The Journal of Organic Chemistry
Article
out of the glovebox, and the crude reaction mixture was washed with
water then extracted with ethyl acetate three times. The organic phase
was collected and dried over anhydrous magnesium sulfate. The solvent
was evaporated in a rotary evaporator and characterized by NMR.
Procedure for Blank Experiments of Comparison of 4-
Methoxyphenyl Neopentylglycolboronate with 4-Methoxyl-
phenyl Pinacolboronate in THF. To an oven-dried test tube (15 ×
85 mm) were added two arylboron-based nucleophiles (0.30 mmol
each), Ni(II)Cl(1-naphthyl)(PPh3)2 (11 mg, 0.015 mmol), and
K3PO4 (191 mg, 0.9 mmol). The tube was taken into a glovebox.
PCy3 (0.030 mmol) was added. Dried THF (1.0 mL) was then added,
and the tube was capped with a rubber septum. The reaction was stirred
at room temperature under nitrogen in the glovebox for 3 h. A sample
was taken via syringe inside the glovebox. The sample was dissolved in
distilled THF and was filtered through a short column of silica gel. The
solvent was evaporated, and the NMR spectrum of the crude reaction
mixture was examined.
1H NMR (500 MHz, CDCl3) δ 7.48 (d, J = 8.5, 1H), 6.96 (d, J = 8.6, 1H),
3.85 (s, 1H); 13C NMR (126 MHz, CDCl3) δ 158.9, 133.6, 127.9, 114.3,
55.6.
Methyl 4′-Methoxy(1,1′-biphenyl)-2-carboxylate (3c): color-
less oil (Table 5: from 4-methoxyphenyl neopentylglycolboronate:
64.0 mg; 89%; from 4-methoxyphenyl pinacolboronate: 56.0 mg, 77%;
Table 6: from 4-methoxyphenyl neopentylglycolboronate: 65.0 mg;
90%; from 4-methoxyphenyl pinacolboronate: 58.0 mg, 81%); 1H NMR
(500 MHz, CDCl3) δ 7.90−7.70 (m, 1H), 7.51 (td, J = 7.6, 1.4, 1H),
7.41−7.31 (m, 2H), 7.28−7.20 (m, 4H), 6.99−6.88 (m, 2H), 3.85
(s, 3H), 3.67 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 169.5, 159.1,
142.2, 133.8, 131.3, 131.0, 130.9, 129.9, 129.6, 126.9, 113.7, 100.1, 55.4,
52.1. NMR spectrum is identical with the literature data.21
2,4′-Dimethoxy-1,1′-biphenyl (3d): white solid (Table 5: from
4-methoxyphenyl neopentylglycolboronate: 56.0 mg; 87%; from 4-
methoxyphenyl pinacolboronate: 28.0 mg, 44%; Table 6: from 4-metho-
xyphenyl neopentylglycolboronate: 57.0 mg; 89%; from 4-methox-
yphenyl pinacolboronate: 55.2 mg, 86%); mp 69 °C (lit.21 mp 64−
66 °C); 1H NMR (500 MHz, CDCl3) δ 7.50 − 7.43 (m, 1H), 7.30 (td,
J = 7.4, 1.6, 1H), 7.04 − 6.92 (m, 2H), 3.85 (s, 2H), 3.81 (s, 1H); 13C
NMR (126 MHz, CDCl3) δ 158.5, 156.4, 130.8, 130.6, 130.5, 130.2,
128.1, 120.7, 113.4, 111.1, 55.5, 55.2.
Methyl 4′-methoxy(1,1′-biphenyl)-4-carboxylate (3e): white
solid (Table 5: from 4-methoxyphenyl neopentylglycolboronate:
58.3 mg; 81%; from 4-methoxyphenyl pinacolboronate: 66 mg, 92%;
Table 6: from 4-methoxyphenyl neopentylglycolboronate: 62.0 mg;
86%; from 4-methoxyphenyl pinacolboronate: 63.0 mg, 88%); mp
175 °C (lit.21 mp 173−174 °C); 1H NMR (500 MHz, CDCl3) δ 8.09
(d, J = 8.2, 1H), 7.63 (d, J = 8.2, 1H), 7.59 (d, J = 8.8, 1H), 7.01 (d, J =
8.8, 1H), 3.95 (s, 2H), 3.87 (s, 2H); 13C NMR (126 MHz, CDCl3)
δ 167.1, 160.0, 145.4, 132.6, 130.3, 128.5, 128.4, 126.6, 114.5, 55.5, 52.2.
