PCN pincer palladium(II) complex catalyzed enantioselective hydrophosphination of enones: Synthesis of pyridine-functionalized chiral phosphine oxides as NCsp3O pincer preligands

Article abstract of DOI:10.1021/jo5015307

A series of chiral PCN pincer Pd(II) complexes VI- XIII with aryl-based aminophosphine-imidazoline or phosphinite-imidazoline ligands were synthesized and characterized. They were examined as enantioselective catalysts for the hydrophosphination of enones

Full text of DOI:10.1021/jo5015307

Article
pubs.acs.org/joc
PCN Pincer Palladium(II) Complex Catalyzed Enantioselective
Hydrophosphination of Enones: Synthesis of Pyridine-Functionalized
3
Chiral Phosphine Oxides as NCsp O Pincer Preligands
Xin-Qi Hao, Juan-Juan Huang, Tao Wang, Jing Lv, Jun-Fang Gong,* and Mao-Ping Song*
College of Chemistry and Molecular Engineering, Henan Key Laboratory of Chemical Biology and Organic Chemistry,
Zhengzhou University, Zhengzhou 450001, People’s Republic of China
S
* Supporting Information
ABSTRACT: A series of chiral PCN pincer Pd(II) complexes
VI−XIII with aryl-based aminophosphine−imidazoline or
phosphinite−imidazoline ligands were synthesized and char-
acterized. They were examined as enantioselective catalysts for
the hydrophosphination of enones. Among them, complex IX,
which features a Ph2PO donor as well as an imidazoline donor
with (4S)-phenyl and N-Tol-p groups, was found to be the
optimal catalyst. Thus, in the presence of 2−5 mol % of com-
plex IX a wide variety of enones reacted smoothly with diaryl-
phosphines to give the corresponding chiral phosphine derivatives in high yields with enantioselectivities of up to 98% ee. In
particular, heteroaryl species such as 2-thienyl-, 2-furyl-, and 2-pyridinyl-containing enones that have a strong coordination ability
to the Pd center were also appropriate substrates for the current catalytic system. For example, hydrophosphination of
2-alkenoylpyridines with diphenylphosphine followed by oxidation with H2O2 afforded the corresponding pyridine-functionalized
chiral phosphine oxides in good yields with good to excellent enantioselectivities (10 examples, up to 95% ee). Furthermore, it
had been demonstrated that the obtained pyridine-containing phosphine oxide acted as a tridentate ligand in the reaction with
3
3
PdCl2 to form an intriguing NCsp O pincer Pd(II) complex via Csp −H bond activation, which to our knowledge is the first
3
example of a chiral DCsp D′ Pd pincer (D ≠ D′; D and D′ denote donor atoms such as P, N, etc.).
high levels of stereoselectivities (13 examples, 90−99% ees).5b
INTRODUCTION
■
Despite this impressive progress, the development of widely
applicable catalysts is still of interest. Recently, we have also
explored the application of pincer Pd(II) complexes in hydro-
phosphination, which is involved in the evaluation of the PCN
Pd(II) pincers I−IV containing aryl-based aminophosphine−
imidazoline or phosphinite−imidazoline ligands (Chart 1) in
the asymmetric addition of diarylphosphines to β-aryl en-
ones.12,13 Among the four pincers utilized, complex III af-
forded the best result (up to 82% ee) in the addition of diphe-
nylphosphine to chalcone and the other three complexes gave
rather low ee values (0−30% ees) under the same reaction
conditions. Thus, with complex III as the catalyst, moderate
to excellent enantioselectivities could be obtained (13 ex-
amples, 40−94% ees). Overall, there is still room to improve
the performance of complexes I−IV in catalysis, and this can
be fulfilled through modifying the ligands. Meanwhile, the
structural modification of these pincer Pd complexes is a rela-
tively easy task. Consequently, we set out to further modify
the PCN Pd(II) pincers and examine their potential in the
hydrophosphination of enones with diarylphosphines. The
results are given below.
Chiral phosphorus compounds have been extensively employed
as ligands in organometallic chemistry and catalysis.1 Therefore,
the synthesis of these species has attracted great interest and
catalytic enantioselective strategies have recently been devel-
oped.2 Among them, the asymmetric addition of phosphorus
nucleophiles such as secondary phosphines and phosphine
oxides is one of the most efficient approaches to construct new
carbon−phosphorus bonds and concurrently provide direct
access to the chiral phosphanes.2c,3 In particular, great progress
has been achieved in the metal- or organo-catalyzed hydro-
phosphination of electron-deficient alkenes with secondary
phosphines (conjugate addition of R2PH to the alkenes) over
the past decade. Successful examples include methacrylonitrile,4
enones,5 enals,6 nitroalkenes,7 α,β-unsaturated N-acylpyrroles,8
unsaturated carboxylic and sulfonic esters,9 and α,β-unsaturated
imines.10 Among the transition-metal catalysts for the above
hydrophosphination, the CP palladacycle A and the PCP pincer
Pd complex B (Chart 1), which are chiral cyclopalladated
complexes, are found to be particularly effective. The former
was developed by Leung’s group and the latter by Duan’s
group.11 Both A and B could catalyze hydrophosphination of
several kinds of activated alkenes with diarylphosphines, pro-
ducing the chiral phosphine derivatives with excellent enan-
tioselectivities in all cases.5,6d,7b,8−10 For example, in the hydro-
phosphination of β-substituted enones, complex B exhibited
Received: July 10, 2014
© XXXX American Chemical Society
A
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Chart 1
Scheme 1. Synthesis of the PCN Pincer Pd(II) Complexes VI−VIII with Aryl-Based Aminophosphine−Imidazoline Ligands
Scheme 2. Synthesis of the PCN Pincer Pd(II) Complexes IX−XIII with Aryl-Based Phosphinite−Imidazoline Ligands
Additionally, an X-ray single-crystal analysis of complex IX
confirmed the PCN pincer coordination mode (Figure 1).
With the expected pincer Pd(II) complexes in hand, they
were first evaluated in the hydrophosphination of chalcones
with diphenylphosphine under the optimized reaction con-
ditions12 previously established (for convenience of operation
in the experiments, the phosphine adducts were oxidized to the
corresponding phosphine oxides for analysis). In the series of
Pd pincers possessing aminophosphine−imidazoline ligands,
RESULTS AND DISCUSSION
■
In our previous studies complex III, with a (4S)-phenyl sub-
stituent on the imidazoline ring, displayed higher enantio-
selectivity than complexes I and II with a (4S)-isopropyl or
-benzyl group; therefore, the (4S)-phenyl group was used in the
following investigations. Three new PCN pincer Pd(II) com-
plexes with aminophosphine−imidazoline ligands, VI−VIII
(Scheme 1),12 and five complexes with phosphinite−imidazo-
line ligands, IX−XIII (Scheme 2),14 were prepared according
to the procedures previously reported by us. These complexes
have different electronic and steric properties, which were
realized by employing different chiral amino alcohols (for R1),
primary amines (for R2) and dialkylchlorophosphines (for R3).
All of the new Pd complexes were well characterized by
t
the bulky and more electron-rich Bu2PNH donor in complex
VI led to an obvious decrease in both yield and enanantio-
selectivity in comparison with complex III (Table 1, entry 1 vs 2).
Complexes VII and VIII also did not provide better enantio-
selectivities (entries 3 and 4). The two complexes have a different
NR2 group or an additional (5S)-phenyl substitutent on the
imidazoline ring in comparison with complex III. Gratifyingly,
1
elemental analysis and H, 13C, and 31P{1H} NMR spectra.
B
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III and VI−VIII with aminophosphine−imidazoline ligands. In
addition, complex IX was found to be the optimal catalyst.
The hydrophosphination of a wide variety of enones with
diphenylphosphine were then investigated using complex IX as
the catalyst (Table 2). Both electron-withdrawing and electron-
donating substituents on the aryl (R1) attached to carbonyl
group or β-aryl (R2) in the β-aryl α,β-unsaturated aryl ketone
substrates were tolerated, and all of them furnished high enan-
tioselectivities (18 examples, 85−96% ees, entries 1−8 and
22−31). In fact, excellent enantioselectivities (≥90% ees) could
be obtained in most cases (14 examples). The substituents
include Br, F, NO2, Me, and OMe. However, the enantio-
selectivities decreased drastically when the substituent was
located on the ortho position of the β-aryl group (entry 12 vs 8
and entry 13 vs 7). The β-naphthyl enone was also an appropriate
substrate for the current catalytic system (81% ee, entry 9). In the
cases of β-heteroaryl species such as β-furyl and β-thienyl enones
that may bind to the Pd center through the heteroatom, good
stereocontrol could still be achieved (82% and 88% ee, respec-
tively, entries 10 and 11). In addition, the enone substrates
bearing an alkyl attached to the carbonyl group such as methyl
Figure 1. Molecular structure of the PCN pincer Pd(II) complex IX.
Hydrogen atoms and solvent molecules are omitted for clarity.
Selected bond lengths (Å) and angles (deg): Pd(1)−C(1) 1.963(5),
Pd(1)−P(1) 2.1978(12), Pd(1)−N(1) 2.098(3), Pd(1)−Cl(1)
2.3837(12); C(1)−Pd(1)−N(1) 78.92(18), C(1)−Pd(1)−P(1)
79.80(13), P(1)−Pd(1)−Cl(1) 101.51(5), N(1)−Pd(1)−Cl(1)
99.64(13), N(1)−Pd(1)−P(1) 158.60(13), C(1)−Pd(1)−Cl(1)
177.09(13).
i
(entries 14−21) or Bu (entries 32 and 33) also afforded high
levels of stereoselectivities. In particular, the ee values were invari-
ably higher than 90% in the case of methyl enones (8 examples,
93−97% ees). In contrast, hydrophosphination did not occur
when the β group was a β-alkyl such as cyclohexyl instead of a
β-aryl. 2-Cyclohexen-1-one (a cyclic enone) also did not undergo
hydrophosphination (data not shown in Table 2). When the
catalyst loading was lowered to 2 mol %, excellent enantio-
selectivities could also be reached in some cases (entries 2, 14−
16, 20, and 32). It was worth pointing out that in the reaction of
12 specific β-aryl enones, complex IX consistently provided better
enantioselectivities than the very related complex III12 under the
same conditions. Although the results on hydrophosphination
with diphenylphosphine were quite promising, the reactions of
chalcone with bis(4-methylphenyl)- and bis(4-methoxyphenyl)-
phosphines were somewhat disappointing and the corresponding
products were isolated in a rather low yield (23% yield with
83% ee, entry 34) or with a rather low enantioselectivity (26% ee,
entry 35).
Table 1. Evaluation of PCN Pincer Pd(II) Complexes
VI−XIII in the Enantioselective Hydrophosphination of
a
Chalcone with Diphenylphosphine
b
cd
,
entry
cat.
yield (%)
ee (%)
e
e
1
2
3
4
5
6
7
8
9
III
88
82
VI
16
98
78
99
20
88
83
92
18
72
39
92
33
91
84
52
VII
VIII
IX
On the other hand, pyridine-functionalized chiral phosphines
are a type of important bidentate N,P ligand in organometallic
chemistry and are widely used in asymmetric catalysis.15 There-
fore, in the following experiments pyridinyl was introduced into
the enone substrates and hydrophosphination of 2-alkenoylpyr-
idines was examined (Table 3). At first, the addition of diphe-
nylphosphine to (E)-2-(3-phenylacryloyl)pyridine was carried
out under the aforementioned optimized conditions. The reac-
tion proceeded well to provide the desired product in a 95%
yield, although the substrate has a strong coordination ability to
the Pd catalyst and the enantioselectivity was just 78% ee
(Table 3, entry 1). The results (especially the enantioselectivity)
were inferior to those of chalcone (Table 2, entry 1), indicating
that introduction of pyridinyl to the enone was unfavorable to
the stereocontrol of the hydrophosphination. Pleasingly, low-
ering the temperature from 0 to −10 °C could increase the
enantioselectivity to 89% ee (entry 2). A further decrease in
temperature did not lead to a much improved ee value (90% ee),
while the yield was reduced drastically (67% yield, entry 3). Then
reactions of some other 2-alkenoylpyridines with diphenylphos-
phine were investigated at −10 °C (entries 4−12). The sub-
strates that contain diverse β-aryl with an electron-withdrawing
or -donating group such as bromo, nitro, methyl, and methoxy
X
XI
XII
XIII
a
Hydrophosphination reactions were performed with Ph2PH
(0.2 mmol) and chalcone (0.3 mmol) in the presence of PCN pincer
Pd complex (5 mol %) and KOAc base (10 mol %) in 2 mL of toluene
b
c
d
at 0 °C for 12 h. Isolated yield. Determined by chiral HPLC. The
absolute configuration of the product was assigned to be S by com-
e
parison of optical rotation with that in refs 5b and 12. Data from
ref 12.
an almost quantitative yield with excellent enanantioselectivity
was observed when complex IX was used as the catalyst (99%
yield and 92% ee, entry 5). In contrast to complex III, complex
IX contains a Ph2PO instead of a Ph2PNH donor group.
t
Similarly, the Bu2PO donor in complex X gave drastically
decreased yield and enantioselectivity (entry 6 vs 5). Further
changing NR2 or R1 substitutent on the imidazoline ring in the
series of Pd pincers possessing phosphinite−imidazoline ligands
also did not afford better results (entries 7−9). In general, the
pincers IX−XI and XIII with phosphinite−imidazoline ligands
gave better stereoselectivities than did the corresponding pincers
C
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Table 2. Enantioselective Hydrophosphination of β-Aryl Enones with Diarylphosphines Catalyzed by the PCN Pincer Pd(II)
a
Complex IX
D
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Table 2. continued
a
Hydrophosphination reactions were performed with Ar2PH (0.2 mmol) and β-aryl enones (0.3 mmol) in the presence of complex IX (5 mol %)
b
c
d
and KOAc base (10 mol %) in 2 mL of toluene at 0 °C for 12 h. Isolated yields. Determined by chiral HPLC. The absolute configurations of the
products were assigned to be S by comparison of optical rotations with those in refs 5b and12 or by analogy. Using 2 mol % of the catalyst IX. The
e
f
trivalent phosphine product without oxidation could be isolated in 80% yield.
uniformly afforded the corresponding chiral phosphine oxides in
good yields and stereoselectivities (81−92% yields, 73−95% ees,
entries 4 and 6−9). Even β-heteroaryl species such as β-furyl
and β-thienyl could also be tolerated and good enantioselectiv-
ities were still obtained (82% ee, entries 10 and 11). However,
the stereocontrol was rather bad when the β-aryl bears an ortho
substitutent (38% ee, entry 5) or the β-aryl is a 2-naphthyl
group (46% ee, entry 12). A similar phenomenon was observed
in the cases of enones without a pyridinyl moiety (Table 2,
entries 12 and 13).
To further explore the potential of PCN pincer Pd(II) com-
plexes in the hydrophosphination, the enone substrates were
extended to (E)-2-alkenoylpyridine N-oxides. Meanwhile, it was
reported in the literature that the N-oxides afforded much
higher enantioselectivities than the corresponding nonoxidized
2-alkenoylpyridines under some circumstances, such as in the
Michael type reaction with indoles.16 A brief survey of the
pincer Pd complexes with aryl-based phosphinite−imidazoline
ligands indicated that complex IX was still the most stereo-
selective catalyst for the reaction of (E)-2-(3-phenylacryloyl)-
pyridine N-oxide, though the highest ee value was only 63%
(Table 4, entries 1−5). Then hydrophosphination of several
other 2-alkenoylpyridine N-oxides with diphenylphosphine was
carried out (entries 6−17). In general the enantioselectivities
were not very high, which might be caused by the weak and
inappropriate coordination of pyridine N→O to the catalyst.
Good stereocontrol could be achieved when the aryl (R) in the
pyridine N-oxides was p-BrC6H4, m-O2NC6H4, or m-MeOC6H4
(79−83% ees, entries 6, 10, and 13). Moderate enantiose-
lectivities were observed in the cases of p-ClC6H4, p-O2NC6H4,
p-MeC6H4, p-MeOC6H4, and 2-furyl (55−77% ees, entries 8, 9,
11, 12, and 14). Similar to the above hydrophosphination, the
introduction of an ortho substituent such as Br into the aryl
resulted in greatly reduced enantioselectivity (entry 7 vs 6).
(E)-2-(3-(2-Thienyl)acryloyl)pyridine and (E)-2-(3-(1-naphthyl)-
acryloyl)pyridine N-oxides were also not appropriate substrates
(21% and 9% ees, respectively, entries 15 and 17). Interestingly,
in the case of (E,E)-2-(5-phenyl-2,4-pentadienoyl)pyridine
N-oxide the expected 1,4-addition product was obtained in 77%
yield with 72% ee and the 1,6-adduct was not isolated (entry 16).
To determine the absolute configurations of the catalytic
products and illustrate the utility of the current method, the
pyridine-functionalized phosphine oxide 7pp was treated with
PdCl2 for complexation. After the mixture was stirred in
3
CH2Cl2 at room temperature for 18 h, the chiral NCsp O pincer
Pd(II) complex 8 was easily isolated, albeit in a modest yield
(Scheme 3). The formation of this complex resulted from the
expected coordinations of the pyridine nitrogen and phosphine
oxide oxygen to Pd(II) as well as activation of the sp3 C−H
bond, which was somewhat unexpected. This interesting tri-
dentate pincer type of bonding was unambiguously confirmed
by X-ray single-crystal analysis (Figure 2). Notably, reports on
E
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Table 3. Enantioselective Hydrophosphination of 2-Alkenoylpyridines with Diphenylphosphine Catalyzed by the PCN Pincer
a
Pd(II) Complex IX
a
Hydrophosphination reactions were performed with Ph2PH (0.2 mmol) and 2-alkenoylpyridines (0.3 mmol) in the presence of complex IX (5 mol
b
c
d
%) and KOAc base (10 mol %) in 2 mL of toluene for 12 h. Isolated yields. Determined by chiral HPLC. The absolute configuration of the
product in entry 9 was determined to be S according to the X-ray crystal diffraction analysis of its complex with Pd(II) (vide infra). Those of the
other products were assigned to be S by analogy.
3
3
the sp -carbometalated DCsp D (D and the undermentioned D′
found that complex 8 was an active but not stereoselective
catalyst for the reaction, giving almost racemic product (2% ee)
in 80% yield.
denote donor atoms such as N, P, O, etc.) pincer Pd(II) com-
plexes17 remain rare, although the related aryl-based DCsp D
2
pincers with sp2-hybridized carbon have been studied exten-
sively. Moreover, to the best of our knowledge, there has been
In addition to various enones, hydrophosphinations of α,β-
unsaturated carboxylic esters and nitroalkenes with diphenyl-
phosphine by using the PCN pincer Pd(II) complex IX as the
catalyst were briefly investigated. It was found that no reaction
occurred when the addition of Ph2PH to trans-phenyl cinnamate
was carried out in toluene at 0 °C or room temperature under
conditions similar to those above. However, the reaction did occur
with tert-amyl alcohol as the solvent at room temperature, giving
the desired adduct in an 18% yield with 83% ee (Scheme 4).
Finally, trans-β-nitrostyrene could react smoothly with diphenyl-
phosphine in toluene at 0 °C to afford the expected product in
98% yield. Unfortunately, the ee value was only 14% (Scheme 5).
3
3
no report on the chiral DCsp D and DCsp D′ (D ≠ D′) Pd
pincers. Thus, complex 8 represents the first example of the
DCsp D′ type. In addition, the X-ray single-crystal structure of
complex 8 (Figure 2) showed clearly the R,R configurations of
the two C stereocenters, including the newly formed center in
this complex. On the basis of the X-ray results, the absolute
configuration of the catalytic product 7pp was assigned to be S.
