Novel synthesis of chiral 1,3-diphosphines via palladium template promoted hydrophosphination and functional group transformation reactions

Article abstract of DOI:10.1021/om100505w

A novel cyano-functionalized monophosphine palladium substrate containing the ortho-metalated (R)-(1-(dimethylamino)ethyl)naphthalene as the chiral auxiliary was synthesized from 3-chloropropionaldehyde diethylacetal via a one-pot process. The asymmetric hydrophosphination reactions between diphenylphosphine and the trans-or cis-monophosphine substrates were carried out under mild conditions, which gave the corresponding cyano-substituted chiral 1,3-bis(diphenylphosphino)propane palladium complexes with good yields and stereoselectivities. Subsequent functional group transformation reactions were conducted by successive treatment of the hydrophosphination products with Dibal-H and chemoselectively yielded the formyl-and hydroxyl-functionalized chiral 1,3-diphosphine complexes. The absolute configurations and coordination information of the novel 1,3-diphosphine complexes were analyzed by X-ray crystallography. The optically pure 1,3-bis(diphenylphosphino)propane ligands with cyano, formyl, and hydroxyl functionalities could be liberated in high yields from the corresponding dihalo palladium complexes by treatment with aqueous potassium cyanide.

Full text of DOI:10.1021/om100505w

3
582 Organometallics 2010, 29, 3582–3588
DOI: 10.1021/om100505w
Novel Synthesis of Chiral 1,3-Diphosphines via Palladium
Template Promoted Hydrophosphination and Functional
Group Transformation Reactions
Mingjun Yuan, Sumod A. Pullarkat, Yongxin Li, Zhi-Yi Lee, and Pak-Hing Leung*
Division of Chemistry & Biological Chemistry, School of Physical & Mathematical Sciences,
Nanyang Technological University, Singapore 637371, Singapore
Received May 23, 2010
A novel cyano-functionalized monophosphine palladium substrate containing the ortho-metalated
R)-(1-(dimethylamino)ethyl)naphthalene as the chiral auxiliary was synthesized from 3-chloropro-
(
pionaldehyde diethylacetal via a one-pot process. The asymmetric hydrophosphination reactions
between diphenylphosphine and the trans- or cis-monophosphine substrates were carried out under
mild conditions, which gave the corresponding cyano-substituted chiral 1,3-bis(diphenylphosphino)-
propane palladium complexes with good yields and stereoselectivities. Subsequent functional group
transformation reactions were conducted by successive treatment of the hydrophosphination
products with Dibal-H and chemoselectively yielded the formyl- and hydroxyl-functionalized chiral
1
1
,3-diphosphine complexes. The absolute configurations and coordination information of the novel
,3-diphosphine complexes were analyzed by X-ray crystallography. The optically pure 1,3-bis-
(diphenylphosphino)propane ligands with cyano, formyl, and hydroxyl functionalities could be
liberated in high yields from the corresponding dihalo palladium complexes by treatment with
aqueous potassium cyanide.
Introduction
by the organopalladium complexes containing (R)- or (S)-(1-
(dimethylamino)ethyl)naphthalene as the chiral auxiliary.
3,4
The design and synthesis of new chiral phosphine ligands
In the course of these series of studies, the use of stoichio-
metric amounts of palladium complex as reaction promoter
offers practical advantages. (1) By means of coordination, it
can protect the phosphine species from oxidation or racemi-
zation especially when it comes to the synthesis of P-stereo-
genic phosphine ligands. (2) By tuning the chloro ligand that
is trans to the naphthalene ring, it can alternatively provide
one or two distinct coordination sites around the square-
planar palladium center to selectively synthesize functiona-
lized mono- or diphosphine ligands. (3) It can offer high
stereoselectivity during the asymmetric process and can also
serve as a resolving agent when there are more than one
continues to be a research topic of great interest in modern
organophosphorus chemistry, since the enantiomerically
pure phosphines have established their position as highly
effective ligands in transition metal catalyzed asymmetric re-
1
actions on both research laboratory and industrial scales. It
is conceivable that the presence of proper functional groups,
for instance hydroxyl, amino, or ester, on these chiral phos-
phine frameworks can efficiently improve both reactivity
and enantioselectivity in many reactions through the secon-
2
dary interactions with the reacting substrates. Over the past
few years, our group has successfully prepared a series of
functionalized chiral phosphine ligands by means of asymmetric
hydrophosphination and Diels-Alder reactions, promoted
(
3) 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. (g) Yuan, M.; Zhang, N.; Pullarkat, S. A.; Li, Y.; Liu, F.; Pham,
P.-T.; Leung, P. H. Inorg. Chem. 2010, 49, 989. (h) Huang, Y.; Pullarkat,
S. A.; Yuan, M.; Ding, Y.; Li, Y.; Leung, P. H. Organometallics 2010, 29,
536.
(4) For Diels-Alder reactions, see: (a) Leung, P. H. Acc. Chem. Res.
2004, 37, 169, and references therein. (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.
*
To whom correspondence should be addressed. E-mail: pakhing@
ntu.edu.sg.
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Zablocka, M. Chem. Rev. 1994, 94, 1375. (d) Ohff, M.; Holz, J.; Quirmbach,
M.; B €o rner, A. Synthesis 1998, 1391. (e) Hayashi, T. Acc. Chem. Res. 2000,
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pubs.acs.org/Organometallics
Published on Web 07/28/2010
r 2010 American Chemical Society

Article
Organometallics, Vol. 29, No. 16, 2010 3583
isomer produced, thus facilitating their easy separation and
isolation. (4) We can in situ study the coordination properties
and absolute stereochemistries of the chiral phosphine pal-
ladium complexes, which may give us some insights on how
the metal complex interacts with substrates during the
asymmetric transformations. And last, (5) the air-stable
optically pure phosphine complexes could easily yield the
free phosphine ligands by treatment with aqueous potassium
cyanide.
Scheme 1
Unlike the classical 1,2-diphosphines, 1,3-diphosphines
can form six-membered chelates involving transition metals
5
with interesting coordinated conformations and have
played an important role as ligands in a large family of
efforts in the development of new chiral phosphines by
employing chiral cyclopalladated amine complexes.
6
homogeneous transition metal catalysis. However, reports
on the asymmetric synthesis of functionalized chiral 1,3-
diphosphine ligands are relatively rare. This paper describes
a facile synthesis of three novel chiral 1,3-bis(diphenylphos-
phino)propane ligands with cyano, formyl, and hydroxyl
functionalities, via an organopalladium complex promoted
hydrophosphination and subsequent in situ functional group
transformation reactions. This current work is part of our
Results and Discussion
From the perspective of atom economy, the addition of
diphenylphosphine to R,β-unsaturated nitriles provides a
direct route to a large family of useful functionalized phos-
phine ligands. Furthermore, the cyano group is suitable for
conversion to other functionalities such as acid, amide, amine,
7
7h-j,8
aldehyde, or alcohol by simple organic manipulations.