4,4′-Dimethoxy-1,1′-biphenyl (3f): white solid (Table 5: from
4-methoxyphenyl neopentylglycolboronate: 51.0 mg; 80%; from 4-
methoxyphenyl pinacolboronate: 29.5 mg, 46%; Table 6: from 4-metho-
xyphenyl neopentylglycolboronate: 53.5 mg; 93%; from 4-methox-
yphenyl pinacolboronate: 40.5 mg, 63%); mp 174 °C (lit.21 mp 171−
172 °C); 1H NMR (500 MHz, CDCl3) δ 7.53 − 7.44 (m, 1H), 7.01 −
6.91 (m, 1H), 3.84 (s, 2H); 13C NMR (126 MHz, CDCl3) δ 158.6,
133.4, 127.6, 114.1, 55.3.
Methyl 4′-methoxy(1,1′-biphenyl)-2-carboxylate (3g): color-
less oil (Table 5: from 4-methoxyphenyl neopentylglycolboronate:
67.0 mg; 93%; from 4-methoxyphenyl pinacolboronate: 65.0 mg, 90%;
Table 6: from 4-methoxyphenyl neopentylglycolboronate: 70 mg; 98%;
from 4-methoxyphenyl pinacolboronate: 70 mg, 98%); 1H NMR (500
MHz, CDCl3) δ 7.84 − 7.73 (m, 1H), 7.50 (tt, J = 13.6, 6.8, 1H), 7.43 −
7.31 (m, 2H), 7.31 − 7.19 (m, 4H), 6.99 − 6.89 (m, 2H), 3.85 (s, 3H),
3.67 (s, 3H); 13C (126 MHz, CDCl3) δ 169.3, 158.9, 141.9, 133.6, 131.1,
130.8, 130.6, 129.6, 129.4, 126.7, 113.5, 55.2, 51.9. NMR spectrum
matches with literature data.21
General Procedure for Kinetic Studies of the Cross-Coupling
Reactions. To an oven-dried test tube (15 × 85 mm) were added the
aryl mesylate (69 mg, 0.3 mmol), the aryl boronate (0.30 mmol), and
K3PO4 (191 mg, 0.9 mmol). The tube was taken into a glovebox.
Ni(COD)2 and PCy3 (10.1 mg, 0.036 mmol) was added. Dry THF
(2 mL) was added inside the glovebox. The tube was capped and allowed
to stir at room temperature. Samples were taken in the glovebox at
predetermined times and then dissolved in THF, passed though a short
neutral alumina gel column, and dried under vacuo. The conversion was
determined by 1H NMR spectroscopy. A representative example for the
determination of conversion is provided in the Supporting Information.
General Procedure for Kinetic Studies of the Diol-Exchange
Reactions. To an oven-dried test tube (15 × 85 mm) were added the
aryl boronates (0.3 mmol), the diol (0.30 mmol), and K3PO4 (191 mg,
0.9 mmol). The tube was taken into a glovebox. Dry THF (2 mL) was
added inside the glovebox. The tube was capped and allowed to stir
at room temperature. Samples were taken in the glovebox at pre-
determined times and then dissolved in THF, passed though a short
cotton column, and dried under vacuo. The conversion was determined
1
by HNMR spectroscopy. A representative example of the determi-
nation of conversion is provided in the Supporting Information.