As a preliminary investigation, complex 8 was used as the
catalyst for the hydrophosphination of chalcone with Ph2PH
under the same conditions as shown in Tables 1 and 2. It was
3
F
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Table 4. Enantioselective Hydrophosphination of 2-Alkenoylpyridine N-Oxides with Diphenylphosphine Catalyzed by PCN
a
Pincer Pd(II) Complexes
a
Hydrophosphination reactions were performed with Ph2PH (0.2 mmol) and 2-alkenoylpyridine N-oxides (0.3 mmol) in the presence of pincer
b
c
d
Pd(II) complex (5 mol %) and KOAc (10 mol %) in 2 mL of toluene at 0 °C for 12 h. Isolated yields. Determined by chiral HPLC. The absolute
configurations of the products were assigned to be S by analogy. The absolute configuration was assigned to be R.
e
On the basis of the literature reports5b and our previous
results12 on the pincer Pd(II) catalyzed hydrophosphination of
enones, a plausible catalytic cycle for the current hydro-
phosphination is proposed in Scheme 6. First, the chloride in
the PCN pincer Pd(II) complex IX was replaced by the acetate
to afford the Pd-OAc complex in the presence of KOAc.
Second, the transphosphination reaction occurred between
the Pd-OAc complex and diarylphosphine, giving a Pd-PAr2
G
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3
of complex IX, the central aryl ring, the imidazoline ring, and
the two five-membered palladacycles are approximately
coplanar. The Pd(II) center adopts a typical distorted-square-
planar configuration. Thus, to minimize the unfavorable steric
repulsions between the R2 substituent at the β position (or the
R1 attached to carbonyl group) of the enone and the phenyl
group on the imidazoline ring of the catalyst, the enone
substrate approaches the Pd-PPh2 intermediate with its Si face
preferentially; this facial selectivity leads to the formation of S
isomers.
Scheme 3. Synthesis of the New Chiral NCsp O Pincer Pd(II)
Complex 8 on the Basis of the Obtained Pyridine-
Functionalized Phosphine Oxide 7pp
CONCLUSIONS
■
In summary, we have synthesized and fully characterized eight
new chiral PCN pincer Pd(II) complexes. These complexes
were found to be able to catalyze the enantioselective hydro-
phosphination of enones, of which complex IX displayed the
best stereocontrol. By use of complex IX as the catalyst, the re-
actions of various enones with diphenylphosphine could easily
afford the optically active phosphine derivatives in high yields
with excellent enantioselectivities (up to 98% ee). In particular,
heteroaryl-containing enones such as 2-alkenoylpyridines that
may bind tightly to the catalyst were also tolerated, producing
the corresponding pyridine-functionalized chiral phosphine
oxides in good yields with good enantioselectivities. In addition,
it was found that the obtained pyridine-functionalized phos-
3
phine oxide acted as a NCsp O pincer preligand in the reaction
with PdCl2, which illustrated preliminarily the utility of the
current hydrophosphination. The formed pincer Pd(II) complex
represented the first example of an sp3-carbometalated chiral
3
Figure 2. Molecular structure of the NCsp O pincer Pd(II) complex 8.
3
DCsp D′ Pd pincer. Further efforts to optimize the synthetic
Hydrogen atoms, except for those on the two C stereocenters, are
omitted for clarity. Selected bond lengths (Å) and angles (deg):
Pd(1)−C(7) 2.040(3), Pd(1)−N(1) 2.007(3), Pd(1)−O(3) 2.076(2),
Pd(1)−Cl(1) 2.3832(10); C(7)−Pd(1)−N(1) 81.76(13), C(7)−
Pd(1)−O(3) 87.38(11), O(3)−Pd(1)−Cl(1) 95.09(7), N(1)−
Pd(1)−Cl(1) 95.86(9), N(1)−Pd(1)−O(3) 168.77(10), C(7)−
Pd(1)−Cl(1) 176.98(10).
3
procedure for the chiral NCsp O Pd pincers and synthesize
complexes with other metals, including achiral ones, as well as
their catalytic applications are currently in progress.
EXPERIMENTAL SECTION
■
General Procedures. Solvents were dried with standard methods
and freshly distilled prior to use if needed. 2-Acetylpyridine N-oxide,18
2-alkenoylpyridines and the corresponding N-oxides,16 other enone
substrates,19 and bis(4-methoxyphenyl)phosphine20 were prepared
according to the literature methods. All other chemicals were used as
purchased. NMR spectra were recorded with CDCl3 as the solvent and
TMS as an internal standard for 1H and 13C NMR and 85% H3PO4 as
an external standard for 31P{1H} NMR. The 1H and 13C NMR spectra
of the new compounds were assigned by using a combination of 13C
intermediate. Then, nucleophilic attack of the diarylphosphido
group on palladium at the enone produced an oxa-π-allylpalladium
intermediate, which underwent protonolysis with acetic acid,
leading to the formation of the phosphine adduct along with
regeneration of the active pincer Pd-OAc catalyst. The possible
stereochemical pathway for the formation of S product is also
shown in Scheme 7. According to the X-ray single-crystal structure
Scheme 4. Enantioselective Hydrophosphination of trans-Phenyl Cinnamate with Diphenylphosphine Catalyzed by the PCN
Pincer Pd(II) Complex IX
Scheme 5. Enantioselective Hydrophosphination of trans-β-Nitrostyrene with Diphenylphosphine Catalyzed by the PCN Pincer
Pd(II) Complex IX
H
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Scheme 6. Proposed Catalytic Cycle for the Hydrophosphination of Enones with Diarylphosphines Catalyzed by the PCN
Pincer Pd(II) Complex IX
Scheme 7. Possible Stereochemical Pathway
DEPT (135°) and HSQC experiments if necessary. HRMS were deter-
mined on a Q-Tof Micro MS/MS System ESI spectrometer.
NCH), 2.18 (s, 3H, CH3). 13C NMR (100 MHz, CDCl3): δ 161.5,
148.1, 143.0, 142.8, 140.1, 135.7, 135.0, 133.0, 129.9, 129.3, 129.2,
128.9, 128.1, 127.7, 126.9, 126.6, 124.9, 124.8, 124.2, 79.4, 78.7, 20.9.
HRMS (positive ESI): [M + H]+ calcd for C28H24N3O2 434.1869,
found 434.1866.
Synthesis of PCN Pincer Pd(II) Complexes VI−VIII with Aryl-
Based Aminophosphine-Imidazoline Ligands. The complexes
were synthesized according to the procedure previously reported by
us.12 The analytical data of the new compounds are given as follows.
(S)-1-(2,6-Diisopropylphenyl)-2-(3-nitrophenyl)-4-phenyl-4,5-di-
hydro-1H-imidazole (2b). Purified by column chromatography on
silica gel with EtOAc/petroleum ether (1/30) as eluent; yellow solid
(2.18 g, 5.10 mmol, 51% based on the 3-nitrobenzamido alcohol 1a);
(S)-3-(1-(2,6-Diisopropylphenyl)-4-phenyl-4,5-dihydro-1H-imidazol-
2-yl)aniline (3b). With EtOAc/petroleum ether (1/5) as eluent;
yellow solid (0.78 g, 1.96 mmol, 84% based on 2b); mp 57−58 °C.
20
1
[α]D = −79° (c 0.100, CH2Cl2). H NMR (400 MHz, CDCl3): δ
7.45 (d, J = 7.1 Hz, 2H, Ph-H), 7.38 (t, J = 7.6 Hz, 2H, Ph-H), 7.30−
7.24 (m, 2H, Ar-H and Ph-H), 7.13 (dd, J = 1.5 and 7.7 Hz, 1H, NAr-
H), 7.09−7.06 (m, 2H, NAr-H and Ar-H), 6.90 (t, J = 7.8 Hz, 1H,
NAr-H), 6.68−6.66 (m, 1H, Ar-H), 6.60−6.57 (m, 1H, Ar-H), 5.40
(dd, J = 9.0 and 11.3 Hz, 1H, NCH), 4.19 (dd, J = 9.5 and 11.3 Hz,
1H, NCHH), 3.66 (app t, J = 9.3 Hz, 1H, NCHH), 3.53 (br s, 2H,
NH2), 3.39−3.32 (m, 1H, CH(CH3)2), 3.19−3.12 (m, 1H,
CH(CH3)2), 1.26 (d, J = 6.9 Hz, 3H, CH(CH3)2), 1.05 (d, J =
6.6 Hz, 3H, CH(CH3)2), 1.03 (d, J = 6.5 Hz, 3H, CH(CH3)2), 0.92 (d,
J = 6.8 Hz, 3H, CH(CH3)2). 13C NMR (100 MHz, CDCl3): δ 164.5,
147.5, 147.1, 146.1, 144.8, 136.4, 131.0, 128.6, 128.5, 128.3, 127.1,
126.9, 124.5, 124.4, 118.8, 116.7, 115.7, 67.5, 63.2, 28.04, 28.02, 25.6,
25.3, 23.5, 23.3. HRMS (positive ESI): [M + H]+ calcd for C27H32N3
398.2596, found 398.2594.
20
mp 118−119 °C. [α]D = −125° (c 0.100, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 8.24 (s, 1H, Ar-H), 8.16 (dd, J = 1.0 and 8.2 Hz,
1H, Ar-H), 8.06 (d, J = 8.0 Hz, 1H, Ar-H), 7.47−7.40 (m, 5H, Ph-H),
7.34−7.28 (m, 2H, Ar-H and NAr-H), 7.17 (d, J = 7.8 Hz, 1H,
NAr-H), 7.10 (d, J = 7.7 Hz, 1H, NAr-H), 5.49 (dd, 1H, J = 9.6 and
11.2 Hz, NCH), 4.29 (dd, J = 10.0 and 11.2 Hz, 1H, NCHH), 3.77
(app t, J = 9.5 Hz, 1H, NCHH), 3.38−3.31 (m, 1H, CH(CH3)2),
3.16−3.09 (m, 1H, CH(CH3)2), 1.29 (d, J = 6.8 Hz, 3H, CH(CH3)2),
1.07 (d, J = 6.6 Hz, 3H, CH(CH3)2), 1.05 (d, J = 6.5 Hz, 3H,
CH(CH3)2), 0.91 (d, J = 6.8 Hz, 3H, CH(CH3)2). 13C NMR
(100 MHz, CDCl3): δ 162.2, 147.5, 147.4, 147.0, 144.1, 135.3, 134.7,
132.1, 129.1, 129.0, 128.8, 127.4, 126.8, 124.8, 124.7, 123.5, 68.0, 63.1,
28.15, 28.12, 25.7, 25.4, 23.2, 23.0. HRMS (positive ESI): [M + H]+
calcd for C27H30N3O2 428.2338, found 428.2330.
(S,S)-3-(4,5-Diphenyl-1-(p-tolyl)-4,5-dihydro-1H-imidazol-2-yl)-
aniline (3c). With EtOAc/petroleum ether (1/2) as eluent; white solid
(0.65 g, 1.61 mmol, 70% based on 2c); mp 81−82 °C. [α]D20 = +327°
(c 0.100, CH2Cl2). 1H NMR (400 MHz, CDCl3): δ 7.43−7.39 (m, 4H,
Ph-H), 7.36−7.24 (m, 6H, Ph-H), 7.20 (t, J = 1.8 Hz, 1H, Ar-H), 7.06
(t, J = 7.7 Hz, 1H, Ar-H) 7.02−6.99 (m, 1H, Ar-H), 6.85 (d, J =
8.2 Hz, 2H, NAr-H), 6.70−6.67 (m, 1H, Ar-H), 6.65 (d, J = 8.2 Hz,
2H, NAr-H), 5.05 (d, J = 6.2 Hz, 1H, NCH), 4.69 (d, J = 6.2 Hz, 1H,
NCH), 3.68 (br s, 2H, NH2), 2.18 (s, 3H, CH3). 13C NMR (100 MHz,
(S,S)-2-(3-Nitrophenyl)-4,5-diphenyl-1-(p-tolyl)-4,5-dihydro-1H-
imidazole (2c). With EtOAc/petroleum ether (1/6) as eluent; yellow
solid (3.73 g, 8.60 mmol, 86% based on the 3-nitrobenzamido alcohol
20
1
1b); mp 52−53 °C. [α]D = +233° (c 0.100, CH2Cl2). H NMR
(400 MHz, CDCl3): δ 8.62 (s, 1H, Ar-H), 8.21 (dd, J = 3.2 and 8.2 Hz,
1H, Ar-H), 8.02 (d, J = 7.8 Hz, 1H, Ar-H), 7.49−7.27 (m, 11H, Ph-H
and Ar-H), 6.89 (d, J = 8.2 Hz, 2H, NAr-H), 6.67 (d, J = 8.2 Hz, 2H,
NAr-H), 5.17 (d, 1H, J = 7.4 Hz, NCH), 4.74 (d, J = 7.4 Hz, 1H,
I
dx.doi.org/10.1021/jo5015307 | J. Org. Chem. XXXX, XXX, XXX−XXX

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CDCl3): δ 163.5, 146.4, 143.9, 143.7, 141.0, 134.1, 132.0, 129.4, 129.1,
128.7, 127.7, 127.4, 126.6, 126.5, 123.6, 119.5, 117.0, 115.7, 78.45,
78.37, 20.8. HRMS (positive ESI): [M + H]+ calcd for C28H26N3
404.2127, found 404.2124.
(s, 3H, CH3). 13C NMR (100 MHz, CDCl3): δ 169.5, 166.8, 150.8,
138.9, 135.7, 129.7, 128.9, 127.9, 126.7, 125.0, 124.5, 120.7, 66.2, 56.2,
21.1. HRMS (positive ESI): [M + H]+ calcd for C17H18NO4 300.1236,
found 300.1232; [M + Na]+ calcd for C17H17NNaO4 322.1055, found
322.1099.
(S)-2-(4-Phenyl-1-(p-tolyl)-4,5-dihydro-1H-imidazol-2-yl)-6-((di-
tert-butylphosphino)amino)phenylpalladium(II) Chloride (VI). With
CH2Cl2 as eluent; yellow solid (67.4 mg, 0.11 mmol, 22% based on
(S)-3-(4-Phenyl-1-(p-tolyl)-4,5-dihydro-1H-imidazol-2-yl)phenol
(5a). With EtOAc/petroleum ether (2/1) as eluent; white solid (1.33 g,
4.05 mmol, 54% based on 4a); mp 87−88 °C. [α]D20 = +229° (c 0.464,
20
3a); mp >290 °C. [α]D = +148° (c 0.100, CH2Cl2). 1H NMR
1
(400 MHz, CDCl3): δ 7.49 (d, J = 7.5 Hz, 2H, Ph-H), 7.32 (t, J =
7.5 Hz, 2H, Ph-H), 7.24−7.15 (m, 5H, Ph-H and NAr-H), 6.64−6.56
(m, 2H, Ar-H), 5.99 (d, J = 7.5 Hz, 1H, Ar-H), 5.52 (dd, J = 3.8 and
10.7 Hz, 1H, NCH), 4.41 (app t, J = 10.2 Hz, 1H, NCHH), 4.22 (s,
1H, NH), 3.93 (dd, J = 3.8 and 9.7 Hz, 1H, NCHH), 2.39 (s, 3H,
CH3), 1.43 (d, J = 7.6 Hz, 9H, C(CH3)3), 1.39 (d, J = 7.6 Hz, 9H,
C(CH3)3). 13C NMR (100 MHz, CDCl3): δ 170.7 (d, JCP = 2.2 Hz),
155.4 (d, JCP = 18.5 Hz), 150.2 (d, JCP = 2.6 Hz), 143.5, 137.9, 137.8,
CH2Cl2). H NMR (400 MHz, CDCl3): δ 7.41 (d, J = 7.2 Hz, 2H,
Ph-H), 7.38−7.34 (m, 3H, Ar-H and Ph-H), 7.27 (t, J = 7.1 Hz, 1H, Ph-
H), 6.94 (d, J = 8.0 Hz, 2H, NAr-H), 6.91 (t, J = 7.7 Hz, 1H, Ar-H),
6.67−6.64 (m, 3H, NAr-H and Ar-H), 6.60 (d, J = 7.6 Hz, 1H, Ar-H),
5.37 (dd, J = 7.6 and 10.8 Hz, 1H, NCH), 4.56 (dd, J = 9.4 and 10.8 Hz,
1H, NCHH), 3.83 (dd, J = 7.6 and 9.4 Hz, 1H, NCHH), 2.23 (s, 3H,
CH3). 13C NMR (100 MHz, CDCl3): δ 164.2, 157.9, 143.7, 139.1,
133.8, 130.3, 129.3, 129.1, 128.7, 127.4, 126.5, 122.8, 119.2, 118.3, 116.6,
65.8, 61.3, 20.8. HRMS (positive ESI): [M + H]+ calcd for C22H21N2O
329.1654, found 329.1656.
135.0, 130.3, 128.4, 127.2, 126.8, 126.6, 124.2, 117.7, 111.1 (d, JCP
15.4 Hz), 64.3 (d, JCP = 2.8 Hz), 63.3 (d, JCP = 2.0 Hz), 38.2 (d, JCP
1.8 Hz), 37.9 (d, JCP = 1.9 Hz), 28.36 (d, JCP = 5.5 Hz), 28.30 (d, JCP
=
=
=
(S)-3-(1-(2,6-Diisopropylphenyl)-4-phenyl-4,5-dihydro-1H-imidazol-
2-yl)phenol (5b). With EtOAc/petroleum ether (2/0.3) as eluent;
yellow solid (0.89 g, 2.23 mmol, 30% based on 4a); mp 167−168 °C.
5.4 Hz), 21.2. 31P{1H} NMR (162 MHz, CDCl3): δ 139.1. Anal. Calcd
for C30H37ClN3PPd: C, 58.83; H, 6.09; N, 6.86. Found: C, 58.68; H,
6.23; N, 6.74.
20
1
[α]D = +291° (c 0.100, CH2Cl2). H NMR (400 MHz, CDCl3): δ
7.89 (t, J = 1.8 Hz, 1H, Ar-H), 7.61 (d, J = 7.2 Hz, 2H, Ph-H), 7.48
(t, J = 7.7 Hz, 2H, Ph-H), 7.35 (t, J = 7.4 Hz, 1H, Ph-H), 7.23 (t, J =
7.7 Hz, 1H, NAr-H), 7.16 (dd, J = 1.6 and 7.7 Hz, 1H, NAr-H), 6.92
(dd, J = 1.6 and 7.6 Hz, 1H, NAr-H), 6.78 (t, J = 7.9 Hz, 1H, Ar-H),
6.61 (dd, J = 1.7 and 8.1 Hz, 1H, Ar-H), 6.30 (d, J = 7.7 Hz, 1H,
Ar-H), 5.51 (dd, J = 9.8 and 11.5, 1H, NCH), 4.45 (dd, J = 9.8 and
11.5, 1H, NCHH), 3.60−3.50 (m, 2H, NCHH and CH(CH3)2),
2.88−2.81 (m, 1H, CH(CH3)2), 1.32 (d, J = 6.8 Hz, 3H, CH(CH3)2),
1.31 (d, J = 6.8 Hz, 3H, CH(CH3)2), 0.96 (d, J = 6.8 Hz, 3H,
CH(CH3)2), 0.30 (d, J = 6.7 Hz, 3H, CH(CH3)2). 13C NMR (100 MHz,
CDCl3): δ 166.8, 158.0, 147.5, 146.9, 144.9, 134.7, 129.5, 128.7, 128.6,
127.3, 126.6, 124.7, 124.2, 118.3, 118.2, 117.5, 65.7, 63.1, 28.2, 28.0, 25.7,
25.3, 23.7, 22.5. HRMS (positive ESI): [M + H]+ calcd for C27H31N2O
399.2436, found 399.2431.
