Asymmetrie synthesis of functionalized 1,3-diphosphines via chiral palladium complex promoted hydrophosphination of activated Olefins

Article abstract of DOI:10.1021/ic9018053

Aldehyde, ester- and keto-functionalized monophosphine palladium complexes containing the ortho-metalated (R)-(1-(dimethylamino)ethyl)naphthalene as the chiral auxiliary and reaction promoter were synthesized via hydrophosphination of acrolein and the sub

Full text of DOI:10.1021/ic9018053

Inorg. Chem. 2010, 49, 989–996 989
DOI: 10.1021/ic9018053
Asymmetric Synthesis of Functionalized 1,3-Diphosphines via Chiral Palladium
Complex Promoted Hydrophosphination of Activated Olefins
Mingjun Yuan, Na Zhang, Sumod A. Pullarkat, Yongxin Li, Fengli Liu, Phuong-Tu Pham, and Pak-Hing Leung*
Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences, Nanyang
Technological University, Singapore 637371, Singapore
Received September 10, 2009
Aldehyde, ester- and keto-functionalized monophosphine palladium complexes containing the ortho-metalated
(R)-(1-(dimethylamino)ethyl)naphthalene as the chiral auxiliary and reaction promoter were synthesized via
hydrophosphination of acrolein and the subsequent Wittig reactions in a one-pot process. Under very mild conditions,
the second-stage hydrophosphination of the monophosphine substrates gave the corresponding ester-, keto-, and
hydroxyl-functionalized chiral 1,3-bis(diphenylphosphino)propane palladium complexes with good yields and stereo-
selectivities. The coordination properties and absolute configurations of the novel 1,3-diphosphine complexes were
established by single crystal X-ray crystallography. The enantiomerically pure functionalized diphosphine ligands with
ester and keto functionalities could be subsequently liberated stereospecifically by treatment of the corresponding
dichloro palladium complexes with aqueous potassium cyanide in high yields.
Introduction
diversity. To our best knowledge, there has been no report
on the asymmetric synthesis of functionalized chiral 1,3-
bis(diphenylphosphino)propane ligands.
In terms of synthetic value and atom economy, the addi-
tion of secondary phosphines to activated olefins such as R,β-
unsaturated carbonyl derivatives, acrylonitriles, and ni-
troalkenes is an important process in organophosphrus
chemistry,4 since it allows to create a phosphorus-carbon
bond and to introduce various functional groups into the
Optical pure diphosphines containing the 1,3-bis-
(diphenylphosphino)propane backbone, such as (S,S)-skew-
phos and (S)-chairphos, have long been proven to be
powerful bidentate ligands in transition metal catalyzed
asymmetric reactions.1,2
(2) (a) MacNeil, P. A.; Roberts, N. K.; Bosnich, B. J. Am. Chem. Soc.
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1981, 103, 2273. (b) Bakos, J.; Toth, I.; Heil, B.; Marko, L. J. Organomet. Chem.
1985, 279, 23. (c) Halterman, R. L.; Nimmons, H. L. Organometallics 1990, 9,
273. (d) Brunner, H.; Terfort, A. Tetrahedron: Asymmetry 1995, 6, 919.
(e) Dubrovina, N. V.; Tararov, V. I.; Monsees, A.; Kadyrov, R.; Fischer, C.;
Compared with classical 1,2-diphosphines, the 1,3-di-
phosphines can form the six-membered metallacycles
involving transition metals with new catalytic activity
and interesting ring conformations.3 However, literature
review shows that such chiral diphosphine ligands are
generally synthesized by tedious resolution or derived
from chiral pools,2 which may limit their structural
€
Borner, A. Tetrahedron: Asymmetry 2003, 14, 2739. (f) Herseczki, Z.; Gergely,
00
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I.; Heged€us, C.; Szollosy, A.; Bakos, J. Tetrahedron: Asymmetry 2004, 15, 1673.
(g) Fries, G.; Wolf, J.; Ilg, K.; Walfort, B.; Stalke, D.; Werner, H. Dalton Trans.
2004, 1873. (h) Dubrovina, N. V.; Tararov, V. I.; Monsees, A.; Spannenberg, A.;
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*To whom correspondence should be addressed. E-mail: pakhing@
ntu.edu.sg.
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J. Organomet. Chem. 1989, 370, 263.
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Brodner, K.; Helmchen, G. Eur. J. Org. Chem. 2005, 3246. (b) Enders, D.;
(1) (a) Baratta, W.; Herdtweck, E.; Siega, K.; Toniutti, M.; Rigo, P.
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Soc. 2004, 126, 16820. (c) Portscheller, J. L.; Lilley, S. E.; Malinakova, H. C.
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Chem. Commun. 2004, 98. (g) Blanc, D.; Henry, J.-C.; Ratovelomanana-Vidal,
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Saint-Dizier, A.; Lannou, M.-I.; Lenzen, A. Eur. J. Org. Chem. 2006, 29.
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r
2009 American Chemical Society
Published on Web 12/30/2009
pubs.acs.org/IC

990 Inorganic Chemistry, Vol. 49, No. 3, 2010
Yuan et al.
molecule in a single step. In general, transition metal com-
plexes can offer better stabilization and selectivity for hydro-
phosphination reactions, as they can protect the reactive
phosphine species from oxidation by means of coordination.
Furthermore, the metal complexes will be able to provide two
or more coordination sites to synthesize chiral versions of
bidentate diphosphine ligands,5 thus providing avenues for
ligand activation and stereochemical control. Over the past
few years, our group has established that organopalladium
complexes containing (R)- or (S)-(1-(dimethylamino)ethyl)-
naphthalene as the chiral auxiliary are good promoters for
synthesis of various chiral phoshine ligands by means of
asymmetric Diels-Alder reactions and hydrophosphination
reactions.5,6 Continuing our efforts in the development of
new kinds of chiral diphosphines ligands utilizing these useful
auxiliaries, we now describe a facile strategy to synthesize
four monophosphine palladium complexes with aldehyde,
ester- and keto-functionalities from acrolein, and their sec-
ond-stage hydrophosphination reactions under mild condi-
tions and in the absence of any protection that generate the
corresponding novel chiral 1,3-diphosphine products.
at room temperature for 2 h generated the ester-functiona-
lized monophosphine palladium complex R-3a in 85% yield
as indicated by a singlet resonance signal at δ 35.0 in the 31P
NMR spectrum (CDCl3, 121 MHz). The keto-functionalized
product R-3b could be obtained by using 1-(triphenylphos-
phoranylidene)acetone for the Wittig reaction in 81% yield.
However this reaction needs to be performed at an elevated
temperature (50 °C) for 24 h because of the relatively inactive
nature of the employed Wittig reagent. The 121 MHz 31P
NMR spectrum in CDCl3 of R-3b indicated a singlet reso-
nance signal at δ 35.2. Similarly, R-3c was isolated as a pale
yellow powder in 79% yield after the reaction of R-2
with (phenacylidene)triphenylphosphorane in chloroform
at 50 °C for 36 h and exhibited a phosphorus signal at
δ 35.1 in CDCl3.
