Palladium-catalyzed asymmetric allylic substitutions in the presence of chiral phosphine-imine type ligands

Article abstract of DOI:10.1016/j.jorganchem.2011.04.036

Chiral bidentate phosphine-imine type ligand L9 is fairly effective in the asymmetric allylic substitution of 1,3-diphenylpropenyl acetate with dimethyl malonate to give the corresponding adduct in moderate yield and good ee.

Full text of DOI:10.1016/j.jorganchem.2011.04.036

Journal of Organometallic Chemistry 696 (2011) 2850e2856
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Note
Palladium-catalyzed asymmetric allylic substitutions in the presence of chiral
phosphine-imine type ligands
,b,
Yin-Wei Sun a, Jia-Jun Jiang a, Mei-Xin Zhao a, Fei-Jun Wang a, Min Shi a
*
a Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology,
130 Mei Long Lu, Shanghai 200237, China
b State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Chiral bidentate phosphine-imine type ligand L9 is fairly effective in the asymmetric allylic substitution
of 1,3-diphenylpropenyl acetate with dimethyl malonate to give the corresponding adduct in moderate
yield and good ee.
Received 16 August 2010
Received in revised form
26 April 2011
Ó 2011 Elsevier B.V. All rights reserved.
Accepted 28 April 2011
Keywords:
Asymmetric allylic substitution
Palladium-catalyzed
Phosphine-imine type ligands
1. Introduction
ligands have attracted much attention because they can coordinate
with a variety of transition metal ions to afford the corresponding
Homogeneous enantioselective catalysis with chiral transition
metal complexes is an attractive synthetic methodology, where
a small amount of chiral materials can produce a large amount of
chiral products [1e3]. Chiral C2-symmetric ligand 2,20-bis(diphe-
nylphosphino)-1,10-binaphthyl (BINAP) LA [4e7] and C1-symmetric
ligand 2-(diphenylphosphino)-1,10-binaphthyl (MOP) LB (X ¼ OMe)
[8e10] possessing the axially chiral 1,10-binaphthalene framework
have been widely utilized in asymmetric catalysis (Fig. 1). Signifi-
cant efforts have been devoted to the design and synthesis of novel
binaphthalene-templated ligands. Representative examples are the
binaphthyl P,X-heterodonor ligands LB where X is a variety of
heteroatoms (X ¼ NMe2, SMe, AsPh2, P(O)Ph2, P(S)Ph2, PAr2)
[11e18], phosphaneephosphite ligand BINAPHOS LC [19e21], and
phosphineepyridine ligand LD [22], derived from 2-amino-20-
hydroxy-1,1’binaphthyl (NOBIN). Most of these axially chiral
ligands are effective in the palladium-catalyzed asymmetric allylic
substitution of 1,3-diphenylpropenyl acetate with dimethyl malo-
nate in the presence of a base, which has become a famous and
fundamental asymmetric CeC bonding formation reaction [23]. On
the other hand, recently, phosphine-imine type (salen-type) chiral
stable chiral metal complexes in good yields and these chiral metal
complexes are in general quite efficient in many asymmetric
reactions including asymmetric allylic alkylation [24].
These results have promoted us to explore new chiral
phosphine-imine type ligands for asymmetric reactions since we
envisioned that these chiral ligands can also coordinate with
a variety of metal ions under mild conditions. In this paper we wish
to report that the chiral phosphine-imine type ligand L9 prepared
from (R)-(ꢀ)-2-(diphenylphosphino)-1,10-binaphthyl-20-amine is
fairly effective in the asymmetric allylic substitution of 1,3-
diphenylpropenyl acetate with dimethyl malonate to give the cor-
responding adduct in moderate yield and good ee. In the mean
time, its bidentate coordination pattern to the Pd metal center with
both P and N atoms has been unambiguously established by X-ray
diffraction.
2. Results and discussion
2.1. Synthesis of ligands L1eL13
Chiral phosphine-imine type ligands L1eL13 were synthesized
from the reaction of salicylaldehydes as well as its analogs with (R)-
(ꢀ)-2-(diphenylphosphino)-1,10-binaphthyl-20-amine in absolute
ethanol under reflux for 12 h, respectively (Scheme 1). After usual
workup, these ligands can be obtained in good yields.
* Corresponding author. State Key Laboratory of Organometallic Chemistry,
Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin
Lu, Shanghai 200032, China. Fax: þ86 21 64166128.
E-mail address: Mshi@mail.sioc.ac.cn (M. Shi).
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.04.036

Y.-W. Sun et al. / Journal of Organometallic Chemistry 696 (2011) 2850e2856
2851
O
C
O
N
Y
PPh2
PPh2
X
O P
NH
O
PPh2
PPh2
PPh2
LA
LB
LC
LD
Y = H, Me
X = OMe, NMe2, SMe, AsPh2, P(O)Ph2, P(S)Ph2, PAr2
Fig. 1. The structure of C2-symmetric BINAP and C1-symmetric binaphthyl P,X-heterodonor ligands.