(S)-2-(1-(2,6-Diisopropylphenyl)-4-phenyl-4,5-dihydro-1H-imidazol-
2-yl)-6-((diphenylphosphino)amino)phenylpalladium(II) Chloride
(VII). With CH2Cl2 as eluent; yellow solid (184.3 mg, 0.255 mmol,
51% based on 3b); mp >290 °C. [α]D20 = +199° (c 0.100, CH2Cl2). 1H
NMR (400 MHz, CDCl3): δ 7.90−7.82 (m, 4H, PPh-H), 7.52 (d, J = 7.3
Hz, 2H, Ph-H), 7.44−7.32 (m, 9H, PPh-H and NAr-H), 7.25−7.20 (m,
3H, Ph-H), 6.64−6.57 (m, 2H, Ar-H), 5.65−5.61 (m, 2H, Ar-H and
NCH), 4.81 (s, 1H, NH), 4.35 (app t, J = 10.6 Hz, 1H, NCHH), 3.80
(dd, J = 4.6 and 9.9 Hz, 1H, NCHH), 3.06−2.99 (m, 2H, CH(CH3)2),
1.24 (d, J = 6.9 Hz, 3H, CH(CH3)2), 1.06 (d, J = 6.8 Hz, 3H,
CH(CH3)2), 0.97 (d, J = 6.9 Hz, 3H, CH(CH3)2), 0.93 (d, J = 6.8 Hz,
3H, CH(CH3)2). 13C NMR (100 MHz, CDCl3): δ 171.7, 153.2 (d, JCP
24.3 Hz), 151.8, 147.9, 147.7, 143.8, 134.8, 134.2 (d, JCP = 51.9 Hz),
133.5 (d, JCP = 57.4 Hz), 133.2, 132.0 (d, JCP =13.8 Hz), 131.9 (d, JCP
13.9 Hz), 131.0 (d, JCP = 3.8 Hz), 129.7, 128.7 (d, JCP = 11.5 Hz), 128.6
=
=
(S)-3-(1-Isopropyl-4-phenyl-4,5-dihydro-1H-imidazol-2-yl)phenol
(5c). With EtOAc/Et3N (50/1) as eluent; yellow solid (0.92 g, 3.28 mmol,
(d, JCP = 8.9 Hz), 127.3, 126.4, 125.0, 124.8, 124.4, 117.6, 112.6 (d, JCP
=
20
18.2 Hz), 63.8, 63.7, 28.3, 28.2, 25.3, 24.2, 23.9, 23.7. 31P{1H} NMR
(162 MHz, CDCl3): δ 91.4. Anal. Calcd for C39H39ClN3PPd: C, 64.82;
H, 5.44; N, 5.82. Found: C, 64.84; H, 5.58; N, 5.67.
44% based on 4a); mp 45−46 °C. [α]D = +86° (c 0.100, CH2Cl2).
1HNMR (400 MHz, CDCl3): δ 7.41 (d, J = 7.2 Hz, 2H, Ph-H), 7.36 (t,
J = 7.6 Hz, 2H, Ph-H), 7.26−7.21 (m, 2H, Ph-H and Ar-H), 7.07 (t, J =
7.8 Hz, 1H, Ar-H), 6.71 (d, J = 7.5 Hz, 1H, Ar-H), 6.65 (dd, J = 1.8 and
8.2 Hz, 1H, Ar-H), 5.56 (br s, 1H, OH), 5.21 (dd, J = 8.4 and 11.4 Hz,
1H, NCH), 3.96 (dd, J = 9.8 and 11.4 Hz, 1H, NCHH), 3.87−3.80
(m, 1H, CH(CH3)2), 3.38 (app t, J = 9.1 Hz, 1H, NCHH), 1.14 (d, J =
6.7 Hz, 3H, CH(CH3)), 0.92 (d, J = 6.6 Hz, 3H, CH(CH3)). 13C NMR
(100 MHz, CDCl3): δ 167.9, 158.7, 144.8, 130.3, 129.2, 128.6, 127.2,
126.4, 118.2, 117.2, 116.8, 65.2, 51.2, 46.6, 20.9, 19.7. HRMS (positive
ESI): [M + H]+ calcd for C18H21N2O 281.1654, found 281.1650.
(S,S)-3-(4,5-Diphenyl-1-(p-tolyl)-4,5-dihydro-1H-imidazol-2-yl)-
(S,S)-2-(4,5-Diphenyl-1-(p-tolyl)-4,5-dihydro-1H-imidazol-2-yl)-6-
((diphenylphosphino)amino)phenylpalladium(II) Chloride (VIII).
With CH2Cl2 as eluent; yellow solid (72.9 mg, 0.10 mmol, 20%
20
1
based on 3c); mp >290 °C. [α]D = +140° (c 0.100, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 7.87−7.77 (m, 4H, PPh-H), 7.43 (d, J =
7.2 Hz, 2H, Ph-H), 7.38−7.06 (m, 18H, PPh-H, Ph-H and NAr-H),
6.70−6.63 (m, 2H, Ar-H), 6.04 (d, J = 7.3 Hz, 1H, Ar-H), 5.36 (d, J =
5.4 Hz, 1H, NCH), 5.12 (s, 1H, NH), 4.74 (d, J = 5.4 Hz, 1H, NCH),
2.31 (s, 3H, CH3). 13C NMR (100 MHz, CDCl3): δ 170.8 (d, JCP = 2.8
Hz), 153.8 (d, JCP = 24.3 Hz), 152.0, 143.2, 140.8, 138.0, 137.0, 134.9,
phenol (5d). With EtOAc/petroleum ether (1/3) as eluent; white solid
20
134.1 (d, JCP = 52.6 Hz), 133.7 (d, JCP = 54.1 Hz), 132.1 (d, JCP
=
(1.28 g, 3.16 mmol, 42% based on 4b); mp 136−137 °C. [α]D
=
+588° (c 0.100, CH2Cl2). 1H NMR (400 MHz, CDCl3): δ 7.86 (t, J =
1.8 Hz, 1H, Ar-H), 7.49−7.33 (m, 10H, Ph-H), 6.96 (t, J = 7.9 Hz, 1H,
Ar-H), 6.81 (d, J = 8.3 Hz, 2H, NAr-H), 6.78 (d, J = 7.6 Hz, 1H, Ar-H),
6.71 (dd, J = 1.7 and 8.1 Hz, 1H, Ar-H), 6.58 (d, J = 8.3 Hz, 2H,
NAr-H), 5.16 (d, J = 5.5 Hz, 1H, NCH), 4.72 (d, J = 5.5 Hz, 1H,
NCH), 2.16 (s, 3H, CH3). 13C NMR (100 MHz, CDCl3): δ 165.3,
158.0, 143.7, 143.3, 139.8, 134.8, 130.7, 129.4, 129.34, 129.28, 128.9,
128.1, 127.6, 126.4, 126.3, 124.0, 119.5, 118.4, 116.9, 78.0, 76.6, 20.8.
HRMS (positive ESI): [M + H]+ calcd for C28H25N2O 405.1967, found
405.1965.
13.6 Hz), 132.0 (d, JCP = 13.5 Hz), 130.8 (d, JCP = 3.7 Hz), 130.1,
129.1, 128.7 (d, JCP = 10.0 Hz), 128.6 (d, JCP = 11.4 Hz), 128.4, 127.6,
127.2, 126.5, 124.9, 118.1, 112.9 (d, JCP = 18.3 Hz), 80.5 (d, JCP
=
3.3 Hz), 74.2, 21.2. 31P{1H} NMR (162 MHz, CDCl3): δ 91.5. Anal.
Calcd for C40H33ClN3PPd: C, 65.94; H, 4.57; N, 5.77. Found: C,
65.84; H, 4.58; N, 5.67.
Synthesis of PCN Pincer Pd(II) Complexes IX−XIII with Aryl-
Based Phosphinite−Imidazoline Ligands. The complexes were
synthesized according to the procedure previously reported by us.14
The analytical data of the new compounds are given as follows.
(S)-3-Acetoxy-N-(2-hydroxy-1-phenylethyl)benzamide (4a). With
(S)-2-(4-Phenyl-1-(p-tolyl)-4,5-dihydro-1H-imidazol-2-yl)-6-
(diphenylphosphinoxy)phenylpalladium(II) Chloride (IX). With
CH2Cl2 as eluent; yellow solid (291.1 mg, 0.445 mmol, 81%); mp
248−249 °C. [α]D20 = +187° (c 0.070, CH2Cl2). 1H NMR (400 MHz,
CDCl3): δ 8.03−7.93 (m, 4H, PPh-H), 7.53 (dd, J = 1.3, 7.2 Hz, 2H,
Ph-H), 7.46−7.43 (m, 6H, PPh-H), 7.36 (t, J = 7.5 Hz, 2H, Ph-H),
7.30−7.27 (m, 1H, Ph-H), 7.23 (d, J = 8.2 Hz, 2H, NAr-H), 7.18
(d, J = 8.2 Hz, 2H, NAr-H), 6.91 (d, J = 8.0 Hz, 1H, Ar-H), 6.78
EtOAc/petroleum ether (1/2) as eluent; white solid (2.51 g, 8.39 mmol,
20
84% based on 3-acetoxybenzoyl chloride); mp 119−120 °C. [α]D
=
1
−21° (c 0.340, CH2Cl2). H NMR (400 MHz, CDCl3): δ 7.64 (d, J =
8.0 Hz, 1H, Ar-H), 7.53 (t, J = 1.8 Hz, 1H, Ar-H), 7.41 (t, J = 8.0 Hz,
1H, Ar-H), 7.36−7.27 (m, 5H, Ph-H), 7.22 (ddd, J = 0.8, 2.2, and
8.1 Hz, 1H, Ar-H), 7.06 (d, J = 6.8 Hz, NH), 5.23−5.19 (m, 1H,
CHNH), 3.92 (d, J = 5.2 Hz, 2H, CH2OH), 2.58 (br s, 1H, OH), 2.30
J
dx.doi.org/10.1021/jo5015307 | J. Org. Chem. XXXX, XXX, XXX−XXX

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(dt, J = 1.1, 7.9 Hz, 1H, Ar-H), 6.24 (d, J = 7.6 Hz, 1H, Ar-H), 5.53
(dd, J = 4.4 and 10.9 Hz, 1H, NCH), 4.46 (dd, J = 9.8 and 10.9 Hz,
1H, NCHH), 4.01 (dd, J = 4.4 and 9.8 Hz, 1H, NCHH), 2.41 (s, 3H,
CH2Cl2 as eluent; yellow solid (124.4 mg, 0.171 mmol, 31%); mp
154−155 °C. [α]D20 = +111° (c 0.100, CH2Cl2). 1H NMR (400 MHz,
CDCl3): δ 8.04−7.94 (m, 4H, PPh-H), 7.44−7.27 (m, 17H, PPh-H,
Ph-H and NAr-H), 7.17−7.04 (m, 3H, Ph-H), 6.95 (d, J = 8.0 Hz, 1H,
Ar-H), 6.80 (t, J = 7.6 Hz, 1H, Ar-H), 6.23 (d, J = 7.7 Hz, 1H, Ar-H),
5.40 (d, J = 5.6 Hz, 1H, NCH), 4.78 (d, J = 5.6 Hz, 1H, NCH), 2.31
CH3). 13C NMR (100 MHz, CDCl3): δ 170.7, 162.5 (d, JCP
=
11.5 Hz), 151.8, 142.9, 138.3, 137.3, 135.4, 133.9 (d, JCP = 51.8 Hz),
133.2 (d, JCP = 53.7 Hz), 131.8, 131.7 (d, JCP = 14.9 Hz), 131.6 (d,
JCP = 14.5 Hz), 130.5, 128.8 (d, JCP = 11.3 Hz), 128.7, 127.6, 126.8,
126.7, 125.6, 121.4, 114.6 (d, JCP = 16.6 Hz), 64.2 (d, JCP = 3.4 Hz),
64.0 (d, JCP = 2.6 Hz), 21.2. 31P{1H} NMR (162 MHz, CDCl3): δ
155.0. Anal. Calcd for C34H28ClN2OPPd·0.75CH2Cl2: C, 58.20; H,
4.15; N, 3.91. Found: C, 58.23; H, 4.52; N, 3.63.
(s, 3H, CH3). 13C NMR (100 MHz, CDCl3): δ 170.6 (d, JCP
=
2.9 Hz), 162.7 (d, JCP = 11.5 Hz), 152.1, 142.9, 140.6, 138.4, 136.6,
135.6, 133.8 (d, JCP = 52.4 Hz), 133.5 (d, JCP = 53.4 Hz), 131.9 (d,
JCP = 1.6 Hz), 131.73 (d, JCP = 14.7 Hz), 131.66 (d, JCP = 14.7 Hz),
130.3, 129.1, 128.9, 128.8 (d, JCP = 12.1 Hz), 128.6, 127.8, 127.2,
126.6, 125.8, 121.5, 114.7 (d, JCP = 16.9 Hz), 80.0 (d, JCP = 3.5 Hz),
74.2 (d, JCP = 2.1 Hz), 21.2. 31P{1H} NMR (162 MHz, CDCl3): δ
154.8. Anal. Calcd for C40H32ClN2OPPd·0.2CH2Cl2: C, 64.68; H,
4.37; N, 3.75. Found: C, 65.18; H, 4.52; N, 3.63.
(S)-2-(4-Phenyl-1-(p-tolyl)-4,5-dihydro-1H-imidazol-2-yl)-6-(di-
tert-butylphosphinoxy)phenylpalladium(II) Chloride (X). With
CH2Cl2 as eluent; yellow solid (175.4 mg, 0.286 mmol, 52%); mp
20
1
157−158 °C. [α]D = +95° (c 0.100, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 7.48 (d, J = 7.3 Hz, 2H, Ph-H), 7.34 (t, J = 7.5 Hz, 2H, Ph-
H), 7.27−7.25 (m, 1H, Ph-H), 7.22 (d, J = 8.3 Hz, 2H, NAr-H), 7.17
(d, J = 8.3 Hz, 2H, NAr-H), 6.79 (d, J = 7.9 Hz, 1H, Ar-H), 6.72 (dt,
J = 0.8 and 8.0 Hz, 1H, Ar-H), 6.19 (d, J = 7.5 Hz, 1H, Ar-H), 5.50
(dd, J = 4.0 and 10.8 Hz, 1H, NCH), 4.44 (app t, J = 10.3 Hz, 1H,
NCHH), 3.95 (dd, J = 4.0 and 9.7 Hz, 1H, NCHH), 2.40 (s, 3H,
CH3), 1.45 (d, J = 4.4 Hz, 9H, C(CH3)3), 1.41 (d, J = 4.4 Hz, 9H,
C(CH3)3). 13C NMR (100 MHz, CDCl3): δ 170.5 (d, JCP = 2.8 Hz),
164.8 (d, JCP = 7.0 Hz), 151.3, 143.2, 138.1, 137.5, 135.5, 130.4, 128.5,
127.4, 126.8, 126.6, 124.9, 120.7, 113.6 (d, JCP = 14.5 Hz), 64.2 (d,
JCP = 3.0 Hz), 63.5 (d, JCP = 2.0 Hz), 39.4 (d, JCP = 16.3 Hz), 39.3 (d,
JCP = 16.9 Hz), 27.75 (d, JCP = 5.5 Hz), 27.69 (d, JCP = 5.4 Hz), 21.2.
31P{1H} NMR (162 MHz, CDCl3): δ 210.3. Anal. Calcd for
General Procedure for the Enantioselective Hydrophosphi-
nation of Enones with Diarylphosphines. A mixture of pincer Pd
catalyst (5 mol %) and KOAc (2.0 mg, 10 mol %) in toluene (2 mL)
was stirred for 30 min at 0 °C under a N2 atmosphere. Then diphenyl-
phosphine (37.2 mg, 0.2 mmol) was added, and stirring was continued
for another 30 min. After addition of enone (0.3 mmol), the resulting
mixture was stirred for an additional 12 h at 0 °C and then directly
oxidized with H2O2 aqueous solution (30%, 60 μL). After this mixture
was stirred at room temperature for 2 h, saturated Na2S2O3 aqueous
solution was added. The organic layer was separated and the aqueous
phase extracted with CH2Cl2. The combined organic phases were
dried (Na2SO4), and the volatiles were removed under reduced pres-
sure. Purification by column chromatography on silica gel provided the
chiral phosphine oxide products. For the reactions of 2-alkenoylpyr-
idine N-oxides, a mixture of CH2Cl2 and acetone (1/1) was used as
eluent. For the other enones, CH2Cl2/acetone (10/1) was used as
eluent unless otherwise stated.
C30H36ClN2OPPd: C, 58.74; H, 5.91; N, 4.57. Found: C, 58.71; H,
6.01; N, 4.35.
(S)-2-(1-(2,6-Diisopropylphenyl)-4-phenyl-4,5-dihydro-1H-imidazol-
2-yl)-6-(diphenylphosphinoxy)phenylpalladium(II) Chloride (XI).
With CH2Cl2 as eluent; yellow solid (111.4 mg, 0.154 mmol, 28%);
mp 276−277 °C. [α]D20 = +165° (c 0.100, CH2Cl2). 1H NMR (400 MHz,
CDCl3): δ 8.04−7.96 (m, 4H, PPh-H), 7.53 (d, J = 7.3 Hz, 2H, Ph-H),
7.46−7.35 (m, 9H, PPh-H, NAr-H and Ph-H), 7.30−7.22 (m, 3H, Ph-H
and NAr-H), 6.90 (d, J = 8.0 Hz, 1H, Ar-H), 6.71 (dt, J = 0.8 and 8.0 Hz,
1H, Ar-H), 5.82 (d, J = 7.7 Hz, 1H, Ar-H), 5.65 (dd, J = 4.8 and 11.3 Hz,
1H, NCH), 4.39 (app t, J = 10.7 Hz, 1H, NCHH), 3.83 (dd, J = 4.8 and
10.1 Hz, 1H, NCHH), 3.06−2.97 (m, 2H, CH(CH3)2), 1.24 (d, J =
6.8 Hz, 3H, CH(CH3)2), 1.05 (d, J = 6.8 Hz, 3H, CH(CH3)2), 0.99 (d, J =
6.9 Hz, 3H, CH(CH3)2), 0.91 (d, J = 6.8 Hz, 3H, CH(CH3)2). 13C NMR
(100 MHz, CDCl3): δ 171.5 (d, JCP = 2.9 Hz), 162.5 (d, JCP = 11.5 Hz),
(S)-3-(Diphenylphosphinyl)-1,3-diphenylpropan-1-one (7a).5b,12
White solid (81.3 mg, 99%). The enantiomeric excess was determined
on a Daicel Chiralcel OD-H column with hexane/2-propanol (85/15)
and flow rate 0.2 mL/min and detected at a UV wavelength of 228 nm.
Retention times: 30.5 min (major), 36.6 min, 92% ee. [α]D20 = −150°
1
(c 0.200, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.00−7.96 (m,
2H), 7.85 (d, JHH = 7.5 Hz, 2H), 7.53−7.43 (m, 6H), 7.40−7.33 (m,
5H), 7.25−7.22 (m, 2H), 7.17−7.10 (m, 3H), 4.47 (ddd, JHH = 9.8
and 2.1 Hz, JHP = 7.1 Hz, 1H, PCHCH2), 4.03 (ddd, JHH = 18.1 and
10.4 Hz, JHP = 4.3 Hz, 1H, PCHCHH), 3.38 (ddd, JHH = 18.1 and
2.1 Hz, JHP = 11.3 Hz, 1H, PCHCHH).
151.9, 147.9, 147.6, 143.5, 135.2, 134.0 (d, JCP = 51.8 Hz), 133.5 (d, JCP
=
(S)-3-(4-Bromophenyl)-3-(diphenylphosphinyl)-1-phenylpropan-
1-one (7b).5b,12 White solid (92.0 mg, 94%). The enantiomeric excess
was determined on a Daicel Chiralcel OD-H column with hexane/
2-propanol (95/5) and flow rate 0.5 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 27.9 min (major), 42.8 min,
91% ee. [α]D = −153° (c 0.200, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 7.99−7.94 (m, 2H), 7.83 (d, JHH = 7.8 Hz, 2H), 7.53−7.47
(m, 7H), 7.39 (app t, JHH = 7.8 Hz, 3H), 7.31−7.26 (m, 5H), 4.43
(app t, J = 7.7 Hz, 1H, PCHCH2), 3.96 (ddd, JHH = 18.0 and 10.4 Hz,
JHP = 4.0 Hz, 1H, PCHCHH), 3.35 (dd, J = 18.1 and 10.7 Hz, 1H,
PCHCHH).
