J. Lu et al. / Tetrahedron 71 (2015) 7842e7846
7845
comparison to authentic standards. This methodology enables the
efficient synthesis of a variety of functionalized o-carborane clus-
ters derived from 1-haloalkyl-o-carboranes.
500 MHz, ppm):
d
3.48 (s, 1H), 2.11 (t, 2H, J¼8.5 Hz), 1.41e1.35 (m,
13
2H), 1.25e1.15 (m, 4H), 0.81 (t, 3H, J¼7.2 Hz). C NMR (CDCl
3
,
11
125 MHz, ppm):
d 75.5, 60.9, 38.1, 31.0, 28.8, 22.2, 13.8. B NMR
(
CDCl , 160 MHz, ppm):
3
d
ꢁ2.3 (d, J¼149.9 Hz, 1B), ꢁ5.8 (d,
1
ꢁ
4
4
. Experimental section
J¼147.0 Hz, 1B), ꢁ8.8e(ꢁ13.6) (m, 8B). FTIR (KBr, cm ):
n 3066,
þ
2
958, 2932, 2864, 2593, 1465, 1380, 723. EIMS [MþH] m/z 217.2.
.1. General information
Anal. calcd for C
7 22
H B10: C, 39.22; H, 10.34. Found: C, 39.90; H,
10.26.
Unless otherwise stated, all chemical reagents were purchased
and used as received from Aladdin Industrial Inc. without further
purification. Solvents were purchased from Guangdong Guanghua
Sci-Tech Co., Ltd. Magnesium, 1-bromopropane, 1-bromobutane, 1-
bromopentane, 1-bromooctane, tert-butylmagnesium chloride, and
N-methyl-2-pyrrolidone were purchased and used as received from
4.2.3. 1-(n-Hexyl)-1,2-dicarba-closo-dodecaborane
(6).7b Eluent:
1
hexane. Yield 80% (92 mg). Colorless liquid. H NMR (CDCl
500 MHz, ppm):
2H), 1.27e1.25 (m, 6H), 0.88 (t, 3H, J¼6.8 Hz). C NMR (CDCl
3
,
d
3.55 (s, 1H), 2.18 (t, 2H, J¼8.5 Hz), 1.46e1.43 (m,
1
3
3
,
B
11
125.7 MHz, ppm):
d
75.5, 60.9, 38.1, 31.3, 29.2, 28.6, 22.4, 13.9.
Meryer (Shanghai) Chemical Technology Co., Ltd. 1-BrCH
2
-1,2-
NMR (CDCl , 160.5 MHz, ppm):
3
d
ꢁ2.4 (d, J¼148.7 Hz, 1B), ꢁ5.9 (d,
ꢁ1
C
2
B
10
H11 were synthesized according to literature procedures. Re-
J¼147.4 Hz, 1B), ꢁ8.8e(ꢁ13.6) (m, 8B). FTIR (KBr, cm ):
n 3066,
þ
actions were monitored using thin layer chromatography (TLC)
plates. o-Carborane-containing species were visualized with 0.2%
2957, 2931, 2860, 2593, 1465, 1379, 723. EIMS [MþH] m/z 231.2.
Anal. calcd for C
8
24
H B10: C, 42.07; H,10.59. Found: C, 41.60; H,10.44.
2
PdCl in hydrochloric acid (3.0 M) which, upon heating, gave dark
brown spots. Column chromatography was accomplished with ul-
trapure silica gel (Yucheng Chemical Co., Ltd.).
4.2.4. 1-(n-Nonyl)-1,2-dicarba-closo-dodecaborane
(8).13 Eluent:
1
hexane. Yield 73% (99 mg). Colorless liquid. H NMR (CDCl
500 MHz, ppm): 3.55 (s,1H), 2.19e2.16 (m, 2H),1.48e1.42 (m, 2H),
1.30e1.25 (m,12H), 0.87 (t, 3H, J¼6.7 Hz). C NMR (CDCl
ppm): 75.5, 60.9, 38.1, 31.8, 29.3, 29.2, 29.1, 29.0, 28.9, 22.6, 14.0.
