14
S. Yasuike et al. / Journal of Organometallic Chemistry 788 (2015) 9e16
bromide (5.97 g, 16.5 mmol) in THF (50 mL) was added dropwise
at ꢁ10 ꢀC, and the resulting mixture was gradually raised to room
temperature and stirred overnight. The reaction mixture was
diluted with ether (200 mL) quenched with water and insoluble
substances were filtered off. The mixture was extracted with ether
(200 mL). The combined extracts were washed with brine and dried
over anhydrous magnesium sulfate. The dried organic layer was
concentrated under reduced pressure. The residue was purified on
silica gel column chromatography (hexane:CH2Cl2 ¼ 4:1) to give 1j
(4.6 g, 54% yield). Colorless needles (mp 205e207 ꢀC). 1H NMR
5,5-Dimethyl-phenyl-1,3,2-dioxaborinane (3a) [14]: Colorless
plates (mp 62e64.5 ꢀC). 1H NMR (400 MHz, CDCl3)
: 1.04 (6H, s),
d
3.78 (4H, s), 7.27e7.44 (3H, m), 7.81 (2H, d, J ¼ 6.9 Hz).
5,5-Dimethyl-2-(4-methoxyphenyl)-1,3,2-dioxaborinane
(3b)
[14]: Colorless prisms (mp 54e56 ꢀC). 1H NMR (400 MHz, CDCl3)
d:
1.01 (6H, s), 3.75 (4H, s), 3.82 (3H, s), 6.88 (2H, d, J ¼ 8.7 Hz), 7.74
(2H, d, J ¼ 8.7 Hz).
5,5-Dimethyl-2-(4-t-butylphenyl)-1,3,2-dioxaborinane (3c) [22]:
Colorless prisms (mp 78e78.5 ꢀC). 1H NMR (400 MHz, CDCl3)
d: 1.01
(6H, s), 1.32 (9H, s), 3.76 (4H, s), 7.39 (2H, d, J ¼ 8.2 Hz), 7.74 (2H, d,
(400 MHz, CDCl3) d: 7.29e7.36 (6H, m), 7.63 (3H, s), 7.79 (3H, d,
J ¼ 8.2 Hz).
J ¼ 7.8 Hz), 7.83 (3H, d, J ¼ 7.3 Hz). 13C NMR (100 MHz, CDCl3)
d
:
5,5-Dimethyl-2-(2,4,6-trimethylphenyl)-1,3,2-dioxaborinane (3d)
[23]: Colorless prisms (mp 45e46.5 ꢀC). 1H NMR (400 MHz, CDCl3)
122.04 (d), 123.51 (d), 124.22 (d), 124.57 (d), 134.31 (s), 134.71 (d),
140.56 (s), 144.85 (s). LRMS (EI) m/z: 520 (25), 266 (100), 254 (52),
134 (3). Anal. Calc. for C24H15S3Sb: C, 55.29; H, 2.90. Found: C, 55.11;
H, 3.06.
d: 1.09 (6H, s), 2.23 (3H, s), 2.35 (6H, s), 3.77 (4H, s), 6.77 (2H, s).
5,5-Dimethyl-2-(4-trimethylsilylphenyl)-1,3,2-dioxaborinane (3e)
[24]: Colorless prisms (mp 73.5e75 ꢀC). 1H NMR (400 MHz, CDCl3)
d
: 0.30 (9H, s), 1.05 (6H, s), 3.80 (4H, s), 7.55 (2H, d, J ¼ 7.8 Hz), 7.81
Synthesis of tris(3,5-dichlorophenyl)stibane (1n) and tris[3,5-
bis(trifluoromethyl)phenyl]stibane (1o): general procedure
3,5-Dichloro-1-bromobenzene (7.46 g, 33.0 mmol) or 3,5-
bis(trifluoromethyl)-1-bromobenzene (9.67 g, 33.0 mmol) was
dissolved in ether (70 mL). To this solution, BuLi (1.58 M in hexane,
20.9 mL, 33.0 mmol) was added using syringe through septum cap
at ꢁ78 ꢀC for 20 min, and the mixture was stirred for 2 h at ꢁ78 ꢀC.