Asymmetric Hydrophosphination of Ester-Functiona-
lized Monophosphine Palladium Complex R-3a. It has
been well established that the chloro ligand trans to the
ortho-metalated aromatic carbon in R-3a is inert to
displacement by any incoming phosphorus donor atoms.5,6
Treatment of complex R-3a with aqueous silver perchlo-
rate in dichloromethane gave the intermediate cationic
perchlorate complex R-4a in essentially quantitative yield
(Scheme 2). In routine synthesis, however, this highly
reactive species is not isolated, and therefore upon
removal of the silver chloride, the CH3CN/CH2Cl2 (1:2)
solution of R-4a was subsequently treated with 1 equiv of
diphenylphosphine at -78 °C for the second-stage hydro-
phosphination reaction to generate the 1,3-diphosphine
products. The process was monitored by 31P NMR
spectroscopy and was found to be completed within 2 h.
Prior to purification, the 31P NMR spectrum of the crude
product in CDCl3 exhibited four pairs of doublets at
δ -6.1, 38.8 (JPP = 55.3 Hz); 0.9, 36.2 (JPP = 51.9 Hz);
8.6, 28.6 (JPP = 55.3 Hz), and 10.1, 28.5 (JPP = 51.7 Hz)
with the intensity ratio of 15:1:9:5, respectively. The
signals indicated that all the four possible isomeric pro-
ducts, i.e., 5a, 6a, 7a, and 8a, were formed in the hydro-
phosphination reaction as shown in Scheme 2. It should
be noted that complexes 5a and 6a are regioisomers which
adopt the same R absolute configuration at the newly
formed chiral carbon centers. Similarly, complexes 7a and
8a are regioisomers with S absolute configuration at the
new stereogenic centers. Apart from electronic effect, the
chelate stabilization of a 6-membered ring as compared to
the 7-membered analogue also contributes to the regios-
electivity seen in the hydrophosphination process.
Results and Discussion
Substituted R,β-unsaturated aldehydes, like cinnamalde-
hyde, have been known to be reactive toward diphenylpho-
sphine and its analogues, wherein the addition reactions can
occur either at the activated olefin or at the carbonyl group.7
However, acrolein was found to be inert toward diphenyl-
phosphine when the addition reaction was performed in a
series of solvent systems in the presence of external base.
Literature reports reveal that the previous synthesis of the
free monophosphine ligand 3-(diphenylphosphino)propanal
involves tedious organic manipulations from 3-chloropropa-
nol or chloro-substituted dimethylacetal.8 Interestingly, in
the presence of chiral palladium complex R-1 as the promoter,
the Michael-type hydrophosphination reaction of acrolein
proceeded chemoselectively to afford the monomeric complex
R-2 with the carbonyl group intact (Scheme 1). The addition
process was monitored by 31P NMR spectroscopy, and was
found to be complete within 30 min at 0 °C in acetonitrile
to afford the product R-2 as a white solid in 87% yield. The
121 MHz 31P NMR spectrum in CDCl3 of R-2 exhibited a
sharp singlet at δ 35.6.
As illustrated in Scheme 1, in situ reaction of product R-2
with methyl (triphenylphosphoranylidene)acetate in chloroform
(5) For hydrophosphination reactions, see: (a) Pullarkat, S. A.; Ding, Y.;
Li, Y.; Tan, G. K.; Leung, P. H. Inorg. Chem. 2006, 45, 7455. (b) Tang, L. L.;
Zhang, Y.; Luo, D.; Li, Y.; Mok, K. F.; Yeo, W. C.; Leung, P. H. Tetrahedron Lett.
2007, 48, 33. (c) Zhang, Y.; Tang, L.; Ding, Y.; Chua, J.-H.; Li, Y.; Yuan, M.;
Leung, P. H. Tetrahedron Lett. 2008, 49, 1762. (d) Yuan, M.; Pullarkat, S. A.;
Ma, M.; Zhang, Y.; Huang, Y.; Li, Y.; Goel, A.; Leung, P. H. Organometallics
2009, 28, 780. (e) Zhang, Y.; Pullarkat, S. A.; Li, Y.; Leung, P. H. Inorg. Chem.
2009, 48, 5535. (f) Liu, F.; Pullarkat, S. A.; Li, Y.; Chen, S.; Yuan, M.; Lee, Z. Y.;
Leung, P. H. Organometallics 2009, 28, 3941.
(6) For Diels-Alder reactions, see: (a) Leung, P. H. Acc. Chem. Res. 2004,
37, 169. (b) Yeo, W. C.; Chen, S.; Tan, G. -K.; Leung, P. H. J. Organomet. Chem.
2007, 692, 2539. (c) Yuan, M.; Pullarkat, S. A.; Yeong, C. H.; Li, Y.; Krishnan, D.;
Leung, P. H. Dalton Trans. 2009, 3668. (d) Ma, M.; Pullarkat, S. A.; Yuan, M.;
Zhang, N.; Li, Y.; Leung, P. H. Organometallics 2009, 28, 4886. (e) Pullarkat,
S. A.; Cheow, Y. L.; Li, Y.; Leung, P. H. Eur. J. Inorg. Chem. 2009, 2375.
(7) (a) Imamoto, T.; Oshiki, T.; Onozawa, T.; Kusumoto, T.; Sato, K.
J. Am. Chem. Soc. 1990, 112, 5244. (b) Moiseev, D. V.; Patrick, B. O.; James, B.
R. Inorg. Chem. 2007, 46, 11467.
The two major products 5a and 6a could be isolated
efficiently as equilibrium mixture by column chromato-
graphy in 66% yield.9 The 31P NMR spectrum (CDCl3,
121 MHz) indicated two pairs of doublets at δ -6.1, 38.8
(JPP = 55.3 Hz) and 8.6, 28.6 (JPP = 55.3 Hz). Unfortu-
nately, attempts to crystallize the isomeric complex mix-
tures for X-ray crytallography from various solvent
systems were unsuccessful. The chiral amine auxiliary
on complexes 5a and 6a however, could be chemoselec-
tively removed from palladium template by treatment
with concentrated hydrochloric acid (Scheme 3). The
(9) The interconversion between regioisomers 5 and 6 is very fast
especially in coordinating solvent, such as acetonitrile, compared with the
similar 1,2-diphosphine palladium complexes (see ref 5). The equilibrium can
be attained within 2 h at room temperature.
(8) (a) Lutz, C.; Graf, C. D.; Knochel, P. Tetrahedron 1998, 54, 10317.
(b) Vaughn, G. D.; Gladysz, J. A. J. Am. Chem. SOC. 1986, 108, 1473.

Article
Inorganic Chemistry, Vol. 49, No. 3, 2010 991
Scheme 1
The six-membered chelate ring in 9a has a novel boat
conformation with the ester functionality occupying the
sterically favorable equatorial position. The phenyl rings
on the phosphorus atom that is adjacent to the ester
substituent are of axial (ipso atom C1) and equatorial
(ipso atom C7) disposition, respectively, while the other
two phenyl rings on P2 adopt bisectional orientations
(see Supporting Information).