2.2. Catalytic asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl
acetate in the presence of chiral phosphine-imine type ligands
bis(trimethylsilyl)acetamide (BSA) as an organic base, the corre-
sponding product was obtained in moderate to good yields in
a variety of solvents in the presence of L1 (15 mol %) and palladium
salt (5 mol %) at room temperature and up to 35% ee was achieved
using tetrahydrofuran (THF) as a solvent (Table 1, entries 1e3). By
screening chiral phosphine-imine type ligands L1eL13 in THF and
some salt additives, we found that L9 was the best chiral
phosphine-imine type ligand for this asymmetric allylic alkylation,
Initial examinations using 1,3-diphenylpropenyl acetate and
dimethyl malonate as the substrates in the presence of chiral
phosphine-imine type ligand L1 and Pd(II) salt were aimed at
determining the optimal conditions and the results of these
experiments are summarized in Table 1. We found that using
Scheme 1. Preparation of phosphine-imine type ligands L1eL13.

2852
Y.-W. Sun et al. / Journal of Organometallic Chemistry 696 (2011) 2850e2856
Table 1
The asymmetric allylic alkylation catalyzed by Pd(II) in the presence of chiral phosphine-imine type ligands L1eL13.
Entry
Ligand
Salt
Solvent
Yield(%)a
ee(%)b
Absolute configurationc
1
2
3
4
5
6
7
8
L1
L1
L1
L2
L3
L4
L5
L6
L7
L8
L9
L10
L11
L12
L13
L1
L1
L1
L1
L1
L8
L9
L9
L9
e
CH2CI2
PhCH3
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
38
95
95
87
90
95
67
59
37
84
79
95
99
67
95
50
81
64
23
99
64
62
31
63
47
63
99
61
77
0
20
35
0
12
18
35
33
20
20
47
25
7
S
S
S
S
S
S
S
R
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
e
e
e
e
e
e
e
9
e
10
11
12
13
14
15
16
17
18
19
20d
21
22
23e
24
25f
26
27
28
29
e
e
e
e
e
4
5
e
KOAc
37
47
33
33
33
44
67
76
71
70
44
59
55
60
LiOAc∙2H2O
Bu4NBr
Bu4NI
LiOAc∙2H2O
LiOAc∙2H2O
LiOAc∙2H2O
LiOAc∙2H2O
LiCl∙H2O
LiOAc∙2H2O
LiCl∙H2O
LiCl∙H2O
LiCl∙H2O
LiCl∙H2O
L9
L10
L11
L12
L13
a
Isolated yields.
b
c
d
e
f
Determined by chiral HPLC analysis.
The absolute configuration was determined by comparing the sign of specific rotation with authentic sample reported in the literature.
1.0 equiv of salt was added.
The reaction was performed at 0 ꢁC.
0.2 equiv of salt was added.
affording the corresponding product in 71% ee and 63% yield at
room temperature in the presence of LiCl$H2O (10 mol%) (Table 1,
entries 4e29). It should be noted that chiral phosphine-imine type
ligand L2 showed no enantioselectivity for this asymmetric allylic
alkylation under identical conditions (Table 1, entry 4). In addition,
we unexpectedly found that chiral ligands L6 and L9 produced the
corresponding products with opposite absolute configuration
(Table 1, entries 8 and 11). These results suggested that the
substituent on the benzene ring in the chiral phosphine-imine type
ligands played a very important role in chiral induction in this
asymmetric allylic alkylation reaction. The presence of salt addi-
tives, such as Bu4NX (X ¼ Br, I) or KOAc did not improve the ees in
this reaction and the products were obtained in relatively lower
yields (Table 1, entries 16, 18 and 19). Recently, Furukawa and co-
workers disclosed that using BSA as a base in the presence of
lithium salt in this reaction, the enantioselectivity of the reaction
product in the palladium-catalyzed asymmetric reaction could be
greatly improved [25]. On the basis of this result, we examined the
effect of lithium salt such as LiCl or LiOAc (10 mol%) and found that
the achieved ee reached 71% under similar conditions (Table 1,
entries 22 and 24). We found that these factors such as the amount
of lithium salt loading and reaction temperature had little effect on
the improvement of enantioselectivity (Table 1, entries 20, 23 and
25). Comparing the reaction outcomes with L9 and L11eL13, it can
be seen that the nitro group at the 4-position of the benzene ring is
crucial to get the corresponding product in good ee value (Table 1,
entries 11, 13e15). Moreover, the hydroxyl group was also impor-
tant in ligand L9 bearing a nitro group on the 4-position of the
benzene ring, giving the corresponding product in higher ee value
under identical conditions (Table 1, entries 11 and 12, 24 and 26).