To the reaction mixture a solution of antimony (III) boromide
(3.61 g, 10.0 mmol) in ether (50 mL) was added dropwise at ꢁ78 ꢀC,
and the resulting mixture was gradually raised to room tempera-
ture and stirred overnight. The reaction mixture was diluted with
ether (150 mL) quenched with water. The mixture was extracted
with ether (150 mL). The combined extracts were washed with
brine and dried over anhydrous magnesium sulfate. The dried
organic layer was concentrated under reduced pressure. The res-
idue was purified on silica gel column chromatography to give 1n
(hexane, 4.5 g, 80% yield) and 1o (hexane:CH2Cl2 ¼ 4:1, 6.9 g, 91%
yield).
(2H, d, J ¼ 7.8 Hz).
5,5-Dimethyl-2-(4-methylphenyl)-1,3,2-dioxaborinane (3f) [14]:
Colorless plates (mp 92e95 ꢀC). 1H NMR (400 MHz, CDCl3)
d: 1.01
(6H, s), 2.36 (3H, s), 3.75 (4H, s), 7.17 (2H, d, J ¼ 7.8 Hz), 7.69 (2H, d,
J ¼ 7.8 Hz).
5,5-Dimethyl-2-(3-methylphenyl)-1,3,2-dioxaborinane (3g) [25]:
Colorless prisms (mp 94e95 ꢀC). 1H NMR (400 MHz, CDCl3)
(6H, s), 2.35 (3H, s), 3.77 (4H, s), 7.24e7.62 (4H, m).
d: 1.02
5,5-Dimethyl-2-(2-methylphenyl)-1,3,2-dioxaborinane (3h) [14]:
Colorless oil. 1H NMR (400 MHz, CDCl3)
d
: 1.03 (6H, s), 2.51 (3H, s),
3.77 (4H, s), 7.13e7.29 (3H, m), 7.72 (1H, d, J ¼ 7.3 Hz).
5,5-Dimethyl-2-(1-naphthyl)-1,3,2-dioxaborinane
(3i)
[14]:
: 1.10
Colorless prisms (mp 68e70 ꢀC). 1H NMR (400 MHz, CDCl3)
d
(6H, s), 3.89 (4H, s), 7.44e7.51 (3H, m), 7.82 (1H, d, J ¼ 8.7 Hz), 7.89
(1H, d, J ¼ 8.3 Hz), 8.03 (1H, d, J ¼ 6.9 Hz), 8.73 (1H, d, J ¼ 8.2 Hz).
5,5-Dimethyl-2-(2-benzo[b]thienyl)-1,3,2-dioxaborinane
(3j)
[26]: Colorless prisms (mp 138e139.5 ꢀC). 1H NMR (400 MHz,
CDCl3) : 1.04 (6H, s), 3.79 (4H, s), 7.31e7.36 (2H, m), 7.81 (1H, s),
d
Tris(3,5-dichlorophenyl)stibane (1n): Colorless prisms (mp
7.83e7.90 (2H, m).
136e137 ꢀC). 1H NMR (400 MHz, CDCl3)
d
: 7.23 (6H, s), 7.40 (3H, s).
5,5-Dimethyl-2-(4-fluorophenyl)-1,3,2-dioxaborinane (3k) [14]:
13C NMR (100 MHz, CDCl3)
d
: 129.95 (d), 133.56 (d), 136.25 (s),
Colorless needles (mp 65e67 ꢀC). 1H NMR (400 MHz, CDCl3)
(6H, s), 3.76 (4H, s), 7.00e7.05 (2H, m), 7.76e7.80 (2H, m).
d: 1.02
139.96 (s). LRMS (EI) m/z: 560 (19), 413 (19), 268 (100). Anal. Calc.
for C18H9Cl6Sb: C, 38.62; H, 1.62. Found: C, 38.66; H, 1.85.
