Palladium/chiral phosphine-olefin complexes: X-ray crystallographic analysis and the use in catalytic asymmetric allylic alkylation

Article abstract of DOI:10.1016/j.tetasy.2005.08.050

X-ray crystallographic studies on π-allylpalladium complexes coordinated with a chiral phosphine-olefin ligand (-)-1b demonstrate that the phosphine ligand shows a larger trans-influence than the π-bound olefin. The palladium/chiral phosphine-olefin compl

Full text of DOI:10.1016/j.tetasy.2005.08.050

Tetrahedron:
Asymmetry
Tetrahedron: Asymmetry 16 (2005) 3400–3405
Palladium/chiral phosphine–olefin complexes:
X-ray crystallographic analysis and the use in catalytic
asymmetric allylic alkylation
Ryo Shintani, Wei-Liang Duan, Kazuhiro Okamoto and Tamio Hayashi*
Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
Received 24August 2005; accepted 30 August 2005
Available online 21 October 2005
Abstract—X-ray crystallographic studies on p-allylpalladium complexes coordinated with a chiral phosphine–olefin ligand (ꢀ)-1b
demonstrate that the phosphine ligand shows a larger trans-influence than the p-bound olefin. The palladium/chiral phosphine–ole-
fin complex efficiently catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate with 96% enantioselectivity.
ꢀ 2005 Elsevier Ltd. All rights reserved.
1. Introduction
marily responsible for the stereochemical outcome of
the catalytic reaction.
The development of new chiral ligands for transition
metals is of high importance in the advancement of
asymmetric catalysis. Historically, for the late transition
metals, the use of phosphorus- and/or nitrogen-based
chiral ligands has been most extensively investigated.1
Many of the effective ligands in this class are bidentate,
as in the case of binap2 and bisoxazolines.3 In addition
to bisphosphine or dinitrogen ligands, P,N-bidentate
chiral ligands have also been well-described (e.g., phos-
phinooxazolines).4 As conceptually novel chiral ligands,
a series of chiral dienes were recently introduced,5,6 and
they showed their high effectiveness in various rhodium-
catalyzed asymmetric processes, exhibiting superiority
to conventional chiral bisphosphine ligands in some
cases.
More recently, we have developed new chiral phos-
phine–olefins 1 and demonstrated that these ligands
are highly effective for the rhodium-catalyzed asymmet-
ric 1,4-addition of arylboronic acids to maleimides.8
Herein we report that these ligands can also be used in
the context of palladium-catalyzed asymmetric pro-
cesses. Structural features of the palladium complexes
by X-ray crystallographic analysis are also described.
2. Results and discussion
As shown in Scheme 1, the synthesis of 1 begins with
known compound ( )-2.9 Thus, Swern oxidation of
alcohol ( )-2, followed by ketalization and phosphine
oxide introduction, gives ( )-3, which can be resolved
by chiral HPLC on a Chiralcel OD-H column to give
each enantiomer of 3. The removal of the ketal protec-
tion, followed by triflation, affords enantiopure enol tri-
flate (ꢀ)-4. Grignard cross-coupling of (ꢀ)-4, and then
reduction with silane, completes the synthesis of (ꢀ)-
(1S,4R,7S)-1a (R = Bn) and (ꢀ)-(1S,4R,7S)-1b (R =
Ph).8
Although these dienes demonstrate that a good chiral
environment can be created by the use of a framework
based on substituted olefins, phosphine–olefin hybrid
chiral ligands have been rarely studied to date. In fact,
until recently, only one report by Grutzmacher had
¨
addressed this issue, achieving 86% ee in the iridium-cat-
alyzed asymmetric hydrogenation of an imine.7 Unfor-
tunately, however, these ligands possess another
chirality derived from menthol and it is this that is pri-
Treatment of ligand (ꢀ)-1b with [PdCl(g3-C3H5)]2
(1.0 equiv Pd) in chloroform in the presence of NH4PF6
at room temperature generated [Pd(g3-C3H5)((ꢀ)-
1b)]PF6 5 (Scheme 2). Recrystallization of this complex
*
Corresponding author. Tel.: +81 75 753 3983; fax: +81 75 753
3988; e-mail: thayashi@kuchem.kyoto-u.ac.jp
0957-4166/$ - see front matter ꢀ 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetasy.2005.08.050

R. Shintani et al. / Tetrahedron: Asymmetry 16 (2005) 3400–3405
3401
O
O
PPh2
R
PPh2
PPh2
Br
(a)–(c)
(d)–(f)
(g),(h)
O
O
OH
OTf
( )-2
(–)-4
(–)-1a: R = Bn
(–)-1b: R = Ph
( )-3
Scheme 1. Reagents and conditions: (a) oxalyl chloride, DMSO, Et3N, CH2Cl2, 96%; (b) cat. TsOH, ethylene glycol, C6H6, 94%; (c) (i) t-BuLi, THF;
then ClPPh2; (ii) H2O2 aq, acetone, 63% (over two steps); (d) chiral HPLC resolution (OD-H column); (e) 1 M HCl aq, THF, 99%; (f) LDA, THF;
then PyNTf2, 89%; (g) cat. NiCl2(dppp), BnMgBr, Et2O, 86% (for R = Bn); or cat. PdCl2(dppf), PhMgBr, Et2O, 86% (for R = Ph); (h) HSiCl3, Et3N,
C6H6, 90% for (ꢀ)-1a and 84% for (ꢀ)-1b.
