Organometallics
Article
Preparation of [PPh2(o-C6H4BPh3)][PPh4]. A solution of tBuLi
in pentane (1.54 M, 519 μL, 0.80 mmol) was added over 5 min to a
solution of (2-bromophenyl)diphenylphosphine (273 mg, 0.80 mmol)
in THF (5 mL) at −98 °C. After the solution was stirred for 1 h, Ph3B
(193.7 mg, 0.80 mmol) in THF (2.5 mL) was added at −98 °C. The
resulting mixture was allowed to warm gradually to room temperature
over 2 h. The volatiles were removed under reduced pressure, and
then Ph4PBr (335.4 mg, 0.80 mmol) in CH2Cl2 (3 mL) was added to
the flask. The resulting mixture was stirred, and then it was filtered on
a pad of Celite. The filtrate was evaporated. The residue was
redissolved in MeCN, and then the mixture was allowed to stand
overnight. The forming precipitates were filtered to give [PPh2(o-
C6H4BPh3)][PPh4] as a white solid (316.3 mg, 47% yield). mp 246−
248 °C. 1H NMR (400 MHz, acetone-d6): δ 6.63 (t, J = 7.2 Hz, 3H),
6.76 (t, J = 7.2 Hz, 6H), 6.79−6.86 (m, 5H), 6.91 (t, J = 7.2 Hz, 1H),
6.98−7.04 (m, 6H), 7.08 (dd, J = 7.6, 4.0 Hz, 1H), 7.36 (br-m, 6H),
7.42 (br-m, 1H), 7.80−7.88 (m, 16H), 7.95−8.01 (m, 4H). All
coupling constants could not be extracted due to broadening of the
hexane. mp 193 °C (decomp.). 1H NMR (400 MHz, CD2Cl2): δ 0.93
(t, J = 7.2 Hz, 12H), 1.14−1.31 (m, 16H), 2.54−2.65 (m, 8H), 3.05
(d, J = 12.4 Hz, 1H), 3.91−4.02 (m, 2H), 4.86 (t, J = 6.8 Hz, 1H),
5.74−5.85 (m, 1H), 6.89 (td, J = 7.2 Hz, JH−P = 3.2 Hz, 3H), 6.97 (t, J
= 7.2 Hz, 3H), 7.27 (t, J = 7.2 Hz, 1H), 7.44 (t, J = 7.2 Hz, 2H), 7.56
(d, J = 7.2 Hz, 3H), 8.04−8.12 (m, 5H). 13C{1H} NMR (100.5 MHz,
CD2Cl2): δ 13.8 (4C), 19.9 (4C), 24.0 (4C), 55.2, 58.6 (4C), 82.2 (d,
JC−P = 30.7 Hz), 116.6 (d, JC−P = 4.7 Hz), 122.0 (d, JC−P = 17.4 Hz,
3C), 123.7, 126.7 (3C), 127.0 (2C), 131.4 (d, JC−P = 5.8 Hz, 3C),
132.4 (d, JC−P = 25.9 Hz, 3C), 136.8 (2C), 140.7 (d, JC−P = 43.1 Hz,
3C), 154.0 (q, JC−B = 60.4 Hz), 167.8 (q, JC−B = 45.9 Hz, 3C). 31P{1H}
NMR (161.8 MHz, CD2Cl2): δ − 6.8 (partially relaxed 1:1:1:1 quartet,
JP−B = ∼ 15 Hz). 11B{1H} NMR (128.3 MHz, CD2Cl2): − 9.3 (d, JB−P
= 12.3 Hz). IR (ATR): 3040.0, 2961.7, 2872.1, 1485.8, 1427.5, 1381.7,
879.8, 756.4, 709.1, 695.3 cm−1. ESI-HRMS (m/z): [M−NBu4]− calcd
for C27H22BClPPd, 529.02874 (considering isotope natural abundan-
ces); found, 529.02667. Anal. Calcd for C43H58BClNPPd: C, 66.85; H,
7.57; N, 1.81. Found: C, 66.62; H, 7.58; N, 1.80.
signals. 13C{1H} NMR (100.5 MHz, acetone-d6): δ 118.9 (d, JC−P
=
Preparation of [Pd(η3-allyl)(MeCN)(L)]. A mixture of L-Na (29.6
mg, 0.08 mmol), [PdCl(η3-allyl)]2 (14.6 mg, 0.04 mmol), MeCN (1
mL) and CH2Cl2 (1 mL) was stirred at room temperature for 30 min.