53.2 Hz), 132.9, 131.8 (t, JCP = 2.9 Hz), 131.7 (d, JCP = 14.7 Hz), 131.6 (d,
JCP = 14.7 Hz), 130.0, 128.8 (d, JCP = 11.7 Hz), 128.7, 127.5, 126.4, 125.6,
125.1, 124.5, 120.7, 114.8 (d, JCP = 16.8 Hz), 64.0 (d, JCP = 2.6 Hz), 63.6
(d, JCP = 3.3 Hz), 28.32, 28.29, 25.3, 24.2, 23.9, 23.7. 31P{1H} NMR
(162 MHz, CDCl3): δ 154.9. Anal. Calcd for C39H38ClN2OPPd: C, 64.74;
H, 5.29; N, 3.87. Found: C, 64.78; H, 5.65; N, 3.69.
(S)-2-(1-Isopropyl-4-phenyl-4,5-dihydro-1H-imidazol-2-yl)-6-
(diphenylphosphinoxy)phenylpalladium(II) Chloride (XII). With
CH2Cl2 as eluent; white solid (109.9 mg, 0.182 mmol, 33%); mp
259−260 °C. [α]D20 = +222° (c 0.100, CH2Cl2). 1H NMR (400 MHz,
CDCl3): δ 8.01−7.91 (m, 4H, PPh-H), 7.47−7.40 (m, 8H, PPh-H and
Ph-H), 7.34−7.22 (m, 4H, Ph-H and Ar-H), 7.11 (t, J = 7.8 Hz, 1H,
Ar-H), 7.01 (d, J = 8.0 Hz, 1H, Ar-H), 5.37 (dd, J = 4.8 and 11.4 Hz,
1H, NCH), 4.75−4.68 (m, 1H, CH(CH3)2), 4.14 (app t, J = 10.7 Hz,
1H, NCHH), 3.65 (dd, J = 4.8 and 10.0 Hz, 1H, NCHH), 1.31 (d, J =
6.6 Hz, 3H, CH(CH3)2), 1.28 (d, J = 6.6 Hz, 3H, CH(CH3)2). 13C
20
1
(S)-3-(3-Bromophenyl)-3-(diphenylphosphinyl)-1-phenylpropan-
1-one (7c).5b White solid (95.9 mg, 98%). The enantiomeric excess
was determined on a Daicel Chiralcel OD-H column with hexane/
2-propanol (90/10) and flow rate 0.5 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 16.5 min (major), 20.8 min,
20
1
96% ee. [α]D = −156° (c 0.264, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 7.99−7.94 (m, 2H), 7.84 (d, JHH = 7.2 Hz, 2H), 7.53−7.45
(m, 7H), 7.41−7.24 (m, 6H), 7.23 (d, JHH = 7.2 Hz, 1H), 7.02 (t,
JHH = 7.9 Hz, 1H), 4.42 (ddd, JHH = 9.8 and 2.4 Hz, JHP = 7.0 Hz, 1H,
PCHCH2), 3.96 (ddd, JHH = 18.2 and 10.3 Hz, JHP = 4.4 Hz, 1H,
PCHCHH), 3.39 (ddd, JHH = 18.2 and 2.4 Hz, JHP = 11.2 Hz, 1H,
NMR (100 MHz, CDCl3): δ 171.3 (d, JCP = 2.7 Hz), 162.8 (d, JCP
11.8 Hz), 151.8, 143.7, 136.0, 134.0 (d, JCP = 51.4 Hz), 133.3 (d, JCP
=
=
53.4 Hz), 131.8, 131.7 (d, JCP = 14.8 Hz), 131.6 (d, JCP = 14.8 Hz),
128.8 (d, JCP = 11.7 Hz), 128.6, 127.4, 126.7, 126.2, 119.9, 114.7 (d,
JCP = 16.9 Hz), 62.7 (d, JCP = 2.2 Hz), 53.4 (d, JCP = 3.6 Hz), 46.7,
21.4, 20.2. 31P{1H} NMR (162 MHz, CDCl3): δ 154.6. Anal. Calcd for
C30H28ClN2OPPd: C, 59.52; H, 4.66; N, 4.63. Found: C, 59.49; H,
4.95; N, 4.50.
PCHCHH). 13C NMR (100 MHz, CDCl3): δ 196.3 (d, JCP
12.9 Hz), 138.4 (d, JCP = 5.5 Hz), 136.2, 133.5, 132.9 (d, JCP
=
=
5.8 Hz), 132.2 (d, JCP = 2.7 Hz), 131.7 (d, JCP = 2.7 Hz), 131.6 (d,
JCP = 25.0 Hz), 131.3 (d, JCP = 8.5 Hz), 130.9 (d, JCP = 8.9 Hz), 130.6
(d, JCP = 19.8 Hz), 130.2 (d, JCP = 2.5 Hz), 129.8 (d, JCP = 1.8 Hz),
(S,S)-2-(4,5-Diphenyl-1-(p-tolyl)-4,5-dihydro-1H-imidazol-2-yl)-6-
(diphenylphosphinoxy)phenylpalladium(II) Chloride (XIII). With
K
dx.doi.org/10.1021/jo5015307 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
129.0 (d, JCP = 11.2 Hz), 128.6, 128.4, 128.3 (d, JCP = 12.0 Hz), 128.1,
122.2 (d, JCP = 2.2 Hz), 40.9 (d, JCP = 67.9 Hz), 38.9. 31P{1H} NMR
(162 MHz, CDCl3): δ 33.9.
CDCl3): δ 7.99−7.94 (m, 2H), 7.84 (d, JHH = 7.4 Hz, 2H), 7.52−7.47
(m, 6H), 7.39−7.33 (m, 3H), 7.28−7.25 (m, 4H), 6.95 (d, JHH
=
7.9 Hz, 2H), 4.45 (ddd, JHH = 9.9 and 2.3 Hz, JHP = 7.0 Hz, 1H,
PCHCH2), 3.99 (ddd, JHH = 18.1 and 10.5 Hz, JHP = 4.3 Hz, 1H,
PCHCHH), 3.36 (ddd, JHH = 18.1 and 2.3 Hz, JHP = 11.2 Hz, 1H,
PCHCHH), 2.20 (s, 3H, CH3).
(S)-3-(Diphenylphosphinyl)-3-(4-fluorophenyl)-1-phenylpropan-
1-one (7d). White solid (78.8 mg, 92%); mp 245−246 °C. The enan-
tiomeric excess was determined on a Daicel Chiralcel OD-H column
with hexane/2-propanol (90/10) and flow rate 0.4 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 16.0 min
(S)-3-(Diphenylphosphinyl)-3-(4-methoxyphenyl)-1-phenylpropan-
1-one (7h). White solid (81.1 mg, 92%); mp 227−228 °C. The enan-
tiomeric excess was determined on a Daicel Chiralpak AD-H column
with hexane/2-propanol (60/40) and flow rate 1.0 mL/min and de-
tected at a UV wavelength of 228 nm. Retention times: 21.3 min
20
1
(major), 20.7 min, 92% ee. [α]D = −147° (c 0.270, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 8.00−7.95 (m, 2H), 7.83 (d, JHH
=
7.3 Hz, 2H), 7.54−7.45 (m, 6H), 7.40−7.34 (m, 5H), 7.29−7.25 (m,
20
1
(major), 30.5 min, 86% ee. [α]D = −127° (c 0.252, CH2Cl2). H
2H), 6.84 (t, JHH = 8.7 Hz, 2H), 4.45 (ddd, JHH = 10.1 and 2.3 Hz,
NMR (400 MHz, CDCl3): δ 8.00−7.94 (m, 2H), 7.83 (d, JHH
7.2 Hz, 2H), 7.52−7.46 (m, 6H), 7.38−7.24 (m, 7H), 6.69 (d, JHH
=
=
JHP = 6.8 Hz, 1H, PCHCH2), 3.97 (ddd, JHH = 18.1 and 10.5 Hz, JHP
4.3 Hz, 1H, PCHCHH), 3.36 (ddd, JHH = 18.1 and 2.4 Hz, JHP
=
=
10.8 Hz, 1H, PCHCHH). 13C NMR (100 MHz, CDCl3): δ 196.6 (d,
JCP = 13.4 Hz), 161.9 (dd, JCP = 2.8 Hz, JCF = 244 Hz), 136.3, 133.5,
132.1 (d, JCP = 2.7 Hz), 131.9 (d, JCP = 33.6 Hz), 131.7 (dd, JCP = 6.4
Hz, JCF = 3.3 Hz), 131.6 (d, JCP = 2.6 Hz), 131.4 (dd, JCP = 5.8 Hz,
JCF = 7.9 Hz), 131.2 (d, JCP = 8.6 Hz), 130.91 (d, JCP = 28.0 Hz),
130.88 (d, JCP = 9.0 Hz), 129.0 (d, JCP = 11.1 Hz), 128.6, 128.2 (d,
JCP = 11.7 Hz), 128.1, 115.2 (dd, JCP = 1.6 Hz, JCF = 21.3 Hz), 40.3 (d,
JCP = 69.0 Hz), 39.1. 31P{1H} NMR (162 MHz, CDCl3): δ 34.1.
HRMS (positive ESI): [M + H]+ calcd for C27H23FO2P 429.1420,
found 429.1416.
8.6 Hz, 2H), 4.43 (ddd, JHH = 10.0 and 2.3 Hz, JHP = 7.0 Hz, 1H,
PCHCH2), 3.97 (ddd, JHH = 18.0 and 10.5 Hz, JHP = 4.3 Hz, 1H,
PCHCHH), 3.68 (s, 3H, OCH3), 3.34 (ddd, JHH = 18.0 and 2.4 Hz,
JHP = 10.9 Hz, 1H, PCHCHH). 13C NMR (100 MHz, CDCl3): δ
196.8 (d, JCP = 13.4 Hz), 158.6 (d, JCP = 2.2 Hz), 136.5, 133.3, 132.2
(d, JCP = 23.5 Hz), 132.0 (d, JCP = 2.5 Hz), 131.4 (d, JCP = 2.7 Hz),
131.28 (d, JCP = 8.3 Hz), 131.26 (d, JCP = 16.7 Hz), 131.0 (d, JCP
=
8.9 Hz), 130.9 (d, JCP = 5.8 Hz), 128.9 (d, JCP = 11.3 Hz), 128.5,
128.11 (d, JCP = 11.7 Hz), 128.10, 127.8 (d, JCP = 5.6 Hz), 113.8
(d, JCP = 1.8 Hz), 55.1, 40.2 (d, JCP = 69.7 Hz), 39.1. 31P{1H} NMR
(162 MHz, CDCl3): δ 34.3. HRMS (positive ESI): [M + H]+ calcd for
C28H26O3P: 441.1620, found 441.1620.
(S)-3-(Diphenylphosphinyl)-3-(naphthalen-1-yl)-1-phenylpropan-
1-one (7i).21 White solid (91.2 mg, 99%); mp 225−226 °C. The
enantiomeric excess was determined on a Daicel Chiralpak AD-H
column with hexane/2-propanol (70/30) and flow rate 1.0 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 19.2 min
(major), 23.7 min, 81% ee. [α]D20 = −179° (c 0.218, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 8.40 (s, 1H), 8.05−8.00 (m, 2H), 7.91−7.87 (m,
2H), 7.81−7.77 (m, 2H), 7.58−7.42 (m, 9H), 7.36−7.32 (m, 1H),
7.27−7.23 (m, 2H), 7.17−7.07 (m, 3H), 4.53 (ddd, JHH = 9.8 and
2.3 Hz, JHP = 6.7 Hz, 1H, PCHCH2), 4.19 (ddd, JHH = 17.9 and
10.4 Hz, JHP = 4.4 Hz, 1H, PCHCHH), 3.52 (ddd, JHH = 17.9 and
2.4 Hz, JHP = 11.1 Hz, 1H, PCHCHH).
(S)-3-(Diphenylphosphinyl)-3-(4-nitrophenyl)-1-phenylpropan-1-
one (7e).5b,12 White solid (90.2 mg, 99%). The enantiomeric excess
was determined on a Daicel Chiralcel OD-H column with hexane/
2-propanol (70/30) and flow rate 0.3 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 21.6 min (major), 33.5 min,
20
1
95% ee. [α]D = −254° (c 0.200, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 8.02−7.97 (m, 4H), 7.84 (d, JHH = 7.8 Hz, 2H), 7.60−7.48
(m, 8H), 7.42−7.36 (m, 3H), 7.32−7.29 (m, 2H), 4.57 (ddd, JHH = 9.7
and 2.2 Hz, JHP = 6.7 Hz, 1H, PCHCH2), 4.03 (ddd, JHH = 18.4 and
10.6 Hz, JHP = 4.3 Hz, 1H, PCHCHH), 3.43 (ddd, JHH = 18.4 and
2.2 Hz, JHP = 10.5 Hz, 1H, PCHCHH).
(S)-3-(Diphenylphosphino)-3-(4-nitrophenyl)-1-phenylpropan-1-
one.5a,d According to the general procedure, the reaction was stirred at
0 °C for 12 h, and then the solvent was removed under vacuum. The
residue was directly purified by column chromatography on silica gel
in a glovebox under nitrogen with petroleum ether/EtOAc (5/1) as
eluent to afford the trivalent phosphine as the product. White solid
(S)-3-(Diphenylphosphinyl)-3-(furan-2-yl)-1-phenylpropan-1-one
(7j). White solid (47.2 mg, 59%); mp 194−195 °C. The enantiomeric
excess was determined on a Daicel Chiralpak AD-H column with
hexane/2-propanol (70/30) and flow rate 0.9 mL/min and detected at
a UV wavelength of 228 nm. Retention times: 17.7 min (major),
1
(70.3 mg, 80%). H NMR (300 MHz, CDCl3): δ 7.98 (d, JHH = 8.5
Hz, 2H), 7.78 (d, JHH = 7.7 Hz, 2H), 7.71−7.66 (m, 2H), 7.54−7.49
(m, 1H), 7.43−7.31 (m, 7H), 7.21−7.14 (m, 5H), 4.48−4.42 (m, 1H,
PCHCH2), 3.73 (ddd, JHH = 17.6 and 11.2 Hz, JHP = 4.2 Hz, 1H,
PCHCHH), 3.27 (ddd, JHH = 17.6 and 2.5 Hz, JHP = 7.6 Hz, 1H,
PCHCHH). 13C NMR (75 MHz, CDCl3): δ 197.1 (d, JCP = 12.5 Hz),
149.2 (d, JCP = 8.2 Hz), 146.3 (d, JCP = 2.6 Hz), 135.68 (d, JCP = 109.6
Hz), 135.65 (d, JCP = 109.9 Hz), 135.1, 133.7 (d, JCP = 20.5 Hz), 133.3
(d, JCP = 19.3 Hz), 129.9, 129.7 (d, JCP = 7.2 Hz), 129.3, 129.0 (d,
JCP = 7.5 Hz), 128.6, 128.3 (d, JCP = 7.3 Hz), 127.9, 123.4, 41.8 (d,
JCP = 21.4 Hz), 40.0 (d, JCP = 13.3 Hz). 31P{1H} NMR (121 MHz,
CDCl3): δ 0.8.
20
29.3 min, 82% ee. [α]D = −72° (c 0.124, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 7.92−7.87 (m, 4H), 7.60−7.45 (m, 7H), 7.42−
7.35 (m, 4H), 7.16 (s, 1H), 6.16−6.15 (m, 1H), 6.08−6.06 (m, 1H),
4.73 (ddd, JHH = 10.4 and 2.6 Hz, JHP = 7.8 Hz, 1H, PCHCH2), 3.94
(ddd, JHH = 18.0 and 10.7 Hz, JHP = 4.6 Hz, 1H, PCHCHH), 3.42
(ddd, JHH = 18.0 and 2.7 Hz, JHP = 10.0 Hz, 1H, PCHCHH). 13C
NMR (100 MHz, CDCl3): δ 196.4 (d, JCP = 12.4 Hz), 149.0 (d, JCP
6.7 Hz), 141.8 (d, JCP = 2.9 Hz), 136.2, 133.4, 132.2 (d, JCP = 2.7 Hz),
131.9 (d, JCP = 2.6 Hz), 131.4 (d, JCP = 26.3 Hz), 131.32 (d, JCP
=
=
8.8 Hz), 131.28 (d, JCP = 9.2 Hz), 130.4 (d, JCP = 29.4 Hz), 128.9
(d, JCP = 11.6 Hz), 128.6, 128.3 (d, JCP = 11.8 Hz), 128.2, 110.7 (d,
JCP = 2.7 Hz), 108.8 (d, JCP = 5.9 Hz), 36.5, 35.9 (d, JCP = 70.2 Hz).
31P{1H} NMR (162 MHz, CDCl3): δ 32.8. HRMS (positive ESI):
(S)-3-(Diphenylphosphinyl)-3-(3-nitrophenyl)-1-phenylpropan-1-
one (7f).21 White solid (88.4 mg, 97%); mp 248−249 °C. The enan-
tiomeric excess was determined on a Daicel Chiralpak AD-H column
with hexane/2-propanol (70/30) and flow rate 1.0 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 15.8 min
[M + H]+ calcd for C25H22O3P 401.1307, found 401.1303.
(S)-3-(Diphenylphosphinyl)-1-phenyl-3-(thien-2-yl)propan-1-one
(7k). Pale yellow solid (67.0 mg, 80%); mp 219−220 °C. The enan-
tiomeric excess was determined on a Daicel Chiralcel OD-H column
with hexane/2-propanol (90/10) and flow rate 1.0 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 9.5 min
20
1
(major), 28.1 min, 90% ee. [α]D = −185° (c 0.270, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 8.17 (d, JHH = 1.7 Hz, 1H), 8.02−7.95
(m, 3H), 7.86−7.79 (m, 3H), 7.57−7.48 (m, 6H), 7.42−7.28 (m, 6H),
4.58 (ddd, JHH = 10.1 and 2.2 Hz, JHP = 6.9 Hz, 1H, PCHCH2), 4.05
(ddd, JHH = 18.4 and 10.7 Hz, JHP = 4.3 Hz, 1H, PCHCHH), 3.44
(ddd, JHH = 18.4 and 2.3 Hz, JHP = 10.5 Hz, 1H, PCHCHH).
(S)-3-(Diphenylphosphinyl)-1-phenyl-3-(p-tolyl)propan-1-one
(7g).5b,12 White solid (83.2 mg, 98%). The enantiomeric excess was
determined on a Daicel Chiralcel OD-H column with hexane/
2-propanol (85/15) and flow rate 0.2 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 29.1 min (major), 41.3 min,
20
1
(major), 12.0 min, 88% ee. [α]D = −121° (c 0.139, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 7.98−7.93 (m, 2H), 7.87−7.85 (m, 2H),
7.61−7.49 (m, 6H), 7.41−7.32 (m, 5H), 7.04−7.00 (m, 2H), 6.79 (dd,
JHH = 3.6 and 5.0 Hz, 1H), 4.83 (ddd, JHH = 10.1 and 2.3 Hz, JHP
7.6 Hz, 1H, PCHCH2), 3.97 (ddd, JHH = 18.0 and 10.4 Hz, JHP
4.2 Hz, 1H, PCHCHH), 3.35 (ddd, JHH = 18.0 and 2.4 Hz, JHP
=
=
=
10.3 Hz, 1H, PCHCHH). 13C NMR (100 MHz, CDCl3): δ 196.4
(d, JCP = 12.6 Hz), 137.6 (d, JCP = 6.4 Hz), 136.3, 133.5, 132.2
20
1
94% ee. [α]D = −151° (c 0.200, CH2Cl2). H NMR (400 MHz,
L
dx.doi.org/10.1021/jo5015307 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
(d, JCP = 2.5 Hz), 131.7 (d, JCP = 2.7 Hz), 131.5 (d, JCP = 19.3 Hz),
7.40−7.36 (m, 1H), 7.31−7.28 (m, 2H), 4.34 (ddd, JHH = 10.0 and
2.7 Hz, JHP = 6.9 Hz, 1H, PCHCH2), 3.35 (ddd, JHH = 18.5 and
10.4 Hz, JHP = 4.8 Hz, 1H, PCHCHH), 2.99 (ddd, JHH = 18.5 and
2.7 Hz, JHP = 10.8 Hz, 1H, PCHCHH), 2.00 (s, 3H, COCH3).
(S)-4-(Diphenylphosphinyl)-4-(3-nitrophenyl)butan-2-one (7q).12
White solid (77.1 mg, 98%). The enantiomeric excess was determined
on a Daicel Chiralpak AD-H column with hexane/2-propanol (70/30)
and flow rate 0.5 mL/min and detected at a UV wavelength of 228 nm.