The optically pure 1,3-diphosphine ligand 10a could be
liberated stereospecifically from 9a by treatment of the
dichloro complex with aqueous potassium cyanide. The
liberated diphosphine was obtained as a white solid in
95% yield, [R]D = þ19.0 (c 1.0, CH2Cl2). The 31P NMR
spectrum in CDCl3 of 10a exhibited a pair of singlet at
δ -15.3 and -6.4. To determine the optical purity of the
diphosphine 10a, the liberated ligand was recoordinated
to the bis(acetonitrile) complex R-11 (Scheme 4), the
121 MHz 31P NMR of the recomplexation products in
CDCl3 indeed exhibited two pairs of doublets at δ -6.1,
38.8 (JPP = 55.3 Hz) and 8.6, 28.6 (JPP = 55.3 Hz). These
resonance signals are identical with the two major pro-
ducts from the original hydrophosphination reaction,
which indicated the formation of the regioisomers 5a
and 6a. In a further check, the recoordination of the free
ligand to equally accessible enantiomeric complex S-11
generated the regioisomers 12a and 13a with two clearly
different pairs of doublet phosphorus signals at δ 0.9, 36.2
(JPP = 51.9 Hz) and 10.1, 28.5 (JPP = 51.7 Hz). Note that
products 13a and 14a are the enantiomeric forms of 7a
and 8a, respectively. Importantly, no resonance signals
were observed at δ -6.1, 38.8, 8.6, and 28.6 thus con-
firming that the liberated 1,3-diphosphine ligand 10a was
optically pure.
Scheme 2
Asymmetric Hydrophosphination of Keto-Functiona-
lized Monophosphine Palladium Complexes R-3b and R-
3c. By following the similar procedure as described for the
hydrophosphination of R-3a, the keto-functionalized
precursor R-3b was converted to the reactive perchlorato
species by treatment with silver salt. The perchlorato
complex R-4b was subsequently reacted with 1 equiv of
diphenylphosphine for the second-stage hydrophosphi-
nation reaction at 0 °C for 2 h in acetonitrile. The 121 MHz
31P NMR spectrum of the crude product in CDCl3
resultant enantiomerically pure dichloro complex 9a was
obtained as pale yellow prisms in 88% isolated yield upon
crystallization from dichloromethane and diethyl ether,
[R]D = -17.5 (c 1.7, CH2Cl2). The 121 MHz 31P NMR in
CDCl3 of the neutral product 9a showed a pair of doub-
lets at δ 15.5, 21.9 (JPP = 13.0 Hz).
indicated four pairs of doublets at δ -6.7, 36.7 (JPP
=
55.7 Hz); 1.0, 38.8 (JPP = 51.8 Hz); 8.8, 27.2 (JPP =56.3Hz)
and 10.9, 28.5 (JPP = 52.0 Hz) with the intensity ratio of
17.5:1:11.2:3.1. The two major regioisomers 5b and 6b
was subsequently isolated efficiently by column chroma-
tography in 75% yield with two pairs of doublets at δ -6.7,
36.7 (JPP = 55.7 Hz); and 8.8, 27.2 (JPP = 56.3 Hz) in the
31P NMR spectrum.
The chelating properties and the absolute stereochem-
istry of the coordinated ester-substituted 1,3-diphosphine
complex 9a were studied by X-ray crystallography. There
are two crystallographically distinguishable molecules in
the asymmetric unit with similar bond lengths, angles,
and the same R absolute configuration at the newly
formed chiral center. Figure 1 shows the ORTEP drawing
of molecule 1, the selected bond, and angle parameters,
and other crystallographic data are listed in Table 1 and
Table 4, respectively. The Pd atom adopts the expected
distorted square planar coordination geometry. The PdP2
plane is rotated at an angle of 9.5(2)° with respect to that
of PdCl2, while the angles around the palladium center are
in the ranges 87.3(1)-91.8(1) and 171.1(1)-175.3(1)°.
Upon removal of the chiral amine auxiliary of 5b and 6b
with concentrated hydrochloric acid, the optically pure
dichloro complex 9b was crystallized as pale yellow
prisms in 85% yield from dichloromethane and diethyl
ether, [R]D = -20.4 (c 0.9, CH2Cl2). The 31P NMR
spectrum (121 MHz, CDCl3) showed a pair of doublets
at δ 16.3, 22.5 (JPP = 12.7 Hz). The single-crystal X-ray
crystallographic analysis clearly established its coordina-
tion mode and the absolute configuration (Figure 2). The
newly formed chiral carbon center at C13 is R, and the
novel six-membered metallacycle adopts a boat confor-
mation with the keto-substituent occupying the sterically
˚
Both the Pd-P bond (2.258(2), 2.249(3) A) and the
P-Pd-P bite angle (90.2(1)°) are larger than in the case
of 1,2-diphosphine metallacycles previously reported.5

992 Inorganic Chemistry, Vol. 49, No. 3, 2010
Yuan et al.
(JPP = 56.9 Hz); 0.4, 38.6 (JPP = 51.9 Hz); 8.6, 26.9 (JPP
Scheme 3
=
56.3 Hz), and 10.6, 27.8 (JPP = 53.0 Hz) with the intensity
ratio of 12:1:7:3.5, which indicated the formation of the
four isomeric hydrophosphination products 5c, 6c, 7c,
and 8c. The two major regioisomers 5c and 6c could be
isolated efficiently by column chromatography in 70%
yield [δ -6.3, 37.8 (JPP = 56.9 Hz); and 8.6, 26.9 (JPP
=
56.3 Hz)]. The regioisomers 5c and 6c were treated with
concentrated hydrochloric acid to remove the chiral
amine auxiliary chemoselectively. The resultant dichloro
complex 9c showed a pair of doublets at δ 15.8, 22.4
(JPP = 13.8 Hz) in CDCl3 in 31P NMR spectrum, [R]D =
þ12.6 (c 1.0, CH2Cl2). Further treatment of 9c with
aqueous potassium cyanide at room temperature liberated
the chiral keto-functionalized 1,3-diphosphine ligand 10c
in quantitative yield, [R]D = þ11.4 (c 0.7, CH2Cl2). The
31P NMR spectrum of the free ligand in CDCl3 exhibited
a pair of singlets at δ -15.7 and -6.4. The recoordination
process of the free ligand to R-11 and S-11 confirmed that
the chiral diphosphine ligand 10c is optically pure.
Asymmetric Hydrophosphination of R-2 to Synthesize
Hydroxyl-Functionalized Chiral 1,3-Diphosphine Palla-
dium Complex. Unlike the ester- and keto-functionalized
monophosphine substrates R-3, the perchlorato analogue
of R-2 generated from abstraction of the chloro ligand
with silver perchlorate is quite unstable. However, the
second-stage hydrophosphination of acrolein can occur
at the carbonyl group by treatment of R-2 with 1 equiv
diphenylphosphine in the presence of LiClO4 (Scheme 5).
The reaction was conducted at room temperature and was
completed in 2 h to afford the hydroxyl-functionalized
1,3-phosphine products 14, 15, 16, and 17. The 31P NMR
spectrum (202 MHz, CDCl3) of the crude reaction mixture
Figure 1. Molecular structure and absolute stereochemistry of complex
9a.
˚
Table 1. Selected Bond Lengths (A) and Angles (deg) of 9a
Pd1-P1
2.258(2)
1.866(9)
1.521(14)
90.2(1)
175.3(1)
91.3(1)
116.2(7)
Pd1-P2
2.249(3)
1.514(14)
1.818(9)
91.8(1)
171.1(1)
87.3(1)
114.2(7)
exhibited four pairs of doublets at δ -5.1, 30.1 (JPP
=
C13-P1
C13-C17
56.7 Hz); 0.0, 39.3 (JPP = 53.0 Hz); 5.3, 25.8 (JPP =54.1Hz),
and 13.1, 26.0 (JPP = 52.5 Hz) with the intensity ratio of
1:4.1:1:6.6.
