2
568
X.-Y. Wu et al. / Tetrahedron: Asymmetry 12 (2001) 2565–2569
to carboxyl group did not sever any bond connected to
the stereogenic center of the molecule, the configuration
of (−)-exo-2-phenylnorbornane should be the same as
the configuration of the oxidation product (−)-exo-2-
norbornanecarboxylic acid, which is (1R,2R).
1H), 2.34 (s, 1H), 2.70 (dd, J=8.8, 5.6 Hz, 1H), 3.78 (s,
3H), 6.80–6.85 (m, 2H), 7.12–7.18 (m, 2H). E.e. deter-
mination: HPLC with DAICEL Chiracel OJ column
(hexane/propan-2-ol=90/10, 0.5 mL/min), t =16.3
R
min (major) and 18.3 min (minor).
3
.2.4. exo-2-(m-Nitrophenyl)bicyclo[2.2.1]heptane. Yel-
1
3. Experimental
low oil. H NMR: 1.24–1.27 (m, 1H), 1.28–1.30 (m,
H), 1.32–1.42 (m, 1H), 1.47–1.53 (m, 1H), 1.55–1.65
1
3
.1. General
(m, 3H), 1.80–1.85 (m, 1H), 2.43 (s, 2H), 2.83 (dd,
J=9.1, 5.4 Hz, 1H), 7.42 (t, J=12.7 Hz, 1H), 7.55 (d,
J=7.7 Hz, 1H), 8.01 (d, J=8.5 Hz, 1H), 8.08 (s, 1H).
IR: 3080, 2950, 2880, 1520, 1350, 1100, 810, 740, 690
DMSO and DMF were dried over CaH and distilled
under reduced pressure. THF was distilled from
sodium-benzophenone. Dichloromethane was distilled
from CaH . The chiral quinolinyl-oxazoline ligands
were prepared by a previous method. Pd(dba) was
2
−
1
+
cm . MS (m/e, %): 217 (9.15, M ), 151 (50.43), 149
(26.87), 134 (28.28), 128 (21.20), 115 (25.30), 81 (35.86),
68 (53.83), 67 (100). HRMS: calcd for C H NO
2
2
9a
2
13 15
19
prepared by Takahashi’s method. Pd(OAc) was pur-
217.1103; found 217.1116. E.e. determination: HPLC
2
chased from Acros. All reactions were carried out
under an argon atmosphere using Schlenck technique.
with DAICEL Chiracel OJ column (hexane/propan-2-
ol=99/1, 0.5 mL/min), t =13.4 min (major) and 14.2
R
−
1 1
IR (film): selected bands in cm . H NMR (CDCl , 300
min (minor).
3
or 500 MHz): l in ppm (TMS), J in Hz. MS (EI):
selected peaks, m/z (%).
3.2.5. exo-2-(p-Nitrophenyl)bicyclo[2.2.1]heptane. Yel-
1
low oil. H NMR: 1.22–1.26 (m, 1H), 1.27–1.32 (m,
3
.2. Enantioselective hydroarylation of norbornene.
1H), 1.35–1.42 (m, 1H), 1.45–1.51 (m, 1H), 1.58–1.65
(m, 3H), 1.80–1.90 (m, 1H), 2.41 (s, 2H), 2.83 (dd,
J=8.9, 5.5 Hz, 1H), 7.37 (d, J=8.4 Hz, 2H), 8.13 (d,
J=8.8 Hz, 2H). IR: 3080, 2950, 2880, 1600, 1520, 1460,
General procedure
Under an argon atmosphere, palladium(II) acetate (5.6
mg 0.025 mmol) and the chiral nitrogen ligand (0.052
mmol) were dissolved in dry solvent (2 mL) and stirred
at 25°C for 2 h. The base (1.75 mmol), formic acid (1.5
mmol), the substrate (0.5 mmol) and the arylating
reagent (ArX, 1.5 mmol) in dry solvent (3 mL) were
added rapidly in one portion. After stirring at the
corresponding temperature until complete conversion
−
1
1350, 1110, 860, 840, 750, 700 cm . MS (m/e, %): 217
+
(5.38, M ), 151 (41.16), 149 (20.28), 128 (17.62), 115
(22.54), 103 (20.25), 81 (22.13), 68 (47.09), 67 (100).
HRMS: calcd for C H NO 217.1103; found
13
15
2
217.1111.
3.2.6. exo-2-[3-(4-Chloropyridinyl)]bicyclo[2.2.1]heptane.