131.3 (d, JCP = 8.5 Hz), 131.1 (d, JCP = 8.8 Hz), 130.6 (d, JCP
=
13.0 Hz), 129.0 (d, JCP = 11.3 Hz), 128.6, 128.24 (d, JCP = 11.6 Hz),
128.19, 127.4 (d, JCP = 6.5 Hz), 126.8 (d, JCP = 2.3 Hz), 124.9 (d, JCP
=
2.7 Hz), 39.9, 36.5 (d, JCP = 70.5 Hz). 31P{1H} NMR (162 MHz,
CDCl3): δ 33.3. HRMS (positive ESI): [M + H]+ calcd for
C25H22O2PS 417.1078, found 417.1077.
(S)-3-(Diphenylphosphinyl)-3-(2-methoxyphenyl)-1-phenylpropan-
1-one (7l).5b,12 Colorless oil (87.7 mg, >99%). The enantiomeric
excess was determined on a Daicel Chiralcel OD-H column with
hexane/2-propanol (95/5) and flow rate 0.6 mL/min and detected at a
UV wavelength of 228 nm. Retention times: 31.1 min (major), 40.4 min,
Retention times: 24.0 min (major), 45.7 min, 96% ee. [α]D20 = −180°
1
(c 0.200, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.06 (d, JHH
=
1.9 Hz, 1H), 7.99−7.96 (m, 3H), 7.71 (d, JHH = 7.0 Hz, 1H), 7.62−
7.55 (m, 3H), 7.49−7.44 (m, 2H), 7.36 (app t, JHH = 8.0 Hz, 2H),
7.29−7.24 (m, 2H), 4.33 (ddd, JHH = 10.2 and 2.8 Hz, JHP = 7.2 Hz,
1H, PCHCH2), 3.35 (ddd, JHH = 18.6 and 10.2 Hz, JHP = 5.0 Hz, 1H,
PCHCHH), 2.99 (ddd, JHH = 18.6 and 2.8 Hz, JHP = 10.7 Hz, 1H,
PCHCHH), 2.00 (s, 3H, COCH3).
20
54% ee. [α]D = −65° (c 1.300, CH2Cl2). 1H NMR (400 MHz,
CDCl3): δ 8.05−8.00 (m, 2H), 7.86 (d, JHH = 7.5 Hz, 2H), 7.63 (d,
JHH = 7.6 Hz, 1H), 7.56−7.50 (m, 3H), 7.48−7.29 (m, 7H), 7.21−7.16
(m, 2H), 6.89 (app t, JHH = 7.4 Hz, 1H), 6.53 (d, JHH = 8.2 Hz, 1H),
5.16 (ddd, JHH = 10.1 and 2.5 Hz, JHP = 7.3 Hz, 1H, PCHCH2), 4.08
(ddd, JHH = 17.2 and 10.5 Hz, JHP = 5.4 Hz, 1H, PCHCHH), 3.46 (s,
3H, OCH3), 3.40 (ddd, JHH = 18.0 and 2.5 Hz, JHP = 10.1 Hz, 1H,
PCHCHH).
(S)-4-(Diphenylphosphinyl)-4-(p-tolyl)butan-2-one (7r). White
solid (68.1 mg, 94%); mp 194−195 °C. The enantiomeric excess
was determined on a Daicel Chiralcel OD-H column with hexane/
2-propanol (90/10) and flow rate 0.8 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 10.3 min (major), 12.9 min,
(S)-3-(Diphenylphosphinyl)-1-phenyl-3-(o-tolyl)propan-1-one
(7m). Colorless oil (69.6 mg, 82%). The enantiomeric excess was
determined on a Daicel Chiralcel OD-H column with hexane/
2-propanol (85/15) and flow rate 0.3 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 19.8 min (major), 28.9 min,
20
1
93% ee. [α]D = −106° (c 0.168, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 7.91 (t, JHH = 8.7 Hz, 2H), 7.55−7.46 (m, 5H), 7.33 (d,
JHH = 7.4 Hz, 1H), 7.27−7.23 (m, 2H), 7.17 (d, JHH = 6.9 Hz, 2H),
6.96 (d, JHH = 7.7 Hz, 2H), 4.19 (ddd, JHH = 10.0 and 2.6 Hz, JHP
7.4 Hz, 1H, PCHCH2), 3.29 (ddd, JHH = 17.7 and 10.2 Hz, JHP
5.2 Hz, 1H, PCHCHH), 2.91 (ddd, JHH = 17.8 and 2.6 Hz, JHP
=
=
=
20
1
63% ee. [α]D = −139° (c 0.302, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 8.03−7.98 (m, 2H), 7.84 (d, JHH = 7.2 Hz, 2H), 7.78 (d,
JHH = 7.6 Hz, 1H), 7.59−7.53 (m, 3H), 7.48 (t, JHH = 7.4 Hz, 1H),
7.38−7.31 (m, 3H), 7.24−7.14 (m, 5H), 7.05 (t, JHH = 7.5 Hz, 1H),
6.90 (d, JHH = 7.5 Hz, 1H), 4.68 (ddd, JHH = 9.8 and 2.3 Hz, JHP = 7.2
Hz, 1H, PCHCH2), 4.08 (ddd, JHH = 18.2 and 10.3 Hz, JHP = 4.4 Hz,
1H, PCHCHH), 3.40 (ddd, JHH = 18.2 and 2.3 Hz, JHP = 11.1 Hz, 1H,
PCHCHH), 2.06 (s, 3H, CH3). 13C NMR (100 MHz, CDCl3): δ
11.1 Hz, 1H, PCHCHH), 2.22 (s, 3H, CH3), 1.94 (s, 3H, COCH3).
13C NMR (100 MHz, CDCl3): δ 205.5 (d, JCP = 13.0 Hz), 136.7 (d,
JCP = 2.2 Hz), 132.5 (d, JCP = 5.9 Hz), 132.0 (d, JCP = 2.4 Hz), 131.4
(d, JCP = 2.6 Hz), 131.3 (d, JCP = 8.6 Hz), 131.0 (d, JCP = 8.8 Hz),
130.7 (d, JCP = 11.5 Hz), 129.6 (d, JCP = 5.6 Hz), 129.1, 128.92 (d,
JCP = 13.0 Hz), 128.86 (d, JCP = 11.2 Hz), 128.1 (d, JCP = 11.7 Hz),
43.6, 40.6 (d, JCP = 68.7 Hz), 30.6, 21.0. 31P{1H} NMR (162 MHz,
CDCl3): δ 33.8. HRMS (positive ESI): [M + H]+ calcd for C23H24O2P
363.1514, found 363.1511.
196.9 (d, JCP = 13.5 Hz), 137.4 (d, JCP = 6.2 Hz), 136.3, 134.3 (d, JCP
5.8 Hz), 133.4, 132.30, 132.27 (d, JCP = 2.6 Hz), 131.7 (d, JCP
=
=
8.3 Hz), 131.6 (d, JCP = 2.8 Hz), 131.3, 131.0 (d, JCP = 9.4 Hz), 130.1,
129.0 (d, JCP = 11.2 Hz), 128.8, 128.6, 128.1, 127.8 (d, JCP = 11.7 Hz),
(S)-4-(Diphenylphosphinyl)-4-(4-fluorophenyl)butan-2-one (7s).
White solid (65.9 mg, 90%); mp 210−211 °C. The enantiomeric
excess was determined on a Daicel Chiralcel OD-H column with
hexane/2-propanol (90/10) and flow rate 0.8 mL/min and detected at a
UV wavelength of 228 nm. Retention times: 10.6 min (major), 12.8 min,
127.1 (d, JCP = 2.4 Hz), 126.2 (d, JCP = 2.5 Hz), 39.8, 36.1 (d, JCP
=
68.3 Hz), 19.7. 31P{1H} NMR (162 MHz, CDCl3): δ 34.9. HRMS
(positive ESI): [M + H]+ calcd for C28H26O2P 425.1670, found 425.1669.
(S)-4-(Diphenylphosphinyl)-4-phenylbutan-2-one (7n).12 White
solid (69.0 mg, 99%). The enantiomeric excess was determined on a
Daicel Chiralpak AD-H column with hexane/2-propanol (70/30) and
flow rate 0.5 mL/min and detected at a UV wavelength of 228 nm.
Retention times: 20.6 min (major), 32.7 min, 97% ee. [α]D20 = −146°
20
93% ee. [α]D = −131° (c 0.222, CH2Cl2). 1H NMR (400 MHz,
CDCl3): δ 7.95−7.90 (m, 2H), 7.59−7.51 (m, 3H), 7.47−7.42 (m, 2H),
7.37−7.24 (m, 5H), 6.86 (t, JHH = 8.6 Hz, 2H), 4.21 (ddd, JHH = 10.1
and 2.8 Hz, JHP = 7.1 Hz, 1H, PCHCH2), 3.28 (ddd, JHH = 18.0 and
10.3 Hz, JHP = 5.1 Hz, 1H, PCHCHH), 2.91 (ddd, JHH = 18.1 and
2.8 Hz, JHP = 10.9 Hz, 1H, PCHCHH), 1.96 (s, 3H, COCH3). 13C
1
(c 0.200, CH2Cl2). H NMR (400 MHz, CDCl3): δ 7.96−7.91 (m,
2H), 7.57−7.50 (m, 3H), 7.45−7.41 (m, 2H), 7.36−7.22 (m, 5H),
7.18−7.13 (m, 3H), 4.22 (ddd, JHH = 10.2 and 2.8 Hz, JHP = 7.2 Hz,
1H, PCHCH2), 3.34 (ddd, JHH = 17.9 and 10.2 Hz, JHP = 5.3 Hz, 1H,
PCHCHH), 2.94 (ddd, JHH = 17.9 and 2.8 Hz, JHP = 11.2 Hz, 1H,
PCHCHH), 1.96 (s, 3H, COCH3).
NMR (100 MHz, CDCl3): δ 205.2 (d, JCP = 12.7 Hz), 161.9 (dd, JCP
2.4 Hz, JCF = 244 Hz), 132.1 (d, JCP = 2.7 Hz), 131.8 (d, JCP = 19.2 Hz),
131.65 (t, JCP = 2.6 Hz), 131.56 (d, JCP = 2.8 Hz), 131.232 (dd, JCP
5.4 Hz, JCF = 7.9 Hz), 131.229 (d, JCP = 8.5 Hz), 130.9 (d, JCP = 8.8 Hz),
=
=
(S)-4-(4-Bromophenyl)-4-(diphenylphosphinyl)butan-2-one
(7o).5b,12 White solid (76.9 mg, 90%). The enantiomeric excess was
determined on a Daicel Chiralpak AD-H column with hexane/
2-propanol (70/30) and flow rate 1.0 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 12.7 min (major), 33.6 min,
130.8 (d, JCP = 13.3 Hz), 129.0 (d, JCP = 11.3 Hz), 128.2 (d, JCP
=
=
11.7 Hz), 115.3 (dd, JCP = 1.8 Hz, JCF = 21.5 Hz), 43.7, 40.2 (d, JCP
68.7 Hz), 30.6. 31P{1H} NMR (162 MHz, CDCl3): δ 33.5. HRMS
(positive ESI): [M + H]+ calcd for C22H21FO2P 367.1263, found
367.1265.
20
1
96% ee. [α]D = −164° (c 0.200, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 7.94−7.89 (m, 2H), 7.58−7.51 (m, 3H), 7.49−7.44 (m,
2H), 7.39−7.35 (m, 1H), 7.30−7.26 (m, 4H), 7.21−7.18 (m, 2H),
4.18 (ddd, JHH = 10.0 and 2.7 Hz, JHP = 7.0 Hz, 1H, PCHCH2), 3.27
(ddd, JHH = 18.1 and 10.2 Hz, JHP = 5.0 Hz, 1H, PCHCHH), 2.91
(ddd, JHH = 18.2 and 2.7 Hz, JHP = 10.9 Hz, 1H, PCHCHH), 1.97 (s,
3H, COCH3).
(S)-4-(4-Chlorophenyl)-4-(diphenylphosphinyl)butan-2-one
(7t).12 White solid (74.3 mg, 97%). The enantiomeric excess was
determined on a Daicel Chiralpak AD-H column with hexane/
2-propanol (70/30) and flow rate 1.0 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 11.1 min (major), 30.8 min,
97% ee. [α]D = −160° (c 0.200, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 7.94−7.89 (m, 2H), 7.59−7.51 (m, 3H), 7.49−7.44 (m,
2H), 7.39−7.35 (m, 1H), 7.30−7.24 (m, 4H), 7.14 (d, JHH = 8.4 Hz,
2H), 4.19 (ddd, JHH = 10.0 and 2.8 Hz, JHP = 7.0 Hz, 1H, PCHCH2),
3.28 (ddd, JHH = 18.1 and 10.3 Hz, JHP = 5.0 Hz, 1H, PCHCHH), 2.91
(ddd, JHH = 18.1 and 2.8 Hz, JHP = 10.9 Hz, 1H, PCHCHH), 1.97 (s,
3H, COCH3).
20
1
(S)-4-(Diphenylphosphinyl)-4-(4-nitrophenyl)butan-2-one (7p).12
White solid (71.6 mg, 91%). The enantiomeric excess was determined
on a Daicel Chiralcel OD-H column with hexane/2-propanol (70/30)
and flow rate 0.4 mL/min and detected at a UV wavelength of 228 nm.
Retention times: 16.6 min (major), 23.5 min, 97% ee. [α]D20 = −210°
(c 0.200, CH2Cl2). 1H NMR (400 MHz, CDCl3): δ 8.03 (d, JHH = 8.7 Hz,
2H), 7.96−7.91 (m, 2H), 7.61−7.54 (m, 3H), 7.52−7.45 (m, 4H),
(S)-4-(Diphenylphosphinyl)-4-(4-methoxyphenyl)butan-2-one
(7u). White solid (49.9 mg, 66%); mp 184−185 °C. The enantiomeric
M
dx.doi.org/10.1021/jo5015307 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
excess was determined on a Daicel Chiralcel OD-H column with
hexane/2-propanol (90/10) and flow rate 0.6 mL/min and detected at
a UV wavelength of 228 nm. Retention times: 19.2 min (major), 24.2 min,
3.32 (ddd, JHH = 18.0 and 2.4 Hz, JHP = 11.1 Hz, 1H, PCHCHH). 13
C
NMR (100 MHz, CDCl3): δ 194.7 (d, JCP = 13.0 Hz), 163.8, 138.5 (d,
JCP = 5.6 Hz), 132.8 (d, JCP = 5.8 Hz), 132.2 (d, JCP = 2.6 Hz), 131.69
(d, JCP = 28.3 Hz), 131.66 (d, JCP = 2.6 Hz), 131.3 (d, JCP = 8.4 Hz),
130.9 (d, JCP = 8.9 Hz), 130.6, 130.4, 130.2 (d, JCP = 2.4 Hz), 129.7 (d,
20
96% ee. [α]D = −111° (c 0.248, CH2Cl2). 1H NMR (400 MHz,
CDCl3): δ 7.94−7.89 (m, 2H), 7.53−7.43 (m, 5H), 7.35−7.32 (m, 1H),
7.27−7.21 (m, 4H), 6.70 (d, JHH = 8.6 Hz, 2H), 4.18 (ddd, JHH = 10.1 and
2.7 Hz, JHP = 7.3 Hz, 1H, PCHCH2), 3.70 (s, 3H, OCH3), 3.28 (ddd,
J
CP = 1.8 Hz), 129.3, 129.0 (d, JCP = 11.4 Hz), 128.4 (d, JCP = 5.7 Hz),
128.2 (d, JCP = 11.8 Hz), 122.2 (d, JCP = 2.2 Hz), 113.7, 55.5, 40.9 (d,
JCP = 68.0 Hz), 38.4. 31P{1H} NMR (162 MHz, CDCl3): δ 34.1.
HRMS (positive ESI): [M + H]+ calcd for C28H25BrO3P 519.0725,
found 519.0723.
JHH = 17.7 and 10.4 Hz, JHP = 5.3 Hz, 1H, PCHCHH), 2.90 (ddd, JHH
17.8 and 2.7 Hz, JHP = 10.8 Hz, 1H, PCHCHH), 1.94 (s, 3H, COCH3).
13C NMR (100 MHz, CDCl3): δ 205.6 (d, JCP = 13.0 Hz), 158.6 (d, JCP
=
=
(S)-3-(4-Bromophenyl)-3-(diphenylphosphinyl)-1-(4-
methoxyphenyl)propan-1-one (7z).21 White solid (24.9 mg, 24%);
mp 245−246 °C. The enantiomeric excess was determined on a Daicel
Chiralcel OD-H column with hexane/2-propanol (90/10) and flow
rate 0.5 mL/min and detected at a UV wavelength of 228 nm.
Retention times: 23.7 min (major), 32.8 min, 90% ee. [α]D20 = −161°
2.3 Hz), 132.0 (d, JCP = 2.8 Hz), 131.9, 131.4 (d, JCP = 2.7 Hz), 131.3 (d,
JCP = 8.4 Hz), 131.0 (d, JCP = 8.8 Hz), 130.7 (d, JCP = 5.7 Hz), 128.9 (d,
JCP = 11.2 Hz), 128.1 (d, JCP = 11.7 Hz), 127.6 (d, JCP = 5.6 Hz), 113.8
(d, JCP = 1.4 Hz), 55.1, 43.6, 40.2 (d, JCP = 69.2 Hz), 30.7. 31P{1H} NMR
(162 MHz, CDCl3): δ 33.9. HRMS (positive ESI): [M + H]+ calcd for
C23H24O3P 379.1463, found 379.1465.
1
(c 0.122, CH2Cl2). H NMR (400 MHz, CDCl3): δ 7.99−7.94 (m,
(S)-3-(Diphenylphosphinyl)-1-(4-methoxyphenyl)-3-phenylpropan-
1-one (7v).5b White solid (87.7 mg, >99%). The enantiomeric excess
was determined on a Daicel Chiralpak AD-H column with hexane/
2-propanol (60/40) and flow rate 0.7 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 26.0 min (major), 36.7 min, 95%
2H), 7.82 (d, JHH = 8.9 Hz, 2H), 7.53−7.52 (m, 5H), 7.39−7.35 (m,
1H), 7.30−7.26 (m, 6H), 6.84 (d, JHH = 8.9 Hz, 2H), 4.44 (ddd, JHH
=
9.1 and 2.2 Hz, JHP = 6.6 Hz, 1H, PCHCH2), 3.92 (ddd, JHH = 17.9
and 10.6 Hz, JHP = 4.2 Hz, 1H, PCHCHH), 3.81 (s, 3H, OCH3), 3.28
(ddd, JHH = 17.9 and 2.2 Hz, JHP = 10.8 Hz, 1H, PCHCHH).
(S)-3-(Diphenylphosphinyl)-3-(4-fluorophenyl)-1-(4-
methoxyphenyl)propan-1-one (7aa). White solid (83.4 mg, 91%
yield); mp 240−241 °C. The enantiomeric excess was determined on a
Daicel Chiralcel OD-H column with hexane/2-propanol (90/10) and
flow rate 0.5 mL/min and detected at a UV wavelength of 228 nm.
Retention times: 23.4 min (major), 29.2 min, 90% ee. [α]D20 = −128°
ee. [α]D20 = −154° (c 0.200, CH2Cl2). H NMR (400 MHz, CDCl3): δ
1
8.01−7.96 (m, 2H), 7.83 (d, JHH = 8.9 Hz, 2H), 7.53−7.31 (m, 8H),
7.26−7.07 (m, 5H), 6.84 (d, JHH = 8.9 Hz, 2H), 4.47 (ddd, JHH = 9.9 and
2.3 Hz, JHP = 6.8 Hz, 1H, PCHCH2), 3.98 (ddd, JHH = 17.9 and 10.4 Hz,
JHP = 4.3 Hz, 1H, PCHCHH), 3.81 (s, 3H, OCH3), 3.32 (ddd, JHH = 17.9
and 2.3 Hz, JHP = 11.3 Hz, 1H, PCHCHH).