(
5) (a) Farkas, E.; Koll ꢀa r, L.; Moret, M.; Sironi, A. Organometallics
996, 15, 1345. (b) Mikami, K.; Yusa, Y.; Hatano, M.; Wakabayashi, K.;
In principle, if a phosphorus atom was introduced into the
R,β-unsaturated nitrile substrates, the subsequent hydro-
phosphination and functional group transformation reac-
tions will generate a class of novel diphosphines, for example,
the chiral cyano-, formyl-, and hydroxyl-substituted 1,3-
bis(diphenylphosphino)propane ligands.
1
Aikawa, K. Tetrahedron 2004, 60, 4475. (c) J ꢀa nosi, L.; Koll ꢀa r, L.; Macchi,
P.; Sironi, A. J. Organomet. Chem. 2006, 691, 2846. (d) Bakos, J.; T ꢀo th, I.;
Heil, B.; Szalontai, G.; P ꢀa rk ꢀa nyi, L.; F €u l €o p, V. J. Organomet. Chem. 1989,
70, 263. (e) Steffen, W. L.; Palenik, G. J. Inorg. Chem. 1976, 15, 2432.
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1432. (g) Keim, W.; Kraneburg, P.; Dahmen, G.; Deckers, G.; Englert, U.;
Linn, K.; Spaniol, T. P.; Raabe, G.; Kr €u ger, C. Organometallics 1994, 13,
085. (h) Dodge, T.; Curtis, M. A.; Russell, J. M.; Sabat, M.; Finn, M. G.;
3
(
1
The one-pot synthesis of cyano-functionalized monopho-
sphine palladium complex R-3 is illustrated in Scheme 1. The
3
Grimes, R. N. J. Am. Chem. Soc. 2000, 122, 10573. (i) Yang, J. Y.; Bullock,
R. M.; Shaw, W. J.; Twamley, B.; Fraze, K.; DuBois, M. R.; DuBois, D. L.
J. Am. Chem. Soc. 2009, 131, 5935. (j) Suzuki, T.; Tsuji, N.; Kashiwabara,
K.; Tatsumi, K. Inorg. Chem. 2000, 39, 3938. (k) Suzuki, T.; Kashiwabara,
K.; Usami, T.; Imamura, T.; Kiki, M.; Fujita, J.; Kaizaki, S. Bull. Chem. Soc.
Jpn. 2001, 74, 1055.
3
-chloropropionaldehyde diethylacetal reacted smoothly
with sodium diphenylphosphide, and the resulting inter-
mediate was hydrolyzed and subsequently treated with (tri-
phenylphosphoranylidene)acetonitrile to afford 5-(diphenyl-
phosphino)pent-2-enenitrile 1. This new phosphine species
was not isolated and was in situ coordinated to palladium
template R-2 to generate the monomeric phosphine complex
R-3 as a mixture of Z/E (1:1.8) isomers in 82% yield. The two
products could be easily separated by column chromatogra-
(
6) (a) MacNeil, P. A.; Roberts, N. K.; Bosnich, B. J. Am. Chem. Soc.
981, 103, 2273. (b) Bakos, J.; T ꢀo th, I.; Heil, B.; Mark ꢀo , L. J. Organomet.
Chem. 1985, 279, 23. (c) Halterman, R. L.; Nimmons, H. L. Organometallics
1
1990, 9, 273. (d) Brunner, H.; Terfort, A. Tetrahedron: Asymmetry 1995, 6,
9
19. (e) Dubrovina, N. V.; Tararov, V. I.; Monsees, A.; Kadyrov, R.; Fischer,
C.; B €o rner, A. Tetrahedron: Asymmetry 2003, 14, 2739. (f) Herseczki, Z.;
Gergely, I.; Heged €u s, C.; Sz €o llosy, A.; Bakos, J. Tetrahedron: Asymmetry
3
1
ꢀ
phy. The P NMR spectrum in CDCl of trans-R-3 exhi-
3
2004, 15, 1673. (g) Fries, G.; Wolf, J.; Ilg, K.; Walfort, B.; Stalke, D.; Werner,
bited a sharp singlet at δ 34.6, while the cis-R-3 isomer
indicated a singlet resonance signal at δ 34.8. Both isomers
can be easily recrystallized from ethyl acetate/hexanes as pale
yellow prisms. The molecular structure and coordination
property of trans-R-3 were characterized by means of single-
crystal diffraction analysis, as shown in Figure 1. Selected
bond lengths and angles and other crystallographic data are
listed in Tables 1 and 4, respectively. The geometry at the
palladium atom is distorted square planar with angles at the
H. Dalton Trans. 2004, 1873. (h) Dubrovina, N. V.; Tararov, V. I.; Monsees,
A.; Spannenberg, A.; Kostasc, I. D.; B €o rner, A. Tetrahedron: Asymmetry
2005, 16, 3640.
(7) (a) Baillie, C.; Xiao, J. Curr. Org. Chem. 2003, 7, 477. (b) Odinets,
I. L.; Vinogradova, N. M.; Matveeva, E. V.; Mastryukova, T. A. Curr. Org.
Chem. 2005, 9, 1899. (c) Wiese, B.; Kn €u hl, G.; Flubacher, D.; Priess, J. W.;
Ulriksen, B.; Br €o dner, K.; Helmchen, G. Eur. J. Org. Chem. 2005, 3246.
(
d) Wicht, D. K.; Kourkine, I. V.; Lew, B. M.; Nthenge, J. M.; Glueck, D. S.
J. Am. Chem. Soc. 1997, 119, 5039. (e) Sadow, A. D.; Togni, A. J. Am.
Chem. Soc. 2005, 127, 17012. (f) Kovacik, I.; Wicht, D. K.; Grewal, N. S.;
Glueck, D. S. Organometallics 2000, 19, 950. (g) Gourdel, Y.; Pellon, P.;
Toupet, L.; Corre, M. L. Tetrahedron Lett. 1994, 35, 1197. (h) Ando, K.;
Suzuki, Y. Tetrahedron 1995, 51, 2325. (i) Li, Y.; Li, Z.; Li, F.; Wang, Q.;
Tao, F. Tetrahedron Lett. 2005, 46, 6159. (j) Blinn, D. A.; Button, R. S.;
Farazi, V.; Neeb, M. K.; Tapley, C. L.; Trehearne, T. E.; West, S. D.; Kruger,
T. L.; Storhoff, B. N. J. Organomet. Chem. 1990, 393, 143.
metal center in the range 80.6(1)-97.0(1)° and 169.6(1)-
˚
1
69.9(1)°. The C17-C18 bond length is 1.295(5) A, which
exhibits clearly double-bond character. As expected, the
monodentate phosphorus donor atom is located trans to
the σ-donating nitrogen group of the chiral auxiliary.
