Ruthenium-catalyzed ortho -alkenylation of phenylphosphine oxides through regio- and stereoselective alkyne insertion into C-H bonds

Article abstract of DOI:10.1021/jo401393b

Direct ortho-substitution took place efficiently upon treatment of tri-, di-, and monoarylphosphine oxides with internal alkynes in the presence of a ruthenium catalyst to produce (o-alkenylphenyl)phosphine oxides regio- and stereoselectively. Chemoselective reduction of a product gave the corresponding (o-alkenylphenyl)phosphine, which may be useful as a ligand for transition metals.

Full text of DOI:10.1021/jo401393b

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Article
Ruthenium-Catalyzed ortho-Alkenylation of Phenylphosphine Oxides
through Regio- and Stereoselective Alkyne Insertion into C-H Bond
Masaki Itoh, Yuto Hashimoto, Koji Hirano, Tetsuya Satoh, and Masahiro Miura
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/jo401393b • Publication Date (Web): 24 Jul 2013
Downloaded from http://pubs.acs.org on August 5, 2013
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Ruthenium-Catalyzed ortho-Alkenylation of
Phenylphosphine Oxides through Regio- and
Stereoselective Alkyne Insertion into C–H Bond
Masaki Itoh,† Yuto Hashimoto,† Koji Hirano,† Tetsuya Satoh, *,†,‡ and Masahiro Miura*,†
†Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871,
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Japan
‡JST, ACT-C, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
satoh@chem.eng.osaka-u.ac.jp; miura@chem.eng.osaka-u.ac.jp
RECEIVED DATE (to be automatically inserted after your manuscript is accepted if required)
R1
O
P
R2
H
ꢀ
R1
R2
O
R2 R1
P
R3
P
R3
Ru-cat.
AcOH
R4
R4
+
R4
R3
Abstract: Direct ortho-substitution took place efficiently upon treatment of tri-, di, and
monoarylphosphine oxides with internal alkynes in the presence of a ruthenium catalyst to produce (o-
alkenylphenyl)phosphine oxides regio- and stereoselectively. Chemoselective reduction of a product
gave the corresponding (o-alkenylphenyl)phosphine, which may be useful as a ligand for transition-
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metals.
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Introduction
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Well-designed arylphosphine oxides (ArnR3-nP=O) have attracted considerable attention in organic
materials field due to their wide bandgaps and application as host materials in phosphorescent organic
light-emitting diodes.1 They have also been utilized as potential antitumor agents2 as well as
organocatalysts.3 Furthermore, needless to say, phosphine oxides have been recognized as important
intermediates in the preparation of the corresponding phosphine ligands.4 Therefore, simple methods for
their precious synthesis and modification have been continuously demanded to be developed in these
wide fields.
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Meanwhile, the transition-metal-catalyzed ortho C–H bond functionalization of aromatic substrates
possessing a directing group has been significantly developed in recent years as atom- and step-
economical tools in precise organic synthesis.5 As directing groups, carbonyl, hydroxy, imino, amide,
and pyridyl groups have been widely employed to realize regioselective substitution on arenes. Recently,
the palladium-,5h,m,r,s,w,x rhodium-,5c,f,g,i,o,q and ruthenium-catalyzed5a,b ortho-alkenylation of aromatic
substrates possessing such common directing groups has been explosively developed. Against the recent
trend, we have explored new directing groups and found that the P=O function of phenylphosphine
oxides can exhibit an effective function to allow the ortho-alkenylation upon treatment of them with
alkenes in the presence of a silver salt as oxidant under rhodium catalysis (Scheme 1).6 This is a rare
example of ortho-fuctionalization with the aid of P=O groups,7 whose coordination abilities toward a
transition-metal center have been presumed to be relatively weak. During our further studies on the
utilization of this uncommon directing group, we succeeded in finding that a wide range of tri-, di-, and
monoarylphosphine oxides efficiently undergo ortho-alkenylation through insertion of alkynes under
ruthenium catalysis. Such a ruthenium-catalyzed reaction is attractive because of its lower catalyst cost
relative to Rh.8 Furthermore, the present reaction appears to be more environmentally-benign because
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The Journal of Organic Chemistry
no oxidant such as stoichiometric silver or copper salts is needed. Under the ruthenium catalysis, a
similar ortho-alkylation could also be achieved by using an alkene in place of alkynes.9 The results
obtained with respect to these reactions are described herein.
