Palladium-Diphosphine Catalysis
Organometallics, Vol. 21, No. 23, 2002 4967
Hz, 2H, CH2), 2.45 (s, 6H, CH3-Ar), 4.70 (m, 2H, CHCH3),
7.34 (d, J (HH) ) 8.3 Hz, 4H, Ar), 7.80 (d, J (HH) ) 8.3 Hz,
4H, Ar).
40.8 (d, 2J (PP) ) 53.2 Hz), 8.0 (d). 1H NMR (CDCl3): δ 0.58
(dd, 3H, 3J (PH) ) 7.1 Hz, 3J (PH) ) 2.15 Hz, PdCH3), 1.09 (dd,
3H, 3J (PH) ) 12.2 Hz, 3J (HH) ) 7.1 Hz, CHCH3), 1.21 (dd,
3H, 3J (PH) ) 15.5 Hz, J (HH) ) 7.0 Hz, CHCH3), 1.91 (m, 2H,
CH2), 2.05 (s, 3H, MeCN), 2.73 (m, 1H, CHCH3), 2.88 (m, 1H,
CHCH3), 7.30-7.83 (m, 20H, Ar). IR (Nujol mull, KBr
plates): (MeCN) 2317, 2289 cm-1, (BF4) 1055 cm-1. Anal. Calcd
for C32H36BF4NP2Pd: C, 55.74; H, 5.22; N, 2.03. Found: C,
55.85; H, 5.32; N, 2.15. 6P F 6: 31P{1H} NMR (CD2Cl2): δ 40.8
3
3
r a c-2,4-Bis(d ip h en ylp h osp h in o)p en ta n e (r a c-bd p p ).3a
BuLi (7.80 mL, 12.5 mmol) was added to a solution of
diphenylphosphine (2.18 mL, 12.5 mmol) in 50 mL of THF,
cooled to 0 °C. The solution was stirred for 10 min, and then
a solution of the rac-tosylate (2.46 g, 6 mmol) in 20 mL of THF
was added and the reaction mixture was stirred at room
temperature for 2 h. Water (2 mL) was added, and the solvent
was removed under reduced pressure. CH2Cl2 and water were
added (100 mL each), and the organic layer was separated.
The water layer was extracted with 2 × 50 mL of CH2Cl2, and
the combined organic layers were dried over Na2SO4. Evapora-
2
1
(d, J (PP) ) 52.7 Hz), 8.0 (d). H NMR (CD2Cl2): δ 0.53 (dd,
3
3
3H, J (PH) ) 7.0 Hz, J (PH) ) 2.1 Hz PdCH3), 1.05 (dd, 3H,
3J (PH) ) 11.8 Hz, 3J (HH) ) 7.0 Hz, CHCH3), 1.18 (dd, 3H,
3J (PH) ) 15.7 Hz, 3J (HH) ) 7.1 Hz, CHCH3), 1.89 (m, 2H,
CH2), 1.92 (s, MeCN), 2.70 (m, 1H, CHCH3), 2.90 (m, 1H,
CHCH3), 7.33-7.80 (m, 20H, Ar). IR (Nujol mull, KBr
plates): (MeCN) 2317, 2289 cm-1, (PF6) 839 cm-1. Anal. Calcd
for C32H36F6NP3Pd: C, 51.41; H, 4.81; N, 1.87. Found: C,
51.54; H, 4.90; N, 1.95.
tion of the solvent left
a colorless oil, which contained
exclusively rac-bdpp and impurities of phosphine oxides.
Overall yield: 2.36 g (90%). All our attempts to crystallize the
diphosphine were unsuccessful.