1
(
traced by GC or TLC), the reaction mixture was
Colorless oil. H NMR: 1.17–1.25 (m, 2H), 1.26–1.33
partitioned between water and ethyl acetate. The
aqueous phase was extracted three times with ethyl
acetate. The resulting organic layer was washed with
water and dried over magnesium sulfate. After evapora-
tion of the solvent, the residue was purified by flash
column chromatography on silica gel. The product was
then subjected to analysis.
(m, 1H), 1.35–1.40 (m, 1H), 1.43–1.60 (m 3H), 1.70–
1.77 (m, 1H), 2.26 (d, J=3.1 Hz, 1H), 2.32 (s, 1H), 2.64
(dd, J=9.0, 5.4 Hz, 1H), 7.15 (d, J=8.2 Hz, 1H), 7.41
(dd, J=8.2, 2.6 Hz, 1H), 8.17 (d, J=2.6 Hz, 1H). IR:
3050, 2950, 2880, 1590, 1580, 1460, 1390, 1320, 1310,
−
1
1300, 1200, 1200, 1140, 1100, 1020, 830, 740 cm . MS
+
+
(m/e, %): 209 (8.10, M ), 207 (24.17, M ), 142 (36.04),
41 (60.64), 140 (98.08), 139 (100), 127 (27.12), 104
(24.93). HRMS: calcd for C H ClN 207.0815; found
1
3
.2.1. exo-2-Phenylbicyclo[2.2.1]heptane. Colorless oil
12
14
1
with fragrance. H NMR: 1.15–1.40 (m, 4H), 1.48–1.70
m, 3H), 1.70–1.83 (m, 1H), 2.38 (s, 2H), 2.75 (dd,
207.0806. E.e. determination: HPLC with DAICEL
Chiralcel OJ column (n-hexane/2-PrOH=99/1, 1 mL/
(
J=8.6, 5.6 Hz, 1H), 7.07–7.35 (m, 5H). E.e. determina-
min), t =9.0 min (major) and 9.7 min (minor).
R
tion: HPLC with DAICEL Chiracel OJ column (hex-
ane/propan-2-ol=90/10, 1 mL/min), t =6.38 min
3.2.7. exo-5-Phenylbicyclo[2.2.1]heptane-2,3-dicarboxylic
R
1
(
major) and 7.12 min (minor).
acid dimethyl ester. White solid, mp 80–81°C. H NMR:
1
.36 (dq, J=10.2, 1.4 Hz, 1H), 1.68–1.76 (m, 2H),
3
.2.2. exo-2-(p-Methylphenyl)bicyclo[2.2.1]heptane. Col-
2.10–2.18 (m, 1H), 2.65 (dd, J=3.6, 1.4 Hz, 1H), 2.71
(s, 1H), 2.99 (dd, J=11.7, 3.8 Hz, 1H), 3.15 (ddd,
J=11.7, 4.5, 1.7 Hz, 1H), 3.51 (t, J=7.6 Hz, 1H), 3.69
(t, J=8.2 Hz, 6H) 7.14–7.18 (m, 1H), 7.26–7.32 (m,
4H). E.e. determination: HPLC with DAICEL Chiracel
OJ column (hexane/propan-2-ol=90/10, 1 mL/min),
tR=7.6 min (major) and 8.8 min (minor).
1
orless oil. H NMR: 1.10–1.20 (m, 1H), 1.20–1.75 (m
2
2
H), 1.50–1.67 (m, 4H), 1.70–1.80 (m, 1H), 2.31 (s, 3H),
.34 (s, 2H), 2.69 (dd, J=8.8, 5.8 Hz, 1H), 7.10 (dd,
J=13.3, 8.3 Hz, 4H). E.e. determination: HPLC with
DAICEL Chiracel OJ column (hexane/propan-2-ol=
90/10, 1 mL/min), t =4.5 min (major) and 6.8 min
R
(
minor).
3
.2.8. exo-2-Phenyl-5,6-benzobicyclo[2.2.1]heptane. Col-
1
3
.2.3.
Colorless oil. H NMR: 1.10–1.22 (m, 1H), 1.23–1.37
m, 2H), 1.48–1.67 (m, 4H), 1.70–1.78 (m, 1H), 2.30 (s,
exo-2-(p-Methoxyphenyl)bicyclo[2.2.1]heptane.
orless oil. H NMR: 1.8–1.85 (m, 2H), 1.92 (d, J=7.9
Hz, 1H), 1.97–2.05 (m, 1H), 2.84 (dd, J=9.8, 5.6 Hz,
1H), 3.45 (s, 2H), 7.07–7.11 (m, 2H), 7.18–7.25 (m, 3H),
1
(