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Scheme 1. Catalytic ortho-Alkenylation of Phenylphosphine Oxides
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R1
R3
O
R2
P
Rh-cat.
R3
Ag-salt oxidant
R1
our previous work
O
R2
P
R5
R1
R4
O
R2
P
R4
Ru-cat.
R5
w/o oxidant
this work
Results and Discussion
In an initial attempt, triphenylphosphine oxide (1a) (0.5 mmol) was treated with diphenylacetylene
(2a) (0.25 mmol) in the presence of [Ru(p-cymene)Cl2]2 (5 mol%), AgSbF6 (20 mol%), and 1-AdCO2H
(Ad = adamantyl) (1 mmol) in dioxane at 100 oC for 3 h. As a result, ortho-alkenylated product 3aa was
obtained in 74% yield (Table 1, entry 1). In this case, formation of multiply alkenylated products was
also detected. To our delight, 3aa was obtained quantitatively by using an excess amount of 1a (entry 2).
It was confirmed that the reaction did not proceed at all without [Ru(p-cymene)Cl2]2 (entry 3) or AgSbF6
entry 4). Other acids such as AcOH, PivOH, and 2,6-dimethylbenzoic acid were found to be comparably
effective as 1-AdCO2H (entries 5-7). Therefore, we decided to use the cheapest acid, AcOH, in further
experiments.
Table 1. Reaction of Triphenylphosphine Oxide (1a) with Diphenylacetylene (2a)a
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Ph
Ph
[Ru(p-cymene)Cl2]2 (5 mol%)
O
O
1
AgSbF6 (20 mol%)
Ph
Ph
P
Ph
P
Ph
2
3
+
Ph
acid/dioxane, 100 o
C
Ph
4
5
1a
2a
3aa
6
7
8
yield of 3aa
entry
acid
(%)b
9
1c
2
3d
4e
5
74
>99 (82)
0
1-AdCO2H
1-AdCO2H
1-AdCO2H
1-AdCO2H
AcOH
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0
97 (86)
>99
95
PivOH
2,6-Me2C6H3CO2H
6
7
a
Reaction conditions: 1a (1.25 mmol), 2a (0.25 mmol), [Ru(p-cymene)Cl2]2 (0.013 mmol), AgSbF6
(0.05 mmol), acid (1 mmol) in dioxane (3 mL) under N2 at 100 C for 3 h. GC yield based on the
o
b
c
d
amount of 2a used. Value in parentheses indicates yield after purification. With 1a (0.5 mmol).
Without [Ru(p-cymene)Cl2]2. e Without AgSbF6.
The reactions of various arylphosphine oxides 1b-n with 2a were next examined under conditions
using AcOH. A series of tris(p-substituted phenyl)phosphine oxides 1b-f underwent alkenylation to
produce 3ba-3fa in good yields (Table 2, entries 1-5). Although the reaction of 1f was relatively
sluggish, the corresponding product 3fa was obtained in 80% yield by extending the reaction time to 24
h under refluxing conditions (entry 5). While tris(m-tolyl)phosphine oxide (1g) underwent the reaction
smoothly, the reaction of m-chlorinated substrate 1h required 18 h to be completed (entries 6 and 7).
Even sterically hindered tris(o-tolyl)phosphine oxide (1i) coupled with 2a efficiently to produce 3ia in
77% yield (entry 8). Similarly to triarylphosphine oxides, alkyl(diphenyl)phosphine oxides 1j,k and
dialkyl(phenyl)phosphine oxides 1l,m also underwent ortho-alkenylation (entries 9-12). Note that the
oxide of CyJohnPhos (1n) could be employed as the substrate to produce 3na in an excellent yield
(entry 13). Only in the last case, the product was formed as an E/Z mixture.