C17-C18
C18-P2
P2-Pd1-P1
P1-Pd1-Cl2
P1-Pd1-Cl1
C17-C13-P1
Cl2-Pd1-Cl1
P2-Pd1-Cl1
P2-Pd1-Cl2
C17-C18-P2
The major regioiosmers 14 and 15 could be isolated as
an equilibrium mixture by column chromatography in
42% yield. The 31P NMR spectrum exhibited two pairs
of doublets at δ 0.0, 39.3 (JPP = 53.0 Hz) and 13.1, 26.0
(JPP = 52.5 Hz). Upon slow diffusion of diethyl ether into
the dichloromethane solution of the isomeric mixture, the
product 14 was obtained as pale yellow prisms in 40%
yield, [R]D = -90.7° (c 0.8, CH2Cl2). The 31P NMR
spectrum of crystallized 14 showed a pair of doublets at δ
13.1, 26.0 (JPP = 52.5 Hz). The molecular structure was
analyzed by means of single-crystal X-ray diffraction
analysis (Figure 3 and Table 3). The six-membered chelating
diphosphine ring has a skew conformation of δ helicity,
with the hydroxyl group occupying the sterically favor-
able equatorial position. The newly formed stereogenic
center at C27is in the R absolute configuration.
favorable equatorial position. Both bond lengths and
angles are comparable with the analogous ester complex
9a as showed in Table 2. Treatment of a CH2Cl2 solution
of 9b with aqueous potassium cyanide liberated the
optical pure keto-functionalized 1,3-diphosphine ligand
10b as a white solid in 92% yield, with [R]436 = þ30.8
(c 0.9, CH2Cl2). The 31P NMR spectrum of the free
diphosphine exhibited two singlets at δ -15.8 and -6.6.
The optical purity of 10b was confirmed by a similar
recoordination process (Scheme 4). The recomplexation
products involving the bis(acetonitrile) complex R-11
showed two pairs of doublets at δ -6.7, 36.7 (JPP
=
55.7 Hz); and 8.8, 27.2 (JPP = 56.3 Hz), which indicated
the formation of the regioisomers 5b and 6b. Upon
recoodination of the free ligand 10b to complex S-11,
the 31P NMR of the recomplexation products gave two
distinct pairs of doublets at δ 1.0, 38.8 (JPP = 51.8 Hz);
and 10.9, 28.5 (JPP = 52.0 Hz).
The addition of a secondary phosphine to an aldehyde
is usually more complex, as the process has been proven to
be reversible, and the corresponding adducts are prone
to undergo isomerization to form phosphine oxides.10
The monophosphine substrate R-3c, upon abstraction
of the chloro ligand with silver perchlorate, was reacted
with diphenyphosphine at 0 °C for 2 h in acetonitrile. The
121 MHz 31P NMR spectrum of the crude product
in CDCl3 showed four pairs of doublets at δ -6.3, 37.8
(10) (a) Chikkali, S.; Gudat, D. Eur. J. Inorg. Chem. 2006, 3005.
(b) Kolodiazhnyi, O. I.; Guliaiko, I. V.; Kolodiazhna, A. O. Tetrahedron Lett.
2004, 45, 6955. (c) Bourumeau, K.; Gaumont, A.-C.; Denis, J.-M. J. Organomet.
Chem. 1997, 529, 205. (d) Suzuki, K.; Hashimoto, T.; Maeta, H.; Matsumoto, T.
Synlett 1992, 125. (e) Epstein, M.; Buckler, S. A. Tetrahedron 1962, 18, 1231.

Article
Inorganic Chemistry, Vol. 49, No. 3, 2010 993
Scheme 4
Scheme 5
Figure 2. Molecular structure and absolute stereochemistry of complex
9b.
˚
Table 2. Selected Bond Lengths (A) and Angles (deg) of 9b
Pd1-P1
2.245(2)
1.869(8)
1.487(14)
90.1(1)
175.1(1)
91.4(1)
114.3(6)
Pd1-P2
2.246(3)
1.552(12)
1.861(8)
92.4(1)
172.0(1)
86.5(1)
114.2(6)
palladium complex promoted Michael-type hydropho-
sphination reactions. The reactions proceeded with good
yields, regio- and stereoselectivities under mild condi-
tions. Further investigations on the synthesis of a similar
class of chiral diphosphines with various functionalities
and the screening of transition metal catalyzed reactions
are currently in progress.
C13-P1
C13-C17
C17-C18
C18-P2
P2-Pd1-P1
P1-Pd1-Cl2
P1-Pd1-Cl1
C17-C13-P1
Cl2-Pd1-Cl1
P2-Pd1-Cl1
P2-Pd1-Cl2
C17-C18-P2
Interestingly, the chiral hydroxyl group in coordinated
1,3-diphosphine palladium complexes are quite stable.
The dichloromethane solution of the complex 14 can be
kept for 15 d without racemization of the chiral carbon
center. The subsequent liberation of the R-hydroxyl
functionalized 1,3-phosphine ligand from complex 14
was unsuccessful because of its unstable nature.
In conclusion, we have demonstrated an efficicent
synthesis of a new kind of ester- and keto-functionalized
chiral 1,3-bis(diphenylphosphino)propane ligands, as
well as hydroxyl-functionlized chiral 1,3-diphosphine
palladium complex from acrolein, by means of organo-
Experimental Section
Reactions involving air-sensitive compounds were per-
formed under a positive pressure of argon using a standard
Schlenk line. NMR spectra were recorded at 25 °C on Bruker
ACF 300 (1Hat300MHz,13Cat75MHz,and31Pat121MHz),
400 (1H at 400 MHz, 13C at 100 MHz, and 31P at 161 MHz)
and 500 (1H at 500 MHz and 31P at 202 MHz) spectrometers.
Chemical shifts (δ) are reported in parts per million. Proton
and carbon chemical shifts are relative to the residual solvent
peaks, and phosphorus chemical shifts are referenced to 85%
aqueous H3PO4. Coupling constants are reported in hertz.

994 Inorganic Chemistry, Vol. 49, No. 3, 2010
Yuan et al.