To analyze this reaction in more detail, we synthesized a
Pd/(ꢀ)-1b complex bearing an g3-1,3-diphenyl-2-prope-
nyl moiety as shown in Scheme 4. This complex turned
out to be a mixture of two diastereomers in solution
(ratio = 56:44 in chloroform), but upon recrystallization
from dichloromethane/hexane, crystals of one diastereo-
mer were obtained and analyzed by X-ray crystallogra-
phy (Fig. 2, Tables 1 and 2). It is worth noting that the
Pd(1)–C(3) bond length is longer than the Pd(1)–C(1)
(–)-1b, NH4PF6
PdCl
Pd((–)-1b)
PF6
2
CHCl3, r.t.
5
Scheme 2.
from dichloromethane/hexane afforded single crystals
suitable for X-ray analysis. The crystal structure of com-
plex 5 is illustrated in Figure 1 and its data summarized
in Tables 1 and 2.
˚
˚
bond length [2.291(4) A vs 2.122(6) A], indicating that
the phosphine ligand [trans to C(3)] shows larger
Ph
Ph
Ph
(–)-1b, NH4PF6
PdCl
Pd((–)-1b)
PF6
2
EtOH, r.t.
Ph
6
Scheme 4.
Figure 1. ORTEP illustration of [Pd(g3-C3H5)((ꢀ)-1b)]PF6 5 with
thermal ellipsoids drawn at the 50% probability level (hydrogens and
PF6 are omitted for clarity).
Knowing that a mixture of (ꢀ)-1b and [PdCl(g3-C3H5)]2
gives a Pd/(ꢀ)-1b complex, we carried out the asymmet-
ric allylic alkylation of 1,3-diphenyl-2-propenyl acetate
with dimethyl malonate under Pd/1 catalysis (Scheme
3). We have determined that the use of benzyl-substi-
tuted ligand (ꢀ)-1a gives the alkylation product in
96% yield with 81% ee (S), whereas the use of phenyl-
substituted ligand (ꢀ)-1b affords it in 87% yield with
96% ee (S).
Figure 2. ORTEP illustration of [Pd(g3-PhCHCHCHPh)((ꢀ)-1b)]PF6
6 with thermal ellipsoids drawn at the 50% probability level (hydrogens
and PF6 are omitted for clarity).
[PdCl(η3-C3H5)]2
(3 mol% Pd)
(–)-1a or (–)-1b
(3 mol%)
MeO2C
CO2Me
Ph
Ph
(3.0 equiv)
P
Ph
MeO2C
Ph
CO2Me
Ph
Pd
Nu
(S)-product
Ph
OAc
KOAc (6 mol%)
BSA (3.0 equiv)
CH2Cl2, r.t., 14 h (–)-1a: 96% yield, 81% ee (S)
(–)-1b: 87% yield, 96 % ee (S)
Ph
Ph
Nu–
(1.0 equiv)
Scheme 3.
Figure 3. Proposed stereochemical pathway for the asymmetric allylic
alkylation catalyzed by Pd/(ꢀ)-1b.

3402
R. Shintani et al. / Tetrahedron: Asymmetry 16 (2005) 3400–3405
Table 1. Crystallographic data for complexes 5 and 6
Complex 5
28H28F6P2Pd
Complex 6
Formula
fw
C
C40H36F6P2Pd
799.06
646.87
Color, habit
Cryst size (mm)
Cryst syst
Space group
Pale yellow, block
0.20 · 0.20 · 0.20
Monoclinic
P21
Yellow, needle
0.60 · 0.20 · 0.20
Hexagonal
P61
˚
a (A)
8.7620(5)
11.2456(4)
˚
b (A)
17.8940(9)
9.2613(5)
˚
c (A)
47.138(3)
a (deg)
b (deg)
c (deg)
113.0580(10)
3
˚
V (A )
Z
1336.05(12)
2
1.608
8.73
652.00
5162.5(5)
6
1.542
6.94
Dcalcd (g cmꢀ3
)
l (cmꢀ1
F000
)
2436.00
2hmax (deg)
56.456.4
Total no. of data (Rint
No. of unique data
No. of obsd data
No. of variables
R1
)
8063 (0.012)
805413,973
5374(all reflections)
335
0.020 (I > 2.00r(I))
0.055 (all reflections)
1.040
14,005 (0.025)
4078 (all reflections)
443
0.032 (I > 2.00r(I))
0.077 (all reflections)
1.035
0.01(2)
+0.42, ꢀ0.35
wR2
Goodness-of-fit
Flack parameter
0.03(1)
+1.07, ꢀ0.36
ꢀ3
˚
Residual q (e A
)
˚
Table 2. Selected bond distances (A) and angles (deg) for complexes 5
and 6
the alkylation product with high enantiomeric excess in
(S)-configuration.