(S)-3-(Diphenylphosphinyl)-1-(4-methoxyphenyl)-3-(4-
nitrophenyl)propan-1-one (7w).12 White solid (96.6 mg, >99%). The
enantiomeric excess was determined on a Daicel Chiralcel OD-H
column with hexane/2-propanol (70/30) and flow rate 0.6 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 13.9 min
(major), 20.7 min, 94% ee. [α]D20 = −245° (c 0.200, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 8.02−7.97 (m, 4H), 7.82 (d, JHH = 8.8 Hz, 2H),
7.58−7.47 (m, 7H), 7.40−7.36 (m, 1H), 7.31−7.27 (m, 2H), 6.86 (d,
JHH = 8.8 Hz, 2H), 4.57 (ddd, JHH = 10.6 and 2.0 Hz, JHP = 6.9 Hz, 1H,
PCHCH2), 3.98 (ddd, JHH = 18.1 and 10.6 Hz, JHP = 6.5 Hz, 1H,
PCHCHH), 3.83 (s, 3H, OCH3), 3.36 (ddd, JHH = 18.1 and 2.0 Hz,
JHP = 10.4 Hz, 1H, PCHCHH).
(S)-3-(Diphenylphosphinyl)-1-(4-methoxyphenyl)-3-(p-tolyl)-
propan-1-one (7x). White solid (81.8 mg, 90% yield); mp 234−
235 °C. The enantiomeric excess was determined on a Daicel Chiralcel
OD-H column with hexane/2-propanol (90/10) and flow rate 0.5 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 23.7 min
(major), 41.3 min, 91% ee. [α]D20 = −146° (c 0.380, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 7.99−7.94 (m, 2H), 7.82 (d, JHH = 8.9 Hz, 2H),
7.51−7.46 (m, 5H), 7.36−7.32 (m, 1H), 7.27−7.23 (m, 4H), 6.94 (d,
JHH = 7.9 Hz, 2H), 6.83 (d, JHH = 8.9 Hz, 2H), 4.45 (ddd, JHH = 9.8 and
2.3 Hz, JHP = 6.9 Hz, 1H, PCHCH2), 3.94 (ddd, JHH = 17.9 and 10.5 Hz,
JHP = 4.4 Hz, 1H, PCHCHH), 3.80 (s, 3H, OCH3), 3.29 (ddd, JHH = 17.8
and 2.4 Hz, JHP = 11.2 Hz, 1H, PCHCHH), 2.19 (s, 3H, CH3). 13C NMR
1
(c 0.232, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.01−7.96 (m,
2H), 7.82 (d, JHH = 8.9 Hz, 2H), 7.53−7.45 (m, 5H), 7.38−7.33 (m,
3H), 7.29−7.24 (m, 2H), 6.85−6.81 (m, 4H), 4.46 (ddd, JHH = 9.2
and 2.2 Hz, JHP = 6.7 Hz, 1H, PCHCH2), 3.94 (ddd, JHH = 17.9 and
10.6 Hz, JHP = 4.2 Hz, 1H, PCHCHH), 3.80 (s, 3H, OCH3), 3.29
(ddd, JHH = 17.9 and 2.3 Hz, JHP = 10.8 Hz, 1H, PCHCHH). 13C
NMR (100 MHz, CDCl3): δ 195.0 (d, JCP = 13.4 Hz), 163.8, 161.8
(dd, JCP = 2.4 Hz, JCF = 244 Hz), 132.1 (d, JCP = 2.8 Hz), 131.9 (d,
JCP = 40.2 Hz), 131.8 (dd, JCP = 5.5 Hz, JCF = 3.2 Hz), 131.5 (d, JCP
=
2.7 Hz), 131.3 (dd, JCP = 5.8 Hz, JCF = 7.9 Hz), 131.2 (d, JCP
=
8.6 Hz), 130.92 (d, JCP = 33.0 Hz), 130.86 (d, JCP = 8.9 Hz), 130.4,
129.4, 129.0 (d, J = 11.2 Hz), 128.2 (d, J = 11.7 Hz), 115.2 (dd, JCP
=
1.6 Hz, JCF = 21.4 Hz), 113.7, 55.5, 40.3 (d, JCP = 69.1 Hz), 38.6.
31P{1H} NMR (162 MHz, CDCl3): δ 34.4. HRMS (positive ESI):
[M + H]+ calcd for C28H25FO3P 459.1525, found 459.1526.
(S)-3-(Diphenylphosphinyl)-1-(4-nitrophenyl)-3-phenylpropan-1-
one (7bb).5b White solid (90.2 mg, 99%). The enantiomeric excess
was determined on a Daicel Chiralpak AD-H column with hexane/
2-propanol (60/40) and flow rate 1.0 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 36.0 min (major), 47.8 min,
20
1
85% ee. [α]D = −142° (c 0.200, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 8.20 (d, JHH = 8.6 Hz, 2H), 8.00−7.95 (m, 4H), 7.54−7.43
(m, 5H), 7.37−7.33 (m, 3H), 7.26−7.09 (m, 5H), 4.42 (ddd, JHH
=
(100 MHz, CDCl3): δ 195.2 (d, JCP = 13.5 Hz), 163.6, 136.5 (d, JCP
=
10.2 and 2.8 Hz, JHP = 7.0 Hz, 1H, PCHCH2), 4.01 (ddd, JHH = 18.1
2.6 Hz), 132.9 (d, JCP = 5.7 Hz), 132.3 (d, JCP = 18.8 Hz), 131.9 (d, JCP
=
and 9.2 Hz, JHP = 4.1 Hz, 1H, PCHCHH), 3.45 (ddd,
= 18.1 and
HH
2.6 Hz), 131.33 (d, JCP = 16.9 Hz), 131.32 (d, JCP = 2.0 Hz), 131.29 (d,
JCP = 8.6 Hz), 131.0 (d, JCP = 8.8 Hz), 130.4, 129.7 (d, JCP = 5.7 Hz),
2.8 Hz, JHP = 10.7 Hz, 1H, PCHCHH).
(S)-3-(4-Bromophenyl)-3-(diphenylphosphinyl)-1-(4-nitrophenyl)-
propan-1-one (7cc).21 White solid (104.7 mg, 98%); mp 246−247 °C.
The enantiomeric excess was determined on a Daicel Chiralcel OD-H
column with hexane/2-propanol (85/15) and flow rate 0.5 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 40.4 min
(major), 57.7 min, 88% ee. [α]D20 = −138° (c 0.420, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 8.22 (d, JHH = 8.9 Hz, 2H), 7.99−7.94 (m, 4H),
7.56−7.48 (m, 5H), 7.41−7.37 (m, 1H), 7.32−7.25 (m, 6H), 4.40 (ddd,
JHH = 10.0 and 2.7 Hz, JHP = 7.0 Hz, 1H, PCHCH2), 3.95 (ddd, JHH
18.4 and 10.0 Hz, JHP = 5.0 Hz, 1H, PCHCHH), 3.43 (ddd, JHH = 18.4
and 2.7 Hz, JHP = 10.4 Hz, 1H, PCHCHH).
(S)-1-(4-Bromophenyl)-3-(diphenylphosphinyl)-3-phenylpropan-
1-one (7dd).5b White solid (97.4 mg, >99%). The enantiomeric excess
was determined on a Daicel Chiralpak AD-H column with hexane/
2-propanol (60/40) and flow rate 0.7 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 29.7 min (major), 44.4 min,
129.6, 129.0 (d, JCP = 1.8 Hz), 128.9 (d, JCP = 11.1 Hz), 128.1 (d, JCP
=
11.7 Hz), 113.6, 55.5, 40.6 (d, JCP = 69.2 Hz), 38.6, 21.0. 31P{1H} NMR
(162 MHz, CDCl3): δ 34.4. HRMS (positive ESI): [M + H]+ calcd for
C29H28O3P 455.1776, found 455.1774.
(S)-3-(3-Bromophenyl)-3-(diphenylphosphinyl)-1-(4-
methoxyphenyl)propan-1-one (7y). White solid (90.4 mg, 87%); mp
198−199 °C. The enantiomeric excess was determined on a Daicel
Chiralcel OD-H column with hexane/2-propanol (90/10) and flow
rate 0.4 mL/min and detected at a UV wavelength of 228 nm.
Retention times: 31.1 min (major), 37.1 min, 89% ee. [α]D20 = −143°
=
1
(c 0.276, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.00−7.95 (m,
2H), 7.83 (d, JHH = 8.9 Hz, 2H), 7.53−7.46 (m, 6H), 7.38−7.21 (m,
5H), 7.01 (t, JHH = 7.9 Hz, 1H), 6.84 (d, JHH = 8.9 Hz, 2H), 4.43 (ddd,
JHH = 9.8 and 2.3 Hz, JHP = 6.9 Hz, 1H, PCHCH2), 3.92 (ddd, JHH
=
18.0 and 10.4 Hz, JHP = 4.3 Hz, 1H, PCHCHH), 3.80 (s, 3H, OCH3),
N
dx.doi.org/10.1021/jo5015307 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
20
1
92% ee. [α]D = −145° (c 0.200, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 7.97−7.95 (m, 2H), 7.69 (d, JHH = 8.6 Hz, 2H), 7.53−7.43
(S)-3-(Bis(4-methoxyphenyl)phosphinyl)-1,3-diphenylpropan-1-
one (7ii).5b,12 White solid (70.6 mg, 75%). The enantiomeric excess
was determined on a Daicel Chiralcel OD-H column with hexane/
2-propanol (60/40) and flow rate 0.6 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 9.6 min (major), 17.2 min,
(m, 7H), 7.37−7.32 (m, 3H), 7.26−7.08 (m, 5H), 4.43 (ddd, JHH
=
10.3 and 2.5 Hz, JHP = 6.9 Hz, 1H, PCHCH2), 3.95 (ddd, JHH = 18.0
and 10.3 Hz, JHP = 4.6 Hz, 1H, PCHCHH), 3.35 (ddd, HH = 18.0 and
2.5 Hz, JHP = 11.0 Hz, 1H, PCHCHH).
20
26% ee. [α]D = −31° (c 0.116, CH2Cl2). 1H NMR (400 MHz,
(S)-1,3-Bis(4-bromophenyl)-3-(diphenylphosphinyl)propan-1-one
(7ee).21 White solid (112.5 mg, 99%); mp 261−262 °C. The enan-
tiomeric excess was determined on a Daicel Chiralcel OD-H column
with hexane/2-propanol (85/15) and flow rate 0.7 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 10.8 min
CDCl3): δ 7.89−7.83 (m, 4H), 7.49 (t, JHH = 7.4 Hz, 1H), 7.38−7.30
(m, 6H), 7.18−7.11 (m, 3H), 7.00 (dd, JHH = 8.8 and 2.1 Hz, 2H),
6.74 (dd, JHH = 8.8 and 2.2 Hz, 2H), 4.37 (ddd, JHH = 9.9 and 2.2 Hz,
JHP = 7.3 Hz, 1H, PCHCH2), 3.98 (ddd, JHH = 18.1 and 10.3 Hz, JHP
=
4.5 Hz, 1H, PCHCHH), 3.82 (s, 3H, OCH3), 3.73 (s, 3H, OCH3),
3.40 (ddd, JHH = 18.1 and 2.4 Hz, JHP = 11.3 Hz, 1H, PCHCHH).
(S)-3-(Diphenylphosphinyl)-3-phenyl-1-(pyridin-2-yl)propan-1-
one (7jj). With CH2Cl2/acetone (5/1) as eluent; pale yellow solid
(77.7 mg, 95%); mp 188−190 °C. The enantiomeric excess was deter-
mined on a Daicel Chiralcel OD-H column with hexane/2-propanol
20
1
(major), 13.6 min, 92% ee. [α]D = −137° (c 0.292, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 7.98−7.93 (m, 2H), 7.68 (d, JHH = 8.6
Hz, 2H), 7.54−7.47 (m, 7H), 7.39−7.35 (m, 1H), 7.31−7.24 (m, 6H),
4.40 (ddd, JHH = 10.0 and 2.5 Hz, JHP = 6.8 Hz, 1H, PCHCH2), 3.89
(ddd, JHH = 18.1 and 10.4 Hz, JHP = 4.6 Hz, 1H, PCHCHH), 3.33
(ddd, JHH = 18.1 and 2.5 Hz, JHP = 10.7 Hz, 1H, PCHCHH).
(S)-1-(Diphenylphosphinyl)-5-methyl-1-(4-nitrophenyl)hexan-3-
one (7ff).12 White solid (86.7 mg, >99%). The enantiomeric excess
was determined on a Daicel Chiralpak AD-H column with hexane/
2-propanol (70/30) and flow rate 1.0 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 16.7 min (major), 55.9 min,
(80/20) and flow rate 1.0 mL/min and detected at a UV wavelength of
20
228 nm. Retention times: 7.5 min (major), 9.4 min, 89% ee. [α]D
=
1
−133° (c 0.303, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.61 (dd,
JHH = 0.6 and 4.7 Hz, 1H), 8.02−7.97 (m, 2H), 7.83 (d, JHH = 7.8 Hz,
1H), 7.73−7.69 (m, 1H), 7.52−7.46 (m, 5H), 7.41−7.23 (m, 6H),
7.14−7.08 (m, 3H), 4.49−4.35 (m, 2H), 3.61−3.54 (m, 1H). 13C
NMR (100 MHz, CDCl3): δ 198.8 (d, JCP = 13.5 Hz), 152.7, 149.0,
20
1
98% ee. [α]D = −155° (c 0.200, CH2Cl2). H NMR (400 MHz,
CDCl3): δ 8.02 (d, JHH = 8.6 Hz, 2H), 7.96−7.92 (m, 2H), 7.60−7.54
(m, 3H), 7.52−7.46 (m, 4H), 7.39−7.36 (m, 1H), 7.30−7.26 (m, 2H),
4.36 (ddd, JHH = 9.8 and 2.6 Hz, JHP = 6.8 Hz, 1H, PCHCH2), 3.31
(ddd, JHH = 18.4 and 10.2 Hz, JHP = 4.8 Hz, 1H, PCHCHH), 2.92
(ddd, JHH = 18.4 and 2.6 Hz, JHP = 11.0 Hz, 1H, PCHCHH), 2.09
136.7, 135.8 (d, JCP = 5.8 Hz), 132.1 (d, JCP = 31.2 Hz), 131.9 (d, JCP
=
2.7 Hz), 131.5 (d, JCP = 8.5 Hz), 131.4 (d, JCP = 2.6 Hz), 131.14 (d,
JCP = 26.2 Hz), 131.12 (d, JCP = 8.8 Hz), 130.0 (d, JCP = 5.4 Hz), 128.8
(d, JCP = 11.1 Hz), 128.2 (d, JCP = 1.9 Hz), 128.1 (d, JCP = 11.7 Hz),
127.3, 127.0 (d, JCP = 2.3 Hz), 121.8, 41.5 (d, JCP = 68.2 Hz), 38.2.
31P{1H} NMR (162 MHz, CDCl3): δ 33.7. HRMS (positive ESI):
(d, JHH = 6.9 Hz, 2H), 1.90 (heptet, JHH = 6.8 Hz, 1H), 0.70 (d, JHH
6.8 Hz, 3H), 0.66 (d, JHH = 6.8 Hz, 3H).
=
[M + H]+ calcd for C26H23NO2P 412.1466, found 412.1469.
(S)-3-(4-Bromophenyl)-3-(diphenylphosphinyl)-1-(pyridin-2-yl)-
propan-1-one (7kk). Pale yellow solid (90.3 mg, 92%); mp 219−
221 °C. The enantiomeric excess was determined on a Daicel Chiralcel
OD-H column with hexane/2-propanol (90/10) and flow rate 1.0 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 17.0 min
(major), 20.4 min, 87% ee. [α]D20 = −146° (c 0.163, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 8.61 (d, JHH = 4.5 Hz, 1H), 8.00−7.96 (m, 2H),
7.83 (d, JHH = 7.8 Hz, 1H), 7.73 (t, JHH = 7.6 Hz, 1H), 7.55−7.50 (m, 5H),
7.42−7.20 (m, 8H), 4.44−4.32 (m, 2H), 3.55−3.48 (m, 1H). 13C NMR
(100 MHz, CDCl3): δ 198.7 (d, JCP = 13.5 Hz), 152.6, 149.0, 136.8, 135.0
(d, JCP = 5.8 Hz), 132.0 (d, JCP = 2.9 Hz), 131.64 (d, JCP = 3.5 Hz), 131.60
(d, JCP = 5.1 Hz), 131.4 (d, JCP = 8.5 Hz), 131.3 (d, JCP = 1.9 Hz),
131.0 (d, JCP = 8.8 Hz), 130.9 (d, JCP = 30.7 Hz), 128.9 (d, JCP = 11.4 Hz),
128.3 (d, JCP = 11.7 Hz), 127.4, 121.8, 121.1 (d, JCP = 3.2 Hz), 41.0 (d,
JCP = 68.0 Hz), 38.1. 31P{1H} NMR (162 MHz, CDCl3): δ 33.1. HRMS
(positive ESI): [M + H]+ calcd for C26H22BrNO2P 490.0572, found
490.0573.
(S)-3-(2-Bromophenyl)-3-(diphenylphosphinyl)-1-(pyridin-2-yl)-
propan-1-one (7ll). With CH2Cl2/acetone (5/1) as eluent; pale yellow
solid (72.7 mg, 74%); mp 102−105 °C. The enantiomeric excess was
determined on a Daicel Chiralcel OD-H column with hexane/
2-propanol (80/20) and flow rate 1.0 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 8.1 min (major), 10.8 min, 38%
ee. [α]D20 = −53° (c 0.221, CH2Cl2). 1H NMR (400 MHz, CDCl3): δ
8.62 (dd, JHH = 0.5 and 4.6 Hz, 1H), 8.14−8.08 (m, 2H), 7.91−7.88 (m,
1H), 7.83 (d, JHH = 7.8 Hz, 1H), 7.74−7.70 (m, 1H), 7.59−7.56 (m,
3H), 7.42−7.17 (m, 8H), 6.99−6.95 (m, 1H), 5.10 (ddd, JHH = 10.6 and
3.0 Hz, JHP = 7.2 Hz, 1H, PCHCH2), 4.30 (ddd, JHH = 17.5 and
11.0 Hz, JHP = 6.0 Hz, 1H, PCHCHH), 3.69 (ddd, JHH = 17.8 and
3.1 Hz, JHP = 9.6 Hz, 1H, PCHCHH). 13C NMR (100 MHz, CDCl3): δ
198.5 (d, JCP = 13.5 Hz), 152.6, 148.9, 136.8, 135.6 (d, JCP = 5.1 Hz),
132.5 (d, JCP = 1.7 Hz), 132.2 (d, JCP = 2.7 Hz), 131.7 (d, JCP = 8.6 Hz),
131.54 (d, JCP = 2.7 Hz), 131.52 (d, JCP = 72.1 Hz), 131.2 (d,
JCP = 9.4 Hz), 130.7 (d, JCP = 4.1 Hz), 130.6 (d, JCP = 66.6 Hz), 128.9
(d, JCP = 11.2 Hz), 128.5 (d, JCP = 2.3 Hz), 127.8 (d, JCP = 11.9 Hz),
127.7 (d, JCP = 2.4 Hz), 127.3, 126.4 (d, JCP = 7.4 Hz), 121.8, 40.1 (d,
JCP = 67.1 Hz), 38.9. 31P{1H} NMR (162 MHz, CDCl3): δ 34.1. HRMS
(positive ESI): [M + H]+ calcd for C26H22BrNO2P 490.0572. found
490.0573.