On the other hand, when the nitro group was introduced on the
5-position of the benzene ring and OH groups were methylated, the
corresponding product was given in similar yield and ee value
under identical conditions (for example, using L12 and L13 as the
ligands) (Table 1, entries 14 and 15, 28 and 29). The best result was
obtained if using L9 as a ligand in THF in the presence of LiCl
(10 mol%) at room temperature to give the corresponding product
in 63% yield and 71% ee (Table 1, entry 24). The opposite absolute
configuration was obtained if using L6 as a ligand which contains
a
a-naphthol group, presumably due to the steric effect since
naphthyl group is a sterically larger substituent than that of the
corresponding phenyl group (Table 1, entry 8).
Furthermore, when diethyl malonate was used as the substrate,
the corresponding product 3b was obtained in 21% yield along with
73% ee value (Scheme 3). As for the allylation substrate having
a chlorine atom at the 4-position of the benzene ring, the corre-
sponding product 3c was formed in 56% yield and 40% ee in the
reaction with dimethyl malonate (Scheme 3).
On the other hand, using benzyl amine or morpholine instead of
dimethyl malonate as the nucelophile, the corresponding asymmetric

Y.-W. Sun et al. / Journal of Organometallic Chemistry 696 (2011) 2850e2856
2853
amination products 3d and 3e were obtained in 50% yield along with
48% ee and 69% yield along with 40% ee, respectively (Scheme 4).
2.3. Synthesis of complex E
In order to get straightforward evidence of the coordination
pattern of L1 to Pd center, we decided to prepare a Pd(II) complex from
L1 with bis(benzonitrile)palladium dichloride [Pd(PhCN)2Cl2]
because it is known that nitrogen and phosphorus atoms can coor-
dinate to Pd(II) center to give a stable Pd(II) complex, which can be
subjected to the X-ray diffraction. The synthesis of the Pd(L1)Cl2
complex E was carried out by the reaction of the appropriate amount
of Pd(PhCN)2Cl2 with 1.0 equiv of L1 in CH2Cl2 at room temperature
under an argon atmosphere (Scheme 2). The single crystal suitable for
X-ray diffraction was obtained by recrystallization from dichloro-
methane and petroleum ether (1:4). The ORTEP drawing of Pd
complex E is shown in Fig. 2 in which L1 acts as a cis-bidentate ligand
to Pd(II) center in a slightly distorted planar geometry with both
nitrogen and phosphorus atoms providing a seven-membered chelate
ring. The angle of N(1)-Pd-P(1) plane is 89.55ꢁ, and the bond lengths
of N(1)-Pd and Pd-P(1) are 2.021 Å and 2.2559 Å, respectively.
Fig. 2. ORTEP drawing of Pd(L1)Cl2 complex E with thermal ellipsoids at the 30%
probability level. Selected bond distances (Å) and angles (deg): Pd-P1 ¼ 2.2559(12),
Pd-N1 ¼ 2.021(4), N1-C21 ¼ 1.277(6), Cl1-Pd ¼ 2.3438(13), Cl2-Pd ¼ 2.2954(14), N1-
Pd-P1
¼
89.55(11), Pd-N1-C1
¼
105.8(3), N1-Pd-Cl1
¼
87.98(11), Cl1-Pd-
Cl2 ¼ 93.25(5), Cl2-Pd-P1 ¼ 88.85(5), C12-C11-C10-C9 ¼ 74.3(6).
3. Experimental
a solution of CHCl3 or CH2Cl2 at 20 ꢁC by using a PerkineElmer-
241 MC polarimeter; [
]D-values are given in units of 10ꢀ1 deg
cm2 ꢀ1. Infra-red spectra were measured on a spectrometer. 1H
a
3.1. Instrumentation
g
NMR spectra were recorded for solution in CDCl3 with tetrame-
MP was obtained with a Yanagimoto micro melting point
apparatus and is uncorrected. Optical rotations were determined in
thylsilane (TMS) as internal standard; 31P NMR spectra were
HO
Me
N
N
CH2Cl2, rt, 1 h
Cl
Me
HO
+
Pd(PhCN)2Cl2
Pd
P
PPh2
Cl
Ph2
L1
complex E
Scheme 2. Synthesis of the phosphine-imine type-Pd(II) complex E.
Scheme 3. Asymmetric Alkylations Catalyzed by Pd/L9.
[PdCl(η3-C3H5)]2 (5 mol%)
L9 (15 mol%)
NHBn
OAc
Ph
NH2
*
Ph
Ph
+
BSA (3.0 equiv.), THF
Ph
3d: 50% yield, 48% ee
LiCl . H2O (10 mol%), rt
O
N
[PdCl(η3-C3H5)]2 (5 mol%)
L9 (15 mol%)
O
OAc
Ph
+
Ph
BSA (3.0 equiv.), THF
N
H
*
LiCl . H2O (10 mol%), rt
Ph
3e
Ph
: 69% yield, 40% ee
Scheme 4. Asymmetric Aminations Catalyzed by Pd/L9.

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Y.-W. Sun et al. / Journal of Organometallic Chemistry 696 (2011) 2850e2856
recorded at 121 MHz for a solution in CDCl3 with 85% H3PO4 as the
external reference. J-values are in Hz. Mass spectra were recorded
with an HP-5989 instrument and HRMS was measured by a Fin-
nigan MA þ mass spectrometer. Organic solvents used were dried
by standard methods when necessary. Commercially obtained
reagents were used without further purification. All reactions were
monitored by TLC with Huanghai GF254 silica gel coated plates.