Asymmetric Hydrophosphination of Cyano-Functionalized
Monophosphine Palladium Complex R-3. The chloro ligand
in trans-R-3 and similar complexes that is trans to the ortho-
metalated aromatic carbon is well known to be both kineti-
(8) (a) Kawasaki, S.; Nakamura, A.; Toyota, K.; Yoshifuji, M. Bull.
Chem. Soc. Jpn. 2005, 78, 1110. (b) Marvin, C. C.; Voight, E. A.; Suh, J. M.;
Paradise, C. L.; Burke, S. D. J. Org. Chem. 2008, 73, 8452. (c) Kromann, H.;
Larsen, M.; Boesen, T.; Schønning, K.; Nielsen, S. F. Eur. J. Med. Chem.
2004, 39, 993. (d) Papahatjis, D. P.; Nahmias, V. R.; Nikas, S. P.; Andreou, T.;
Alapafuja, S. O.; Tsotinis, A.; Guo, J.; Fan, P.; Makriyannis, A. J. Med.
Chem. 2007, 50, 4048. (e) Magatti, C. V.; Kaminski, J. J.; Rothberg, I. J. Org.
Chem. 1991, 56, 3102. (f) Newkome, G. R.; Arai, S.; Fronczek, F. R.;
Moorefield, C. N.; Lin, X.; Weis, C. D. J. Org. Chem. 1993, 58, 898.
3
cally and thermodynamically stable. This terminal ligand,
however, can be replaced efficiently by treatment of the
complex with aqueous silver perchlorate to provide a vacant
coordination site (Scheme 2). The highly reactive perchlor-
ato complex R-4 was not isolated and was subsequently
reacted with one equivalent of diphenylphosphine in the
(
4
g) Ravindranathan, M.; Kalyanam, N.; Sivaram, S. J. Org. Chem. 1982, 47,
812. (h) Frejd, T.; Klingstedt, T. Synthesis 1987, 40. (i) Badorrey, R.;
Cativiela, C.; Díaz-de-Villegas, M. D.; G ꢀa lvez, J. A.; Gil, A. Tetrahedron:
Asymmetry 2003, 14, 2209. (j) Fitz, M.; Forr ꢀo , E.; Vig ꢀo czki, E.; L ꢀa z ꢀa r, L.;
F €u l €o p, F. Tetrahedron: Asymmetry 2008, 19, 1114.

3
584 Organometallics, Vol. 29, No. 16, 2010
Yuan et al.
Scheme 2
Figure 1. Molecular structure of complex trans-R-3.
˚
Table 1. Selected Bond Lengths (A) and Angles (deg) of trans-R-3
Pd1-C1
2.000(2)
2.389(1)
1.843(2)
1.486(4)
1.441(5)
80.6(1)
Pd1-N1
2.135(2)
2.249(1)
1.525(4)
1.295(5)
1.119(5)
97.0(1)
Pd1-Cl1
Pd1-P1
P1-C15
C15-C16
C16-C17
C17-C18
10
C18-C19
C19-N2
hydrochloric acid in the presence of NaI (Scheme 3). Thus,
the optically pure diiodo palladium complex 9a was obtained
as a red solid in 79% yield, [R] = -10.7 (c 1.3, CH Cl ). The
C1-Pd1-N1
P1-Pd1-Cl1
N1-Pd1-P1
P1-C15-C16
C17-C18-C19
C1-Pd1-P1
N1-Pd1-Cl1
C1-Pd1-Cl1
C16-C17-C18
C18-C19-N2
89.8(1)
94.1(1)
D
2
2
169.9(1)
116.4(2)
123.5(4)
169.6(1)
125.7(3)
175.3(6)
31
P NMR spectrum (CD Cl , 162 MHz) of product 9a
2
2
exhibited a pair of doublets at δ 4.2, 8.8 (JPP = 21.3 Hz).
Unfortunately, efforts to crystallize the neutral complex 9a
from various solvent systems to get suitable crystals for
presence of triethylamine as external base at -78 °C to yield the
novel hydrophosphination products. The process was mon-
11
X-ray crystallography were unsuccessful.
Treatment of a CH Cl solution of product 9a with
3
itored by P NMR spectroscopy and was found to be com-
1
2
2
3
1
pleted within 2 h. In CDCl , the 162 MHz P NMR spectrum
3
aqueous potassium cyanide can conveniently liberate the
enantiomerically pure cyano-functionalized 1,3-diphosphine
of the crude product exhibited the presence of three pairs of
doublets at δ -10.2, 33.0 (JPP = 55.7 Hz); -1.1, 35.3 (JPP
=
2.1 Hz); and 8.3, 27.1 (JPP = 51.7 Hz) with the intensity
ligand 10a as a white solid in high yield, [R] = -28.5 (c 1.3,
D
31
CH Cl ). The P NMR (CDCl , 162 MHz) spectrum of the
5
2
2
3
ratio of 1:1.3:3.7, respectively. The signals indicated that
three of the four possible isomeric products, i.e., 5a, 6a, 7a,
and 8a, were generated during the hydrophosphination
process, as shown in Scheme 2. It is noteworthy that com-
plexes 5a and 6a are regioisomers that adopt the same S
absolute configuration at the newly formed chiral carbon
centers. Similarly, complexes 7a and 8a are regioisomers with
R absolute configuration at the new stereogenic centers.
Therefore the diastereomeric ratio was 1:5 for the overall
process.
free ligand showed two singlet signals at δ -17.5 (s), -8.3 (s).
As illustrated in Scheme 4, in order to confirm the optical
31
purity of the free phosphine ligand 10a and the P NMR
assignment for the regioisomers, the liberated ligand was
recoordinated to the bis(acetonitrile) complex R-11. The
resultant recomplexation products in CDCl indeed exhi-
3
bited two pairs of phosphorus doublets at δ -1.1, 35.3 (JPP
=
2.1 Hz) and 8.3, 27.1 (JPP = 51.7 Hz), which were identical
5
with the two major products from the original hydropho-
sphination reaction and, therefore, indicated the formation
of the regioisomers 5a and 6a. Furthermore, the recoordina-
tion of 10a to the equally accessible bis(acetonitrile) complex
S-11 will generate the regioisomers 12a and 13a, which
exhibited two distinct pairs of doublets at δ - 10.2, 33.0
(JPP = 55.7 Hz) and 6.2, 26.6 (JPP = 54.9 Hz). Note that the
products 12a and 13a are the enantiomeric forms of 7a and
The two major regioisomers 5a and 6a can be efficiently
separated as off-white solids by column chromatography in
9
31
7
0% yield. The P NMR spectrum (CDCl , 162 MHz)
3
showed two pairs of doublets at δ -1.1, 35.3 (JPP = 52.1 Hz)
and 8.3, 27.1 (JPP = 51.7 Hz). The chiral naphthylamine
auxiliary on complexes 5a and 6a could be chemoselectively
removed by treatment of the isomers with concentrated
8
a, respectively. Thus no resonance signals were observed at
δ -1.1, 8.3, 27.1, and 35.3, and the free 1,3-diphosphine 10a
was hence confirmed to be optically pure.