(S)-1-(Diphenylphosphinyl)-5-methyl-1-phenylhexan-3-one
(7gg). White solid (36.7 mg, 47%); mp 169−170 °C. The enan-
tiomeric excess was determined on a Daicel Chiralpak AD-H column
with hexane/2-propanol (70/30) and flow rate 1.0 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 8.6 min
(major), 12.8 min, 80% ee. [α]D = −89° (c 0.124, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 7.96−7.91 (m, 2H), 7.58−7.50 (m, 3H),
7.45−7.40 (m, 2H), 7.35−7.27 (m, 3H), 7.26−7.21 (m, 2H), 7.18−
7.10 (m, 3H), 4.26 (ddd, JHH = 9.9 and 2.8 Hz, JHP = 7.0 Hz, 1H,
PCHCH2), 3.31 (ddd, JHH = 17.8 and 10.1 Hz, JHP = 5.3 Hz, 1H,
PCHCHH), 2.86 (ddd, JHH = 17.8 and 2.8 Hz, JHP = 11.4 Hz, 1H,
PCHCHH), 2.07 (d, JHH = 7.0 Hz, 2H), 1.97−1.85 (m, 1H), 0.68 (d,
JHH = 6.6 Hz, 3H), 0.64 (d, JHH = 6.6 Hz, 3H). 13C NMR (100 MHz,
CDCl3): δ 207.5 (d, JCP = 12.4 Hz), 135.6 (d, JCP = 5.4 Hz), 132.1 (d,
JCP = 2.7 Hz), 131.57 (d, JCP = 17.3 Hz), 131.54 (d, JCP = 2.8 Hz),
20
1
131.3 (d, JCP = 8.7 Hz), 130.9 (d, JCP = 9.0 Hz), 130.6 (d, JCP
=
11.7 Hz), 129.8 (d, JCP = 5.6 Hz), 129.0 (d, JCP = 11.5 Hz), 128.3 (d,
JCP = 1.9 Hz), 128.1 (d, JCP = 11.9 Hz), 127.2 (d, JCP = 2.4 Hz), 52.4,
43.0, 40.9 (d, JCP = 68.5 Hz), 24.5, 22.2 (d, JCP = 25.3 Hz), 20.7.
31P{1H} NMR (162 MHz, CDCl3): δ 35.0. HRMS (positive ESI):
[M + H]+ calcd for C25H28O2P 391.1827, found 391.1828.
(S)-3-(Bis(4-methylphenyl)phosphinyl)-1,3-diphenylpropan-1-
one (7hh). With CH2Cl2/EtOAc (10/1) as eluent; white solid (20.0 mg,
23%); mp 203−205 °C. The enantiomeric excess was determined on a
Daicel Chiralcel OD-H column with hexane/2-propanol (90/10) and
flow rate 1.0 mL/min and detected at a UV wavelength of 228 nm.
20
Retention times: 6.9 min (major), 9.4 min, 83% ee. [α]D = −117°
1
(c 0.165, CH2Cl2). H NMR(400 MHz, CDCl3): δ 7.86−7.82 (m, 4H),
7.51−7.47 (m, 1H), 7.40−7.30 (m, 8H), 7.17−7.03 (m, 5H), 4.42 (ddd,
JHH = 9.9 and 2.2 Hz, JHP = 7.1 Hz, 1H, PCHCH2), 4.00 (ddd, JHH = 18.1
and 10.4 Hz, JHP = 4.2 Hz, 1H, PCHCHH), 3.37 (ddd, JHH = 18.1 and
2.2 Hz, JHP = 11.1 Hz, 1H, PCHCHH), 2.38 (s, 3H, CH3), 2.26 (s, 3H,
CH3). 13C NMR (100 MHz, CDCl3): δ 196.8 (d, JCP = 13.4 Hz), 142.4
(d, JCP = 2.5 Hz), 141.7 (d, JCP = 2.6 Hz), 136.4, 136.2 (d, JCP = 5.5 Hz),
133.3, 131.2 (d, JCP = 8.7 Hz), 131.0 (d, JCP = 9.3 Hz), 129.9 (d, JCP
=
5.7 Hz), 129.6 (d, JCP = 11.6 Hz), 128.9 (d, JCP = 33.4 Hz), 128.8 (d,
JCP = 12.0 Hz), 128.5, 128.3 (d, JCP = 1.4 Hz), 128.1, 127.9 (d, JCP = 28.1
Hz), 126.9 (d, JCP = 2.1 Hz), 41.2 (d, JCP = 68.7 Hz), 39.1, 21.55, 21.47.
31P{1H} NMR (162 MHz, CDCl3): δ 34.8. HRMS (positive ESI):
[M + H]+ calcd for C29H28O2P: 439.1827, found 439.1829.
O
dx.doi.org/10.1021/jo5015307 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
(S)-3-(3-Bromophenyl)-3-(diphenylphosphinyl)-1-(pyridin-2-yl)-
propan-1-one (7mm). Pale yellow solid (84.2 mg, 86%); mp 210−
213 °C. The enantiomeric excess was determined on a Daicel Chiralcel
OD-H column with hexane/2-propanol (90/10) and flow rate 1.0 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 15.4 min
(major), 23.0 min, 85% ee. [α]D20 = −120° (c 0.090, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 8.62 (dd, JHH = 0.6 and 4.6 Hz, 1H), 8.01−7.95 (m,
2H), 7.85−7.83 (m, 1H), 7.75−7.71 (m, 1H), 7.53−7.48 (m, 5H), 7.43−
7.37 (m, 3H), 7.33−7.27 (m, 3H), 7.23−7.21 (m, 1H), 7.01 (t, JHH = 7.8
Hz, 1H), 4.43−4.30 (m, 2H), 3.60−3.53 (m, 1H). 13C NMR (100 MHz,
CDCl3): δ 198.5 (d, JCP = 13.2 Hz), 152.6, 149.0, 138.3 (d, JCP = 5.4 Hz),
(d, JCP = 5.8 Hz), 127.3, 121.8, 113.6 (d, JCP = 1.7 Hz), 55.1, 40.6 (d, JCP =
69.1 Hz), 38.3. 31P{1H} NMR (162 MHz, CDCl3): δ 33.6. HRMS
(positive ESI): [M + H]+ calcd for C27H25NO3P 442.1572, found
442.1573.
(S)-3-(Diphenylphosphinyl)-3-(furan-2-yl)-1-(pyridin-2-yl)propan-
1-one (7qq). Pale yellow solid (69.9 mg, 87%); mp 149−151 °C. The
enantiomeric excess was determined on a Daicel Chiralcel OD-H
column with hexane/2-propanol (80/20) and flow rate 1.0 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 9.7 min
20
1
(major), 12.7 min, 82% ee. [α]D = −76° (c 0.105, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 8.64 (d, JHH = 4.6 Hz, 1H), 7.92−7.87
(m, 3H), 7.76 (t, JHH = 7.6 Hz, 1H), 7.62−7.38 (m, 9H), 7.14 (s, 1H),
136.8, 133.0 (d, JCP = 5.5 Hz), 132.1 (d, JCP = 2.6 Hz), 131.7 (d, JCP
33.4 Hz), 131.65 (d, JCP = 2.5 Hz), 131.5 (d, JCP = 8.4 Hz), 131.1 (d, JCP
=
=
6.16 (t, JHH = 2.9 Hz, 1H), 6.08 (t, JHH = 3.2 Hz, 1H), 4.74 (ddd, JHH
=
8.8 Hz), 130.7 (d, JCP = 28.9 Hz), 130.1 (d, JCP = 2.6 Hz), 129.7 (d,
JCP = 2.0 Hz), 128.9 (d, JCP = 11.4 Hz), 128.5 (d, JCP = 5.4 Hz), 128.2 (d,
14.1 and 3.0 Hz, JHP = 11.1 Hz, 1H, PCHCH2), 4.24 (ddd, JHH = 18.5
and 10.9 Hz, JHP = 5.5 Hz, 1H, PCHCHH), 3.67 (ddd, JHH = 18.5 and
3.0 Hz, JHP = 9.9 Hz, 1H, PCHCHH). 13C NMR (100 MHz, CDCl3):
δ 198.5 (d, JCP = 12.5 Hz), 152.7, 149.3 (d, JCP = 6.5 Hz), 149.0, 141.7
JCP = 11.7 Hz), 127.4, 122.1 (d, JCP = 2.4 Hz), 121.8, 41.4 (d, JCP
=
67.6 Hz), 38.0. 31P{1H} NMR (162 MHz, CDCl3): δ 33.3. HRMS
(positive ESI): [M + H]+ calcd for C26H22BrNO2P 490.0572, found
490.0574.
(d, JCP = 2.9 Hz), 136.8, 132.0 (d, JCP = 2.5 Hz), 131.8 (d, JCP
=
2.7 Hz), 131.6 (d, JCP = 46.6 Hz), 131.51 (d, JCP = 8.8 Hz), 131.50 (d,
JCP = 8.9 Hz), 130.6 (d, JCP = 49.6 Hz), 128.7 (d, JCP = 11.6 Hz), 128.2
(d, JCP = 11.6 Hz), 127.4, 121.9, 110.7 (d, JCP = 2.8 Hz), 108.8 (d,
JCP = 5.9 Hz), 36.2 (d, JCP = 70.0 Hz), 36.0. 31P{1H} NMR (162 MHz,
CDCl3): δ 32.3. HRMS (positive ESI): [M + H]+ calcd for
C24H21NO3P 402.1259, found 402.1263.
(S)-3-(Diphenylphosphinyl)-1-(pyridin-2-yl)-3-(thien-2-yl)propan-
1-one (7rr). With CH2Cl2/acetone (5/1) as eluent; white solid
(55.7 mg, 67%); mp 176−178 °C. The enantiomeric excess was deter-
mined on a Daicel Chiralcel OD-H column with hexane/2-propanol
(S)-3-(Diphenylphosphinyl)-3-(4-nitrophenyl)-1-(pyridin-2-yl)-
propan-1-one (7nn). Pale yellow solid (81.9 mg, 90%); mp 207−
209 °C. The enantiomeric excess was determined on a Daicel Chiralcel
OD-H column with hexane/2-propanol (90/10) and flow rate 1.0 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 34.1 min
(major), 46.2 min, 88% ee. [α]D20 = −191° (c 0.199, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 8.63 (dd, JHH = 1.4 and 4.7 Hz, 1H), 8.03−7.98 (m,
4H), 7.84−7.82 (m, 1H), 7.76−7.72 (m, 1H), 7.56−7.52 (m, 7H), 7.45−
7.37 (m, 2H), 7.33−7.30 (m, 2H), 4.58−4.41 (m, 2H), 3.58 (ddd, JHH
=
18.0 and 2.0 Hz, JHP = 9.8 Hz, 1H). 13C NMR (100 MHz, CDCl3): δ
198.4 (d, JCP = 13.2 Hz), 152.4, 149.1, 146.8 (d, JCP = 2.8 Hz), 144.1 (d,
JCP = 5.7 Hz), 136.9, 132.3 (d, JCP = 2.7 Hz), 131.9 (d, JCP = 2.7 Hz), 131.4
(d, JCP = 49.0 Hz), 131.3 (d, JCP = 8.5 Hz), 130.9 (d, JCP = 8.9 Hz), 130.8
(d, JCP = 5.4 Hz), 130.4 (d, JCP = 45.7 Hz), 129.0 (d, JCP = 11.5 Hz), 128.4
(80/20) and flow rate 1.0 mL/min and detected at a UV wavelength of
20
228 nm. Retention times: 8.9 min (major), 11.5 min, 82% ee. [α]D
=
1
−110° (c 0.100, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.62 (d,
JHH = 4.5 Hz, 1H), 7.99−7.94 (m, 2H), 7.87 (d, JHH = 7.8 Hz, 1H),
7.75−7.70 (m, 1H), 7.63−7.58 (m, 2H), 7.51−7.49 (m, 3H), 7.42−
7.39 (m, 2H), 7.35−7.31 (m, 2H), 7.02−6.97 (m, 2H), 6.79−6.77 (m,
1H), 4.85−4.80 (m, 1H, PCHCH2), 4.33 (ddd, JHH = 18.2 and 10.8 Hz,
JHP = 5.1 Hz, 1H, PCHCHH), 3.58 (ddd, JHH = 18.3 and 2.7 Hz,
JHP =10.0 Hz, 1H, PCHCHH). 13C NMR (100 MHz, CDCl3): δ 198.4
(d, JCP = 13.0 Hz), 152.6, 149.0, 137.6 (d, JCP = 6.5 Hz), 136.7, 132.0 (d,
JCP = 2.5 Hz), 131.68 (d, JCP = 12.7 Hz), 131.65 (d, JCP = 2.8 Hz), 131.5
(d, JCP = 8.7 Hz), 131.3 (d, JCP = 8.8 Hz), 130.7 (d, JCP = 7.8 Hz), 128.8
(d, JCP = 11.4 Hz), 128.2 (d, JCP = 11.7 Hz), 127.40 (d, JCP = 4.9 Hz),
127.38, 126.7 (d, JCP = 2.5 Hz), 124.8 (d, JCP = 2.9 Hz), 121.8, 39.2,
36.9 (d, JCP = 70.1 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 32.7.
HRMS (positive ESI): [M + H]+ calcd for C24H21NO2PS 418.1031,
found 418.1032.
(d, JCP = 11.8 Hz), 127.6, 123.3 (d, JCP = 1.8 Hz), 121.8, 41.8 (d, JCP
=
66.2 Hz), 38.1. 31P{1H} NMR (162 MHz, CDCl3): δ 32.6. HRMS
(positive ESI): [M + H]+ calcd for C26H22N2O4P 457.1317, found
457.1318.
(S)-3-(Diphenylphosphinyl)-1-(pyridin-2-yl)-3-(p-tolyl)propan-1-
one (7oo). Pale yellow solid (68.8 mg, 81%); mp 213−215 °C. The
enantiomeric excess was determined on a Daicel Chiralcel OD-H
column with hexane/2-propanol (80/20) and flow rate 1.0 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 7.4 min
20
1
(major), 9.8 min, 73% ee. [α]D = −112° (c 0.111, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 8.61 (d, JHH = 4.6 Hz, 1H), 8.00−7.95(m,
2H), 7.82 (d, JHH = 7.8 Hz, 1H), 7.70 (t, JHH = 7.6 Hz, 1H), 7.54−7.50
(m, 5H), 7.40−7.34 (m, 2H), 7.29−7.25 (m, 2H), 7.21−7.19 (m, 2H),
6.93 (d, JHH = 7.9 Hz, 2H), 4.47−4.31 (m, 2H), 3.56 (ddd, JHH = 17.7
and 2.0 Hz, JHP = 12.8 Hz, 1H), 2.19 (s, 3H). 13C NMR (100 MHz,
CDCl3): δ 198.9 (d, JCP = 13.6 Hz), 152.8, 149.0, 136.7, 136.5 (d,
JCP = 2.5 Hz), 132.5 (d, JCP = 5.7 Hz), 132.3 (d, JCP = 21.8 Hz), 131.8
(d, JCP = 2.5 Hz), 131.5 (d, JCP = 8.5 Hz), 131.33 (d, JCP = 2.8 Hz),
(S)-3-(Diphenylphosphinyl)-3-(naphthalen-1-yl)-1-(pyridin-2-yl)-
propan-1-one (7ss). With CH2Cl2/acetone (5/1) as eluent; pale
yellow solid (51.1 mg, 55%); mp 156−158 °C. The enantiomeric excess
was determined on a Daicel Chiralcel OD-H column with hexane/
2-propanol (80/20) and flow rate 1.0 mL/min and detected at a UV
wavelength of 228 nm. Retention times: 8.1 min (major), 10.7 min, 46%
ee. [α]D20 = −57° (c 0.106, CH2Cl2). 1H NMR (400 MHz, CDCl3): δ
8.60 (d, JHH = 4.3 Hz, 1H), 8.10−8.05 (m, 4H), 7.71−7.60 (m, 4H),
7.52−7.51 (m, 3H), 7.43−7.32 (m, 6H), 7.08−7.04 (m, 1H), 6.97−6.93
(m, 2H), 5.48−5.42 (m, 1H, PCHCH2), 4.46 (ddd, JHH = 18.1 and
9.8 Hz, JHP = 6.5 Hz, 1H, PCHCHH), 3.87 (ddd, JHH = 18.2 and 3.0 Hz,
JHP = 10.9 Hz, 1H, PCHCHH). 13C NMR (100 MHz, CDCl3): δ 198.9
(d, JCP = 12.6 Hz), 152.6, 148.9, 136.6, 133.5, 132.7 (d, JCP = 5.3 Hz),
132.2, 132.1, 132.0, 131.7 (d, JCP = 8.3 Hz), 131.2 (d, JCP = 2.0 Hz),
131.0, 130.8 (d, JCP = 9.2 Hz), 128.8 (d, JCP = 11.1 Hz), 128.6, 127.7 (d,
JCP = 11.7 Hz), 127.3, 125.8, 125.4, 125.1, 122.9, 121.7, 39.6, 34.8 (d,
JCP = 68.5 Hz). 31P{1H} NMR (162 MHz, CDCl3): δ 33.8. HRMS
(positive ESI): [M + H]+ calcd for C30H25NO2P 462.1623. Found:
462.1624.
131.32 (d, JCP = 16.2 Hz), 131.2 (d, JCP = 8.7 Hz), 129.8 (d, JCP
=
5.6 Hz), 128.9 (d, JCP = 1.9 Hz), 128.7 (d, JCP = 11.1 Hz), 128.1 (d,
JCP = 11.6 Hz), 127.2, 121.8, 41.0 (d, JCP = 68.7 Hz), 38.3, 21.1.
31P{1H} NMR (162 MHz, CDCl3): δ 33.6. HRMS (positive ESI):
[M + H]+ calcd for C27H25NO2P 426.1623, found 426.1624.
(S)-3-(Diphenylphosphinyl)-3-(4-methoxyphenyl)-1-(pyridin-2-
yl)propan-1-one (7pp). Pale yellow solid (75.2 mg, 85%); mp 206−
208 °C. The enantiomeric excess was determined on a Daicel Chiralcel
OD-H column with hexane/2-propanol (80/20) and flow rate 1.0 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 9.9 min
(major), 13.0 min, 95% ee. [α]D20 = −146° (c 0.086, CH2Cl2). 1H NMR
(400 MHz, CDCl3): δ 8.61 (d, JHH = 4.2 Hz, 1H), 8.01−7.96 (m, 2H),
7.83 (d, JHH = 7.8 Hz, 1H), 7.73−7.69 (m, 1H), 7.53−7.48 (m, 5H), 7.41−
7.34 (m, 2H), 7.30−7.23 (m, 4H), 6.67 (d, JHH = 8.6 Hz, 2H), 4.44−4.30
(m, 2H), 3.69 (s, 3H, OCH3), 3.56−3.50 (m, 1H). 13C NMR (100 MHz,
CDCl3): δ 199.0 (d, JCP = 13.8 Hz), 158.5 (d, JCP = 2.3 Hz), 152.8, 149.0,
(S)-2-(3-(Diphenylphosphinyl)-3-phenylpropionyl)pyridine N-
Oxide (7jj′).21 White solid (69.8 mg, 82%); mp 169−170 °C. The en-
antiomeric excess was determined on a Daicel Chiralcel OD-H column
with hexane/2-propanol (70/30) and flow rate 1.0 mL/min and de-
tected at a UV wavelength of 228 nm. Retention times: 18.0 min
136.7, 132.3 (d, JCP = 31.9 Hz), 131.8 (d, JCP = 2.4 Hz), 131.5 (d, JCP
=
8.6 Hz), 131.3 (d, JCP = 2.7 Hz), 131.2 (d, JCP = 8.7 Hz), 131.0 (d,
JCP = 5.5 Hz), 128.8 (d, JCP = 11.1 Hz), 128.1 (d, JCP = 11.6 Hz), 127.6
20
(major), 23.6 min, 63% ee. [α]D = −49° (c 0.896, CH2Cl2).