Calcd for C29H31ClNOPPd: C, 59.8; H, 5.4; N, 2.4. Found: C, 59.5;
H, 5.6; N, 2.5. 31P NMR (CDCl3, 121 MHz): δ 35.6 (s). 1H NMR
(CDCl3, 300 MHz): δ 2.06 (d, 3H, JHH = 6.3 Hz, CHMe), 2.47
(m, 2H, CH2CHO), 2.70 (d, 3H, JPH = 1.3 Hz, NMe), 2.99 (d, 3H,
JPH = 3.4 Hz, NMe), 3.07-3.29 (m, 1H, PCH2), 4.37 (qn, 1H,
J
HH = JPH = 6.2 Hz, CHCH3), 6.64-8.12 (m, 16H, Ar). 9.68 (br,
CHO). 13C NMR (CDCl3, 75 MHz): δ 23.7 (d, JPC = 35.6 Hz),
23.8 (s), 39.7 (d, JPC = 3.6 Hz), 48.3 (s), 51.1 (d, JPC = 2.9 Hz),
72.8 (d, JPC = 3.2 Hz), 123.2 (s), 124.2 (s), 124.7 (d, JPC = 5.7 Hz),
125.7 (s), 128.4 (d, 2C, JPC = 10.4 Hz), 128.7 (s), 128.8 (s), 128.9
(d, 2C, JPC = 10.3 Hz), 129.5 (d, JPC = 45.0 Hz), 130.3 (d, JPC
=
44.8 Hz), 130.9 (d, JPC = 2.4 Hz), 131.1 (d, JPC = 2.4 Hz), 131.1
(s), 133.8 (d, 2C, JPC = 11.6 Hz), 134.1 (d, 2C, JPC = 11.4 Hz),
135.4 (d, JPC = 12.2 Hz), 149.1 (d, JPC = 1.2 Hz), 149.2 (s), 200.4
(d, JPC = 16.6 Hz).
Preparation of Monophosphine Palladium Complex R-3a. R-2
was synthesized as described previously from diphenylpho-
sphine (0.70 g, 3.76 mmol) and R-1 (1.22 g, 1.78 mmol). Upon
removal of the organic solvent under reduced pressure, the
resulting white solid (crude R-2) was redissolved into chloro-
form (50 mL) before methyl (triphenylphosphoranylidene) acet-
ate (1.88 g, 5.62 mmol) was added. The mixture was stirred for
2 h at room temperature and concentrated. Complex R-3a was
isolated by column chromatography on silica (EtOAc/Hexanes
= 1:2) as a pale yellow solid (E/Z > 10, 1.94 g, 85%). R-3a
(trans isomer), [R]D = -11.9° (c 1.4, CH2Cl2). Mp: 120-122 °C.
Anal. Calcd for C32H35ClNO2PPd: C, 60.2; H, 5.5; N, 2.2.
Found: C, 60.5; H, 5.6; N, 2.1. 31P NMR (CDCl3, 121 MHz):
δ 35.0 (s). 1H NMR (CDCl3, 300 MHz): δ 2.05 (d, 3H, JHH = 6.2
Hz, CHMe), 2.26 (m, 2H, PCH2CH2), 2.67 (s, 3H, NMe), 2.86
(m, 1H, PCH0H), 2.97 (d, 3H, JPH = 3.0 Hz, NMe), 3.05 (m, 1H,
PCH0H), 3.64 (s, 3H, CO2Me), 4.34 (qn, 1H, JHH = JPH = 6.1
Hz, CHCH3), 5.73 (d, 1H, JHH = 15.7 Hz, CHCO2Me),
6.66-8.10 (m, 17H, Ar and CH2CH). 13C NMR (CDCl3, 75
MHz): δ 23.7 (s), 27.9 (d, JPC = 3.6 Hz), 29.5 (d, JPC = 32.6 Hz),
48.3 (s), 51.1 (d, JPC = 2.8 Hz), 51.4 (s), 72.8 (d, JPC = 3.1 Hz),
121.2 (s), 123.2 (s), 124.1 (s), 124.7 (d, JPC = 5.7 Hz), 125.8 (s),
128.4 (d, 2C, JPC = 10.3 Hz), 128.7 (s), 128.8 (s), 128.9 (d, 2C,
JPC = 11.2 Hz), 129.7 (d, JPC = 44.6 Hz), 130.6 (d, JPC = 45.6
Hz), 130.8 (d, JPC = 2.3 Hz), 131.0 (d, JPC = 2.5 Hz), 131.1 (s),
133.8 (d, 2C, JPC = 11.5 Hz), 134.2 (d, 2C, JPC = 11.3 Hz), 135.5
(d,JPC = 12.0 Hz), 148.3 (d, JPC =16.8Hz),149.2(d,JPC =2.1Hz),
149.4 (s), 166.8 (s).
Figure 3. Molecular structure and absolute stereochemistry of complex
14.
˚
Table 3. Selected Bond Lengths (A) and Angles (deg) of 14
Pd1-C1
2.048(5)
2.377(1)
1.845(5)
1.548(8)
80.4(2)
173.1(1)
96.1(1)
113.1(4)
118.7(4)
Pd1-N1
2.161(4)
2.255(1)
1.529(8)
1.831(5)
94.8(1)
172.2(2)
89.3(1)
116.7(5)
109.8(3)
Pd1-P1
Pd1-P2
C27-P1
C28-C29
C1-Pd1-N1
N1-Pd1-P2
N1-Pd1-P1
C28-C27-P1
C28-C29-P2
C27-C28
C29-P2
C1-Pd1-P2
C1-Pd1-P1
P2-Pd1-P1
C27-C28-C29
P1-C27-O1
Optical rotations were measured on the specified solution in a
0.1 dm cell at 20 °C with a Perkin-Elmer 341 polarimeter.
Elemental analyses were performed by the Elemental Analy-
sis Laboratory of the Division of Chemistry and Biological
Chemistry at Nanyang Technological University. Melting
points were measured using the SRS Optimelt Automated
Melting Point System, SRS MPA100.
Preparation of Monophosphine Palladium Complexes R-3b
and R-3c. The same procedure was adopted to synthesize
palladium complex R-3b from R-1 (1.22 g, 1.78 mmol). After
dissolving R-2 into chloroform (50 mL), 1-(triphenylpho-
sphoranylidene)-acetone (1.72 g, 5.38 mmol) was added and
stirred at 50 °C for 24 h. Upon removal of the solvent, the
product R-3b was isolated by column chromatography on silica
(EtOAc/Hexanes = 1:2) as a pale yellow powder (1.80 g, 81%).
[R]D = -5.7° (c 1.1, CH2Cl2). Mp: 121-123 °C. Anal. Calcd for
C32H35ClNOPPd: C, 61.7; H, 5.7; N, 2.2. Found: C, 61.5; H, 5.9;
N, 2.0. 31P NMR (CDCl3, 121 MHz): δ 35.2 (s). 1H NMR
(CDCl3, 300 MHz): δ 2.06 (d, 3H, JHH = 6.3 Hz, CHMe), 2.16
The chiral palladium templates R-1,11a,b R-11, and S-1111c
were prepared according to literature methods.
Caution! Perchlorate salts of metal complexes are poten-
tially explosive compounds and should be handled with care.
Preparation of Monophosphine Palladium Complex R-2. A
mixture of diphenylphosphine (0.70 g, 3.76 mmol) and palladium
complex R-1 (1.22 g, 1.78 mmol) in acetonitrile (60 mL) was
stirred at room temperature until all of R-1 had dissolved (ca. 1 h).
The solution was cooled to 0 °C, and fresh distilled acrolein (0.32 g,
5.71 mmol) was added in one portion. The solution was stirred at
0 °C for 30 min. The solvent was then removed via rotary
evaporation, and the resultant white solid was washed with
hexanes/diethyl ether (2:1, 100 mL) and subsequently dissolved
in ethyl acetate/diethyl ether (1:1, 150 mL) and filtered to remove
the insoluble impurity. The filtrate was collected and upon removal
of the solvent yielded the product R-2 as a white solid (1.82 g,
87%). Note: R-2 was not stable for flash column chromatography
on silica. [R]436 = þ94.0° (c 0.8, CH2Cl2). Mp: 126-128 °C. Anal.