Flash column chromatography was carried out using 300e400
mesh silica gel at increased pressure. All reactions were performed
under argon using standard Schlenk techniques. The optical
purities of products were determined by HPLC analysis using
a chiral stationary phase column (column, Daicel Co. Chiralcel OD)
and the absolute configuration of the major enantiomer was
assigned according to the sign of the specific rotation.
3.2.6. (R)-(þ)-1e((2-(Diphenylphosphino)-1,10-binaphthyl-20-
ylimino)methyl)naphthalen-2-ol L6
This is a known compound [28]. 1H NMR (CDCl3, TMS, 300 MHz)
d
6.60 (t, J ¼ 7.2 Hz, 1H, Ar), 6.75 (t, J ¼ 7.2 Hz, 2H, Ar), 6.89 (d,
J ¼ 9 Hz, 1H, Ar), 7.00e7.31 (m, 12H, Ar), 7.43e7.53 (m, 4H, Ar),
7.62e7.73 (m, 4H, Ar), 7.97e8.10 (m, 3H, Ar), 8.12 (d, J ¼ 9 Hz, 1H,
Ar), 8.95 (s,1H, CH]N),13.93 (s, 1H, OH); 31P NMR (CDCl3, 121 MHz,
85% H3PO4)
d
ꢀ12.74.
3.2.7. (R)-(þ)-N-(2,3-Dichlorobenzylidene)-2-(diphenylphosphino)-
1,10-binaphthyl-20-amine L7
This is a known compound [28]. 1H NMR (CDCl3, TMS, 300 MHz)
d
6.92e7.51 (m, 19H, Ar), 7.69e7.93 (m, 5H, Ar), 8.04 (d, J ¼ 8.7 Hz,
1H, Ar), 8.50 (s, 1H, CH]N); 31P NMR (CDCl3, 121 MHz, 85% H3PO4)
ꢀ12.95.
d
3.2. Typical procedure for the preparation of chiral phosphine-imine
type ligands L1eL13
3.2.8. (R,E)-3-((20-(diphenylphosphino)-1,10-binaphthyl-2-ylimino)
methyl)benzene-1,2-diol L8
Yield: (215 mg, 75%). A red solid. Mp: 156e158 ꢁC; IR (CH2Cl2)
n
To a solution of (R)-(ꢀ)-2-(diphenylphosphino)-1,10-binaphthyl-
20-amine [26,27] (227 mg, 0.5 mmol) in absolute ethanol (4.0 mL)
was added salicylaldehyde (68 mg, 0.5 mmol) at room temperature
and the reaction mixture was stirred under reflux for 12 h. After
cooling to room temperature, yellow precipitates settled out, which
were filtered to give the corresponding phosphine-imine type
ligand L3 as a yellow solid (208 mg, 75% yield).
3533, 3044, 2911, 1611, 1582, 1462, 1218, 745 cmꢀ1; 1H NMR (CDCl3,
TMS, 300 MHz)
d 5.53 (s, 1H, OH), 6.61e6.70 (m, 2H, Ar), 6.87e7.28
(m, 15H, Ar), 7.38e7.55 (m, 4H, Ar), 7.94 (d, J ¼ 8.1 Hz, 3H, Ar), 8.07
(d, J ¼ 9.0 Hz,1H, Ar), 8.29 (s,1H, CH]N),12.39 (s,1H, OH); 31P NMR
(CDCl3, 121 MHz, 85% H3PO4)
d
ꢀ12.66; MS (ESI) m/e 574 (Mþþ1,
100); HRMS (ESI) Calcd. For C39H28NO2P (M þ Hþ): 574.1936, found:
20
574.1920; [
a
]
¼ þ108 (c 0.4, CHCl3).
D
3.2.1. (R)-(þ)-2e((2-(Diphenylphosphino)-1,10-binaphthyl-20-ylimino)
methyl)-4-methylphenol L1
3.2.9. (R,E)-3-((20-(diphenylphosphino)-1,10-binaphthyl-2-ylimino)
methyl)-6-nitrobenzene-1,2-diol L9
This is a known compound [28]. 1H NMR (CDCl3, TMS, 300 MHz)
Yield: (170 mg, 55%). A red solid. Mp: 165e167 ꢁC; IR (CH2Cl2)
n
;
d
2.23 (s, 3H, CH3), 6.68 (d, J ¼ 8.4 Hz, 1H, Ar), 6.82e7.52 (m, 20H,
3054, 2333, 1741, 1601, 1509, 1280, 1217, 1089, 818, 745, 694 cmꢀ1
Ar), 7.94e7.96 (m, 3H, Ar), 8.06 (d, J ¼ 9 Hz,1H, Ar), 8.24 (s, 1H, CH]
1H NMR (CDCl3, TMS, 300 MHz)
d
6.72 (d, J ¼ 8.7 Hz, 1H, Ar),
N), 11.55 (s, 1H, OH); 31P NMR (CDCl3, 121 MHz, 85% H3PO4)
6.89e6.99 (m, 5H, Ar), 7.04e7.33 (m, 9H, Ar), 7.44e7.54 (m, 4H, Ar),
7.67 (d, J ¼ 9.0 Hz, 1H, Ar), 7.97e8.03 (m, 3H, Ar), 8.15 (d, J ¼ 8.4 Hz,
1H, Ar), 9.17 (s, 1H, CH]N), 15.22 (s, 1H, OH); 31P NMR (CDCl3,
d
ꢀ12.52.
