4-Methyl-4′-neopentylbiphenyl (3k) was prepared by the
reaction of 1f (136 mg, 0.30 mmol) with neopentylmagnesium
bromide 2b (0.5 M in THF, 1.80 mL, 0.90 mmol + 1.20 mL, 0.60
mmol) in the presence of dppeNiCl2. The crude compound was
purified by column chromatography (EtOAc/n-hexane ) 1:10)
to give 3k (55.78 mg, 78%) as a white solid: TLC Rf 0.74 (EtOAc/
n-hexane ) 1:4); mp 69-70 °C (uncorrected); 1H NMR (300 MHz,
CDCl3) δ 0.94 (s, 9H), 2.39 (s, 3H), 2.53 (s, 2H), 7.18 (d, J ) 8.1
Hz, 2H), 7.24 (d, J ) 8.1 Hz, 2H), 7.48 (d, J ) 8.3 Hz, 2H), 7.50
(d, J ) 8.3 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ 21.1, 29.4 (×3),
31.8, 49.8, 126.1 (×2), 126.8 (×3), 129.4 (×2), 130.8 (×2), 136.7,
138.5, 138.6. Anal. Calcd for C18H22: C, 90.70; H, 9.30. Found:
C, 90.53; H, 9.21.
2-(2-Methyl-2-phenylpropyl)naphthalene (3l) was pre-
pared by the reaction of 1b (106 mg, 0.30 mmol) with 2-methyl-
2-phenylpropylmagnesium chloride 2c (0.5 M in Et2O, 1.8 mL,
0.90 mmol + 1.2 mL, 0.60 mmol) in the presence of dppeNiCl2.
The crude compound was purified by preparative TLC in
n-hexane to afford 3l (58.58 mg, 75%) as a white solid: TLC Rf
0.72 (EtOAc/n-hexane ) 1:4); mp 68-69 °C (uncorrected); 1H
NMR (500 MHz, CDCl3) δ 1.37 (s, 6H), 3.03 (s, 2H), 6.88 (dd, J
) 8.40, 1.61 Hz, 1H), 7.18-7.23 (m, 1H), 7.27-7.34 (m, 5H),
7.37-7.43 (m, 2H), 7.58 (d, J ) 8.40 Hz, 1H), 7.66 (dd, J ) 6.66,
2.42 Hz, 1H), 7.75 (dd, J ) 6.66, 2.42 Hz, 1H); 13C NMR (75
MHz, CDCl3) δ 28.4 (×2), 39.1, 51.4, 125.4, 125.8, 126.0, 126.5,
126.9 (×2), 127.7, 127.8, 128.2 (×2), 129.1, 129.4, 132.3, 133.4,
136.8, 149.2; HRMS (EI, 70 eV) calcd for C20H20 (M+) 260.1565,
versatile means of cleaving the carbon-sulfur bond is
required, such as in the cleavage of polymer-bound
substrates in solid-phase organic synthesis (SPOS).
In summary, various neopentyl arenesulfonates were
reacted with methyl and primary alkylmagnesium bro-
mides in the presence of dppeNiCl2 to give the corre-
sponding alkylarenes in good yields. This reaction rep-
resents a novel method allowing the efficient and creative
substitution of sulfur-containing groups in aromatic
compounds. It also shows that the alkyloxysulfonyl group
might be a suitable alternative to halides and triflate in
some circumstances, especially when a chemoselective
leaving group, which is inert toward palladium catalysts
but reactive with nickel catalysts, is desirable. The
reactions of arenesulfonates with various alkylmagne-
sium halides are currently under investigation and will
be reported in due course.
Experimental Section
General Procedure for Preparation of Arenesulfonates
(1). To 2,2-dimethyl-3-phenyl-1-propanol (5.52 mmol) in chlo-
roform (12 mL) at 0 °C were added pyridine (0.85 mL, 10.5 mmol)
dropwise over a period of 20 min and sulfonyl chloride (5.25
mmol) in small portions. The reaction mixture was stirred at
room temperature for 12 h and diluted with Et2O. The organic
layer was washed with 0.1% aqueous HCl, water, and brine;
dried over MgSO4; and concentrated in vacuo. The crude
sulfonates 1 were purified by either column chromatography or
recrystallization.
found 260.1554. Anal. Calcd for C20H20
: C, 92.26; H, 7.74.
Found: C, 91.98; H, 7.72.
4-(2-Methyl-2-phenylpropyl)biphenyl (3m) was prepared
by the reaction of 1e (114 mg, 0.30 mmol) with 2-methyl-2-
phenylpropylmagnesium chloride 2c (0.5 M in Et2O, 1.8 mL, 0.90
mmol + 1.2 mL, 0.60 mmol) in the presence of dppeNiCl2. The
crude compound was purified by recrystallization in ethanol to
afford 3m (52.41 mg, 61%) as a white solid: TLC Rf 0.72 (EtOAc/
n-hexane ) 1:4); mp 94-95 °C (uncorrected); 1H NMR (500 MHz,
CDCl3) δ 1.35 (s, 6H), 2.91 (s, 2H), 6.87 (d, J ) 8.11 Hz, 2H),
7.18-7.22 (m, 1H), 7.28-7.34 (m, 5H), 7.36-7.42 (m, 4H), 7.55
(d, J ) 7.24 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ 28.4 (×2),
39.0 (×2), 50.9, 125.9, 126.4 (×2), 126.5 (×2), 127.2 (×2), 127.2,
128.2 (×2), 129.0 (×2), 131.1 (×2), 138.3, 139.0, 141.3, 149.3;
HRMS (EI, 70 eV) calcd for C22H22 (M+) 286.1721, found
286.1726. Anal. Calcd for C22H22: C, 92.26; H, 7.74. Found: C,
92.18; H, 7.65.