Table 2. Reaction of Arylphosphine Oxides 1 with 2aa
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The Journal of Organic Chemistry
R3
R3
[Ru(p-cymene)Cl2]2 (5 mol%)
AgSbF6 (20 mol%)
O
O
1
R2
P
R2
P
Ph
Ph
2
+
Ph
3
4
AcOH
dioxane, 100 oC
Ph
R1
R1
5
1
2a
3
6
7
time (h)
product, % yieldb
1
entry
R
R
R
R
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P
P
O
O
Ph
R
R
Ph
3
3
1b: R = Me
1c: R = OMe
1d: R = Cl
1e: R = F
1f: R = CF3
R
3ba: R = Me, 85
3ca: R = OMe, 92
3da: R = Cl, 85
3ea: R = F, 83
3fa: R = CF3, 80
R
1
2
3
3
3
4
5c
24
R
R
P
P
O
O
R
R
Ph
Ph
3
1g: R = Me
1h: R = Cl
Me
3ga: R = Me, 88
3ha: R = Cl, 78
Me
6
7
18
Me
Me
P
P
Me
Me
O
O
Ph
Ph
10
1i
3ia, 77
8
R
O
R
P
P
O
Ph
Ph
18
18
1j: R = Me
1k: R = Cy
3ja: R = Me, 74
3ka: R = Cy, 91
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10
R
R
O
R
R
O
P
P
Ph
Ph
18
40
1l: R = Cy
3la: R = Cy, 82
11
12
1m: R = t-Bu
3ma: R = t-Bu, 44
Cy Cy
P
Cy Cy
Ph
Ph
P
O
O
Ph
Ph
3na, 98d
36
1n
13
a
Reaction conditions: 1 (1.25 mmol), 2a (0.25 mmol), [Ru(p-cymene)Cl2]2 (0.013 mmol), AgSbF6
(0.05 mmol), AcOH (1 mmol) in dioxane (3 mL) at 100 C under N2 Isolated yield. In refluxing
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o
b
c
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dioxane (bath temperature: 120 oC). d E/Z = 84:16.
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The reactions of various internal alkynes 2b-j with 1a were also examined. Bis(p-substituted
phenyl)acetylenes underwent the coupling with 1a to give 3ab-3ae in 90-98% yields (Table 3, entries 1-
4). The reaction of di(2-thienyl)acetylene (2f) took place under similar conditions, albeit with low
efficiency (entry 5). It would be possible that some interaction between the thienyl moiety and Ru
retarded the reaction. Unsymmetrical alkyl(phenyl)acetylenes 2g-i and phenyl(trimethylsilyl)acetylene
(2j) could also be used as alkenyl sources to afford 3ag-3aj stereo- and regioselectively (entries 6-9).
Other isomers were not detected at all. The reaction of 2j proceeded involving desilylation to form 3aj
as a single major product (entry 9). In contrast to internal alkynes, the reactions with terminal alkynes
were found to be inefficient. Under similar conditions, the reaction of 1a with
(triisopropylsilyl)acetylene gave only a trace amount of alkenylated product. In the case using
phenylacetylene, any coupling products could not be detected at all. In both cases, significant amounts
of substrates remained unconsumed.