Complex 5
Complex 6
Bond distances
Pd(1)–C(1)
Pd(1)–C(2)
Pd(1)–C(3)
Pd(1)–C(4)
Pd(1)–C(5)
Pd(1)–P(1)
C(1)–C(2)
3. Conclusions
2.149(3)
2.176(4)
2.200(3)
2.266(2)
2.344(3)
2.2793(6)
1.373(4)
1.378(6)
1.382(3)
2.122(6)
2.201(4)
2.291(4)
2.234(6)
2.323(6)
2.274(1)
1.428(8)
1.412(8)
1.374(5)
We have demonstrated that palladium/chiral phos-
phine–olefin complexes can effectively catalyze asym-
metric allylic alkylation reactions. Through X-ray
crystallographic analysis of Pd(g3-allyl) (ꢀ)-1b com-
plexes, we have also confirmed the difference between
phosphines and p-bound olefins in transition-metal
complexes; specifically, phosphines show larger trans-
influence than p-bound olefins.
C(2)–C(3)
C(4)–C(5)
Bond angles
C(1)–Pd(1)–P(1)
C(4)–Pd(1)–P(1)
C(5)–Pd(1)–P(1)
C(3)–Pd(1)–C(4)
C(3)–Pd(1)–C(5)
C(4)–Pd(1)–C(5)
106.18(7)
84.01(6)
84.23(6)
102.37(9)
101.6(1)
34.83(8)
102.2(1)
84.4(1)
84.4(1)
103.4(2)
108.2(2)
35.0(1)
4. Experimental
4.1. General
All air- and moisture-sensitive manipulations were car-
ried out with standard Schlenk techniques under nitro-
gen or in a glove box under argon. THF and Et2O
were purified by passing through a neutral alumina col-
umn under nitrogen. Benzene was distilled over benzo-
phenone ketyl under nitrogen. Dichloromethane was
distilled over CaH2 under nitrogen. EtOH was distilled
over magnesium turnings under nitrogen. DMSO was
distilled over CaH2 under vacuum. Et3N was distilled
over KOH under vacuum. ( )-2,8 N-(2-pyridyl)trifl-
imide,12 NiCl2(dppp),13 PdCl2(dppf),14 [PdCl(g3-
trans-influence than the p-bound olefin ligand [trans to
C(1)].10 This trend was also observed in complex 5
˚
˚
[2.200(3) A vs 2.149(3) A], which should have smaller
impact of the steric factor to take into account. By anal-
ogy with the analysis in the literature,11 a nucleophile
would preferentially attack C(3) from outside, leading
to an (S)-product (Fig. 3), which is consistent with the
experimental outcome in Scheme 3. Assuming that this
is what happened in the catalytic reaction, the diastereo-
mer shown in Figure 2 would be the more reactive one
out of the two diastereomeric Pd(g3-PhCHCHCHPh)
(ꢀ)-1b intermediates existing in solution, thus affording
C3H5)]2,15 and [PdCl(g3-PhCHCHCHPh)]2 were syn-
16
thesized following the literature procedures.

R. Shintani et al. / Tetrahedron: Asymmetry 16 (2005) 3400–3405
3403
2
4.2. Synthesis of phosphine–olefin ligands 1
73.4Hz), 46.0 (d, JCP = 1.5 Hz), 41.5, 39.1, 29.7 (d,
3JCP = 14.5 Hz), 23.2 (d, JCP = 14.4 Hz). 31P{1H}
3
4.2.1. ( )-Spiro[7-diphenylphosphinylbicyclo[2.2.1]hep-
tane-2,20-[1,3]dioxolane]
NMR (CDCl3): d 28.0 (s). Anal. Calcd for C21H23O3P:
C, 71.17; H, 6.54. Found: C, 71.36; H, 6.36.
( )-3. DMSO
(3.98 mL,
56.1 mmol) was slowly added to a solution of oxalyl
chloride (2.45 mL, 28.1 mmol) in dichloromethane
(60 mL) at ꢀ78 ꢁC, and the resulting mixture stirred
for 30 min at ꢀ78 ꢁC. A solution of ( )-2 (4.77 g,
25.0 mmol) in dichloromethane (45 mL) was added to
this mixture slowly over 3 h, and Et3N (15.6 mL,
112 mmol) then added dropwise. The reaction mixture
was stirred for 1 h at room temperature, and then
quenched with water (60 mL). After extraction with
dichloromethane, the organic layer was washed succes-
sively with HCl (60 mL; 1.0 M aqueous), Na2CO3
(60 mL; saturated aqueous), and then NaCl (saturated
aqueous). The organic phase thus obtained was dried
over MgSO4, filtered, and concentrated under vacuum.