The pale-yellow suspension was filtered through a pad of Celite. The
filtrate was concentrated to ca. 1 mL. White crystals formed upon
concentration. The crystals were collected by filtration to give [Pd(η3-
allyl)(MeCN)(L)] acetonitrile monosolvate as a white solid (33.8 mg,
79% yield). Single crystals of [Pd(η3-allyl)(MeCN)(L)]·(MeCN)
suitable for X-ray diffraction studies were obtained by recrystallization
90.0 Hz, 4C), 121.8 (3C), 123.3, 125.7 (q, JC−B = 2.9 Hz, 6C), 126.7
(2C), 126.9, 127.7 (d, JC−P = 4.8 Hz, 4C), 131.4 (d, JC−P = 12.5 Hz,
8C), 134.0 (d, JC−P = 18.2 Hz, 4C), 135.6 (d, JC−P = 10.6 Hz, 8C),
136.3 (q, JC−B = 2.9 Hz, 6C), 137.2 (overlapping), 137.4, 137.5 (4C),
142.3 (d, JC−P = 13.4 Hz), 144.2 (d, JC−P = 22.9 Hz, 2C). Signals for
carbon directly attached to boron atom was not observed. 31P{1H}
NMR (161.8 MHz, acetone-d6): − 11.5 (partially relaxed 1:1:1:1
quartet, JP−B = ∼ 10 Hz), 24.7. 11B{1H} NMR (128.3 MHz, CDCl3): δ
− 5.2 (d, JB−P = 7.3 Hz). IR (ATR): 3054.9, 1579.5, 1474.4, 1435.0,
1108.3, 995.6, 835.5, 748.6, 724.2, 704.0 cm−1. ESI-HRMS (m/z):
[M−PPh4]− calcd for C36H2910BP−, 502.21417; found, 502.21598.
Anal. Calcd for C60H49BP2: C, 85.51; H, 5.86. Found: C, 84.88; H,
5.75 (although this data is outside the range viewed as establishing
analytical purity, its compound identification is unambiguously
accomplished by NMR and ESI-HRMS spectroscopies).
1
from CH2Cl2/MeCN. mp 170 °C (decomp.). H NMR (400 MHz,
CD2Cl2/CD3CN = 10:1): δ 3.31 (br-s, 1H), 4.11 (dd, J = 14.0, 8.4 Hz,
1H), 4.33 (br-s, 1H), 5.24 (t, J = 6.8 Hz, 1H), 5.92 (m, 1H), 6.92 (tdd,
J = 7.2, 1.6 Hz, JH−P = 3.2 Hz, 3H), 7.01 (tt, J = 7.2, 1.2 Hz, 3H), 7.26
(t, J = 7.2 Hz, 1H), 7.44 (t, J = 7.2 Hz, 2H), 7.58 (br-d, J = 7.2 Hz,
3H), 7.67 (ddd, J = 7.2, 1.2 Hz, JH−P = 9.6 Hz, 3H), 8.03 (br-d, J = 7.2
Hz, 2H). All coupling constants could not be extracted due to
broadening of the signals. 13C{1H} NMR (100.5 MHz, CD2Cl2/
Preparation of [Se-PPh2(o-C6H4BPh3)][PPh4]. A mixture of
[PPh2(o-C6H4BPh3)][PPh4] (84.2 mg, 0.1 mmol), selenium (23.7 mg,
0.3 mmol) and CHCl3 (1 mL) was stirred at 60 °C for 3 h. The
resulting mixture was filtered through a pad of Celite. The volatiles
were removed under reduced pressure, and then reprecipitation from
CHCl3/Et2O followed by CHCl3/hexane gave [Se-PPh2(o-
C6H4BPh3)][PPh4] as a white solid (92.2 mg, > 99%). mp ∼ 125
CD3CN = 10:1): δ 84.4 (d, JC−P = 24.0 Hz), 120.1, 122.3 (d, JC−P
=
14.4 Hz, 3C), 123.8, 127.1 (2C), 127.3 (3C), 131.1 (d, JC−P = 24.9 Hz,
3C), 131.8 (d, JC−P = 7.6 Hz, 3C), 136.5 (2C), 138.7 (d, JC−P = 47.0
Hz, 3C), 167.5 (q, JC−B = 40.2 Hz, 3C). One of the signals for carbon
directly attached to boron atom was not observed. Signals for one of
carbons of the π-allyl moiety and for carbons of the coordinating
MeCN ligand were overlapping to solvent signals. 31P{1H} NMR
(161.8 MHz, CD2Cl2/CD3CN = 10:1): δ − 3.2 (partially relaxed
1:1:1:1 quartet, JP−B = ∼ 10 Hz). 11B{1H} NMR (128.3 MHz,
CD2Cl2/CD3CN = 10:1): δ − 9.2 (d, JB−P = 12.3 Hz). IR (ATR):
2964.6, 1428.0, 1255.0, 1025.8, 882.4, 756.2, 742.3, 719.8, 698.0 cm−1.
ESI-HRMS (m/z): [M + Na]+ calcd for C29H25BNPPdNa, 558.07656
(considering isotope natural abundances); found, 558.07728. Anal.