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The Journal of Organic Chemistry
Table 3. Reaction of 1a with Alkynes 2a
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2
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4
5
6
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8
Ph
Ph
[Ru(p-cymene)Cl2]2 (5 mol%)
O
O
R2
Ph
P
Ph
P
R1
AgSbF6 (20 mol%)
R2
+
AcOH
dioxane, 100 oC
R1
1a
2
3
9
time (h)
product, % yieldb
2
entry
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R
R
O
P
Ph
Ph
R
R
3
3
3
5
2b: R = Me
2c: R = t-Bu
2d: R = Cl
2e: R = CF3
3ab: R = Me, 91
3ac: R = t-Bu, 90
3ad: R = Cl, 92
3ae: R = CF3, 98
1
2
3
4
O
S
Ph
S
P
S
Ph
S
6
2f
3af, 20
5
O
Ph
Ph
P
R
R
3
3
2g: R = Me
2h: R = Bu
3ag: R = Me, 81
3ah: R = Bu, 86
6
7
8
9
3
2i: R = cyclo-Pr
2j: R = TMS
3ai: R = cyclo-Pr, 58
3aj: R = H, 50
18
a
Reaction conditions: 1a (1.25 mmol), 2 (0.25 mmol), [Ru(p-cymene)Cl2]2 (0.013 mmol), AgSbF6
(0.05 mmol), AcOH (1 mmol) in dioxane (3 mL) at 100 oC under N2. b Isolated yield.
Chemoselective reduction methods from phosphine oxides to the corresponding phosphines have been
established.10 As a preliminary attempt, we examined the reduction of one of our alkenylated product
3aj by the Beller’s procedure using (4-NO2C6H4O)2P(O)OH/(EtO)2MeSiH.10a As a result, we succeeded
in obtaining diphenyl(o-styrylphenyl)phosphine (4), as shown in Scheme 2. It is well-known that (o-
substituted phenyl)phosphines are useful as ligands for transition-metals.11 The reduction of more
sterically hindered 3aa also proceeded to some extent under similar conditions. However, considerable
contamination of an isomer of product was observed by GC-MS.
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1
2
3
4
5
6
Scheme 2. Reduction of 3aj
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Ph
Ph
Ph
O
Ph
(4-NO2C6H4O)2P(O)OH
(15 mol%)
P
P
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Ph
Ph
(EtO)2MeSiH (1 mmol)
toluene, 110 oC, 24 h
66%
3aj
(0.25 mmol)
4
The ortho-alkenylation of 1 seems to proceed via ortho-metalation, alkyne insertion, and protonolysis,
as shown in Scheme 3. The added acid may promote the last step.12 The ortho-metalation on parent
triphenylphosphine itself has been reported to produce a four-membered ruthenacycle.13 Unfortunately,
its treatment with 2a under our standard conditions did not give any ortho-alkenylated product at all.
Scheme 3. Possible Pathway for the ortho-Alkenylation
R4
R1
R1
P
[Ru]
O
R1
R2
O
O
R4
R3
P
[Ru]
–H+
P
2
H+
–[Ru]
R2
R2
[Ru]
3
H
R3
1
A
B
For
providing
further
mechanistic
information,
the
reaction
of
deuterated
dicyclohexyl(phenyl)phosphine oxide (1l-d5) with 2a was conducted under standard conditions (Scheme
4). In the early stage (3 h), deuterium incorporation at the alkenyl position of the product was not
1
detected at all by H NMR. This result appears to exclude the possibility of a reaction route involving
initial oxidative addition of an ortho C–H bond, which should result in deuterium incorporation at the
position. During the reaction, no significant D–H exchange at the ortho-positions of recovered 1l-d5 as
well as at the 6-position of product 3la-d4 was observed. More informative is that the reaction rate of 1l-
d5 was considerably lower than that of 1l-d0. Thus, the kinetic isotope effect was determined to be 2.1.
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The Journal of Organic Chemistry
These observations suggest that the ortho C–H bond cleavage step to form intermediate A is likely
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3
irreversible and involved as the rate determining step.
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5
6
7
8
Scheme 4. Parallel Reactions of 1l-d5 and 1l-d0 with 2a
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[Ru(p-cymene)Cl2]2
Cy
Cy
Cy
Cy
(5 mol %)
AgSbF6
O
O
P
P
Ph
D
>96% D
Ph
D
D
D
D
Ph
(20 mol %)
+
H
AcOH (1 mmol)
Dioxane
100 oC, 3 h
D
Ph
D
<1% D
2a
D
D
(0.25 mmol)
3la-d4 (21%)
3la-d0 (41%)
1l-d5
(1.25 mmol)
+
1l-d0
(1.25 mmol)
2a
(0.25 mmol)
3 h
Under similar conditions, ortho-alkylation of phosphine oxide 1a using butyl acrylate (5) in place of
alkynes was finally examined. Treatment of 1a (0.5 mmol) with 5 (0.25 mmol) in the presence of [Ru(p-
cymene)Cl2]2 (5 mol%), AgSbF6 (20 mol%), and 1-AdCO2H (1 mmol) in dioxane at 100 oC for 5 h gave
alkylated product 6 in 33% yield (Scheme 5). At 120 oC in diglyme, the yield of 6 was improved to 58%.