3.2.2. (R)-(þ)-2,4-dichloro-6e((2-(diphenylphosphino)-1,10-binaphthyl-
20-ylimino)methyl) phenol L2
121 MHz, 85% H3PO4)
d
ꢀ13.11; MS (ESI) m/e 619 (Mþþ1, 100);
HRMS (ESI) Calcd. For C39H27N2O4P (M þ Hþ): 619.1787, found:
This is a known compound [28]. 1H NMR (CDCl3, TMS, 300 MHz)
20
619.1792; [
a
]
¼ ꢀ221 (c 0.4, CHCl3).
D
d
6.85e7.54 (m, 20H, Ar), 7.94 (d, J ¼ 8.4 Hz, 3H, Ar), 8.07 (d,
J ¼ 9.3 Hz, 1H, Ar), 8.15 (s, 1H, CH]N), 12.48 (s, 1H, OH); 31P NMR
3.2.10. (R,E)-3-((20-(diphenylphosphino)-1,10-binaphthyl-2-
ylimino)methyl)-6-nitrobenzene-1,2-dimethoxy L10
(CDCl3, 121 MHz, 85% H3PO4)
d
ꢀ12.90.
Yield: (30 mg, 47%). A yellow soild. Mp: 133e135 ꢁC; IR (CH2Cl2)
3.2.3. (R)-(þ)-2e((2-(Diphenylphosphino)-1,10-binaphthyl-20-ylimino)
methyl)phenol L3
n
2927, 1713, 1618, 1575, 1515, 1341, 1279, 1080, 961, 743, 701 cmꢀ1
;
1H NMR (CDCl3, TMS, 400 MHz)
d 2.72 (s, 3H, OMe), 3.88 (s, 3H,
This is a known compound [28]. 1H NMR (CDCl3, TMS, 300 MHz)
OMe), 6.89e6.95 (m, 4H, Ar), 7.00e7.06 (m, 4H, Ar), 7.09e7.16 (m,
5H, Ar), 7.24e7.46 (m, 5H, Ar), 7.54 (d, J ¼ 8.8 Hz, 1H, Ar), 7.71 (d,
J ¼ 8.8 Hz, 1H, Ar), 7.84e7.90 (m, 3H, Ar), 8.05 (d, J ¼ 8.8 Hz, 1H, Ar),
8.48 (s, 1H, CH]N); 31P NMR (CDCl3, 121 MHz, 85% H3PO4)
d
6.70 (d, J ¼ 8.4 Hz, 1H, Ar), 6.77 (t, J ¼ 7.8 Hz, 1H, Ar), 6.85 (t,
J ¼ 8.1 Hz, 2H, Ar), 6.92e7.50 (m,18H, Ar), 7.94 (d, J ¼ 8.4 Hz, 3H, Ar),
8.06 (d, J ¼ 9 Hz, 1H, Ar), 8.29 (s, 1H, CH]N), 11.77 (s, 1H, OH); 31P
NMR (CDCl3, 121 MHz, 85% H3PO4)
d
ꢀ12.58.
d
ꢀ13.42; MS (EI) m/z (%): 646 [Mþ] (13.0), 469 (48.4), 453 (40.0),
452 (48.0), 451 (100), 437 (52.4), 429 (24.9), 267 (62.8), 201 (34.1);
3.2.4. (R)-(þ)-2e((2-(Diphenylphosphino)-1,10-binaphthyl-20-
ylimino)methyl)-5-methoxyphenol L4
HRMS (EI) Calcd. For C41H31N2O4P (Mþ): 646.2021, found:
646.2020; [
a]
20D ¼ þ75 (c 2.5, CHCl3).
This is a known compound [28]. 1H NMR (CDCl3, TMS, 300 MHz)
3.2.11. (R,E)-2-((20-(diphenylphosphino)-1,10-binaphthyl-2-
ylimino)methyl)-4-nitrobenzene-1-ol L11
d
3.74 (s, 3H, CH3), 6.21 (s, 1H, Ar), 6.34 (d, J ¼ 8.4 Hz, 1H, Ar),
6.89e7.28 (m, 15H, Ar), 7.38e7.51 (m, 4H, Ar), 7.91e7.95 (m, 3H, Ar),
8.05 (d, J ¼ 8.7 Hz, 1H, Ar), 8.21 (s, 1H, CH]N), 12.30 (s, 1H, OH); 31P
Yield: (36 mg, 53%). A red solid. Mp: 278e280 ꢁC; IR (CH2Cl2)
n
;
3054, 2962, 1612, 1481, 1340, 1295, 1263, 1096, 805, 743, 699 cmꢀ1
NMR (CDCl3, 121 MHz, 85% H3PO4)
d
ꢀ12.59.