Dineopentyl 4,4′-biphenyldisulfonate (1d) was prepared
by the reaction of neopentyl alcohol (0.63 g, 7.13 mmol) with
sulfonyl chloride (1.0 g, 2.85 mmol). The crude compound was
purified by recrystallization from n-hexane to give 1d (1.08 g,
83%) as a white solid: TLC Rf 0.74 (EtOAc); mp 193-194 °C
1
(uncorrected); H NMR (300 MHz, CDCl3) δ 0.93 (s, 18H), 3.75
(s, 4H), 7.79 (d, J ) 8.56 Hz, 4H), 8.03 (d, J ) 8.56 Hz, 4H); 13
C
NMR (75 MHz, CDCl3) δ 26.1 (×6), 31.8 (×2), 80.1 (×2), 128.4
(×4), 128.9 (×4), 136.3 (×2), 144.6 (×2); HRMS (EI, 70 eV) calcd
for C22H30O6S2 (M+) 454.1484, found 454.1480. Anal. Calcd for
C
22H16O6S2: C, 58.12; H, 6.65; S, 14.11. Found: C, 58.16; H,
6.32; S, 14.03.
4-Methoxy-4′-(2-methyl-2-phenylpropyl)biphenyl (3n) was
prepared by the reaction of 1h (123 mg, 0.30 mmol) with
2-methyl-2-phenylpropylmagnesium chloride 2c (0.5 M in Et2O,
1.8 mL, 0.90 mmol + 1.2 mL, 0.60 mmol) in the presence of
dppeNiCl2. The crude compound was purified by recrystallization
in ethanol to afford 3n (62.66 mg, 66%) as a white solid: TLC
Rf 0.54 (EtOAc/n-hexane ) 1:4); mp 112-113 °C (uncorrected);
1H NMR (500 MHz, CDCl3) δ 1.35 (s, 6H), 2.90 (s, 2H), 3.84 (s,
3H), 6.85 (d, J ) 8.16 Hz, 2H), 6.94 (d, J ) 8.77 Hz, 2H), 7.18-
7.22 (m, 1H), 7.28-7.34 (m, 6H), 7.48 (d, J ) 8.77 Hz, 2H); 13C
NMR (75 MHz, CDCl3) δ 28.3 (×2), 39.0 (×2), 50.9, 55.5, 114.4
(×2), 125.9, 125.7 (×2), 126.5 (×2), 128.2 (×2), 128.2 (×2), 131.1
(×2), 133.9, 137.7, 138.6, 149.3, 159.3; HRMS (EI, 70 eV) calcd
for C23H24O (M+): 316.1827. found 316.1811. Anal. Calcd for
General Procedure for the Cross-Coupling Reactions
of 1 with 2. To a stirred solution of sulfonate 1 (0.30 mmol)
and dppeNiCl2 (0.015 mmol) in THF (10 mL) was slowly added
Grignard reagents 2 (0.90 mmol) at room temperature. The
reaction mixture was heated at reflux for 6 h and cooled to room
temperature, and an additional 0.60 mmol of 2 was added to
the solution. The resulting mixture was heated at reflux for 6
h, cooled to room temperature, and diluted with Et2O. The
organic layer was washed with 1% aqueous HCl, water, and
brine; dried over MgSO4; and concentrated in vacuo.
N,N-Dimethyl-5-methyl-1-naphthalenamine (3c) was pre-
pared by the reaction of 1c (119 mg, 0.30 mmol) with methyl-
magnesium bromide 2a (3.0 M in Et2O, 0.30 mL, 0.90 mmol +
0.20 mL, 0.60 mmol) in the presence of dppeNiCl2. The crude
compound was purified by column chromatography (ethyl acetate:
n-hexane ) 1:10) to give 3c (43.9 mg, 79%) as a yellow oil: TLC
Rf 0.53 (Et2O/n-hexane ) 1:4); 1H NMR (300 MHz, CDCl3) δ 2.68
(s, 3H), 2.89 (s, 6H), 7.10 (d, J ) 7.22 Hz, 1H), 7.28-7.45 (m,
3H), 7.69 (d, J ) 8.39 Hz, 1H), 8.14 (d, J ) 8.39 Hz, 1H); 13C
NMR (75 MHz, CDCl3) δ 19.9, 45.4 (×2), 114.1, 119.3, 122.7,
125.0, 125.8, 126.8, 129.2, 134.2, 134.8, 151.6; HRMS (EI, 70
eV) calcd for C13H15N (M+), 185.1204, found 185.1286.
C
23H24O: C, 87.30; H, 7.64. Found: C, 86.94; H, 7.52.
Supporting Information Available: Detailed experi-
mental procedures and spectroscopic data for 1a-1j and 3c,
3f, 3g, and 3i-3o. This material is available free of charge
JO048300C
J. Org. Chem, Vol. 70, No. 4, 2005 1485