(s, 3H, COMe), 2.26 (m, 2H, PCH2CH2), 2.69 (d, 3H, JPH
=
1.5 Hz, NMe), 2.89 (m, 1H, PCH0H), 2.98 (d, 3H, JPH = 3.4 Hz,
NMe), 3.09 (m, 1H, PCH0H), 4.36 (qn, 1H, JHH = JPH = 6.1 Hz,
CHCH3), 5.93 (d, 1H, JHH = 16.0 Hz, CHCOMe), 6.65-8.12
(m, 17H, ArandCH2CH). 13CNMR(CDCl3, 75MHz):δ 23.8 (s),
26.7 (s), 28.3 (d, JPC = 3.5 Hz), 29.6 (d, JPC = 32.6 Hz), 48.3 (s),
51.1 (d, JPC = 2.8 Hz), 72.8 (d, JPC = 3.2 Hz), 123.2 (s), 124.2
(s), 124.7 (d, JPC = 5.7 Hz), 125.8 (s), 128.4 (d, 2C, JPC = 10.3
Hz), 128.7 (s), 128.8 (s), 128.9 (d, 2C, JPC = 10.3 Hz), 129.6
(d, JPC = 44.7 Hz), 130.6 (d, JPC = 44.4 Hz), 130.9 (d, JPC
2.2 Hz), 131.0 (d, JPC = 2.2 Hz), 131.1 (s), 131.4 (s), 133.7 (d, 2C,
JPC = 11.5 Hz), 134.2 (d, 2C, JPC = 11.4 Hz), 135.5 (d, JPC
12.2 Hz), 147.4 (d, JPC = 16.4 Hz), 149.1 (d, JPC = 2.0 Hz),
149.3 (s), 198.6 (s).
=
(11) (a) Hockless, D. C. R.; Gugger, P. A.; Leung, P. H.; Mayadunne,
R. C.; Pabel, M.; Wild, S. B. Tetrahedron 1997, 53, 4083. (b) Allen, D. G.;
McLaughlin, G. M.; Robertson, G. B.; Steffen, W. L.; Salem, G.; Wild, S. B.
Inorg. Chem. 1982, 21, 1007. (c) Chooi, S. Y. M.; Siah, S. Y.; Leung, P. H.; Mok,
K. F. Inorg. Chem. 1993, 32, 4812.
=

Article
Inorganic Chemistry, Vol. 49, No. 3, 2010 995
Table 4. Crystallographic Data for Complexes 9a, 9b, and 14
9a
9b
14
formula
fw
C
661.78
P1
30H30Cl2O2P2Pd
C30H30Cl2OP2Pd
645.78
P1
C41H42ClNO5P2Pd 2CH2Cl2
1002.40
P2(1)
monoclinic
9.6961(4)
10.1443(4)
22.3638(9)
90
91.964(2)
90
2198.41(15)
2
173(2)
1.514
0.71073
0.844
1024
3
space group
cryst syst
triclinic
8.6202(3)
10.7327(4)
16.3388(6)
96.552(2)
99.248(2)
106.096(2)
1413.29(9)
2
223(2)
1.555
0.71073
0.986
672
triclinic
8.5973(10)
10.8849(12)
16.260(2)
97.704(5)
99.824(5)
107.217(5)
1404.3(3)
2
223(2)
1.527
0.71073
0.987
656
˚
a/A
˚
b/A
˚
c/A
R/deg
β/deg
γ/deg
3
˚
V/A
Z
T/K
Dcalcd/g cm-3
˚
λ/A
μ/mm-1
F(000)
Flack param
R1 (obs data)a
wR2(obs data)b
0.00(4)
0.0467
0.1372
0.06(3)
0.0302
0.0791
0.07(3)
0.0465
0.0931
P
P
P
P
a R1 = ||Fo| - |Fc||/ |Fo|. b wR2 = [ w(Fo2 - Fc2)2/ w(Fo2)2]1/2, w-1 = σ2(Fo)2 þ (aP)2 þ bP.
The same procedure was used to prepare product R-3c from
R-1 (1.22 g, 1.78 mmol). A chloroform solution (50 mL) of R-2
and (phenacylidene)triphenylphosphorane (2.05 g, 5.38 mmol)
was heated at 50 °C for 36 h. The product R-3c was isolated by
column chromatography on silica (EtOAc/Hexanes = 1:2) as a
pale yellow powder (1.93 g, 79%). [R]D = -20.9° (c 1.0,
CH2Cl2). Mp: 116-119 °C. Anal. Calcd for C37H37ClNOPPd:
C, 64.9; H, 5.4; N, 2.0. Found: C, 64.7; H, 5.5; N, 1.9. 31P NMR
chromatography (CH2Cl2/Acetone/Hexanes = 2:1:3) as a pale
yellow powder (1.05 g, 75%) upon removal of solvent. 31P NMR
(CDCl3, 121 MHz): δ -6.7 (d, JPP = 55.7 Hz), 8.8 (d, JPP
56.3 Hz), 27.2 (d, JPP = 56.3 Hz), 36.7 (JPP = 55.7 Hz).
=
By following the same procedure as described for the hydro-
phsophination of R-3c (1.0 g, 1.46 mmol), the regioisomers 5c
and 6c could be isolated by column chromatography (CH2Cl2/
Acetone/Hexanes = 2:1:3) as a pale yellow powder (0.95 g,
70%). 31P NMR (CDCl3, 121 MHz): δ -6.3 (d, JPP = 56.9 Hz),
1
(CDCl3, 121 MHz): δ 35.1 (s). H NMR (CDCl3, 300 MHz):
δ 2.07 (d, 3H, JHH = 6.3 Hz, CHMe), 2.35 (m, 2H, PCH2CH2),
2.69 (d, 3H, JPH = 1.4 Hz, NMe), 2.98 (d, 3H, JPH = 3.4 Hz,
8.6 (d, JPP = 56.3 Hz), 26.9 (d, JPP = 56.3 Hz), 37.8 (JPP
=
56.9 Hz).
Preparation of the Dichloro Palladium Complexes 9a, 9b, and
9c. A solution of regioisomers 5a and 6a (0.8 g, 0.90 mmol) in
dichloromethane (15 mL) was treated with concentrated hydro-
chloric acid (8 mL) for 5 h at room temperature. The mixture
was then washed with water (3 ꢀ 20 mL), dried over MgSO4, and
subsenquently crystallized from CH2Cl2-Et2O to give the di-
NMe), 2.91-2.91 (m, 2H, PCH2), 4.36 (qn, 1H, JHH = JPH
=
6.1 Hz, CHCH3), 6.68-8.11 (m, 23H, Ar and CH=CHCOPh).
13C NMR (CDCl3, 75 MHz): δ 23.7 (s), 28.4 (d, JPC = 3.7 Hz),
29.6 (d, JPC = 32.3 Hz), 48.3 (d, JPC = 2.0 Hz), 51.1 (d, JPC
2.9 Hz), 72.9 (d, JPC = 3.2 Hz), 123.2 (s), 124.1 (s), 124.7 (d, JPC
5.8 Hz), 125.7 (s), 126.3 (s), 128.4 (d, 2C, JPC = 10.0 Hz), 128.5
(s, 2C), 128.6 (s, 2C), 128.7 (s), 128.8 (s), 128.9 (d, 2C, JPC = 10.4 Hz),
129.7 (d, JPC = 44.7 Hz), 130.7 (d, JPC = 44.5 Hz), 130.9 (d, JPC =
2.3 Hz), 131.0 (d, JPC = 2.4 Hz), 131.1 (s), 132.6 (s), 133.8
(d, 2C, JPC = 11.5 Hz), 134.2 (d, 2C, JPC = 11.3 Hz), 135.5
(d, JPC = 12.0 Hz), 137.8 (s), 148.3 (d, JPC = 17.0 Hz), 149.2
(d, JPC = 2.1 Hz), 149.4 (s), 190.8 (s).
