz, CH2), 22.4 (CH2), 21.1
(CH2) ppm. 31P NMR (CDCl ): δ = 28.9 ppm. IR (ATR): ν = 3068,
˜
3
2906, 2853, 1435, 1198, 1178, 1115 cm–1. C27H25FeOP (452.1):
calcd. C 71.70, H 5.57; found C 71.75, H 5.60.
(S)-Dicyclohexyl[2,1Ј-(pent-1-ene-1,5-diyl)ferrocenyl]phosphane Ox-
ide (3b): Yield 52 %; m.p. 217–220 °C. [α]D = +379 (c = 0.31,
1
CH2Cl2). H NMR (CDCl3): δ = 6.42 (d, J = 11.3 Hz, 1 H, CH),
5.72 (dt, J = 5.8, 11.5 Hz, 1 H, CH), 4.49 (m, 1 H, Fc), 4.47 (dd,
J = 2.4, 4.4 Hz, 1 H, Fc), 4.38 (m, 1 H, Fc), 4.24 (dd, J = 2.3,
3.7 Hz, 1 H, Fc), 4.13 (m, 2 H, Fc), 4.00 (dt, J = 1.2, 2.4 Hz, 1 H,
Fc), 3.67 (ddd, J = 4.6, 12.9, 25.3 Hz, 1 H, CH2), 2.62 (m, 1 H,
CH2), 2.34 (m, 1 H, CH2), 2.18 (td, J = 3.6, 8.1 Hz, 1 H, CH2),
2.03 (m, 2 H, CH2 and CH), 1.9 (m, 3 H, CH2), 1.75 (m, 8 H, CH2
and CH), 1.52 (m, 3 H, CH2), 1.28 (m, 8 H, CH2) ppm. 13C NMR
(CDCl3): δ = 129.4 (CH), 125.4 (CH), 86.4 (CqFc), 86.3 (d, J =
8.6 Hz, CqFc), 75.2 (d, J = 8.9 Hz, CHFc), 72.3 (d, J = 92.8 Hz,
CqFc), 71.0 (CHFc), 70.9 (d, J = 9.36 Hz, CHFc), 70.0 (d, J =
12.4 Hz, CHFc), 69.3 (CHFc), 68.2 (CHFc), 67.6 (CHFc), 39.2
(CHCy), 38.7 (CHCy), 27.3 (CH2), 27.2 (d, J = 12.0 Hz, CH2), 27.1
(d, J = 12.5 Hz, CH2), 26.8 (d, J = 23.0 Hz, CH2), 26.8 (d, J =
2.1 Hz, CH2), 26.6 (d, J = 2.9 Hz, CH2), 26.5 (d, J = 3.2 Hz, CH2),
26.3 (d, J = 2.8 Hz, CH2), 26.1 (d, J = 1.3 Hz, CH2), 26.0 (d, J =
1.3 Hz, CH2), 24.5 (CH2), 22.5 (CH2), 20.7 (CH2) ppm. 31P NMR
(CH2) ppm. 31P NMR (CDCl ): δ = –14.6 ppm. IR (ATR): ν =
˜
3
2923, 2846, 1436, 813 cm–1. C27H37FeP (448.4): calcd. C 72.32, H
8.32; found C 71.95, H 8.30.
Procedure for the Catalytic Asymmetric 1,4-Addition of Arylboronic
Acids to α,β-Unsaturated Carbonyl Compounds: Rh(acac)(C2H4)2
(3.0 mg, 0.0126 mmol), ligand 4a (6.0 mg, 0.0139 mmol), and
PhB(OH)2 (305 mg, 2.5 mmol) were dissolved in a mixture of H2O
(0.1 mL) and 1,4-dioxane (1 mL). The resulting mixture was stirred
under N2 at room temp. for 30 min. Cyclohex-2-enone (6b) was
then added (40 mg, 0.42 mmol). The resulting mixture was stirred
at 100 °C for 18 h. When the reaction was complete (monitored by
TLC), the solvent was removed under vacuum. The residue was
dissolved in EtOAc, and the resulting mixture was washed with
a saturated aqueous solution of NaHCO3. The organic layer was
concentrated under reduced pressure, and the residue was purified
by column chromatography (SiO2; eluent) to give the pure addition
product 7b.