B NMR (CDCl , 160 MHz, ppm):
3
,
The 1H, C, and B NMR spectra were recorded on a Bruker
13
11
d
1
13
AV500 spectrometer. H chemical shifts are reported in ppm rela-
3
,125 MHz,
tive to the residual proton signal of the NMR solvents. Coupling
d
1
11
constants (J) are reported in Hertz (Hz). The H NMR spectra of o-
3
d
ꢁ2.3 (d, J¼148.6 Hz, 1B), ꢁ5.8 (d,
1
ꢁ
þ
carboranes typically exhibit a broad signal between 3.00 and
J¼144.2 Hz, 1B), ꢁ8.8e(ꢁ13.6) (m, 8B). FTIR (KBr, cm ):
n 3066,
ꢁ
0.75 ppm arising from the protons attached to the boron atoms of
the cage, which were not reported separately in the ensuing as-
2955, 2927, 2856, 2593, 1465, 1377, 723. EIMS [MþH] m/z 273.3.
Anal. calcd for C11
30
H B10: C, 48.53; H, 11.03. Found: C, 48.47; H,
signments. 13C chemical shifts are reported in ppm relative to the
carbon signal of the NMR solvents. B chemical shifts are reported
in ppm relative to an external standard of BF $Et O. Low resolution
10.95.
11
3
2
4.2.5. 1-(4-Methyl-1-pentyl)-1,2-dicarba-closo-dodecaborane
(10). Eluent: hexane. Yield 75% (86 mg). Colorless liquid. H NMR
1
mass spectra were obtained on a Thermo ITQ700 instrument using
electron impact ionization. Infrared spectra were obtained on
a Bruker Tensor 27 spectrometer using KBr pellets. Melting points
were obtained on a standard melting point apparatus and are un-
corrected. Gas chromatograph were obtained on a Shimadzu GC-
(CDCl
3
, 500 MHz, ppm):
d
3.55 (s, 1H), 2.17 (t, 2H, J¼8.5 Hz),
1.55e1.49 (m, 1H), 1.48e1.41 (m, 2H), 1.15e1.11 (m, 2H), 0.87 (d, 6H,
13
J¼6.6 Hz). C NMR (CDCl
3
, 125 MHz, ppm): 75.5, 60.9, 38.3, 38.0,
d
11
27.6, 27.1, 22.4. B NMR (CDCl , 160 MHz, ppm): ꢁ2.4 (d,
3
d
2
014C.
J¼149.5 Hz, 1B), ꢁ5.9 (d, J¼146.6 Hz, 1B), ꢁ8.8e(ꢁ13.6) (m, 8B).
ꢁ1
FTIR (KBr, cm ):
n
þ
3066, 2957, 2930, 2870, 2593, 1465, 1386, 1368,
4
.2. General synthetic procedure
723. EIMS [MþH] m/z 231.2. Anal. calcd for C
8 24
H B10: C, 42.10; H,
10.52. Found: C, 42.33; H, 10.63.
1
-Bromomethyl-o-carborane (119 mg, 0.5 mmol), NiCl
2
(13 mg,
0
.1 mmol) and NMP (30 mg, 0.3 mmol) were added to a 25-mL
4.2.6. 1-(4-Pentenyl)-1,2-dicarba-closo-dodecaborane
14
1
Schlenk flask charged with a magnetic stirrer. The flask was evac-
uated and backfilled with nitrogen, and then dry THF (4 mL) and
freshly prepared Grignard reagents (1.0 mmol) were added to the
flask under a stream of nitrogen. After completion of the reaction,
the resulting solution was cooled to room temperature, and the
(12). Eluent: hexane. Yield 63% (67 mg). Colorless liquid. H NMR
(CDCl , 500 MHz, ppm): 5.74e5.66 (m, 1H), 5.02e5.01 (m, 1H),
4.99 (s, 1H), 3.54 (s, 1H, CclusterꢁH), 2.20e2.16 (m, 2H), 2.04e2.00
3
d
1
3
(m, 2H),1.59e1.52 (m, 2H). C NMR (CDCl
3
,125 MHz, ppm):
d 136.7,
11
116.0, 75.2, 61.0, 37.4, 32.7, 28.2. B NMR (CDCl , 160 MHz, ppm):
3
reaction was quenched with a saturated aqueous solution of NH
4
Cl
4 mL), and the product was extracted with diethyl ether
. The solvent
d
ꢁ2.3 (d, J¼148.6 Hz, 1B), ꢁ5.7 (d, J¼137.9 Hz, 1B), ꢁ8.8e(ꢁ13.6)
ꢁ
1
(
(
(m, 8B). FTIR (KBr, cm ):
n
3065, 2979, 2957, 2935, 2866, 2594,
þ
10 mLꢂ3). The organic layer was dried over MgSO
4
1459, 1440, 993, 917, 723. EIMS [MþH] m/z 215.2. Anal. calcd for
was removed with the aid of a rotary evaporator, and the residue
was purified by column chromatography on silica gel using n-
hexane as eluent to provide the desired product.