Tris[3,5-bis(trifluoromethyl)phenyl]stibane (1o): Pale yellow
5,5-Dimethyl-2-(4-chlorophenyl)-1,3,2-dioxaborinane (3l) [14]:
Colorless plates (mp 97e99 ꢀC). 1H NMR (400 MHz, CDCl3)
d
: 1.03
prisms (mp 113e115 ꢀC). 1H NMR (400 MHz, CDCl3)
d
: 7.86 (6H, s),
(6H, s), 3.77 (4H, s), 7.33 (2H, d, J ¼ 8.2 Hz), 7.73 (2H, d, J ¼ 8.2 Hz).
5,5-Dimethyl-2-(4-trifluoromethylphenyl)-1,3,2-dioxaborinane
(3m) [22]: Colorless needles (mp 106e108 ꢀC). 1H NMR (400 MHz,
7.95 (3H, s). 13C NMR (100 MHz, CDCl3)
d: 122.89 (d), 124.01 (d),
132.66 (q), 135.62 (d), 139.24 (s). LRMS (EI) m/z: 760 (8), 741 (11),
547 (12), 407 (100). Anal. Calc. for C24H9F18Sb: C, 37.88; H, 1.19.
Found: C, 37.95; H, 1.49.
CDCl3)
J ¼ 7.8 Hz).
5,5-Dimethyl-2-(3,5-dichlorophenyl)-1,3,2-dioxaborinane (3n):
Colorless prisms (mp 64e66 ꢀC). 1H NMR (400 MHz, CDCl3)
1.01(6H, s), 3.76 (4H, s), 7.39 (1H, t, J ¼ 1.8 Hz), 7.63 (2H, d, J ¼ 1.8 Hz).
13C NMR (100 MHz, CDCl3)
: 21.80 (q), 31.88 (s), 72.39 (t),130.45 (d),
131.91 (d),134.50 (s). LRMS (EI) m/z: 258 (100),187 (8). Anal. Calc. for
d: 1.03 (6H, s), 3.79 (4H, s), 7.59 (2H, d, J ¼ 7.8 Hz), 7.90 (2H, d,
Reaction of triarylstibanes with boron trihalides: general procedure
d:
All reactions were carried out under argon using standard
Schlenk techniques. Boron trichloride (1.0 M solution in dichloro-
methane, 1.8 mL, for 1ael) or boron tribromide (1.0 M solution in
dichloromethane, 1.8 mL, for 1meo) was added to a stirred solution
of triarylstibane 1aeo (0.5 mmol) in dichloromethane (0.5 mL) at
0 ꢀC. The mixture was stirred for 2 h at 0 ꢀC (for 1ael) or 4 h at room
temperature (for 1m) or 24 h at room temperature (for 1n and 1o).
The solvent was removed under reduced pressure at room tem-
perature and the residual oil was dissolved in methanol (1.5 mL).
After the mixture was stirred for 30 min, 2,2-dimethyl-1,3-
propanediol (5.0 mmol) was added and the stirring was
continued for 1 h. The solvent was removed under reduced pres-
sure. The residue was purified on silica gel column chromatography
(hexane: CH2Cl2) to give arylboronate 3. The products were
confirmed by comparison of NMR data and MS spectra with that in
the literature.
d
C11H13BCl2O2: C, 51.02; H, 5.06. Found: C, 51.13; H, 4.98.
5,5-Dimethyl-2-[3,5-bis(trifluoromethyl)phenyl]-1,3,2-
dioxaborinane (3o): Colorless prisms (mp 89e93 ꢀC). 1H NMR
(400 MHz, CDCl3)
d
: 1.04 (6H, s), 3.81 (4H, s), 7.91 (1H, s), 8.24 (2H,
s). 13C NMR (100 MHz, CDCl3)
d
: 21.80 (q), 31.96 (s), 72.46 (t), 123.64
(d), 124.14 (d), 130.61 (q), 133.83 (d). LRMS (EI) m/z: 326 (100), 307
(60), 283 (65), 255 (20). Anal. Calc. for C13H13BF6O2: C, 47.89; H,
4.02. Found: C, 47.40; H, 4.03.
One-pot two-step transmetallation/cross-coupling reactions
Synthesis of unsymmetrical biaryls: general procedure
All reactions were carried out under argon using standard
Schlenk techniques. Boron trichloride (1.0
M solution in