Scheme 5. ortho-Alkylation of 1a with Butyl Acrylate (6)
[Ru(p-cymene)Cl2]2
(5 mol %)
Ph
Ph
AgSbF6
O
O
Ph
P
Ph
P
(20 mol %)
+
CO2Bu
CO2Bu
1-AdCO2H (1 mmol)
solvent, 5 h
5
(0.25 mmol)
6
1a
(0.5 mmol)
in dioxane at 100 oC
in diglyme at 120 oC
33%
58%
Conclusions
We have demonstrated that various arylphosphine oxides undergo ortho-alkenylation on treatment
with alkynes under ruthenium catalysis through P=O group-directed C–H bond cleavage. The relevant
alkylation with an acrylate ester has also been achieved. Work is underway toward further utilization of
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related phosphorous-containing groups.
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6
Experimental Section
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9
General. H and 13C NMR spectra were recorded at 400 or 600 and 100 or 150 MHz, respectively, for
CDCl3 solutions. HRMS data were obtained by EI using a double focusing mass spectrometer, unless
noted. GC analysis was carried out using a silicon OV-17 column (i. d. 2.6 mm x 1.5 m). GC-MS
analysis was carried out using a CBP-1 capillary column (i. d. 0.25 mm x 25 m). The structures of all
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1
13
31
products listed below were unambiguously determined by H, C, and P NMR with the aid of NOE,
COSY, HSQC, and HMBC experiments.
Phosphine oxides 1b-n and dicyclohexyl(d5-phenyl)phosphine oxide (1l-d5) were prepared as noted
below. Diarylacetylenes 2b-f14 and 1-cyclopropyl-2-phenylacetylene (2i)15 were prepared according to
published procedures. Phosphine oxides 4a-c were prepared as noted below. Other reagents were
commercially available.
Preparation of Phosphine Oxides 1. Synthesis of 1b is representative. To a solution of tris(p-
tolyl)phosphine (5 mmol, 1.52 g) in THF (5 mL), H2O2 (30% aqueous solution, 3 eq) was dropped
slowly and stirred at room temperature. The exothermic reaction terminated within a few minutes. After
checking a consumption of phosphine by TLC, the reaction mixture was quenched by saturated
NaHCO3 (10 mL) and saturated Na2S2O3 (20 mL), and additionally stirred for a few minutes. Then, the
reaction mixture was extracted by ethyl acetate (20 mL, three times) and dried over Na2SO4. Volatiles
were removed in vacuo to afford tris(p-tolyl)phosphine oxide (1b) quantitatively without further
purification.
General Procedure for the Reaction of Phosphine Oxides 1 with Alkynes 2. To a 20 mL two-
necked flask with a reflux condenser, a balloon filled with N2, and a rubber septum were added
phosphine oxide 1 (1.25 mmol), alkyne 2 (0.25 mmol), [Ru(p-cymene)Cl2]2 (0.013 mmol, 7.7 mg),
AgSbF6 (0.05 mmol, 17 mg), AcOH (1 mmol, 60 mg), 1-methylnaphthalene (ca. 40 mg) as internal
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standard, and dioxane (3 mL). Then, the resulting mixture was stirred under nitrogen at 100 oC for 3-40
h. After cooling, the reaction mixture was extracted with ethyl acetate (100 mL). The organic layer was
washed by water (100 mL, three times), and dried over Na2SO4. After evaporation of the solvents under
vacuum, product 3 was isolated by column chromatography on silica gel using hexane-ethyl acetate (1:1,
v/v) as eluent.