The residue was chromatographed on silica gel with hex-
Compound ( )-3 can be resolved into each enantiomer
by a preparative HPLC using a Daicel Chiralcel OD-
H column with hexane/2-propanol = 80/20, flow =
0.5 mL/min. Retention times: 13.9 min [(+)-enantio-
20
mer], 21.2 min [(ꢀ)-enantiomer]. ½aŠ ¼ ꢀ21:5 (c 1.00,
D
CHCl3).
4.2.2. (ꢀ)-(1S,4R,7S)-7-Diphenylphosphinyl-2-trifluoro-
methanesulfonylbicyclo[2.2.1]hept-2-ene
(ꢀ)-4. HCl
(5.0 mL; 1.0 M aqueous) was added to a solution of
(+)-3 (1.77 g, 5.00 mmol) in THF (25 mL), and the mix-
ture stirred for 18 h at room temperature. After neutral-
ization with NaOH (5.0 mL; 1.0 M aqueous), the solvent
was removed under reduced pressure. The residue was
extracted with EtOAc, dried over MgSO4, filtered, and
concentrated under vacuum. This was chromatographed
on silica gel with EtOAc/MeOH = 20/1 to afford a white
solid (1.54g, 4.96 mmol; 99% yield).
ane/Et2O = 2/1 to afford
24.0 mmol; 96% yield).
a colorless oil (4.54 g,
A mixture of this oil (4.54 g, 24.0 mmol), p-toluenesulf-
onic acid (457 mg, 2.40 mmol; monohydrate), and ethyl-
ene glycol (13.4mL, 0.24mol) in benzene (50 mL) was
refluxed for 17 h with a Dean–Stark trap. After cooling
to room temperature, the mixture was poured into water
and extracted with EtOAc. The organic layer was
washed with NaCl (saturated aqueous), dried over
MgSO4, filtered, and concentrated under vacuum. The
residue was chromatographed on silica gel with hex-
n-BuLi (1.92 mL, 3.00 mmol; 1.56 M solution in hexane)
was added to a solution of diisopropylamine (0.42 mL,
3.0 mmol) in THF (8.0 mL) at ꢀ78 ꢁC. After stirring
for 30 min, a solution of the solid obtained above
(630 mg, 2.00 mmol) in THF (50 mL) was added drop-
wise to it, and the resulting solution stirred for 2.5 h at
ꢀ78 ꢁC. A solution of N-(2-pyridyl)triflimide (1.07 g,
3.00 mmol) in THF (5.0 mL) was then added to this
mixture, and stirred for 18 h at room temperature. The
reaction was quenched with water, concentrated under
vacuum, and extracted with EtOAc. The organic layer
was washed with NaCl (saturated aqueous), dried over
MgSO4, filtered, and concentrated under vacuum. The
residue was chromatographed on silica gel with
EtOAc/MeOH = 20/1 to give a yellow solid, which
was further purified through alumina with hexane/
EtOAc = 1/2 to afford (ꢀ)-4 as a white solid (789 mg,
ane/Et2O = 5/1 to afford
22.5 mmol; 94% yield).
a colorless oil (5.25 g,
t-BuLi (27.0 mL, 40.0 mmol; 1.48 M solution in pentane)
was added to a solution of this oil (3.73 g, 16.0 mmol) in
THF (320 mL) at ꢀ60 ꢁC slowly over 40 min, and the
resulting mixture stirred for 30 min at ꢀ60 ꢁC. Chlorodi-
phenylphosphine (3.45 mL, 19.2 mmol) was then added
dropwise. After stirring for 15 min at ꢀ60 ꢁC, the reac-
tion was quenched with water (0.96 mL), and the solvent
removed under vacuum at room temperature. The resi-
due was dissolved in acetone (80 mL), and H2O2
(4.5 mL; 30 wt% aqueous) then added to it. The reaction
mixture was stirred for 15 min at room temperature, and
MnO2 (260 mg, 2.99 mmol) then added. After stirring for
16 h at room temperature, the precipitate was removed
by filtration, and the remaining solution concentrated
under vacuum. The residue was extracted with EtOAc,
dried over MgSO4, filtered, and concentrated under vac-
uum. This was chromatographed on silica gel with
EtOAc/MeOH = 20/1 to afford ( )-3 as a white solid
(3.60 g, 10.2 mmol; 63% yield). 1H NMR (CDCl3): d
7.82–7.72 (m, 4H), 7.50–7.40 (m, 6H), 3.86 (dt,
JHH = 7.3 and 5.1 Hz 1H), 3.78 (q, JHH = 7.3 Hz, 1H),
1
1.78 mmol; 89% yield). H NMR (CDCl3): d 7.73–7.67
3
(m, 4H), 7.54–7.45 (m, 6H), 5.51 (d, JHH = 3.5 Hz,
1H), 3.39 (s, 1H), 3.23 (s, 1H), 2.52 (s, 1H), 2.01–1.92
(m, 2H), 1.64–1.57 (m, 1H), 1.41–1.35 (m, 1H). 13C
1
NMR (CDCl3): d 151.0, 133.1 (d, JCP = 98.7 Hz),
1
132.7 (d, JCP = 98.7 Hz), 131.4(d, 4JCP = 2.6 Hz),
4
2
131.3 (d, JCP = 2.5 Hz), 130.6 (d, JCP = 9.3 Hz),
130.4(d, 2JCP = 9.3 Hz), 128.31 (d, JCP = 11.9 Hz),
3
3
1
128.26 (d, JCP = 11.3 Hz), 118.0 (q, JCF = 320.9 Hz),
1
2
116.4, 59.4 (d, JCP = 75.5 Hz), 45.8, 43.5 (d, JCP
=
=
3
3
1.0 Hz), 26.8 (d, JCP = 12.4Hz), 25.3 (d, JCP
12.4Hz). 31P{1H} NMR (CDCl3):
d
27.7 (s).