For comparison of the stereoselectivity, the Z-form mono-
phosphine substrate cis-R-3 was also employed for the same
asymmetric hydrophosphination reaction. Under similar
(
9) During the course of column chromatography, a pair of new
doublet phosphorus signals at δ 6.2, 26.6 (JPP = 54.9 Hz) appeared,
which indicated the formation of one of the regioisomers 7a or 8a. So the
3
1
P NMR (CDCl
two pairs of doublets at δ -10.2, 33.0 (JPP = 55.7 Hz); 6.2, 26.6 (JPP
4.9 Hz). However, the minor regioisomers 7a and 8a cannot be isolated
at this stage.
10) Without addition of NaI, the reaction will yield the dichloro
palladium complex. However, the solubility of the dichloro analogue of
0a is too poor for characterization.
3
, 162 MHz) signals of the regioisomers 7a and 8a were
=
5
(
(11) The absolute configurations of the chiral diiodo palladium
complex 9a and the regioisomers 5a and 6a were revealed by the
following functional group transformation reactions.
1

Article
Organometallics, Vol. 29, No. 16, 2010 3585
Scheme 3
Scheme 4
reaction conditions, the addition process could be completed
somers with concentrated hydrochloric acid at room tempera-
ture. The opticallypuredichlorocomplex9bwas subsequently
crystallized from dichloromethane and diethyl ether as yel-
lowishprisms in 68% yield, [R] = þ24.4 (c 0.9, CH Cl ). The
3
within 2 h. Interestingly, the P NMR (CDCl , 162 MHz)
1
3
spectrum of the crude product obtained from this addition
process indicated the same three pairs of doublets at δ -10.2,
D
2
2
3
1
3
2
3.0 (JPP = 55.7 Hz); -1.1, 35.3 (JPP = 52.1 Hz); and 8.3,
7.1 (JPP = 51.7 Hz), however, with the distinct intensity
P NMR spectrum of this neutral dichloro complex 9b in
CD Cl exhibited a pair of doublets at δ 15.3, 21.8 (J = 12.5
2
2
PP
ratio of 1:1.5:5.3, respectively. Apparently, the selectivity at
the newly formed chiral carbon center slightly improved
from 1:5 (for trans-R-3) to 1:6.8 (for cis-R-3).
Hz).
The single-crystal X-ray crystallographic analysis unam-
biguously established its absolute configuration and the
functionality transformation. There are two crystallographi-
cally independent molecules in the asymmetric unit with the
backbone slightly disordered. Both molecules have similar
bond lengths and angles and the identical S absolute config-
uration at the newly formed chiral carbon center. Figure 2
shows the ORTEP drawing of molecule 1; selected bond and
angle parameters are given in Table 2. The coordinated
geometry around the Pd atom is square planar with slight
tetrahedral distortion (9.6°), while the angles around the
palladium center are in the ranges 87.0(5)-93.2(5)° and
171.4(1)-173.9(5)°. The P-Pd-P bite angle (93.2(5)°) is
clearly larger than in the case of 1,2-diphosphine chelates
Functional Group Transformations: Synthesis of Formyl-
and Hydroxyl-Substituted 1,3-Diphosphine Products. Asafore-
mentioned, the cyano group could be converted to other
functionalities, for example, acid, amide, amine, aldehyde,
7h-j,8
or alcohol by simple functional group transformations.
Thus, upon treatment of the CH Cl solution of regioiso-
2
2
3
1
mers 5a and 6a with DIBAL-H at -78 °C for 2 h, the P
NMR spectrum in CDCl of the reduction products showed
3
two new pairs of doublet signals at δ -0.1, 37.2 (JPP = 52.3
Hz) and 9.9, 27.7 (JPP = 52.7 Hz), which indicated the
formation of the formyl-functionalized regioisomers 5b and
6
6
b (Scheme 3). The chiral naphthylamine auxiliary in 5b and
b was removed by stirring a CH Cl solution of the regioi-
3
previously reported. The six-membered chelate in complex
2
2

3
586 Organometallics, Vol. 29, No. 16, 2010
Yuan et al.
Figure 3. Molecular structure and absolute stereochemistry of
complex 9c.
Figure 2. Molecular structure and absolute stereochemistry of
complex 9b.
˚
Table 3. Selected Bond Lengths (A) and Angles (deg) of 9c
˚
Table 2. Selected Bond Lengths (A) and Angles (deg) of 9b
Pd1-P1
2.247(1)
2.245(1)
1.838(3)
1.832(3)
96.5(1)
Pd1-Cl1
2.341(1)
2.373(1)
1.539(4)
1.423(4)
90.6(1)
Pd1-P1
2.270(3)
2.264(8)
1.862(9)
1.807(16)
93.2(5)
Pd1-Cl1
2.343(2)
2.344(3)
1.553(17)
1.177(12)
88.4(1)
Pd1-P2
Pd1-Cl2
Pd1-P2
Pd1-Cl2
C13-P1
C17-P2
P2-Pd1-P1
P1-Pd1-Cl2
P1-Pd1-Cl1
C13-C16
C15-O1
Cl2-Pd1-Cl1
P2-Pd1-Cl1
P2-Pd1-Cl2
C15-P1
C17-P2
P2-Pd1-P1
P1-Pd1-Cl2
P1-Pd1-Cl1
C15-C16
C13-O1
Cl2-Pd1-Cl1
P2-Pd1-Cl1
P2-Pd1-Cl2
176.7(1)
86.2(1)
176.2(1)
86.7(1)
171.4(1)
90.8(1)
173.9(5)
87.0(5)
Table 4. Crystallographic Data for Complexes trans-R-3, 9b,
and 9c
9
b adopts a twist-chair conformation with the formyl group
occupying the sterically favorable equatorial position.
The optically active 1,3-diphosphine 10b could be liber-
ated by treatment of the 9b with aqueous potassium cyanide
as a white solid in 86% yield, [R] = -22.6 (c 1.7, CH Cl ).