7 20
C H B10: C, 39.59; H, 9.49. Found: C, 39.70; H, 9.66.
4.2.7. 1-(2,2-Dimethyl-1-proyl)-1,2-dicarba-closo-dodecaborane
14). Eluent: hexane. Yield 69% (74 mg). White solid,
(
(2).8a Eluent:
hexane. Yield 78% (79 mg). Colorless liquid. H NMR (CDCl
00 MHz, ppm): 3.55 (s, 1H), 2.21e2.17 (m, 2H),1.46e1.40 (m, 2H),
mp¼66e67 C. H NMR (500 MHz, CDCl 3.56 (s,1H), 2.26 (s, 2H),
1.03 (s, 9H). C NMR (126 MHz, CDCl ) d 74.32, 63.10, 51.75, 33.39,
3
29.39. B NMR (160 MHz, CDCl
ꢀ
13
1
4
.2.1. 1-(n-Butyl)-1,2-dicarba-closo-dodecaborane
3
) d
1
3
,
11
5
d
3
)
d
ꢁ2.12 (d, J¼150.2 Hz, 1B), ꢁ5.02
13
ꢁ1
1
.31e1.28 (m, 2H), 0.89 (t, 3H, J¼7.3 Hz). C NMR (CDCl
3
, 125 MHz,
, 160 MHz,
ꢁ2.4 (d, J¼148.8 Hz, 1B), ꢁ5.9 (d, J¼147.9 Hz, 1B),
(d, J¼149.9 Hz, 1B), ꢁ7.90eꢁ14.64 (m, 8B). FTIR (KBr, cm ):
n
3059,
1
1
þ
ppm):
ppm):
d
75.4, 60.9, 37.8, 31.2, 22.1, 13.6. B NMR (CDCl
3
2960, 2940, 2862, 2589, 1444, 1398, 1350, 722. EIMS [MþH] m/z
d
217.3. Anal. calcd for C
7 22
H B10: C, 39.22; H, 10.34. Found: C, 39.38;
ꢁ
1
ꢁ
8.8ꢁ(ꢁ13.6) (m, 8B). FTIR (KBr, cm ):
n 3066, 2961, 2934, 2874,
H, 10.40.
þ
2
593, 1467, 1442, 1382, 723. EIMS [MþH] m/z 203.2. Anal. calcd for
C
H
6 20
B
10: C, 35.97; H, 10.06. Found: C, 36.31; H, 10.54.
4.2.8. 1-[2-(2,4,6-Trimethylphenyl)-1-methyl]-1,2-dicarba-closo-do-
decaborane (16). Eluent: hexane. Yield 66% (91 mg). White solid,
ꢀ
1
4
.2.2. 1-(n-Pentyl)-1,2-dicarba-closo-dodecaborane
(4). Eluent:
mp¼105e106 C. H NMR (500 MHz, CDCl
3
)
d
6.87 (s, 2H), 3.60 (s,
1
13
hexane. Yield 83% (90 mg). Colorless liquid. H NMR (CDCl
3
,
2H), 3.41 (s,1H), 2.30 (s, 6H), 2.27 (s, 3H). C NMR (126 MHz, CDCl
3
)