=
=
chloro complex 9a as pale yellow prisms (0.52 g, 88%). [R]D
=
-17.5° (c 1.7, CH2Cl2). Mp: 275-277 °C (decomp.). Anal.
Calcd for C30H30Cl2O2P2Pd: C, 54.4; H, 4.6. Found: C, 54.8;
H, 4.4. 31P NMR (CDCl3, 121 MHz): δ 15.5 (d, JPP = 13.0 Hz),
21.9 (d, JPP = 13.0 Hz). 1H NMR (CDCl3, 300 MHz): δ
1.93-2.13 (m, 2H, PCH2CH2), 2.22 (m, 1H, JHH = 10.6 Hz,
JHH
=
16.6 Hz, CH0HCO2Me), 2.43-2.53 (m, 3H,
Hydrophosphination of Complex R-3a. A solution of R-3a
(1.0 g, 1.57 mmol) in dichloromethane (40 mL) solution was
treated with AgClO4 H2O (0.53 g, 2.4 mmol) in water (3 mL),
CH0HCO2Me and PCH2), 2.96 (m, 1H, PCHCH2), 3.56
(s, 3H, CO2Me), 7.36-7.87 (m, 20H, Ar). 13C NMR (CDCl3,
3
and stirred for 1 h at room temperature. The organic layer, after
the removal of AgCl precipitate, was washed with H2O(3ꢀ 20 mL),
dried over MgSO4, concentrated and redissolved in dichloro-
methane/acetonitrile (1:1, 40 mL). The solution was allowed to
cool down to -78 °C, and treated with diphenylphosphine (0.30 g,
1.57 mmol) in dichloromethane (6 mL), followed by triethyla-
mine (0.16 g, 1.57 mmol). The mixture was stirred for 2 h, and
then warmed to room temperature. Upon removal of solvent,
the crude product was purified by chromatography on silica
(CH2Cl2/Acetone/Hexanes = 2:1:3) to afford a mixture of
regioisomers 5a and 6a as a pale yellow solid (0.92 g, 66%).
31P NMR (CDCl3, 121 MHz): δ -6.1 (d, JPP = 55.3 Hz), 8.6
(d, JPP = 55.3 Hz), 28.6 (d, JPP = 55.3 Hz), 38.8 (d, JPP = 55.3 Hz).
Hydrophosphination of Complexes R-3b and R-3c. R-3b (1.0 g,
1.61 mmol), upon abstraction of the chloro ligand with silver
perchlorate, was dissolved in acetonitrile (20 mL) and cooled
down to 0 °C. The solution was subsequently treated with
diphenylphosphine (0.30 g, 1.57 mmol) and stirred for 2 h.
The regioisomers 5b and 6b could be isolated by column
75 MHz): δ 24.8 (dd, JPC = 8.0 Hz, JPC = 31.1 Hz), 24.9 (d, JPC =
4.1 Hz), 29.2 (dd, JPC = 10.6 Hz, JPC = 29.3 Hz), 35.3 (s), 52.3
(s), 126.3 (d, JPC = 54.2 Hz), 126.8 (d, JPC = 55.5 Hz), 128.4 (d,
2P, JPC = 11.4 Hz), 128.6 (d, 2P, JPC = 11.5 Hz), 128.7 (d, JPC
56.8 Hz), 128.9 (d, 4P, JPC = 11.2 Hz), 130.1 (d, JPC = 59.0 Hz),
131.3 (d, JPC = 2.9 Hz), 131.6 (d, JPC = 2.6 Hz), 131.7 (d, JPC
=
=
3.1 Hz), 131.9 (d, JPC = 2.7 Hz), 133.3 (d, 2P, JPC = 10.2 Hz),
133.7 (d, 2P, JPC = 9.6 Hz), 133.8 (d, 2P, JPC = 10.9 Hz), 135.3
(d, 2P, JPC = 10.9 Hz), 171.1 (d, JPC = 12.8 Hz).
The same procedure was used to prepare dichloro complexes
9b and 9c. 9b (0.38 g, 85%) from regioisomers 5b and 6b (0.6 g,
0.69 mmol). [R]D = -20.4° (c 0.9, CH2Cl2). Mp: 285-287 °C
(decomp.). Anal. Calcd for C30H30Cl2OP2Pd: C, 55.8; H, 4.7.
Found: C, 55.9; H, 4.5. 31P NMR (CDCl3, 121 MHz): δ 16.3
(d, JPP = 12.7 Hz), 22.5 (d, JPP = 12.7 Hz). 1H NMR (CDCl3,
300 MHz): δ 1.90 (s, 3H, COMe), 1.91-2.06 (m, 2H,
PCH2CH2), 2.34 (m, 1H, JHH = 9.4 Hz, JHH = 18.3 Hz,
CH0HCOMe), 2.47 (m, 2H, PCH2), 2.54 (m, 1H, CH0HCOMe),
3.08 (m, 1H, PCHCH2), 7.35-7.84 (m, 20H, Ar). 13C NMR

996 Inorganic Chemistry, Vol. 49, No. 3, 2010
Yuan et al.
1
(CDCl3, 100 MHz): δ 25.3 (dd, JPC = 8.1 Hz, JPC = 31.4 Hz),
25.4 (d, JPC = 4.0 Hz), 27.6 (dd, JPC = 11.0 Hz, JPC = 29.8 Hz),
30.1 (s), 44.5 (d, JPC = 1.9 Hz), 126.6 (d, JPC = 54.0 Hz), 127.2
(d, JPC = 55.6 Hz), 128.4 (d, 2P, JPC = 11.4 Hz), 128.7 (d, 2P,
JPC = 11.5 Hz), 128.8 (d, 2P, JPC = 10.9 Hz), 128.9 (d, 2P,
MHz): δ - 15.8 (s), - 6.6 (s). H NMR (CDCl3, 300 MHz):
δ 1.48 (m, 1H, PCH2CH0H), 1.57 (m, 1H, PCH2CH0H), 1.95
(s, 3H, COMe), 2.14 (t, 2H, JHH = JPH = 8.4 Hz, CH2COMe),
2.36 (m, 1H, JPH = 8.6 Hz, JHH = 17.6 Hz, PCH0H), 2.45 (m,
1H, JHH = 17.6 Hz, PCH0H), 3.10 (br, 1H, PCHCH2),
7.26-7.44 (m, 20H, Ar).