The P NMR spectrum of the liberated diphosphine ligand
in CDCl showed two singlets at δ -16.4 and -6.8. The
trans-R-3
9b
9c
formula
C
31
H
32
-
C
29
H
28Cl
OP Pd
631.75
P2(1) 2(1) 2(1) P2(1)
2
-
C
29
H
30Cl
2 2
OP Pd
3
ClN
605.41
2
PPd
2
2CH Cl
2
2
D
2
2
3
1
fw
space group
cryst syst
803.62
P2(1)
3
orthorhombic
11.752(1)
13.481(1)
18.026(1)
90
90
90
2855.8(1)
4
173(2)
1.408
0.71073
0.821
1240
monoclinic monoclinic
optical purity of 10b was also confirmed by recoordination
of the chiral ligand to the bis(acetonitrile) complex R-11
˚
a/A
10.865(1)
15.416(1)
16.302(1)
90
100.2(1)
90
2687.0(2)
4
103(2)
1.562
9.171(1)
15.718(1)
12.203(1)
90
97.8(1)
90
1742.9(1)
2
173(2)
1.531
˚
b/A
3
1
˚
c/A
(
Scheme 4). The P NMR spectrum of the recomplexation
products gave two pairs of doublets at δ -0.1, 37.2 (JPP
2.3 Hz) and 9.9, 27.7 (JPP = 52.7 Hz), which were appar-
ently due to the formation of the original regioisomers 5b and
b. However, the recomplexation products involving S-11
R/deg
β/deg
=
5
γ/deg
3
˚
V/A
6
Z
T/K
generated two new regioisomers, 12b and 13b, with two pairs
of different doublets at δ -8.0, 36.6 (JPP = 54.9 Hz) and 7.7,
-3
D
λ/A
μ/mm
F(000)
calcd/g cm
˚
0.71073
1.030
1280
0.71073
1.108
812
2
6.9 (JPP = 55.8 Hz). Thus, the recoordination process
therefore confirmed that the liberated formyl-substituted
,3-diphosphine was enantiomerically pure, and the chirality
-1
1
Flack param
R1 (obsd data)
-0.005(18)
0.0323
0.0728
P
0.06(5)
0.0583
0.1471
-0.003(18)
0.0362
0.0819
a
remained unaffected throughout the reduction reaction.
Continuous treatment of the regioisomers 5b and 6b with
DIBAL-H could chemoselectively yield the novel hydroxyl-
functionalized regioisomers 5c and 6c (Scheme 3). The
reduction process could be finished within 2 h at -78 °C,
and the P NMR spectrum exhibited two pairs of doublets
at δ -0.8, 37.1 (JPP = 53.3 Hz) and 11.3, 28.5 (JPP = 52.8 Hz).
In situ removal of the chiral amine auxiliary of 5c and 6c with
concentrated hydrochloric acid yielded the optically pure
dichloro complex 9c as pale yellow cubic crystals from dichlor-
b
wR2 (obs data)
P
P
a
b
|. wR2 = { [w(F
2
o
2 2
c
- F ) ]/
R1 =
2
||F
o
-1
| - |F
c
||/ |F
o
P
2
1/2
2
2
2
[
w(F
o
) ]} , w = σ (F
o
) þ (aP) þ bP.
3
1
CH Cl ). The dichloro product 9c showed a pair of doublets
2 2
at δ 15.6, 23.5 (d, JPP = 14.5 Hz). The molecular structure
was studied by X-ray crystallography (Figure 3). Selected
bond lengths and angles are listed in Table 3. As expected,
the palladium atom adopted a square-planar geometry but
with a smaller tetrahedral distortion (2.8°), while the angles
omethane and diethyl ether in 72% yield, [R] = þ31.1 (c 1.0,
D

Article
Organometallics, Vol. 29, No. 16, 2010 3587
around palladium are in the ranges 86.2(1)-96.5(1)° and
The mixture was extracted with ethyl acetate (3 ꢀ 20 mL). To the
combined organic phases was added (triphenylphosphoranyli-
dene)acetonitrile (1.94 g, 6.44 mmol). The mixture was stirred
for 2 h at room temperature, palladium dimer R-2 (1.46. g, 2.15
mmol) was added, and the solution was stirred for another 1 h.
Upon removal of the solvent, the complex R-3 was isolated by
chromatography on silica (EtOAc/hexanes, 1:2.5) as a pale
yellow powder (cis/trans = 1:1.8, 2.13 g, 82%). trans-R-3
1
76.2(1)-176.7(1)°. The configuration at the chiral carbon
center is the S form, and the hydroxyl substituent has an
equatorial orientation.
Further treatment of 9c with aqueous potassium cyanide
can liberate the chiral hydroxyl-functionalized 1,3-dipho-
sphine ligand 10c in nearly quantitative yield, [R] = -38.5
D
3
1
c 0.5, CH Cl ). The P NMR spectrum of 10c in CDCl3
(
2 2
(
1
4
1.37 g, 53%): [R]
D
= -19.3 (c 1.1, CH
2 2
Cl ). Mp: 123-
exhibited a pair of singlets at δ -16.3 and -6.6. The optical
purity of the free ligand was confirmed by similar recoordi-
nation reactions (Scheme 4). It is noteworthy that the
recoordination products of 10c with S-11 revealed two
25 °C. Anal. Calcd for C H ClN PPd: C, 61.5; H, 5.3; N,
3
1
32
2
3
1
3
.6. Found: C, 61.3; H, 5.4; N, 4.8. P NMR (CDCl , 162
1
MHz): δ 34.6 (s). H NMR (CDCl , 400 MHz): δ 2.05 (d, 3H,
3
J
HH = 6.3 Hz, CHMe), 2.13-2.27 (m, 2H, PCH
2
CH
2
), 2.70 (s,
3H, NMe), 2.88 (m, 1H, PCH H), 2.98 (d, 3H, JPH = 3.2 Hz,
0
distinct pairs of doublets at δ -7.8, 38.2 (J = 55.9 Hz)
PP
3
1
0
NMe), 3.07 (m, 1H, PCH H), 4.36 (qn, 1H, JHH = JPH = 6.1
Hz, CHCH
and 9.0, 27.1 (JPP = 55.8 Hz) in the P NMR spectrum.
In summary, we have presented a facile synthesis of three
novel 1,3-bis(diphenylphosphino)propane ligands with cya-
no, formyl, and hydroxyl functionalities, by means of orga-
no-palladium complex promoted hydrophosphination and
subsequent functional group transformation reactions. The
reactions proceeded with good yields and stereoselectivities.
Investigations on other organic transformations of the cyano
group to synthesize new chiral 1,3-diphosphine ligands and
the screening of transition metal complexes containing these
optically active diphosphines for catalytic reactions are
currently in progress.