Calcd for C31H28BN2PPd: C, 64.55; H, 4.89; N, 4.86. Found: C, 63.68;
H, 4.78; N, 4.81 (although this data is outside the range viewed as
establishing analytical purity, its compound identification is
unambiguously accomplished by NMR and ESI-HRMS spectroscopies
as well as single crystal X-ray diffractions).
Typical Procedure for Pd-Catalyzed Suzuki−Miyaura Cross-
Coupling of Aryl Chlorides. In a nitrogen-filled glovebox, a mixture
of L-NBu4 (4.7 mg, 0.008 mmol) and DMF (850 μL) was placed in a
10 mL screw-capped glass tube containing magnetic stirring bar. A
solution of [PdCl2(PhCN)2] (1.5 mg, 0.004 mmol) in DMF (150 μL)
was added to the mixture. After the solution was stirred for 5 min, 1-
butyl-4-chlorobenzene (3a, 33.5 mg, 0.20 mmol), phenylboronic acid
(4a, 36.6 mg, 0.30 mmol), and K3PO4 (127.4 mg, 0.6 mmol) were
added successively. The tube was sealed with a screw cap and removed
from the glovebox. The mixture was stirred at 60 °C for 12 h. After the
mixture was cooled to room temperature, the consumption of the
starting material was determined by gas chromatography (1,4-
dimethoxybenzene as internal standard). The mixture was diluted
with Et2O and filtered through a Celite pad (eluting with Et2O). The
volatiles were evaporated, and an internal standard (1,3,5-trimethox-
ybenzene) was added to determine the yield of 4-butyl-1,1′-biphenyl
(5a, 92% yield) by 1H NMR. The crude product was purified by silica
1
°C (decomp.). H NMR (400 MHz, CDCl3): δ 6.68−6.84 (m, 14H),
6.90 (t, J = 7.6 Hz, 1H), 6.94−7.13 (m, 13H), 7.42 (dd, J = 12.8, 8.0
Hz, 8H), 7.54−7.60 (m, 8H), 7.78 (t, J = 7.6 Hz, 4H), 7.98 (dd, J =
18.0, 7.2 Hz, 4H). All coupling constants could not be extracted due to
overlapping of signals. 13C{1H} NMR (100.5 MHz, CDCl3): δ 117.2
(d, JC−P = 90.0 Hz, 4C), 121.5 (3C), 122.1 (d, JC−P = 16.3 Hz), 125.7
(6C), 126.3 (d, JC−P = 12.5 Hz, 4C), 127.6 (d, JC−P = 1.9 Hz, 2C),
128.4 (d, JC−P = 1.9 Hz, 8C), 130.7 (d, JC−P = 12.4 Hz, 8C), 134.2 (d,
JC−P = 10.6 Hz, 8C), 135.7 (d, JC−P = 2.9 Hz, 6C), 135.8 (4C), 135.9
(d, JC−P = 72.8 Hz, 2C), 137.3 (d, JC−P = 21.1 Hz), 138.7 (d, JC−P
=
18.2 Hz), 139.8 (d, JC−P = 73.9 Hz), 164.2 (q, JC−B = 46.0 Hz). One of
the aromatic carbons is missing due to overlapping of signals. One of
the signals for carbon directly attached to boron atom was not
observed. 31P{1H} NMR (161.8 MHz, CDCl3): 23.7, 46.5 (satellite d,
JP−Se = 680 Hz)]. 11B{1H} NMR (128.3 MHz, CDCl3): δ − 6.8. IR
(ATR): 3037.8, 1479.7, 1435.7, 1107.9, 1091.0, 996.8, 749.0, 722.7,
702.4 cm−1. ESI-HRMS (m/z): [M−PPh4]− calcd for C36H29BPSe−,
583.12706; found, 583.12876. Anal. Calcd for C60H49BP2Se: C, 78.18;
H, 5.36. Found: C, 77.65; H, 5.33 (although this data is outside the
range viewed as establishing analytical purity, its compound
identification is unambiguously accomplished by NMR and ESI-
HRMS spectroscopies).
Preparation of [PdCl(η3-allyl)(L-NBu4)]. A mixture of L-NBu4
(47.2 mg, 0.08 mmol), [PdCl(η3-allyl)]2 (14.6 mg, 0.04 mmol) and
CH2Cl2 (2 mL) was stirred at room temperature for 2 h. The volatiles
were evaporated. The residue was recrystallized from CH2Cl2/Et2O to
give [PdCl(η3-allyl)(L-NBu4)] as a pale yellow solid (39.6 mg, 43%
yield). Single crystals of [PdCl(η3-allyl)(L-NBu4)] suitable for X-ray
diffraction studies were obtained by recrystallization from CH2Cl2/
F
Organometallics XXXX, XXX, XXX−XXX