20
½aŠ ¼ ꢀ32:8 (c 1.00, CHCl3). Anal. Calcd for C20H18-
D
F3O4PS: C, 54.30; H, 4.10. Found: C, 54.24; H, 4.10.
3.63 (dt, JHH = 7.3 and 5.1 Hz, 1H), 3.20 (q, JHH
=
7.3 Hz, 1H), 2.83–2.80 (m, 2H), 2.43 (s, 1H), 2.30 (s,
1H), 1.88–1.78 (m, 1H), 1.76–1.66 (m, 1H), 1.54–1.42
(m, 3H). 13C NMR (CDCl3): d 135.9 (d, 1JCP = 98.7 Hz),
134.1 (d, 1JCP = 98.7 Hz), 131.1 (d, 2JCP = 9.3 Hz), 131.0
4.2.3. (ꢀ)-(1S,4R,7S)-2-Benzyl-7-diphenylphosphinobicy-
clo[2.2.1]hept-2-ene (ꢀ)-1a. Benzylmagnesium bromide
(3.50 mL, 1.5 mmol; 0.43 M solution in Et2O) was
added to a mixture of (ꢀ)-4 (133 mg, 0.30 mmol) and
NiCl2(dppp) (8.1 mg, 15 lmol) in Et2O (1.0 mL) at
room temperature, and the resulting mixture refluxed
for 24h. The reaction was quenched with HCl
4
4
(d, JCP = 2.6 Hz), 130.9 (d, JCP = 2.5 Hz), 130.7 (d,
3
2JCP = 8.8 Hz), 128.3 (d, JCP = 10.9 Hz), 128.0 (d,
1
3JCP = 11.4Hz), 115.0, 63.8, 63.6, 50.6 (d, JCP
=

3404
R. Shintani et al. / Tetrahedron: Asymmetry 16 (2005) 3400–3405
(1.5 mL; 1.0 M aqueous) and extracted with EtOAc. The
organic layer was washed with NaCl (saturated aque-
ous), dried over MgSO4, filtered, and concentrated un-
der vacuum. The residue was chromatographed on
alumina with hexane/EtOAc = 1/2 to afford a white
solid (99 mg, 0.26 mmol; 86% yield).
7.45–7.35 (m, 5H), 7.35–7.22 (m, 9H), 7.19 (t,
3
3JHH = 7.3 Hz, 1H), 6.31 (d, JHH = 2.8 Hz, 1H), 3.18
3
(s, 1H), 2.97 (s, 1H), 2.49 (d, JHH = 6.8 Hz, 1H),
1.95–1.80 (m, 2H), 1.33–1.20 (m, 2H). 13C NMR
3
(CDCl3):
d
146.4 (d, JCP = 4.1 Hz), 139.7 (d,
1JCP2 = 48.7 Hz), 139.6 (d, JCP = 48.5 Hz), 135.4, 133.0
1
2
(d, JCP = 19.1 Hz), 132.9 (d, JCP = 19.2 Hz), 128.40,
Trichlorosilane (0.27 mL, 2.7 mmol) was added to a
mixture of this solid (204mg, 0.53 mmol) and Et 3N
(0.55 mL, 4.0 mmol) in benzene (15 mL) at 0 ꢁC, and
the resulting mixture stirred for 3 h at 60 ꢁC. After cool-
ing to room temperature, the solvent was removed
under vacuum. The residue was dissolved in Et2O
(8.0 mL), and Na2CO3 (0.20 mL; saturated aqueous)
then added to it. The mixture was passed through a
pad of celite, and the resulting solution dried over
MgSO4, filtered, and concentrated under vacuum. The
residue was chromatographed on alumina with hex-
ane/Et2O = 5/1 to afford (ꢀ)-1a as a colorless viscous
128.35, 123.29 (d, 3JCP = 2.5 Hz), 128.28 (d,
3JCP = 3.1 Hz), 128.2, 128.1 (3JCP = 3.6 Hz), 127.0,
1
2
125.3, 61.8 (d, JCP = 5.1 Hz), 47.2 (d, JCP = 6.6 Hz),
2
3
47.1 (d, JCP = 6.6 Hz), 27.8 (d, JCP = 3.6 Hz), 25.9
(d, JCP = 4.1 Hz). 31P{1H} NMR (CDCl3): d ꢀ17.1 (s).