3
), 5.27 (d, 1H, JHH = 16.2 Hz, CHCN), 6.64-8.11
1
3
(
m, 17H, Ar and CH CH). C NMR (CDCl , 100 MHz): δ 23.8
2
3
(
s), 29.0 (d, JPC = 4.0 Hz), 29.4 (d, JPC = 32.7 Hz), 48.4 (d, JPC
=
.8 Hz), 51.2 (d, JPC = 2.8 Hz), 72.9 (d, JPC = 3.1 Hz), 100.3 (s),
1
1
1
J
17.3 (s), 123.3 (s), 124.2 (s), 124.8 (d, JPC = 5.8 Hz), 125.8 (s),
28.4 (s), 128.6 (d, 2C, JPC = 11.0 Hz), 128.8 (s), 129.0 (d, 2C,
PC = 10.2 Hz), 129.1 (d, JPC = 44.7 Hz), 130.2 (d, JPC = 44.3
Hz), 131.0 (d, JPC = 2.2 Hz), 131.2 (d, JPC = 2.2 Hz), 131.2 (s),
133.7 (d, 2C, JPC = 11.7 Hz), 134.2 (d, 2C, JPC = 11.4 Hz), 135.4
(d, JPC = 12.3 Hz), 149.0 (s), 149.2 (d, JPC = 2.0 Hz), 154.8 (d,
J
PC = 16.6 Hz).
cis-R-3 (0.76 g, 29%): [R]436 = þ128.6 (c 1.0, CH
31
2 2
Cl ). Mp:
2
N, 4.6. Found: C, 61.4; H, 5.2; N, 4.9. P NMR (CDCl
05-207 °C. Anal. Calcd for C H ClN PPd: C, 61.5; H, 5.3;
3
1
32
2
3
, 162
Experimental Section
1
MHz): δ 34.8 (s). H NMR (CDCl
JHH = 6.3 Hz, CHMe), 2.28 (m, 1H, PCH CH H), 2.49 (m, 1H,
3
, 400 MHz): δ 2.06 (d, 3H,
0
2
All air-sensitive reactions were performed under a positive
pressure of argon using a standard Schlenk line. Solvents were
dried according to standard procedures and degassed prior to
use when necessary. NMR spectra were recorded at 25 °C on a
0
0
PCH CH H), 2.70 (s, 3H, NMe), 2.98 (m, 1H, PCH H), 2.98 (d,
2
0
3
H, JPH = 3.3 Hz, NMe), 3.12 (m, 1H, PCH H), 4.36 (qn, 1H,
J
3
HH = JPH = 6.2 Hz, CHCH ), 5.21 (d, 1H, JHH = 10.9 Hz,
1
3
1
13
31
CHCN), 6.59-8.12 (m, 17H, Ar and CH CH). C NMR
2
Bruker ACF 400 ( H at 400 MHz, C at 100 MHz, and P at
62 MHz) spectrometer. Chemical shifts (δ) are reported in
(
CDCl
3
, 100 MHz): δ 23.8 (s), 27.8 (d, JPC = 3.7 Hz), 29.6 (d,
1
J
7
1
1
1
1
1
1
PC = 32.4 Hz), 48.3 (d, JPC = 1.9 Hz), 51.1 (d, JPC = 2.8 Hz),
parts per million. Proton and carbon chemical shifts are relative
to the residual solvent peaks. Coupling constants are reported in
hertz. 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 Analysis
Laboratory of the Division of Chemistry and Biological Chem-
istry at Nanyang Technological University. Melting points were
measured using the SRS Optimelt Automated Melting Point
System, SRS MPA100.
2.9 (d, JPC = 3.0 Hz), 99.5 (s), 115.6 (s), 123.3 (s), 124.2 (s),
24.7 (d, JPC = 5.8 Hz), 125.7 (s), 128.5 (d, 2C, JPC = 10.3 Hz),
28.6 (s), 128.8 (s), 128.9 (d, JPC = 45.0 Hz), 129.0 (d, 2C, JPC =
0.2 Hz), 130.3 (d, JPC = 44.3 Hz), 131.0 (d, JPC = 2.5 Hz),
31.1 (d, JPC = 2.5 Hz), 131.2 (s), 133.7 (d, 2C, JPC = 11.6 Hz),
34.2 (d, 2C, JPC = 11.5 Hz), 135.5 (d, JPC = 12.3 Hz), 149.1 (s),
49.2 (d, JPC = 2.0 Hz), 154.3 (d, JPC = 16.3 Hz).
Hydrophosphination of Complex R-3 and Synthesis of the
Diiodo Complex 9a. A mixture of trans-R-3 (1.0 g, 1.65 mmol)
1
2a,b
12c
The chiral palladium templates R-2,
and the Wittig reagent (triphenylphosphoranylidene)acetonitrile
R-11, and S-11
13
in dichloromethane (30 mL) and AgClO4 H O (0.56 g, 2.48
2
3
mmol) in water (5 mL) was stirred vigorously for 1 h at room
temperature. The organic layer, upon the removal of AgCl
were prepared according to literature methods. 3-Chloropro-
pionaldehyde diethylacetal is commercially available (CAS:
precipitate, was washed with H O (3 ꢀ 20 mL), concentrated,
3
5573-93-4) and was used as received.
Caution! Perchlorate salts of metal complexes are potentially
explosive compounds and should be handled with care.
2
and redissolved in dichloromethane (20 mL). The solution was
allowed to cool to -78 °C and treated with diphenylphosphine
(
0.31 g, 1.65 mmol) in dichloromethane (6 mL), followed by
Preparation of Monophosphine Palladium Complex R-3. A
sodium diphenylphosphide solution prepared from diphenyl-
phosphine (0.80 g, 4.30 mmol) in THF (20 mL) was cooled to
triethylamine (0.25 g, 2.48 mmol). The mixture was stirred for
h and warmed to room temperature. Upon removal of solvent,
the crude product was purified by chromatography on silica
CH Cl /acetone/hexanes, 2:1:3) to afford an equilibrium mix-
2
0
°C, and 3-chloropropionaldehyde diethylacetal (0.86 g, 5.16
(
mmol) in THF (5 mL) was added dropwisely over 5 min. The
resulting mixture was stirred for 1 h at room temperature, 4 N
HCl (15 mL) was added, and the solution was stirred for 5 h. The
pH of the solution was adjusted with sodium carbonate to 10.
2
2
ture of regioisomers 5a and 6a as an off-white solid (0.99 g,
7
3
1
3
0%). P NMR (CDCl , 162 MHz): δ -1.1 (JPP = 52.1 Hz), 8.3
(
JPP = 51.7 Hz), 27.1 (JPP = 51.7 Hz), 35.3 (J = 52.1 Hz).
