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Wu H, et al. Sci China Chem June (2011) Vol.54 No.6
= 7.5 Hz 4H, CH2), 6.14 (d, J = 14.6 Hz, 2H, CH2), 6.31 (d,
J = 14.6 Hz, 2H, CH2), 7.00 (d, J = 8.7 Hz, 2H, ArH), 7.21
(m, 2H, ArH), 7.39 (m, 2H, ArH), 7.57–7.63 (m, 4H, BzH),
7.70–7.73 (m, 2H, BzH), 7.85–7.88 (m, 2H, BzH), 7.92 (d,
J = 8.1 Hz, 2H, ArH), 8.30 (s, 2H, ArH), 11.73 (s, 2H,
NCHN); 13C NMR (75 MHz, CDCl3): 13.4 (CH3), 19.7
(CH2), 31.2 (CH2), 47.1 (CH2), 47.5 (NCH2Ar), 61.4
(OMe), 113.0, 114.0, 124.0, 125.2, 125.6, 125.9, 127.1,
127.6, 128.5, 130.1, 131.1, 131.2, 131.5, 134.3, 142.9,
154.0; IR (KBr, cm1) v 3391, 2954, 1618, 1559, 1453,
1430, 1373, 1245, 1196, 1149, 1105, 1005, 758; Anal. calcd
for C46H48Br2N4O2 (846.21): C, 65.10; H, 5.70; N, 6.60.
Found: C, 64.64; H, 5.56; N, 6.92.
Scheme 1 Structures of bis-imidazolinium salts 4a and 4b.
reactions were carried out under nitrogen atmosphere. (R)-
2,2′-Dimethoxy-3,3′-dimethyl-1,1′-binaphthalene (1) [30, 31],
1-butylbenzimidazole (3a), and 1-mesitylimidazole (3b)
were synthesized according to previously reported methods
Compound 4b (0.335 g, 55%): mp 258–259 °C; 1H NMR
(300 MHz, CDCl3): 1.97 (s, 6H, o-MesCH3), 1.98 (s, 6H,
o-MesCH3), 2.25 (s, 6H, p-MesCH3), 3.22 (s, 6H, OCH3),
6.03 (d, J = 13.8 Hz, 2H, CH2), 6.26 (d, J = 13.8 Hz, 2H,
CH2), 6.91 (s, 4H, m-MesH), 7.07–7.09 (m, 2H, ArH),
7.22–7.28 (m, 4H, ArH, MesNCH=C), 7.37–7.39 (m, 2H,
ArH), 7.91–7.95 (m, 4H, ArH, MesNC=CH), 8.46 (s, 2H,
ArH), 10.27 (s, 2H, NCHN); 13C NMR (75 MHz, CDCl3):
17.5 (o-MesCH3), 20.9 (p-MesCH3), 49.8 (NCH2Ar),
61.2 (OMe), 123.2, 123.5, 123.7, 125.1, 125.5, 126.7, 127.7,
128.6, 129.6, 130.1, 130.6, 132.3, 134.0 (Mes-2), 134.5,
137.5, 140.9, 154.3; IR (KBr) v 3423, 3124, 3051, 2963,
1620, 1552, 1492, 1450, 1415, 1361, 1245, 1201, 1156,
1104, 1005, 758 cm1; Anal. calcd for C48H48Br2N4O2
(870.21): C, 66.06; H, 5.54; N, 6.42. Found: C, 65.63; H,
5.89; N, 6.05.
1
[32, 33]. H and 13C NMR spectra were recorded on a
Bruker ARX-300 spectrometer. Elemental analyses were
performed on a Perkin-Elmer PE240 elemental analyzer.
Infrared spectra were measured with a Bruker Vector 22
spectrophotometer as KBr pellets. X-ray diffractions were
measured on Bruker Smart Apex CCD diffractometer.
2.2 Preparation of (R)-3,3′-bis(bromomethyl)-2,2′-dime-
thoxy-1,1′-binaphthalene (2)
A mixture of (R)-2,2′-dimethoxy-3,3′-dimethyl-1,1′-bina-
phthalene 1 (3.23 g, 9.34 mmol), NBS (3.33 g, 18.68 mmol),
and a catalytic amount of 2,2′-azobisisobutyronitrile (0.03 g,
0.19 mmol) in anhydrous CCl4 (50 mL) were refluxed for
12 h. The solid was filtered off and washed with CH2Cl2
(2 × 15 mL). After cooled to room temperature, the product
was obtained after removal of the solvent under reduced
pressure. The residue was subjected to column chromatog-
raphy on silica gel (petroleum ether (60–90 °C) and ethyl
acetate, 7/1, v/v) to afford colorless solid (1.94 g, 41%), mp
2.4 General procedure for Heck reaction
Under an atmosphere of nitrogen, Pd(OAc)2 (2.2 mg, 0.01
mmol), 4a or 4b (0.01 mmol), arylhalide (1.0 mmol), base
(2.0 mmol), and DMAc (6 mL) were mixed in a Schlenk
flask. Shortly afterwards, olefin (1.2 mmol) was added, and
subsequently the reaction mixture was stirred at 140 °C oil
bath for 10 h. After cooled to room temperature, the mix-
ture was diluted with H2O (15 mL) and extracted with Et2O
(3 × 15 mL). The combined organic layers were dried over
anhydrous Na2SO4, filtered and evaporated in vacuum. The
residue was subjected to flash column chromatography on
silica gel (ethyl acetate and petroleum ether, 3/1) to afford
the corresponding Heck products.
1
137–138 °C. H NMR (300 MHz, CDCl3): 3.38 (s, 6H,
OCH3), 4.76 (d, J = 9.6 Hz, 2H, CH2), 4.96 (d, J = 9.6 Hz,
2H, CH2), 7.22 (d, J = 8.7 Hz, 2H, ArH), 7.28–7.33 (m, 2H,
ArH), 7.41–7.47 (m, 2H, ArH), 7.91 (d, J = 8.1 Hz, 2H,
ArH), 8.09 (s, 2H, ArH).
2.3 General preparation of bis-imidazolinium salts (4a, 4b)
A solution of (R)-3,3′-bis(bromomethyl)-2,2′-dimethoxy-
1,1′-binaphthalene 2 (0.35 g, 0.7 mmol) and N-substituted
imidazole 3a (or 3b) (2.8 mmol) in CH3CN (50 mL) was
refluxed for 12 h. After cooled to room temperature, the
product was obtained after removal of the solvent under
reduced pressure. The residue was purified by flash column
chromatography (5% methanol in methylene dichloride as
eluent) to afford the pure colorless products (4a, 4b).
2.5 Single crystal structural determination of 4b
Single crystal of 4b, grown by slow evaporation of MeOH/
CH2Cl2 (v/v = 10:1) solution, suitable for X-ray diffraction
analysis was obtained. Data collection was performed at
291(2) K on a Bruker Smart CCD diffractometer with Mo
K radiation ( = 0.71073 Å) using - and -scans (Table
1). Structure solutions were performed with direct methods
using SHELXS-97. Structure refinements were performed
against F2 with SHELXL-97 [34]. All non-hydrogen atoms
Compound 4a (0.284 g, 48%): mp 227–229 °C; 1H NMR
(300 MHz, CDCl3): 0.97 (t, J = 7.2 Hz, 6H, CH3), 1.46 (m,
4H, CH2), 2.07 (m, 4H, CH2), 3.17 (s, 6H, OCH3), 4.65 (t, J