3
20
D
½aŠ ¼ ꢀ287 (c 0.40, CH2Cl2). Anal. Calcd for
C25H23P: C, 84.72; H, 6.54. Found: C, 84.77; H, 6.79.
4.3. Palladium-catalyzed asymmetric allylic alkylation
A mixture of [PdCl(g3-C3H5)]2 (1.1 mg, 6.0 lmol Pd),
ligand (ꢀ)-1 (6.0 lmol), and KOAc (1.2 mg, 12 lmol) in
dichloromethane (0.5 mL) was stirred for 25 min at room
temperature. 1,3-Diphenyl-2-propenyl acetate (50 mg,
0.20 mmol), dimethyl malonate (69 lL, 0.60 mmol), and
N,O-bis(trimethylsilyl)acetamide (148 lL, 0.60 mmol)
were added with additional dichloromethane (1.5 mL).
The resulting mixture was stirred for 14h at room temper-
ature, and passed through a pad of silica gel with EtOAc,
and the solvent removed under vacuum. The residue was
chromatographed on silica gel with EtOAc/hexane = 1/4
to afford the product as a colorless oil.
1
oil (176 mg, 0.48 mmol; 90% yield). H NMR (CDCl3):
d 7.38–7.34(m, 2H), 7.32–7.17 (m, 11H), 7.12–7.09 (m,
2
2H), 5.59 (s, 1H), 3.44 (d, JHH = 15.3 Hz, 1H), 3.40
2
(d, JHH = 15.4Hz, 1H), 2.79 (s, 1H), 2.52 (s, 1H),
3
2.28 (d, JHH = 7.2 Hz, 1H), 1.82–1.74(m, 1H), 1.65–
1.58 (m, 1H), 1.25–1.16 (m, 1H), 1.05–0.95 (m, 1H).
3
13C NMR (CDCl3): d 147.0 (d, JCP = 3.1 Hz), 139.9
1
1
(d, JCP = 43.9 Hz), 139.7 (d, JCP = 43.4 Hz), 139.2,
2
2
133.0 (d, JCP = 19.1 Hz), 132.7 (d, JCP = 19.2 Hz),
129.37, 129.36, 128.24(d,
3JCP = 6.1 Hz), 128.23,
128.13 (d, 3JCP = 4.1 Hz), 128.09, 127.9 (3JCP = 4.1 Hz),
1
2
125.9, 62.2 (d, JCP = 5.1 Hz), 48.5 (d, JCP = 12.4Hz),
The ee was determined on a Daicel Chiralpak AD-H
2
3
46.3 (d, JCP = 12.9 Hz), 36.9, 27.9 (d, JCP = 3.6 Hz),
column
with
hexane/2-propanol = 95/5,
flow =
25.6 (d, JCP = 4.1 Hz). 31P{1H} NMR (CDCl3): d
3
1.0 mL/min. Retention times: 17.4min [( R)-enantio-
mer], 24.9 min [(S)-enantiomer].
20
D
ꢀ17.5 (s). ½aŠ ꢀ56.5 (c 0.56, CH2Cl2). Anal. Calcd for
C26H25P: C, 84.75; H, 6.84. Found: C, 84.96; H, 7.10.
Compound (ꢀ)-1a as a ligand: 96% yield, 81% ee (S).
4.2.4. (ꢀ)-(1S,4R,7S)-7-Diphenylphosphino-2-phenylbicy-
clo[2.2.1]hept-2-ene (ꢀ)-1b. Phenylmagnesium bromide
(1.43 mL, 1.70 mmol; 1.19 M solution in Et2O) was
added to a mixture of (ꢀ)-4 (305 mg, 0.69 mmol) and
PdCl2(dppf) (5.0 mg, 6.9 lmol) in Et2O (8.0 mL) at
room temperature, and the resulting mixture refluxed
for 10 h. The reaction was quenched with HCl
(2.0 mL; 1.0 M aqueous) and extracted with EtOAc.
The organic layer was washed with NaCl (saturated
aqueous), dried over MgSO4, filtered, and concentrated
under vacuum. The residue was chromatographed on
silica gel with EtOAc to afford a white solid (220 mg,
0.59 mmol; 86% yield).
Compound (ꢀ)-1b as a ligand: 87% yield, 96% ee (S).
20
½aŠ ¼ ꢀ19.6 (c 0.55, CHCl3).