[P d (CH2CH2C(O)Me)(m eso-bd p p )]BF 4 (8BF 4). A solution
of 5BF 4 (70 mg, 0.1 mmol) in 2 mL of CH2Cl2 was transferred
into a 10 mm o.d. sapphire tube which was pressurized to 20
bar of CO at room temperature. The gas was vented off, and
the reaction mixture was cooled to - 20 °C. Acetonitrile (20
µL) was added, and the residual CO was removed from the
solution by bubbling nitrogen for 2 min. The tube was
pressurized with ethene (20 bar) at -20 °C. The gaseous phase
was vented off, and the solution was transferred to a Schlenk
tube. The solvent was evaporated under reduced pressure at
-20 °C to leave a brownish oil. 31P{1H} NMR (CD2Cl2): δ 42.2
P d Cl(Me)(P -P ) (P -P ) m eso-bd p p , 2; r a c-bd p p , 3). To
a stirred solution of PdCl(Me)(COD) (0.13 g, 0.50 mmol) in CH2-
Cl2 (20 mL) was added 1 equiv of diphosphine (0.50 mmol) at
room temperature. After 2 h stirring, the solvent was reduced
to 5 mL under reduced pressure, and 15 mL of 1:1 diethyl
ether/petroleum ether was added to the reaction mixture to
complete the precipitation of the product, which was filtered
off, washed with petroleum ether, and dried in a nitrogen
stream. Yield: 80-90%. 2: 31P{1H} NMR (CD2Cl2): δ 42.0 (d,
J (PP) ) 47.0 Hz), 15.5 (d). 1H NMR (CD2Cl2): δ 0.41 (dd,
3J (PH) ) 3.5 Hz, 3J (PH) ) 7.7 Hz, 3H, PdCH3), 0.95 (dd,
3J (HH) ) 7.1 Hz, 3J (PH) ) 10.4 Hz, 3H, CHCH3), 1.05 (dd,
3J (HH) ) 7.3 Hz, 3J (PH) ) 12.6 Hz, 3H, CHCH3), 1.85 (m,
2H, CH2), 2.53 (m, 2H, CHCH3), 7.3-8.0 (m, 20H, aromatic
protons). Anal. Calcd for C30H33ClP2Pd: C, 60.34; H, 5.52.
Found: C, 60.60, 5.54. 3: 31P{1H} NMR (CD2Cl2): δ 39.6 (d,
2J (PP) ) 50.5 Hz), 7.1 (d).1H NMR (CD2Cl2): δ 0.47 (dd, 3H,
3J (PH) ) 7.8 Hz, 3J (PH) ) 3.4 Hz, PdCH3), 0.96 (dd, 3H,
3J (PH) ) 11.8 Hz, 3J (HH) ) 7.1 Hz, CHCH3), 1.12 (dd, 3H,
3J (PH) ) 14.3 Hz, 3J (HH) ) 7.2 Hz, CHCH3), 1.91 (m, 2H,
CH2), 2.64 (m, 1H, CHCH3), 2.87 (m, 1H, CHCH3), 7.25-7.94
(m, 20H, Ar). Anal. Calcd for C30H33ClP2Pd: C, 60.34; H, 5.52.
Found: C, 60.52; H, 5.70.
1
(d, J (PP) ) 52.2 Hz), 15.8 (d). H NMR (CD2Cl2): δ 1.05 (dd,
3
3
3H, J (HP) ) 12.07 Hz, J (HH) ) 7.06 Hz, CHCH3), 1.11 (dd,
3H, 3J (HP) ) 15.14 Hz, 3J (HH) ) 8.17 Hz, CHCH3), 1.34 (tdd,
2H, 3J (HP) ) 8.0 Hz, 3J (HP) ) 1.94 Hz, 3J (HH) ) 6.72 Hz,
PdCH2), 1.89 (m, 2H, CH2), 2.26 (s, 3H, CH3CO), 2.74 (m, 2H,
CHCH3), 3.08 (td, 2H, 3J (HH) ) 6.0 Hz, 4J (PH) ) 6.5 Hz, CH2-
CO), 7.37-7.93 (m, 20H, Ar). IR (Nujol mull, KBr plates): ν-
(CdO) 1626 cm-1. Anal. Calcd for C33H37BF4OP2Pd: C, 56.26;
H, 5.25. Found: C, 56.32; H, 5.30.
[P d (CH2CH2C(O)Me)(r a c-bd p p )]SbF 6 (9SbF 6). PdCl(M-
e)(rac-bdpp) (0.169 mmol) was dissolved in 2 mL of CH2Cl2
and transferred into a 10 mm sapphire tube, which was then
pressurized to 20 bar of CO. After 3 min the tube was
immersed into a cooling bath (at -20 °C) and the CO pressure
was released. The residual CO was removed from the solution
by bubbling a gentle stream of nitrogen through the solution
for 7 min. The solution was transferred into a Schlenk tube
cooled to -20 °C, and a stream of ethene was bubbled through
the solution for 5 min. The reaction mixture was maintained
at -20 °C while AgSbF6 (0.186 mmol) was added. The silver
chloride was separated by filtration through cotton wool.
Removal of the solvent under reduced pressure at -10 °C left
a brownish solid. 31P{1H} NMR (CD2Cl2): δ 39.6 (d, J (PP) )
[P d (Me)(MeCN)(P -P )]Y [P -P ) m eso-bd p p , Y ) BF 4
(5BF 4), P F 6 (5P F 6); P -P ) r a c-bd p p , Y ) BF 4 (6BF 4), P F 6
(6P F 6)]. A solid sample of either AgBF4 or AgPF6 (0.50 mmol)
was added to a magnetically stirred solution of the appropriate
PdCl(Me)(P-P) complex (0.45 mmol) in a 10:1 (v:v) mixture
of CH2Cl2/MeCN. After 1 h stirring at room temperature, AgCl
was removed by filtration on Celite. The resultant colorless
solution was concentrated to ca. 2 mL under reduced pressure.