PP
Concentrated hydrochloric acid (8 mL) and NaI (0.25 g, 1.64
mmol) were added to a solution of regioisomers 5a and 6a (0.35
g, 0.41 mmol) in dichloromethane (15 mL). The mixture was
stirred vigorously at room temperature for 12 h, washed with
water (3 ꢀ 20 mL), concentrated, and subsequently purified by
(
12) (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.
2 2
chromatography on silica (CH Cl /acetone/hexanes, 2:1:3) to
afford the diiodo complex 9a as a red solid (0.26 g, 79%): [R] =
D
(
13) (a) Burling, S.; Paine, B. M.; Nama, D.; Brown, V. S.; Mahon,
-
29
10.7 (c 1.3, CH Cl ). Mp: 330-333 °C (dec). Anal. Calcd for
M. F.; Prior, T. J.; Pregosin, P. S.; Whittlesey, M. K.; Williams, J. M. J.
J. Am. Chem. Soc. 2007, 129, 1987. (b) Kiddle, J. J. Tetrahedron Lett.
2
2
31
C
H
27
I
2
NP
2
Pd: C, 42.9; H, 3.4. Found: C, 42.7; H, 3.6. P NMR
2000, 41, 1339.
2 2
(CD Cl , 162 MHz): δ4.2 (d, JPP = 21.3 Hz), 8.8 (d, JPP = 21.3 Hz).

3
588 Organometallics, Vol. 29, No. 16, 2010
Yuan et al.
1
0
H NMR (CD
.25-2.48 (m, 3H, PCH
2
Cl
2
, 400 MHz): δ 2.05 (m, 1H, PCH
2
CHH ),
organic phase was separated, washed with H
concentrated to give the regioisomers 5c and 6c as a crude pale
2
O (3 ꢀ 20 mL), and
0
2
3
2
CHH and CH
2
CN), 2.54-2.70 (m,
13
31
H, PCHCH and PCH ), 7.46-7.92 (m, 20H, Ar). C NMR
yellow solid. P NMR (CDCl , 162 MHz): δ -0.8, 37.1 (J
=
2
2
3
PP
(
CD
2
Cl
2
, 100 MHz): δ 20.5 (s), 24.1 (d, JPC = 3.3 Hz), 24.7 (dd,
53.3 Hz); 11.3, 28.5 (JPP = 52.8 Hz). By following the same
procedure to remove the chiral amine auxiliary as described in
the synthesis of 9b, 9c was generated from the crude regioi-
somers 5c and 6c as pale yellow prisms upon crystallization from
J
2
1
2
J
PC = 10.7 Hz, JPC = 27.6 Hz), 30.1 (dd, JPC = 13.4 Hz, JPC
=
1.7 Hz), 116.8 (d, JPC = 12.8 Hz), 127.1 (d, JPC = 49.8 Hz),
28.4 (d, 2C, JPC = 11.4 Hz), 128.5 (d, JPC = 53.9 Hz), 128.7 (d,
C, JPC = 11.1 Hz), 128.9 (d, 2C, JPC = 11.0 Hz), 129.0 (d, 2C,
PC = 11.1 Hz), 129.3 (d, JPC = 52.5 Hz), 131.2 (d, JPC = 2.7
dichloromethane/diethyl ether (0.27 g, 72%): [R]
(c 1.0, CH Cl
). Mp: 271-273 °C (dec). Anal. Calcd for
C H Cl OP Pd: C, 55.0; H, 4.8. Found: C, 54.8; H, 4.9.
D
= þ31.1
2
2
3
1
P
Hz), 131.8 (d, JPC = 2.7 Hz), 132.0 (d, JPC = 2.6 Hz), 132.3 (d,
JPC = 2.4 Hz), 133.1 (d, 2C, JPC = 9.8 Hz), 133.2 (d, JPC = 58.0
Hz), 133.4 (d, 2C, JPC = 9.4 Hz), 134.2 (d, 2C, JPC = 10.7 Hz),
29
30
2
2
NMR (CD Cl , 162 MHz): δ 15.6 (d, J = 14.5 Hz), 23.5 (d,
2
2
PP
1
PP = 14.5 Hz). H NMR (CD
J
CHH CH
2
Cl
2
, 400 MHz): δ 1.37 (m, 1H,
OH), 1.70 (m, 1H, CHH -
0
0
0
1
35.6 (d, 2C, JPC = 11.0 Hz).
The same procedure was used for the hydrophosphination of
2
OH), 1.62 (br, 1H, CH
0
2
CH OH), 1.96 (m, 1H, PCH CHH ), 2.17 (m, 1H, PCH CHH ),
2
2
2
cis-R-3.
Preparation of the Formyl-Functionalized Complexes 5b and
b and the Dichloro Palladium Complex 9b. A solution of
regioisomers 5a and 6a (0.5 g, 0.58 mmol) in dichloromethane
2.50 (m, 2H, PCH
CH
MHz): δ 23.4 (d, JPC = 3.5 Hz), 24.8 (dd, JPC = 7.9 Hz, JPC
31.6 Hz), 29.2 (dd, JPC = 9.8 Hz, JPC = 29.9 Hz), 32.5 (d, JPC
2
), 2.62 (m, 1H, PCHCH
OH), 7.40-7.84 (m, 20H, Ar). C NMR (CD
2
), 3.47 (br, 2H,
, 100
1
3
2
2
Cl
2
6
=
=
(
20 mL) was cooled to -78 °C under argon. DIBAL-H (1 M in
2.8 Hz), 59.0 (d, JPC = 10.2 Hz), 126.7 (d, JPC = 53.7 Hz), 127.7
(d, JPC = 55.7 Hz), 128.2 (d, 2C, JPC = 11.1 Hz), 128.5 (d, 4C,
heptane, 1.8 mL, 1.8 mmol) was added, and the solution was stirred
for 2 h at the same temperature. The mixture was quenched with
water (2 mL), warmed to 0 °C, and then treated with H SO acid
JPC = 10.7 Hz), 128.8 (d, 2C, JPC = 10.4 Hz), 129.0 (d, JPC
56.5 Hz), 130.2 (d, JPC = 58.7 Hz), 131.2 (d, JPC = 2.7 Hz),
131.3 (d, JPC = 2.9 Hz), 131.5 (d, JPC = 2.7 Hz), 131.6 (d, JPC =
=
2
4
(
0.5 M, 20 mL). The organic phase was separated, washed with
H
2
O (3 ꢀ 20 mL), and concentrated to give the regioisomers 5b
2.7 Hz), 133.3 (d, 2C, JPC = 10.3 Hz), 133.7 (d, 4C, JPC = 10.9
Hz), 135.4 (d, 2C, JPC = 10.5 Hz).