D
4.4. Preparation of [Pd(g3-C3H5)((ꢀ)-1b)]PF6 5
A mixture of [PdCl(g3-C3H5)]2 (7.3 mg, 40 lmol Pd)
and (ꢀ)-1b (14mg, 40 lmol) in chloroform (1.0 mL)
was stirred for 1 h at room temperature. NH4PF6
(6.5 mg, 40 lmol) was then added to it and the mixture
was stirred for 1 h at room temperature. The resulting
mixture was diluted with dichloromethane (3.0 mL)
and the precipitate removed by filtration. After removal
of the solvent under vacuum, the residue was dissolved
in dichloromethane, and pentane added. The precipitate
that formed was collected, and then washed with pen-
tane and dried under vacuum to afford a pale yellow
solid (18 mg, 28 lmol; 70% yield).
Trichlorosilane (0.21 mL, 2.2 mmol) was added to a
mixture of this solid (160 mg, 0.43 mmol) and Et3N
(0.45 mL, 3.2 mmol) in benzene (13 mL) at 0 ꢁC, and
the resulting mixture stirred for 3 h at 60 ꢁC. After cool-
ing to room temperature, the solvent was removed
under vacuum. The residue was dissolved in Et2O
(8 mL), and Na2CO3 (0.20 mL; saturated aqueous) was
then added to it. The mixture was passed through a
pad of celite, and the resulting solution dried over
MgSO4, filtered, and concentrated under vacuum. The
residue was chromatographed on alumina with hex-
ane/Et2O = 5/1 to afford (ꢀ)-1b as a white solid
31P{1H} NMR (CDCl3): d 46.4 (br s), ꢀ143.5 (sept,
1JPF = 711 Hz). Anal. Calcd for C28H28F6P2Pd: C,
51.99; H, 4.36. Found: C, 51.90; H, 4.31.
Crystals suitable for X-ray analysis were obtained by
recrystallization from dichloromethane/hexane at room
temperature.
1
(126 mg, 0.36 mmol; 84% yield). H NMR (CDCl3): d

R. Shintani et al. / Tetrahedron: Asymmetry 16 (2005) 3400–3405
3405
Chem. Soc. 1991, 113, 728; (d) Muller, D.; Umbricht, G.;
¨
CCDC-281684contains the supplementary crystallo-
graphic data for this complex. These data can be
obtained free of charge from the Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
Weber, B.; Pfaltz, A. Helv. Chim. Acta 1991, 74, 232.
4. (a) von Matt, P.; Pfaltz, A. Angew. Chem., Int. Ed. Engl.
1993, 32, 566; (b) Sprinz, J.; Helmchen, G. Tetrahedron
Lett. 1993, 34, 1769; (c) Dawson, G. J.; Frost, C. G.;
Williams, J. M. J.; Coote, S. J. Tetrahedron Lett. 1993, 34,
3149.
4.5. Preparation of [Pd(g3-PhCHCHCHPh)((ꢀ)-1b)]PF6
5. (a) Hayashi, T.; Ueyama, K.; Tokunaga, N.; Yoshida, K.
J. Am. Chem. Soc. 2003, 125, 11508; (b) Shintani, R.;
Ueyama, K.; Yamada, I.; Hayashi, T. Org. Lett. 2004, 6,
3425; (c) Tokunaga, N.; Otomaru, Y.; Okamoto, K.;
Ueyama, K.; Shintani, R.; Hayashi, T. J. Am. Chem. Soc.
2004, 126, 13584; (d) Shintani, R.; Okamoto, K.; Oto-
maru, Y.; Ueyama, K.; Hayashi, T. J. Am. Chem. Soc.
2005, 127, 54; (e) Otomaru, Y.; Okamoto, K.; Shintani,
R.; Hayashi, T. J. Org. Chem. 2005, 70, 2503; (f) Shintani,
R.; Kimura, T.; Hayashi, T. Chem. Commun. 2005, 3213;
(g) Shintani, R.; Tsurusaki, A.; Okamoto, K.; Hayashi, T.
Angew. Chem. Int. Ed. 2005, 44, 3909; (h) Otomaru, Y.;
Tokunaga, N.; Shintani, R.; Hayashi, T. Org. Lett. 2005,
7, 307; (i) Otomaru, Y.; Kina, A.; Shintani, R.; Hayashi,
T. Tetrahedron: Asymmetry 2005, 16, 1673.
6. (a) Fischer, C.; Defieber, C.; Suzuki, T.; Carreira, E. M. J.
Am. Chem. Soc. 2004, 126, 1628; (b) Defieber, C.; Paquin,
J.-F.; Serna, S.; Carreira, E. M. Org. Lett. 2004, 6, 3873;
(c) Paquin, J.-F.; Defieber, C.; Stephenson, C. R. J.;
Carreira, E. M. J. Am. Chem. Soc. 2005, 127, 10850; (d)
Paquin, J.-F.; Stephenson, C. R. J.; Defieber, C.; Carreira,
E. M. Org. Lett. 2005, 7, 3821; (e) La¨ng, F.; Breher, F.;
6
A
mixture of [PdCl(g3-PhCHCHCHPh)]2 (13 mg,
40 lmol Pd) and (ꢀ)-1b (15 mg, 42 lmol) in EtOH
(2.0 mL) was stirred for 1.5 h at room temperature.