1H NMR (CDCl3, TMS, 400 MHz)
d
6.71 (d, J ¼ 9.2 Hz, 1H, Ar),
3.2.5. (R)-(þ)-2,4-di-tert-butyl-6e((2-(diphenylphosphino)-1,10-
binaphthyl-20-ylimino)methyl) phenol L5
6.86e6.93 (m, 3H, Ar), 6.98 (td, J ¼ 1.2, 8.0 Hz, 2H, Ar), 7.04e7.08 (m,
2H, Ar), 7.13e7.19 (m, 4H, Ar), 7.22e7.30 (m, 3H, Ar), 7.41e7.53 (m,
4H, Ar), 7.94e7.98 (m, 4H, Ar), 8.05e8.09 (m, 2H, Ar), 8.28 (s, 1H,
CH]N), 12.93 (s, 1H, OH); 31P NMR (CDCl3, 121 MHz, 85% H3PO4)
This is a known compound [28]. 1H NMR (CDCl3, TMS, 300 MHz)
d
1.22 (s, 9H, 3CH3), 1.26 (s, 9H, 3CH3), 6.83e7.58 (m, 20H, Ar),
7.88e7.91 (m, 3H, Ar), 8.05 (d, J ¼ 8.7 Hz,1H, Ar), 8.39 (s, 1H, CH]N),
12.64 (s, 1H, OH); 31P NMR (CDCl3, 121 MHz, 85% H3PO4)
ꢀ12.32.
d
ꢀ13.79; MS (EI) m/z (%): 602 [Mþ] (26.0), 603 (10.1), 572 (8.8), 453
(5.7), 438 (33.3), 437 (100), 417 (7.3), 386 (6.1), 281 (8.6); HRMS (EI)
d

Y.-W. Sun et al. / Journal of Organometallic Chemistry 696 (2011) 2850e2856
2855
Calcd. For C39H27N2O4P [Mþ]: 602.1759, found: 602.1757;
1,3-diphenylpropenyl acetate was consumed completely. The
reaction was quenched by the addition of saturated NH4Cl
aqueous solution and the product was extracted with CH2Cl2
(3 ꢂ 10 mL). The combined organic layers were dried over anhy-
drous Na2SO4, filtered, and concentrated in vacuo to yield the
crude product, which was purified by flash chromatography on
silica gel (eluent: PE/EtOAc ¼ 20 : 1) to furnish dimethyl(1,3-
diphenyl-2-propen-1-yl)malonate (3a) as a colorless solid. This
[
a]
20D ¼ þ230 (c 1.8, CHCl3).
3.2.12. (R,E)-3-((20-(diphenylphosphino)-1,10-binaphthyl-2-
ylimino)methyl)-5-nitrobenzene-1,2-diol L12
Yield: (96 mg, 74%). A red solid. Mp: 199e201 ꢁC; IR (CH2Cl2)
n
2925, 2855, 1744, 1626, 1463, 1338, 1272, 1170, 951, 844, 743,
702 cmꢀ1; 1H NMR (CDCl3, TMS, 400 MHz)
d
6.07 (br, 1H, OH),
6.92e7.01 (m, 4H, Ar), 7.04e7.08 (m, 2H, Ar), 7.19e7.21 (m, 5H, Ar),
7.26e7.32 (m, 3H, Ar), 7.45e7.56 (m, 3H, Ar), 7.57e7.59 (m, 2H, Ar),
7.64 (d, J ¼ 2.8 Hz, 1H, Ar), 7.97e8.03 (m, 3H, Ar), 8.14 (d, J ¼ 8.8 Hz,
1H, Ar), 8.19 (s, 1H, CH]N), 14.27 (br, 1H, OH); 31P NMR (CDCl3,
is a known compound [29]. 1H NMR (CDCl3, TMS, 300 MHz)
d 3.52
(s, 3H, CH3), 3.70 (s, 3H, CH3), 3.94 (d, J ¼ 16.5 Hz, 1H, CH), 4.27
(dd, J ¼ 8.4, 16.8 Hz, 1H, CH), 6.32 (dd, J ¼ 8.4, 15.6 Hz, 1H, ¼ CH),
6.48 (d, J ¼ 15.6 Hz, 1H, ¼ CH), 7.19e7.33 (m, 10H, Ar). The
enantiomeric excess was determined by HPLC (Chiralcel AD,
eluent: n-hexane/i-propanol ¼ 90:10), flow rate: 0.7 mL/min,
retention times: 18.26 min (R), 26.19 min (S).