Addition of a 1:10 (v:v) mixture of diethyl ether/n-hexane (20
mL) led to the precipitation of a brownish solid, which was
filtered off, washed with petroleum ether, and dried in a
nitrogen stream. Yield: 50-60%. 5BF 4: 31P{1H} NMR (CDCl3):
δ 41.2 (d, 2J (PP) ) 51.1 Hz), 15.5 (d). 1H NMR (CDCl3): δ 0.46
1
3
54.5 Hz), 8.3 (d). H NMR (CD2Cl2): δ 1.08 (dd, 3H, J (PH) )
15.2 Hz, 3J (HH) ) 7.2 Hz, CHCH3), 1.21 (dd, 3H, 3J (PH) )
7.6 Hz, 3J (HH) ) 3.6 Hz, CHCH3), 1.34 (tdd, 2H, 3J (HH) )
6.4 Hz, 3J (PH) ) 2.2 Hz, 3J (PH) ) 7.3 Hz, PdCH2), 1.8 (m,
2H, CH2), 2.33 (s, 3H, CH3CO), 2.90 (m, 2H, CHCH3), 3.12 (td,
2H, 3J (HH) ) 6.4 Hz, 4J (PH) ) 6.8 Hz, CH2CO), 7.11-8.10
3
3
(dd, 3H, J (PH) ) 2.3 Hz, J (PH) ) 7.2 Hz, PdCH3), 1.08 (dd,
3H, 3J (HH) ) 7.2 Hz, 3J (PH) ) 14.3 Hz, CHCH3), 1.10 (dd,
3H, 3J (HH) ) 7.2 Hz, 3J (PH) ) 11.8 Hz, CHCH3), 1.90 (m,
2H, CH2), 2.03 (s, 3H, MeCN), 2.70 (m, 1H, CHCH3), 2.87 (m,
1H, CHCH3), 7.3-7.9 (m, 20H, aromatic protons). IR (Nujol
(m, 20H, Ar). IR (Nujol mull, KBr plates): ν(CdO) 1632 cm-1
.
mull, KBr plates): (MeCN) 2318, 2290 cm-1, (BF4) 1060 cm-1
.
Anal. Calcd for C33H37F6OSbP2Pd: C, 46.44; H, 4.33. Found:
C, 46.52; H, 4.40.
Anal. Calcd for C32H36BF4NP2Pd: C, 55.75; H, 5.22; N, 2.03.
Found: C, 55.90; H, 5.30; N, 2.20. 5P F 6: 31P{1H} NMR (CD2-
P d Cl2(P -P ) (P -P ) m eso-bd p p , 11; r a c-bd p p , 12).
PdCl2(COD) (135 mg, 0.47 mmol) was added to a solution of
the chelating diphosphine (0.47 mmol) in 20 mL of CH2Cl2.
The solution was stirred at room temperature for 1 h and then
reduced to 2 mL in vacuo. A 1:1 (v:v) mixture of diethyl ether
and petroleum ether was added to the remaining solution,
which separated a pale yellow microcrystalline product. This
was filtered off, washed with a small amount of n-hexane, and
dried under a stream of dry nitrogen. Yields: 85-90%. 11: 31P-
2
1
Cl2): δ 41.7 (d, J (PP) ) 50.8 Hz), 15.6 (d). H NMR (CD2Cl2):
δ 0.46 (dd, 3H, 3J (PH) ) 2.2 Hz, 3J (HP) ) 7.1 Hz, PdCH3),
1.04 (dd, 3H, 3J (PH) ) 13.8 Hz, 3J (HH) ) 6.9 Hz, CHCH3),
1.10 (dd, 3H, 3J (PH) ) 12.0 Hz, 3J (HH) ) 7.1 Hz, CHCH3),
1.92 (s, 3H, MeCN), 1.85 (m, 2H, CH2), 2.63 (m, 1H, CHCH3),
2.78 (m, 1H, CHCH3), 7.31-7.87 (m, 20H, Ar). IR (Nujol mull,
KBr plates): (MeCN) 2317, 2290 cm-1, (PF6) 839 cm-1. Anal.
Calcd for C32H36F6NP3Pd: C, 51.41; H, 4.81; N, 1.87. Found:
C, 51.60; H, 4.95; N, 1.90. 6BF 4: 31P{1H} NMR (CDCl3): δ
1
{1H} NMR (CDCl3): δ 29.7 (s). H NMR (CDCl3): δ 1.04 (dd,