NH4PF6 (10 mg, 61 lmol) was then added to it and
the mixture stirred for 20 min at room temperature.
The resulting mixture was filtered through a pad of celite
with dichloromethane and the solution concentrated
under vacuum until the volume became ca. 1 mL. The
precipitate that formed was collected, and then washed
with pentane and dried under vacuum to afford a yellow
solid (29 mg, 36 lmol; 91% yield). 31P{1H} NMR
(CDCl3): d 44.0 (s, major), 38.1 (s, minor), ꢀ143.3 (sept,
1JPF = 712 Hz). Anal. Calcd for C40H36F6P2Pd: C,
60.12; H, 4.54. Found: C, 60.15; H, 4.52.
Crystals suitable for X-ray analysis were obtained by
recrystallization from dichloromethane/hexane at room
temperature.
Stein, D.; Grutzmacher, H. Organometallics 2005, 24,
¨
2997; For an overview, see: (f) Glorius, F. Angew. Chem.
Int. Ed. 2004, 43, 3364.
7. Maire, P.; Deblon, S.; Breher, F.; Geier, J.; Bo¨hler, C.;
CCDC-281685 contains the supplementary crystallo-
graphic data for this complex. These data can be
obtained free of charge from the Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
Ruegger, H.; Scho¨nberg, H.; Grutzmacher, H. Chem. Eur.
¨
¨
J. 2004, 10, 4198.
8. Shintani, R.; Duan, W.-L.; Nagano, T.; Okada, A.;
Hayashi, T. Angew. Chem. Int. Ed. 2005, 44, 4611.
9. Zalkow, L. H.; Oehlschlager, A. C. J. Org. Chem. 1964,
29, 1625.
Acknowledgments
10. (a) Bennett, M. A.; Chee, H.-K.; Jeffery, J. C.; Robertson,
G. B. Inorg. Chem. 1979, 18, 1071; (b) Appleton, T. G.;
Clark, H. C.; Manzer, L. E. Coord. Chem. Rev. 1973, 10,
335.
11. (a) Sprinz, J.; Kiefer, M.; Helmchen, G.; Reggelin, M.;
Huttner, G.; Walter, O.; Zsolnai, L. Tetrahedron Lett.
1994, 35, 1523; (b) Brown, J. M.; Hulmes, D. I.; Guiry, P.
Support has been provided in part by a Grant-in-Aid for
Scientific Research, the Ministry of Education, Culture,
Sports, Science, and Technology, Japan (21 COE on
Kyoto University Alliance for Chemistry).
J. Tetrahedron 1994, 50, 4493; (c) Schaffner, S.; Muller, J.
¨
F. K.; Neuburger, M.; Zehnder, M. Helv. Chim. Acta
1998, 81, 1223; (d) Helmchen, G. J. Organomet. Chem.
1999, 576, 203; (e) Helmchen, G.; Pfaltz, A. Acc. Chem.
Res. 2000, 33, 336.
References
1. (a) Catalytic Asymmetric Synthesis, 2nd ed.; Ojima, I., Ed.;
Wiley-VCH: New York, 2000; (b) Comprehensive Asym-
metric Catalysis I–III; Jacobsen, E. N., Pfaltz, A.,
Yamamoto, H., Eds.; Springer: New York, 1999.
2. Takaya, H.; Mashima, K.; Koyano, K.; Yagi, M.;
Kumobayashi, H.; Taketomi, T.; Akutagawa, S.; Noyori,
R. J. Org. Chem. 1986, 51, 629.
3. (a) Lowenthal, R. E.; Abiko, A.; Masamune, S. Tetrahe-
dron Lett. 1990, 31, 6005; (b) Evans, D. A.; Woerpel, K.
A.; Hinman, M. M.; Faul, M. M. J. Am. Chem. Soc. 1991,
113, 726; (c) Corey, E. J.; Imai, N.; Zhang, H.-Y. J. Am.
12. Comins, D. L.; Dehghani, A. Tetrahedron Lett. 1992, 33,
6299.
13. Van Hecke, G. R.; Horrocks, W. D. Inorg. Chem. 1966, 5,
1968.
14. Hayashi, T.; Konishi, M.; Kobori, Y.; Kumada, M.;
Higuchi, T.; Hirotsu, K. J. Am. Chem. Soc. 1984, 106, 158.
15. Dent, W. T.; Long, R.; Wilkinson, A. J. J. Chem. Soc.
1964, 1585.
16. Hayashi, T.; Yamamoto, A.; Ito, Y.; Nishioka, E.; Miura,
H.; Yanagi, K. J. Am. Chem. Soc. 1989, 111, 6301.