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Procedure for Reduction of Phosphine Oxide 3aj.10a To a 20 mL two-necked flask with a reflux
condenser, a balloon filled with N2, and a rubber septum were added phosphine oxide 3aj (0.25 mmol,
95 mg), bis(4-nitrophenyl)phosphate (0.038 mmol, 13 mg), diethoxymethylsilane (1 mmol, 134 mg), 1-
methylnaphthalene (ca. 30 mg) as internal standard, and toluene (2 mL). After stirring the solution under
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nitrogen at 110 C for 24 h, the reaction mixture was cooled to 0 C and 3N methanolic KOH (5 mL)
was added slowly. Then, the reaction mixture was stirred at room temperature for 3 h. The reaction
mixture was extracted with ethyl acetate (100 mL). The organic layer was washed by 1N HCl (5 mL)
and saturated NaHCO3 (5 mL), and dried over Na2SO4. Concentration in vacuo followed by column
chromatography on silica gel using hexane-ethyl acetate (20:1, v/v) as eluent gave phosphine 4 (60 mg,
0.16 mmol) in 66% yield.
Procedure for Reaction of Deuterated Substrate 1l-d5. To a 20 mL two-necked flask were added
dicyclohexyl(d5-phenyl)phosphine oxide (1l-d5) (1.25 mmol), diphenylacetylene (2a) (0.25 mmol),
[Ru(p-cymene)Cl2]2 (0.0125 mmol), AgSbF6 (0.05 mmol), AcOH (1 mmol), 1-methylnaphthalene (ca.
o
30 mg) as internal standard, and dioxane (3 mL). The resulting mixture was stirred under N2 at 100 C
for 5 h. After cooling, the reaction mixture was extracted with ethyl acetate (100 mL), washed with
water (100 mL, three times), and dried over Na2SO4. Produced 3la-d4 and recovered 1l-d5 were isolated
by column chromatography on silica gel using ethyl acetate as eluant. Recoverd 1l-d5 (305 mg, 1.03
mmol); 1H NMR (400 MHz, CDCl3) δ 1.09-1.35 (m, 10H), 1.60-1.82 (m, 8H), 1.99-2.06 (m, 4H), 7.67
1
(d, J = 9.7 Hz, 0.06H). Produced 3la-d4 (30 mg, 25%); H NMR (400 MHz, CDCl3) δ 0.93-1.35 (m,
10H), 1.55-1.84 (m, 12H), 6.57 (s, 1H), 7.15-7.26 (m, 10H), 8.06 (d, J = 11.4 Hz, 0.04H).
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(E)-[2-(1,2-Diphenylethenyl)phenyl]diphenylphosphine Oxide (3aa): mp 68-69 C (colorless
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powder), 98 mg (86%); 1H NMR (400 MHz, CDCl3) δ 6.72 (d, J = 6.0 Hz, 2H), 6.83 (s, 1H), 6.99-7.25
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(m, 10H), 7.32-7.44 (m, 8H), 7.73 (dd, J = 7.3, 11.9 Hz, 4H); 13C NMR (100 MHz, CDCl3) δ 126.3 (d, J
= 12.4 Hz), 126.6, 127.1, 127.5, 127.8, 128.2 (d, J = 12.5 Hz), 129.7, 130.6, 131.2 (d, J = 2.9 Hz), 131.3
(d, J = 2.8 Hz), 131.6 (d, J = 9.5 Hz), 131.9 (d, J = 102.5 Hz), 132.0 (d, J = 9.6 Hz), 133.9 (d, J = 104.5
Hz), 134.1, 134.6 (d, J = 12.5 Hz), 136.8, 140.1 (d, J = 3.9 Hz), 140.2, 149.6 (d, J = 8.6 Hz); 31P NMR
(162 MHz, CDCl3) δ 28.97; HRMS m/z calcd for C32H25OP (M+) 456.1643, found 456.1646.