121 MHz, 85% H3PO4)
453 (15.1), 452 (14.9), 451 (22.8), 450 (8.7), 438 (22.5), 437 (100),
d
ꢀ13.86; MS (EI) m/z (%): 618 [Mþ] (22.2),
268 (9.8), 44 (16.7); HRMS (EI) Calcd. For C39H27N2O4P (Mþ):
618.1708, found: 618.1708; [
a]
20D ¼ ꢀ6 (c 0.9, CHCl3).
3.4.1. Diethyl(1,3-diphenyl-2-propen-1-yl)malonate (3b) colorless
3.2.13. (R,E)-3-((20-(diphenylphosphino)-1,10-binaphthyl-2-
ylimino)methyl)-5-nitrobenzene-1,2-dimethoxy L13
oil. This is a known compound [29]
1H NMR (CDCl3, TMS, 400 MHz)
d
0.94 (t, J ¼ 7.2 Hz, 3H, CH3),
Yield: (80 mg, 56%). A yellow solid. Mp: 156e158 ꢁC; IR (CH2Cl2)
1.14 (t, J ¼ 7.2 Hz, 3H, CH3), 3.84 (d, J ¼ 10.8 Hz, 1H, CH), 3.90 (qd,
J ¼ 2.0, 7.2 Hz, 2H, CH2), 4.10 (q, J ¼ 7.2 Hz, 2H, CH2), 4.19 (dd,
J ¼ 8.4, 10.8 Hz, 1H, CH), 6.26 (dd, J ¼ 8.4, 15.6 Hz, 1H, ¼ CH), 6.40
(d, J ¼ 15.6 Hz, 1H, ¼ CH), 7.12e7.25 (m, 10H, Ar). The enantiomeric
excess was determined by HPLC (Chiralcel AD, eluent: n-hexane/
i-propanol ¼ 90:10), flow rate: 0.7 mL/min, retention times:
13.07 min (R), 17.40 min (S).
n
2928, 2856, 1583, 1526, 1479, 1432, 1342, 1286, 997, 743,
701 cmꢀ1; 1H NMR (CDCl3, TMS, 400 MHz)
d
3.60 (s, 3H, CH3), 3.91
(s, 3H, CH3), 6.97e7.06 (m, 6H, Ar), 7.10e7.18 (m, 6H, Ar), 7.26e7.28
(m, 2H, Ar), 7.36e7.47 (m, 4H, Ar), 7.68 (d, J ¼ 2.4 Hz, 1H, Ar),
7.83e7.93 (m, 4H, Ar), 8.04 (d, J ¼ 8.4 Hz, 1H, Ar), 8.53 (s, 1H, CH]
N); 31P NMR (CDCl3, 121 MHz, 85% H3PO4)
d
ꢀ13.58; MS (EI) m/z
(%): 646 [Mþ] (5.2), 469 (6.6), 453 (15.1), 452 (11.4), 451 (6.1), 438
(24.2), 437 (100), 268 (5.6), 267 (14.5); HRMS (EI) Calcd. For
3.4.2. (E)-Dimethyl(1,3-bis(4-chlorophenyl)-2-propen-1-yl)
C41H31N2O4P (M þ): 646.2021, found: 646.2023; [
a
]
20D ¼ þ58
malonate (3c) colorless oil. This is a known compound [30]
(c 1.4, CHCl3).
1H NMR (CDCl3, TMS, 400 MHz)
d 3.54 (s, 3H, CH3), 3.70 (s, 3H,
CH3), 3.90 (d, J ¼ 10.4 Hz, 1H, CH), 4.24 (dd, J ¼ 8.4, 10.4 Hz, 1H, CH),
6.27 (dd, J ¼ 8.4, 15.6 Hz, 1H, ¼ CH), 6.41 (d, J ¼ 15.6 Hz, 1H, ¼ CH),
7.21e7.30 (m, 8H, Ar). The enantiomeric excess was determined by
HPLC (Chiralcel AD, eluent: n-hexane/i-propanol ¼ 85:15), flow
rate: 0.8 mL/min, retention times: 15.60 min (R), 24.25 min (S).
3.3. The preparation of complex E from ligand L1 with PdCl2(PhCN)2
Ligand L1 (57 mg, 0.1 mmol) and bis(benzonitrile)palladium
dichloride (38 mg, 0.1 mmol) were dissolved in dichloromethane
(1.0 mL) under an argon atmosphere and the reaction mixture
stirred for 1 h at room temperature. Degassed hexane (5.0 mL) was
then slowly added, which led to the precipitation of the formed
complex. The mother liquor was filtered off, and the precipitate was
washed with hexane (2 ꢂ 1.0 mL) to afford the (R)-(þ)-complex E as
an orange powder. Yield (60 mg, 80%). The single crystals for X-ray
diffraction were obtained by recrystallization from dichloro-
3.4.3. (E)-N-benzyl-1,3-diphenylprop-2-en-1-amine (3d) yellow oil.