3
1
and 6b as a pale yellow solid. P NMR (CDCl , 162 MHz): δ
3
-
0.1, 37.2 (JPP = 52.3 Hz); 9.9, 27.7 (JPP = 52.7 Hz).
The crude regioisomers 5b and 6b were not isolated, and a
Liberation of the 1,3-Diphosphine Ligands 10a, 10b, and 10c. A
solution of 9a (0.15 g, 0.18 mmol) in dichloromethane (10 mL)
was stirred vigorously with aqueous KCN (0.5 g, 7.68 mmol) for
30 min. The organic layer was separated, washed with water (3 ꢀ
solution of 5b and 6b in dichloromethane (10 mL) was subse-
quently treated with concentrated hydrochloric acid (5 mL) for
3
h at room temperature. The mixture was then washed with water
3 ꢀ 20 mL), concentrated, and purified by column chromato-
graphy on silica (CH Cl /acetone/hexanes, 3:1:1). Upon crystal-
4
12 mL), and dried with MgSO . The diphosphine ligand 10a was
(
obtained as a white solid upon removal of solvent under reduced
pressure (0.077 g, 93%): [R]D = -28.5 (c 1.3, CH Cl ).
3
1
P
2
2
2
1
2
lization in dichloromethane/diethyl ether, product 9b was iso-
lated as pale yellow prisms (0.25 g, 68%): [R]
= þ24.4 (c 0.9,
CH Cl
). Mp: 281-283 °C (dec). Anal. Calcd for C29
OP Pd: C, 55.1; H, 4.5. Found: C, 54.9; H, 4.7. P NMR
NMR (CDCl , 162 MHz): δ -17.5 (s), -8.3 (s). H NMR
3
D
(CDCl
PCH
3
, 400 MHz): δ 1.77 (m, 2H, PCH
2
CH
2
), 2.18 (m, 2H,
),2.32(m, 1H, CHH CN), 2.53 (m, 1H, JHH =4.2Hz, JHH =
0
2
2
H28Cl
2
-
2
3
1
0
17.2 Hz, CHH CN), 2.71 (br, 1H, PCHCH ), 7.28-7.43 (m,
2
2
(
CD
2
Cl
2
, 162 MHz): δ 15.3 (d, JPP = 12.5 Hz), 21.8 (d, JPP
=
20H, Ar).
Similarly the formyl-functionalized 1,3-diphosphine ligand
10b (0.093 g, 86%) was obtained from 9b (0.15 g, 0.24 mmol) as a
1
2.5 Hz). H NMR (CD
1
PCH
2
Cl
2
, 400 MHz): δ 1.86-2.10 (m, 2H,
2
CH ), 2.46 (m, 1H, JHH = 9.8 Hz, JHH = 18.7 Hz,
2
0
0
31
PCHH ), 2.53 (m, 2H, CH CHO), 2.64 (ddd, 1H, PCHH ),
2
white solid: [R]D = -22.6 (c 1.7, CH Cl ). P NMR (CDCl3,
2
2
1
3
J
J
.10 (m, 1H, PCHCH
, 100 MHz): δ 25.0 (d,
PC = 3.7 Hz), 25.1 (dd, JPC = 8.0 Hz, JPC = 31.5 Hz), 26.8 (dd,
2
3
), 7.42-7.87 (m, 20H, Ar), 9.42 (d, 1H,
162 MHz): δ -16.4 (s), -6.8 (s). H NMR (CDCl
3
, 400 MHz): δ
), 2.45 (m, 2H,
), 7.27-7.45 (m, 20H, Ar),
1
PH = 2.3 Hz, CHO). C NMR (CD
2
Cl
2
1.60 (m, 2H, PCH
CH CHO), 3.06 (br, 1H, PCHCH
9.61 (br, 1H, CH CHO).
2 2 2
CH ), 2.15 (m, 2H, PCH
2
2
JPC = 10.8 Hz, JPC = 29.7 Hz), 44.8 (d, JPC = 2.2 Hz), 126.2 (d,
2
J
PC = 53.8 Hz), 127.2 (d, JPC = 56.2 Hz), 128.5 (d, 2C, JPC
=
0.9 Hz), 128.6 (d, 2C, JPC = 11.0 Hz), 128.8 (d, 2C, JPC = 11.0
The hydroxyl-functionalized 1,3-diphosphine 10c (0.10 g,
95%) was prepared from 9c (0.15 g, 0.24 mmol) as a white solid:
1
Hz), 128.85 (d, 2C, JPC = 11.3 Hz), 128.9 (d, JPC = 57.1 Hz),
3
1
[R]D = -38.5 (c 0.5, CH Cl ). P NMR (CDCl , 162 MHz): δ
2
2
3
1
129.9 (d, JPC = 58.7 Hz), 131.4 (d, JPC = 2.8 Hz), 131.6 (d,
JPC = 2.9 Hz), 131.7 (d, JPC = 2.8 Hz), 132.0 (d, JPC = 2.8 Hz),
133.3 (d, 2C, JPC = 10.2 Hz), 133.4 (d, 2C, JPC = 9.8 Hz), 133.7
-16.3 (s), -6.6 (s). H NMR (CDCl , 400 MHz): δ 1.37 (br, 1H,
3
0
CH
1H, CHH CH
2
OH), 1.58 (m, 3H, CHH CH
0
2
OH and PCH
2 2
CH ), 1.73 (m,
), 2.57 (br, 1H,
2
OH), 2.16 (m, 2H, PCH
2
(
J
d, 2C, JPC = 10.7 Hz), 135.3 (d, 2C, JPC = 10.8 Hz), 197.6 (d,
PC = 9.7 Hz).
PCHCH ), 3.59 (m, 2H, CH OH), 7.26-7.47 (m, 20H, Ar).
2
2
Preparation of the Hydroxyl-Functionalized Complexes 5c and
c and the Dichloro Palladium Complex 9c. A solution of
regioisomers 5b and 6b (generated from 5a and 6a, 0.5 g, 0.58
Acknowledgment. We thank Nanyang Technological
University for support of this research and a Ph.D.
scholarship to M.Y.
6
mmol) in dichloromethane (20 mL) was treated with DIBAL-H
(
1 M in heptane, 1.8 mL, 1.8 mmol) at -78 °C for 2 h. The
Supporting Information Available: Crystallographic data in
CIF format for complexes trans-R-3, 9b, and 9c. This material is
available free of charge via the Internet at http://pubs.acs.org.
mixture was quenched with water (2 mL) and warmed to 0 °C,
followed by treatment with H SO acid (0.5 M, 20 mL). The
2
4