3-Phenylcyclopentanone (7a):[18] Colorless oil. HPLC (Diacel Chi-
ralcel AD-H, hexane/propan-2-ol, 95:5, 0.7 mL/min): tR(major) =
10.73 min [(S)-7a], tR(minor) = 13.86 min [(R)-7a]; 88% ee. 1H
NMR (300 MHz, CDCl3): δ = 7.36–7.33 (m, 2 H), 7.26–7.22 (m, 3
H), 3.45–3.38 (m, 1 H), 2.68 (dd, J = 18.3, 7.7 Hz, 1 H), 2.50–2.26
(m, 4 H), 2.05–1.96 (m, 1 H) ppm.
(CDCl ): δ = 45.7 ppm. IR (ATR): ν = 3170, 3056, 2930, 2850,
˜
3
1710, 1436, 1163, 833 cm–1. C27H37FeOP (464.2): calcd. C 69.83,
H 8.03; found C 69.53, H 8.13.
Procedure for the Reduction of the Phosphane Oxide: Into a Schlenk
tube, NEt3 (0.61 mL, 4.40 mmol) and HSiCl3 (0.22 mL, 2.20 mmol)
were added to a solution of alkene 3a (0.18 g, 0.40 mmol) in tolu-
ene (10 mL). The reaction mixture was exposed to microwave irra-
diation at 90 °C for 5.5 h and then heated in an oil bath to 70 °C
for 14 h. After cooling to room temp., the reaction was quenched
with a saturated aqueous solution of NaHCO3 (15 mL). The aque-
ous layer was extracted with EtOAc (3ϫ25 mL), and the combined
organic layers were dried with Na2SO4 and then concentrated. The
crude product was purified by column chromatography [SiO2; hex-
ane/EtOAc (1:1)] to furnish the alkene–phosphane ligand 4a
(121 mg, 69%) as an orange solid.
(S)-1,5-[2-(Diphenylphosphanyl)ferrocene-1,1Ј-diyl]pent-1-ene (4a):
M.p. 85–87 °C. [α]D = +131 (c = 0.3, CH2Cl2). 1H NMR (CDCl3):
δ = 7.46–7.48 (m, 2 H, Ph), 7.32–7.35 (m, 3 H, Ph), 7.22–7.28 (m,
5 H, Ph), 6.04 (d, J = 11.0 Hz, 1 H, CH), 5.71 (dt, J = 5.8, 11.3 Hz,
1 H, CH), 4.48 (m, 1 H, Fc), 4.35 (t, J = 2.5 Hz, 1 H, Fc), 4.16
(m, 1 H, Fc), 4.09 (m, 1 H, Fc), 4.05 (dd, J = 2.3, 3.7 Hz, 1 H,
Fc), 3.74 (m, 1 H, CH2), 3.62 (dt, J = 1.3, 2.4 Hz, 1 H, Fc), 3.55
(td, J = 1.1, 2.3 Hz, 1 H, Fc), 2.63 (m, 1 H, CH2), 2.31 (m, 1 H,
CH2), 1.87 (m, 1 H, CH2), 1.74 (ddt, J = 3.6, 7.9, 13.7 Hz, 1 H,
3-Phenylcyclohexanone (7b):[18] Colorless oil. HPLC (Diacel Chi-
ralcel OD-H, hexane/propan-2-ol, 98:2, 0.7 mL/min): tR(major) =
19.41 min [(S)-7b], tR(minor) = 23.32 min [(R)-7b]; 86% ee. 1H
NMR (300 MHz, CDCl3): δ = 7.33 (t, J = 7.8 Hz, 2 H), 7.26–7.21
(m, 3 H), 3.01 (tt, J = 11.8, 3.9 Hz, 1 H), 2.63–2.35 (m, 4 H), 2.18–
2.07 (m, 2 H), 1.87–1.75 (m, 2 H) ppm.
CH2), 1.59 (tdd, J = 4.1, 13.7, 18.0 Hz, 1 H, CH2) ppm. 13C NMR 3-Phenylcycloheptanone (7c):[19] Colorless oil. HPLC (Diacel Chi-
(CDCl3): δ = 139.0 (d, J = 11.5 Hz, CqPh), 137.5 (d, J = 10.2 Hz,
CqPh), 134.7 (d, J = 20.2 Hz, CHPh), 132.4 (d, J = 18.2 Hz, CHPh),
ralcel AD-H, hexane/propan-2-ol, 95:5, 0.7 mL/min): tR(major) =
11.34 min [(S)-7c], tR(minor) = 14.02 min [(R)-7c]; 90% ee. 1H
130.5 (CH), 128.9 (d, J = 0.7 Hz, CHPh), 128.2 (d, J = 6.0 Hz, NMR (300 MHz, CDCl3): δ = 7.33–7.27 (m, 2 H), 7.23–7.18 (m, 3
6114
www.eurjoc.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2011, 6110–6116