This is a known compound [29]
1H NMR (CDCl3, TMS, 400 MHz)
d
3.76 (d, J ¼ 13.2 Hz, 1H, CH),
3.81 (d, J ¼ 13.2 Hz, 1H, CH), 4.40 (d, J ¼ 7.2 Hz, 1H, CH), 6.32 (dd,
J ¼ 7.2, 15.6 Hz, 1H, ¼ CH), 6.58 (d, J ¼ 15.6 Hz, 1H, ¼ CH), 7.19e7.44
(m, 15H, Ar). The enantiomeric excess was determined by HPLC
(Chiralcel AD, eluent: n-hexane/i-propanol ¼ 199:1), flow rate:
0.5 mL/min, retention times: 41.03 min (R), 47.23 min (S).
methane and PE (1/4). Mp: >300 ꢁC; IR (CH2Cl2)
1810, 1662, 1506, 1436, 1274, 753 cmꢀ1 1H NMR (CDCl3, TMS,
300 MHz) 2.43 (s, 3H, CH3), 6.41e6.53 (m, 2H, Ar), 6.73e6.85 (m,
n 3216, 2928, 2856,
d
4H, Ar), 6.97e7.10 (m, 4H, Ar), 7.31e7.36 (m, 1H, Ar), 7.46e7.74 (m,
11H, Ar), 7.80e7.85 (m, 2H, Ar), 7.91e7.98 (m, 1H, Ar), 8.07 (s, 1H,
3.4.4. (E)-4-(1,3-Diphenylallyl)morpholine (3e) pale siold. This is
a known compound [29]
CH]N), 9.81 (s, 1H, OH); 31P NMR (CDCl3, 121 MHz, 85% H3PO4)
1H NMR (CDCl3, TMS, 400 MHz)
d 2.36e2.41 (m, 2H, CH2), 2.53
20
d
þ25.23; [
a]
¼ þ138 (c 0.25, CHCl3). MS (ESI): m/z 1427.1 (Mþ);
(br, 2H, CH2), 3.69e3.71 (m, 4H, CH2), 3.78 (d, J ¼ 9.2 Hz, 1H, CH),
6.28 (dd, J ¼ 9.2, 16.0 Hz, 1H, ¼ CH), 6.56 (d, J ¼ 16.0 Hz, 1H, ¼ CH),
7.18e7.41 (m, 10H, Ar). The enantiomeric excess was determined by
HPLC (Chiralcel OD, eluent: n-hexane/i-propanol ¼ 90:10), flow
rate: 1.0 mL/min, retention times: 6.36 min (R), 13.54 min (S).
D
HRMS (ESI) Calcd. for C80H60Cl2N2O2P2Pd2: 1427.1614, Found:
1427.1619.
3.4. Typical reaction procedure
To a solution of allyl chloride palladium dimmer [Pd(h3eC3H5)
Cl]2 (4.5 mg, 0.0125 mmol, 5 mol %) in solvent (1.0 mL) was added
enantiomerically pure ligand L1 (0.0375 mmol, 15 mol %) under an
argon atmosphere, and the reaction mixture was stirred at room
temperature for 30 min. A solution of 1,3-diphenylpropenyl
acetate (63 mg, 0.25 mmol) in solvent (0.5 mL) was added, fol-
lowed by the addition of salt (0.025 mmol, 10 mol %). The reaction
solution was then stirred for a further 5 min at room temperature.
Afterward, dimethyl malonate (0.09 mL, 0.75 mmol, 3 equiv) and
bis(trimethylsilyl)acetamide (BSA) (0.19 mL, 0.75 mmol, 3 equiv)
were added and the reaction was monitored by TLC plates until
4. Conclusions
In conclusion, chiral phosphine-imine type ligand L9 prepared
from (R)-2-(diphenylphosphino)-1,10-binaphthyl-20-amine was
found to be a fairly effective chiral ligand for Pd(II)-catalyzed
asymmetric allylic alkylation to give the corresponding product
in moderate enantioselectivity and moderate yield under mild
conditions. In the mean time, its bidentate coordination pattern
to the Pd metal center with both P and N atoms has been
unambiguously established by X-ray diffraction. The result will
promote us to design and synthesize more new effective chiral

2856
Y.-W. Sun et al. / Journal of Organometallic Chemistry 696 (2011) 2850e2856
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Acknowledgments
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Financial support from the Shanghai Municipal Committee of
Science and Technology (08dj1400100-2), National Basic Research
Program of China (973)-2010CB833302, the Fundamental Research
Funds for the Central Universities and the National Natural Science
Foundation of China for financial support (21072206, 20472096,
20872162, 20672127, 20821002 and 20732008) is greatly
acknowledged.
Appendix. Supplementary material
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[21] K. Nozaki, H. Komaki, Y. Kawashima, T. Hiyama, T. Matsubara, J. Am. Chem.
Soc. 23 (2001) 534e544.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.jorganchem.2011.04.036.
[22] X.Q. Hu, H.L. Chen, X.M. Zhang, Angew. Chem. Int. Ed. 38 (1999) 3518e3521.
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[25] H. Kodama, T. Taiji, T. Ohta, I. Furukawa, Tetrahedron: Asymmetry 11 (2000)
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