J
PC = 11.4 Hz), 129.1 (d, JPC = 57.3 Hz), 129.9 (d, JPC = 58.4
Hz), 131.3 (d, JPC = 2.8 Hz), 131.5 (d, JPC = 2.8 Hz), 131.6 (d,
PC = 2.7 Hz), 131.9 (d, JPC = 2.7 Hz), 133.4 (d, 2P, JPC = 10.3
10c (0.21 g, 95%) was prepared from 9c (0.3 g, 0.42 mmol) as a
white solid. [R]D = þ11.4° (c 0.7, CH2Cl2). 31P NMR (CDCl3,
202 MHz): δ - 15.7 (s), - 6.4 (s). 1H NMR (CDCl3, 300 MHz):
δ 1.64 (m, 2H, PCH2CH2), 2.02 (t, 2H, JHH = JPH = 8.5 Hz,
CH2COPh), 2.99 (m, 2H, PCH2), 3.34 (br, 1H, PCHCH2),
7.25-7.80 (m, 25H, Ar).
Hydrophosphination of Monophosphine palladium Complex
R-2. A solution of R-2 (1.0 g, 1.72 mmol) in acetonitrile (25 mL)
was treated with diphenylphosphine (0.32 g, 1.72 mmol), fol-
J
Hz), 133.5 (d, 2P, JPC = 9.3 Hz), 133.8 (d, 2P, JPC = 10.8 Hz),
135.4 (d, 2P, JPC = 10.6 Hz), 204.5 (d, JPC = 8.8 Hz).
9c (0.39 g, 87%) was prepared from regioisomers 5c and 6c
(0.6 g, 0.64 mmol). [R]D = þ12.6 (c 1.0, CH2Cl2). Mp: 160-163 °C.
Anal. Calcd for C35H32Cl2OP2Pd: C, 59.4; H, 4.6. Found: C,
59.7; H, 4.4. 31P NMR (CDCl3, 161 MHz): δ 15.8 (d, JPP = 13.8
1
Hz), 22.4 (d, JPP = 13.8 Hz). H NMR (CDCl3, 500 MHz): δ
2.07 (br, 2H, PCH2CH2), 2.53 (br, 2H, CH2COPh), 2.90 (m, 1H,
lowed by LiClO4 3H2O (0.68 g, 4.30 mmol) and triethylamine
3
J
HH = 10.0 Hz, JHH = 17.4 Hz, PCH0H), 3.01 (dd, 1H, JHH
=
(0.17 g, 1.72 mmol). The mixture was stirred for 2 h at room
temperature, and the solvent was removed under reduced
pressure. The residue was redissolved in dichloromethane,
washed with H2O (3 ꢀ 15 mL), dried over MgSO4, concentrated,
and purified by column chromatography on silica (CH2Cl2/
C2H5OC2H5 = 10:1) to afford a mixture of regioisomers 14 and
15 as a pale yellow solid (0.60 g, 42%). 31P NMR (CDCl3, 202
MHz): δ 0.0 (d, JPP = 53.0 Hz), 13.1 (d, JPP = 52.5 Hz), 26.0 (d,
8.8 Hz, JHH = 17.4 Hz, PCH0H), 3.26 (br, 1H, PCHCH2),
7.36-7.91 (m, 25H, Ar). 13C NMR (CDCl3, 100 MHz): δ 25.2
(dd, JPC = 8.0 Hz, JPC = 31.2 Hz), 25.3 (d, JPC = 4.2 Hz), 27.8
(dd, JPC = 10.9 Hz, JPC = 29.8 Hz), 39.5 (s), 126.8 (d, JPC
=
54.3 Hz), 127.0 (d, JPC = 55.0 Hz), 127.9 (s, 2C), 128.4 (d, 2C,
JPC = 11.4 Hz), 128.7 (d, 2C, JPC = 11.5 Hz), 128.8 (s, 2C),
128.9 (d, 2C, JPC = 11.3 Hz), 128.9 (d, 2C, JPC = 11.0 Hz), 129.2
(d, JPC = 55.0 Hz), 130.0 (d, JPC = 58.4 Hz), 131.3 (d, JPC = 2.8
Hz), 131.6 (d, 2C, JPC = 2.7 Hz), 131.9 (d, JPC = 2.7 Hz), 133.5
(d, 2C, JPC = 10.2 Hz), 133.6 (d, 2C, JPC = 9.3 Hz), 133.7 (d, 2C,
J
PP = 52.5 Hz). 39.3 (d, JPP = 53.0 Hz). Upon crystallization in
dichloromethane-diethyl ether, product 14 was isolated as pale
yellow prisms (0.57 g, 40%). [R]D = -90.7° (c 0.8, CH2Cl2). Mp:
178-180 °C. Anal. Calcd for C41H42ClNO5P2Pd: C, 59.1; H,
5.1; N, 1.7. Found: C, 59.4; H, 5.0; N, 1.8. 31P NMR (CDCl3, 202
MHz): δ 13.1 (d, JPP = 52.5 Hz), 26.0 (d, JPP = 52.5 Hz). 1H
NMR (CDCl3, 500 MHz): δ 1.76-1.89 (m, 1H, PCH2CH0H),
2.06 (d, 3H, JHH = 6.2 Hz, CHMe), 2.16-2.28 (m, 1H,
PCH2CH0H), 2.22 (s, 3H, NMe), 2.44-2.55 (m, 2H, PCH2),
2.48 (s, 3H, NMe), 3.47 (b, 1H, JHH = 4.6 Hz, OH), 4.34 (qn,
1H, JHH = JPH = 6.0 Hz, CHCH3), 4.73 (m, 1H, PCHOH),
6.98-8.27 (m, 26H, Ar).
JPC = 10.7 Hz), 133.9 (s), 135.4 (d, 2C, JPC = 10.6 Hz), 135.8 (s),
196.1 (d, JPC = 10.0 Hz).
Liberation of Functionalized 1,3-Diphosphine Ligand 10a, 10b,
and 10c. A solution of complex 9a (0.3 g, 0.45 mmol) in
dichloromethane (15 mL) was stirred vigorously with aqueous
KCN (1.0 g, 15.4 mmol) for 30 min. The organic layer was
separated, washed with water (3 ꢀ 15 mL), and dried with
MgSO4. The 1,3-diphosphine ligand 10a was obtained as white
solid upon removal of solvent under reduced pressure (0.21 g,
95%). [R]D = þ19.0 (c 1.0, CH2Cl2). 31P NMR (CDCl3, 121
MHz): δ -15.3 (s), -6.4 (s). 1H NMR (CDCl3, 300 MHz): δ 1.51
(m, 2H, PCH2CH2), 2.09-2.19 (m, 3H, CH2CO2Me and
PCH0H), 2.35 (m, 1H, JHH = 6.8 Hz, JHH = 13.8 Hz, PCH0H),
2.88 (br, 1H, PCHCH2), 3.47 (s, 3H, CO2Me), 7.19-7.40 (m,
20H, Ar).
Acknowledgment. We thank Nanyang Technological
University for support of this research and for PhD scholarships
to M.Y. and N.Z.
Supporting Information Available: Crystallographic data in
CIF format for complexes 9a, 9b, and 14. This material is
available free of charge via the Internet at http://pubs.acs.org.
Similarly the keto-functionalized 1,3-diphosphine ligand 10b
(0.20 g, 92%) was achieved from 9b (0.3 g, 0.46 mmol) as a white
solid. [R]D = þ30.8° (c 0.9, CH2Cl2). 31P NMR (CDCl3, 202