General Procedure for the Turnover Number (TON) Measure-
ment. To an oven-dried test tube (15 × 85 mm) were added the aryl
mesylate (69 mg, 0.3 mmol), 4-methoxylphenyl neopentylglycolboro-
nate (0.30 mmol), and K3PO4 (191 mg, 0.9 mmol). To another oven-
dried test tube were added the aryl mesylate (69 mg, 0.3 mmol),
4-methoxylphenyl pinacolboronate (0.30 mmol), and K3PO4 (191 mg,
0.9 mmol). The tubes were taken into a glovebox. A stok solution of
Ni(COD)2 (1.7 mg, 0.002 mmol), PCy3 (3.3 mg, 0.0040 mmol), and dry
THF (1 mL) was prepared in the glovebox. Half of the solution (0.5 mL)
was added in each tube. Another 1 mL of THF was used to rinse the vial
and added evenly to the tubes. The tubes were capped and allowed to
stir at room temperature. After 60 h, the conversion was determined by
1H NMR spectroscopy, and the TONs were calculated.
2-(4-Methoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaboro-
lane (2c): colorless oil (3.48 g, 96%); 1H NMR (500 MHz, CDCl3) δ
7.80−7.71 (m, 2H), 6.93−6.84 (m, 2H), 3.83 (s, 3H), 1.33 (s, 12H); 13C
NMR (126 MHz, CDCl3) δ 136.4, 113.2, 83.5, 55.0, 24.8. NMR
spectrum is identical with literature data.57
Methyl 4′-methoxy(1,1′-biphenyl)-4-carboxylate (3a): white
solid (Table 5: from 4-methoxyphenyl neopentylglycolboronate: 72 mg;
99%; from 4-methoxyphenyl pinacolboronate: 41.0 mg, 57%; Table 6:
from 4-methoxyphenyl neopentylglycolboronate: 64.0 mg; 89%; from
4-methoxyphenyl pinacolboronate: 22.0 mg, 30%); mp 173 °C (lit.21
mp 173−174 °C); 1H NMR (500 MHz, CDCl3) δ 8.08 (d, J = 8.2, 11H),
7.60 (dd, J = 22.7, 8.3, 23H), 7.26 (s, 17H), 7.00 (d, J = 8.5, 11H), 3.90
(d, J = 35.1, 34H); 13C NMR (126 MHz, CDCl3) δ 159.7, 145.1, 132.3,
130.9, 130.0, 128.3, 128.2, 126.4, 114.3, 55.3, 52.0.
2,4′-Dimethoxy-1,1′-biphenyl (3h): white solid (Table 5: from
4-methoxyphenyl neopentylglycolboronate: 60.0 mg; 94%; from 4-
methoxyphenyl pinacolboronate: 56.0 mg, 88%; Table 6: from 4-metho-
xyphenyl neopentylglycolboronate: 64 mg; 99%; from 4-methoxyphenyl
pinacolboronate: 24.5 mg, 38%); mp 68 °C (lit.21 mp 64−66 °C); 1H
NMR (500 MHz, CDCl3) δ 7.51−7.45 (m, 2H), 7.29 (td, J = 7.4, 1.6,
2H), 7.02 (td, J = 7.4, 1.1, 1H), 7.00−6.93 (m, 3H), 3.85 (s, 3H), 3.81
(s, 3H); 13C NMR (126 MHz, CDCl3) δ 157.8, 155.7, 130.0, 129.8,
129.7, 129.5, 127.3, 120.0, 112.6, 110.3, 54.7, 54.4.
ASSOCIATED CONTENT
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S
* Supporting Information
1H NMR of reaction crude of Scheme 2, Tables 3 and 4; 1H NMR
and 13C NMR spectra of compounds 2c, 3a−h. This information
4,4′-Dimethoxy-1,1′-biphenyl (3b): white solid (Table 5: from
4-methoxyphenyl neopentylglycolboronate: 60.0 mg; 94%; from 4-
methoxyphenyl pinacolboronate: 32.3 mg, 50%; Table 6: from 4-metho-
xyphenyl neopentylglycolboronate: 60.2 mg; 94%; from4-methoxyphenyl
pinacolboronate: 36.0 mg, 56%); mp 173 °C (lit.21 mp 171−172 °C);
AUTHOR INFORMATION
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Corresponding Author
H
dx.doi.org/10.1021/jo300547v | J. Org. Chem. XXXX, XXX, XXX−XXX