P
dx.doi.org/10.1021/jo5015307 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
20
1H NMR (400 MHz, CDCl3): δ 8.11 (d, JHH = 6.5 Hz, 1H), 8.01−7.96
(m, 2H), 7.55−7.51 (m, 3H), 7.47−7.43 (m, 2H), 7.37−7.33 (m, 1H),
7.27−7.22 (m, 3H), 7.15−7.05 (m, 7H), 4.44 (ddd, JHH = 12.8 and
4.0 Hz, JHP = 8.9 Hz, 1H, PCHCH2), 4.06 (ddd, JHH = 18.0 and
10.8 Hz, JHP = 8.0 Hz, 1H, PCHCHH), 3.73 (ddd, JHH = 18.0 and
4.0 Hz, JHP = 8.6 Hz, 1H, PCHCHH).
Retention times: 17.3 min (major), 26.6 min, 59% ee. [α]D = −74°
1
(c 0.730, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.10 (d, JHH
=
6.5 Hz, 1H), 7.99−7.94 (m, 2H), 7.54−7.46 (m, 5H), 7.38−7.34 (m,
1H), 7.28−7.24 (m, 3H), 7.08 (d, JHH = 4.6 Hz, 2H), 7.03−7.01 (m,
2H), 6.89 (d, JHH = 7.9 Hz, 2H), 4.41 (ddd, JHH = 13.1 and 4.0 Hz,
JHP = 10.7 Hz, 1H, PCHCH2), 4.03 (ddd, JHH = 18.0 and 10.7 Hz,
(S)-2-(3-(4-Bromophenyl)-3-(diphenylphosphinyl)propionyl)-
pyridine N-Oxide (7kk′).21 Pale yellow solid (84.0 mg, 83%); mp
208−209 °C. The enantiomeric excess was determined on a Daicel
Chiralcel OD-H column with hexane/2-propanol (70/30) and flow
rate 1.0 mL/min and detected at a UV wavelength of 228 nm.
JHP = 8.0 Hz, 1H, PCHCHH), 3.71 (ddd, JHH = 17.7 and 3.9 Hz, JHP
8.6 Hz, 1H, PCHCHH), 2.20 (s, 3H, CH3).
=
(S)-2-(3-(Diphenylphosphinyl)-3-(4-methoxyphenyl)propionyl)-
pyridine N-Oxide (7pp′).21 Pale yellow solid (59.0 mg, 65%); mp
196−198 °C. The enantiomeric excess was determined on a Daicel
Chiralcel OD-H column with hexane/2-propanol (70/30) and flow
rate 1.0 mL/min and detected at a UV wavelength of 228 nm. Reten-
20
Retention times: 20.9 min (major), 32.5 min, 83% ee. [α]D = −69°
1
(c 0.828, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.10 (d, JHH
=
20
tion times: 23.2 min (major), 34.0 min, 77% ee. [α]D = −112° (c
6.4 Hz, 1H), 7.99−7.94 (m, 2H), 7.55−7.47 (m, 5H), 7.40−7.36 (m,
1H), 7.31−7.21 (m, 5H), 7.19−7.06 (m, 4H), 4.42 (ddd, JHH = 12.2
and 3.7 Hz, JHP = 8.8 Hz, 1H, PCHCH2), 4.06 (ddd, JHH = 18.0 and
10.8 Hz, JHP = 7.3 Hz, 1H, PCHCHH), 3.71 (ddd, JHH = 18.0 and
3.7 Hz, JHP = 8.8 Hz, 1H, PCHCHH).
0.418, CH2Cl2). 1H NMR (400 MHz, CDCl3): δ 8.11 (d, JHH
=
6.5 Hz, 1H), 7.99−7.94 (m, 2H), 7.55−7.44 (m, 5H), 7.38−7.34 (m,
1H), 7.28−7.24 (m, 3H), 7.10−7.04 (m, 4H), 6.63 (d, JHH = 8.6 Hz,
2H), 4.39 (ddd, JHH = 12.7 and 3.9 Hz, JHP = 9.0 Hz, 1H, PCHCH2),
4.01 (ddd, JHH = 17.8 and 11.0 Hz, JHP = 7.8 Hz, 1H, PCHCHH),
3.73−3.65 (m, 4H, PCHCHH and OCH3).
(S)-2-(3-(2-Bromophenyl)-3-(diphenylphosphinyl)propionyl)-
pyridine N-Oxide (7ll′).21 Pale yellow oil (55.0 mg, 54%). The enan-
tiomeric excess was determined on a Daicel Chiralcel OD-H column
with hexane/2-propanol (70/30) and flow rate 1.0 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 16.0 min
(S)-2-(3-(Diphenylphosphinyl)-3-(3-methoxyphenyl)propionyl)-
pyridine N-Oxide (7vv).21 Pale yellow oil (80.3 mg, 88%). The enan-
tiomeric excess was determined on a Daicel Chiralcel OD-H column
with hexane/2-propanol (70/30) and flow rate 1.0 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 19.5 min
20
1
(major), 26.0 min, 18% ee. [α]D = −15° (c 0.941, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 8.06−8.02 (m, 3H), 7.73−7.70 (m, 1H),
7.53−7.52 (m, 3H), 7.31−7.16 (m, 5H), 7.13−7.07 (m, 3H), 7.02−
6.98 (m, 2H), 6.90−6.85 (m, 1H), 5.01 (ddd, JHH = 12.0 and 4.2 Hz,
20
1
(major), 28.7 min, 80% ee. [α]D = −104° (c 0.492, CH2Cl2). H
NMR (400 MHz, CDCl3): δ 8.10 (d, JHH = 6.5 Hz, 1H), 8.00−7.95
(m, 2H), 7.54−7.45 (m, 5H), 7.38−7.33 (m, 1H), 7.28−7.23 (m, 3H),
7.11−7.08 (m, 2H), 6.99 (t, JHH = 7.9 Hz, 1H), 6.72 (d, JHH= 7.4 Hz,
1H), 6.67−6.62 (m, 2H), 4.43 (ddd, JHH = 13.2 and 4.1 Hz, JHP = 10.7 Hz,
1H, PCHCH2), 4.06 (ddd, JHH = 18.0 and 10.8 Hz, JHP = 8.2 Hz, 1H,
PCHCHH), 3.72 (ddd, JHH = 17.8 and 4.1 Hz, JHP = 8.6 Hz, 1H,
PCHCHH), 3.60 (s, 3H, OCH3).
JHP = 8.0 Hz, 1H, PCHCH2), 3.91 (ddd, JHH = 19.4 and 11.0 Hz, JHP
8.3 Hz, 1H, PCHCHH), 3.76 (ddd, JHH = 16.9 and 4.2 Hz, JHP
7.4 Hz, 1H, PCHCHH).
=
=
(S)-2-(3-(4-Chlorophenyl)-3-(diphenylphosphinyl)propionyl)-
pyridine N-Oxide (7tt).21 White solid (50.9 mg, 55%); mp 210−
212 °C. The enantiomeric excess was determined on a Daicel Chiralcel
OD-H column with hexane/2-propanol (70/30) and flow rate 1.0 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 19.2 min
(S)-2-(3-(Diphenylphosphinyl)-3-(furan-2-yl)propionyl)pyridine
N-Oxide (7qq′).21 Pale yellow oil (74.0 mg, 89%). The enantiomeric
excess was determined on a Daicel Chiralcel OD-H column with
hexane/2-propanol (60/40) and flow rate 1.0 mL/min and detected at
a UV wavelength of 228 nm. Retention times: 11.9 min (major), 17.0 min,
55% ee. [α]D20 = −20° (c 0.947, CH2Cl2). 1H NMR (400 MHz, CDCl3):
δ 8.14 (d, JHH = 6.4 Hz, 1H), 7.90−7.85 (m, 2H), 7.55−7.43 (m, 6H),
7.40−7.30 (m, 4H), 7.23−7.19 (m, 1H), 7.11 (s, 1H), 6.17 (dd, JHH = 1.9
and 3.2 Hz, 1H), 6.05 (t, JHH = 3.2 Hz, 1H), 4.75 (ddd, JHH = 14.8 and 4.6
Hz, JHP = 10.3 Hz, 1H, PCHCH2), 3.96 (ddd, JHH = 18.2 and 10.1 Hz,
20
1
(major), 28.5 min, 68% ee. [α]D = −98° (c 0.832, CH2Cl2). H NMR
(400 MHz, CDCl3): δ 8.11 (d, JHH = 6.5 Hz, 1H), 7.99−7.94 (m, 2H),
7.56−7.46 (m, 5H), 7.40−7.36 (m, 1H), 7.31−7.27 (m, 3H), 7.19−7.06
(m, 6H), 4.43 (ddd, JHH = 12.4 and 3.8 Hz, JHP = 8.7 Hz, 1H, PCHCH2),
4.05 (ddd, JHH = 18.0 and 10.8 Hz, JHP = 7.4 Hz, 1H, PCHCHH), 3.71
(ddd, JHH = 18.0 and 3.8 Hz, JHP = 8.7 Hz, 1H, PCHCHH).
(S)-2-(3-(Diphenylphosphinyl)-3-(4-nitrophenyl)propionyl)-
pyridine N-Oxide (7nn′).21 Pale yellow solid (65.0 mg, 69%); mp
197−198 °C. The enantiomeric excess was determined on a Daicel
Chiralcel OD-H column with hexane/2-propanol (60/40) and flow
rate 1.0 mL/min and detected at a UV wavelength of 228 nm. Reten-
JHP = 8.6 Hz, 1H, PCHCHH), 3.78 (ddd, JHH = 18.1 and 4.6 Hz, JHP
8.6 Hz, 1H, PCHCHH).
=
(S)-2-(3-(Diphenylphosphinyl)-3-(thien-2-yl)propionyl)pyridine N-
Oxide (7rr′).21 Pale yellow solid (70.0 mg, 80%); mp 167−168 °C.
The enantiomeric excess was determined on a Daicel Chiralpak AD-H
column with hexane/2-propanol (60/40) and flow rate 1.0 mL/min
and detected at a UV wavelength of 228 nm. Retention times: 33.2
min (major), 56.2 min, 21% ee. [α]D20 = −22° (c 0.644, CH2Cl2). 1H
NMR (400 MHz, CDCl3): δ 8.12 (d, JHH = 6.4 Hz, 1H), 7.98−7.93
(m, 2H), 7.57−7.52 (m, 5H), 7.43−7.39 (m, 1H), 7.34−7.28 (m, 3H),
7.23−7.20 (m, 1H), 7.16−7.12 (m, 1H), 7.01−6.99 (m, 1H), 6.85 (t,
20
tion times: 20.6 min (major), 41.8 min, 76% ee. [α]D = −104°
1
(c 0.818, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.13 (d, JHH
=
6.4 Hz, 1H), 8.01−7.97 (m, 4H), 7.58−7.50 (m, 5H), 7.45−7.38 (m,
3H), 7.32−7.28 (m, 4H), 7.17 (t, JHH = 7.4 Hz, 1H), 4.59 (ddd, JHH
=
11.2 and 3.4 Hz, JHP = 8.6 Hz, 1H, PCHCH2), 4.20 (ddd, JHH = 18.2
and 10.8 Hz, JHP = 6.7 Hz, 1H, PCHCHH), 3.79 (ddd, JHH = 18.4 and
3.4 Hz, JHP = 9.1 Hz, 1H, PCHCHH).
(S)-2-(3-(Diphenylphosphinyl)-3-(3-nitrophenyl)propionyl)-
pyridine N-Oxide (7uu).21 Pale yellow solid (85.0 mg, 90%); mp 214−
215 °C. The enantiomeric excess was determined on a Daicel Chiralcel
OD-H column with hexane/2-propanol (60/40) and flow rate
0.8 mL/min and detected at a UV wavelength of 228 nm. Retention
JHH = 2.6 Hz, 1H), 6.77 (dd, JHH = 3.6, 5.0 Hz, 1H), 4.81 (ddd, JHH
=
13.8 and 3.9 Hz, JHP = 10.6 Hz, 1H, PCHCH2), 4.00 (ddd, JHH = 17.9
and 10.8 Hz, JHP = 7.4 Hz, 1H, PCHCHH), 3.72 (ddd, JHH = 17.7 and
4.0 Hz, JHP = 8.0 Hz, 1H, PCHCHH).
20
times: 17.3 min (major), 28.2 min, 79% ee. [α]D = −117° (c 0.994,
(S,E)-2-(3-(Diphenylphosphinyl)-5-phenyl-4-pentenoyl)pyridine
N-Oxide (7ww).21 Pale yellow oil (70.0 mg, 77%). The enantiomeric
excess was determined on a Daicel Chiralcel OD-H column with
hexane/2-propanol (60/40) and flow rate 1.0 mL/min and detected at
a UV wavelength of 228 nm. Retention times: 11.8 min (major), 16.7 min,
72% ee. [α]D20 = −67° (c 0.917, CH2Cl2). 1H NMR (400 MHz, CDCl3):
δ 8.14 (d, JHH = 6.3 Hz, 1H), 7.94−7.89 (m, 2H), 7.79−7.74 (m, 2H),
7.53−7.41 (m, 7H), 7.33−7.29 (m, 1H), 7.24−7.13 (m, 6H), 6.30 (dd, J =
15.9, 4.3 Hz, 1H), 6.08 (ddd, J = 14.9, 9.1, 5.7 Hz, 1H), 4.20−4.12 (m,
1H, PCHCH2), 3.76 (ddd, JHH = 17.7 and 10.0 Hz, JHP = 8.0 Hz, 1H,
PCHCHH), 3.61 (ddd, JHH = 17.5 and 4.0 Hz, JHP = 9.8 Hz, 1H,
PCHCHH).
CH2Cl2). 1H NMR (400 MHz, CDCl3): δ 8.13 (d, JHH = 6.4 Hz, 1H),
8.02−7.96 (m, 3H), 7.90 (d, JHH = 1.9 Hz, 1H), 7.76 (d, JHH = 7.0 Hz,
1H), 7.58−7.50 (m, 5H), 7.40−7.27 (m, 6H), 7.17−7.13 (m, 1H),
4.59 (ddd, JHH = 12.0 and 3.6 Hz, JHP = 8.7 Hz, 1H, PCHCH2), 4.16
(ddd, JHH = 18.2 and 10.7 Hz, JHP = 6.9 Hz, 1H, PCHCHH), 3.80
(ddd, JHH = 18.4 and 3.6 Hz, JHP = 9.1 Hz, 1H, PCHCHH).
(S)-2-(3-(Diphenylphosphinyl)-3-(4-methylphenyl)propionyl)-
pyridine N-Oxide (7oo′).21 Pale yellow solid (71.5 mg, 81%); mp
185−187 °C. The enantiomeric excess was determined on a Daicel
Chiralcel OD-H column with hexane/2-propanol (70/30) and flow
rate 1.0 mL/min and detected at a UV wavelength of 228 nm.
Q
dx.doi.org/10.1021/jo5015307 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
(R)-2-(3-(Diphenylphosphinyl)-3-(naphthalen-1-yl)propionyl)-
pyridine N-Oxide (7ss′).21 Pale yellow oil (75.8 mg, 80%). The enan-
tiomeric excess was determined on a Daicel Chiralcel OD-H column
with hexane/2-propanol (60/40) and flow rate 1.0 mL/min and
detected at a UV wavelength of 228 nm. Retention times: 9.3 min,
13.6 min (major), 9% ee. [α]D = +4° (c 0.984, CH2Cl2). H NMR
(400 MHz, CDCl3): δ 8.15−8.10 (m, 2H), 8.01 (d, JHH = 6.4 Hz, 1H),
7.86−7.83 (m, 1H), 7.74 (d, JHH = 8.5 Hz, 1H), 7.62−7.59 (m, 5H),
7.39 (t, JHH = 7.6 Hz, 1H), 7.28−7.15 (m, 4H), 7.08−6.92 (m, 4H),
6.73 (t, JHH = 7.6 Hz, 1H), 6.65−6.62 (m, 1H), 5.48 (ddd, JHH = 13.6
and 4.6 Hz, JHP = 10.4 Hz, 1H, PCHCH2), 4.10 (ddd, JHH = 14.2 and
7.1 Hz, JHP = 3.3 Hz, 1H, PCHCHH), 3.95 (ddd, JHH = 17.2 and
4.6 Hz, JHP = 7.0 Hz, 1H, PCHCHH).
Kα radiation (λ = 0.7107 Å) at ambient temperature. The structure was
solved by direct methods using the SHELXS-97 program, and all non-
hydrogen atoms were refined anisotropically on F2 by the full-matrix
least-squares technique, which used the SHELXL-97 crystallographic
software package.23 The hydrogen atoms were included but not refined.
Details of the crystal structure determination are summarized in Table S1
in the Supporting Information.
20
1
ASSOCIATED CONTENT
* Supporting Information
■
S
A table giving crystallographic details for the pincer Pd(II)
complexes IX and 8, figures giving NMR spectra of the new
compounds 2−5 and the pincer Pd(II) complexes VI−XIII and
8 and NMR spectra of the catalysis products as well as their
chiral HPLC spectra, and CIF files giving crystallographic data
for complexes IX and 8. This material is available free of charge
via the Internet at http://pubs.acs.org.
(S)-Phenyl 3-(Diphenylphosphinyl)-3-phenylpropanoate (Product
in Scheme 4).9a With CH2Cl2/MeOH (100/1) as eluent. white solid
(15.0 mg, 18%); mp 176−177 °C. The enantiomeric excess was deter-
mined on a Daicel Chiralpak IC-3 column with hexane/2-propanol
(80/20) and flow rate 1.0 mL/min and detected at a UV wavelength of
20
228 nm. Retention times: 24.9 min (major), 32.6 min, 83% ee. [α]D
=
1
−56° (c 0.116, CH2Cl2). H NMR (400 MHz, CDCl3): δ 8.01−7.97
AUTHOR INFORMATION
Corresponding Authors
■
(m, 2H), 7.59−7.46 (m, 5H), 7.37−7.11 (m, 11H), 6.68 (d, JHH
=
7.6 Hz, 2H), 4.15 (ddd, JHH = 11.5 and 3.6 Hz, JHP = 8.2 Hz, 1H), 3.37
(ddd, JHH = 18.0 and 11.5 Hz, JHP = 6.7 Hz, 1H), 3.27 (ddd, JHH = 16.2
and 3.6 Hz, JHP = 8.2 Hz, 1H). 13C NMR (100 MHz, CDCl3): δ 169.0
*J.-F.G.: e-mail, gongjf@zzu.edu.cn.
*M.-P.S.: e-mail, mpsong@zzu.edu.cn; tel/fax, (+86)-371-6778-
3012.
(d, JCP = 17.8 Hz), 149.3, 133.6 (d, JCP = 5.6 Hz), 131.2 (d, JCP
2.6 Hz), 130.6 (d, JCP = 2.7 Hz), 130.4 (d, JCP = 8.6 Hz), 130.1 (d, JCP
=
=
Notes
8.9 Hz), 129.5 (two peaks), 128.8 (d, JCP = 5.3 Hz), 128.2, 128.0 (d,
JCP = 11.2 Hz), 127.4 (d, JCP = 1.3 Hz), 127.1 (d, JCP = 11.8 Hz), 126.5
(two peaks), 124.8, 120.3, 42.2 (d, JCP = 67.5 Hz), 34.0. 31P{1H} NMR
(162 MHz, CDCl3): δ 32.4.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
(R)-(2-Nitro-1-phenylethyl)diphenylphosphine Oxide (Product in
Scheme 5).7b,22 With CH2Cl2/acetone (40/1) as eluent. white solid
(68.9 mg, 98%). The enantiomeric excess was determined on a Daicel
Chiralpak AD-H column with hexane/2-propanol (70/30) and flow
rate 0.5 mL/min and detected at a UV wavelength of 228 nm. Reten-
We are grateful to the National Natural Science Foundation of
China (21272217), the Program for Science & Technology In-
novation Talents in Universities of Henan Province (2012HAS-
TIT003), and the Key Technologies R & D Program of Henan
Province (102101210200) for financial support of this work.
20
tion times: 20.4 min (major), 34.6 min, 14% ee. [α]D = −40°
(c 0.200, CH2Cl2). 1H NMR (400 MHz, CDCl3): δ 7.99 (app t, JHH
=
REFERENCES
9.7 and 8.1 Hz, 2H), 7.63−7.60 (m, 3H), 7.46−7.40 (m, 3H), 7.29−
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5.8 Hz, JHP = 3.2 Hz, 1H, PCHCHH), 4.44−4.34 (m, 1H, PCHCHH).
■
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