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(E)-[2-(1,2-Diphenylethenyl)-4-methylphenyl]bis(4-methylphenyl)phosphine Oxide (3ba): mp
160-161oC (colorless powder), 105 mg (85%); 1H NMR (400 MHz, CDCl3) δ 2.27 (s, 3H), 2.32 (s, 6H),
6.72-6.75 (m, 3H), 6.97-7.04 (m, 5H), 7.07-7.14 (m, 9H), 7.28 (dd, J = 7.8, 13.7 Hz, 1H), 7.59 (dd, J =
8.2, 11.8 Hz, 4H); 13C NMR (100 MHz, CDCl3) δ 21.3, 21.4, 126.5, 126.9, 127.1 (d, J = 13.4 Hz), 127.4,
127.8, 128.9 (d, J = 12.5 Hz), 129.2 (d, J = 104.5 Hz), 129.6, 130.5, 131.1 (d, J = 107.5 Hz), 131.6 (d, J
= 9.6 Hz), 132.5 (d, J = 9.5 Hz), 133.7, 134.7 (d, J = 12.4 Hz), 137.0, 140.1 (d, J = 3.8 Hz), 140.3, 141.3
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(d, J = 2.9 Hz), 141.5 (d, J = 2.9 Hz), 149.3 (d, J = 7.6 Hz); P NMR (162 MHz, CDCl3) δ 28.83;
HRMS m/z calcd for C35H31OP (M+) 498.2113, found 498.2112.
(E)-[2-(1,2-Diphenylethenyl)-4-methoxyphenyl]bis(4-methoxyphenyl)phosphine Oxide (3ca): mp
153-154oC (colorless powder), 126 mg (92%); 1H NMR (400 MHz, CDCl3) δ 3.71 (s, 3H), 3.77 (s, 6H),
6.68-6.69 (m, 1H), 6.73-6.79 (m, 4H), 6.84 (dd, J = 2.3, 8.7 Hz, 4H), 6.99-7.13 (m, 8H), 7.32 (dd, J =
8.5, 13.5 Hz, 1H), 7.61 (d, J = 8.7, 11.2 Hz, 4H); 13C NMR (100 MHz, CDCl3) δ 55.16, 55.20, 111.5 (d,
J = 13.4 Hz), 113.7 (d, J = 13.4 Hz), 117.6 (d, J = 10.5 Hz), 124.3 (d, J = 108.3 Hz), 125.9 (d, J = 111.2
Hz), 126.6, 127.1, 127.4, 127.8, 129.7, 130.5, 133.3 (d, J = 10.5 Hz), 133.7, 136.5 (d, J = 14.3 Hz),
136.9, 139.8 (d, J = 3.8 Hz), 140.1, 151.3 (d, J = 8.6 Hz), 161.5 (d, J = 2.8 Hz), 161.7 (d, J = 2.8 Hz);
31P NMR (162 MHz, CDCl3) δ 28.12; HRMS m/z calcd for C35H31O4P (M+) 546.1960, found 546.1954.
(E)-[4-Chloro-2-(1,2-diphenylethenyl)phenyl]bis(4-chlorophenyl)phosphine Oxide (3da): mp 73-
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74oC (colorless powder), 119 mg (85%); 1H NMR (400 MHz, CDCl3) δ 6.72 (s, 1H), 6.76-6.78 (m, 2H),
7.03-7.29 (m, 11H), 7.33 (dd, J = 2.3, 8.3 Hz, 4H), 7.59 (dd, J = 8.3, 11.0 Hz, 4H); 13C NMR (100 MHz,
CDCl3) δ 126.8 (d, J = 13.4 Hz), 127.2, 127.6, 127.7, 128.1, 128.8 (d, J = 12.5 Hz), 129.53, 129.54 (d, J
= 105.4 Hz), 130.4, 131.6 (d, J = 106.4 Hz), 132.2 (d, J = 10.5 Hz), 132.8 (d, J = 10.6 Hz), 134.7, 135.6
(d, J = 14.4 Hz), 136.1, 138.2 (d, J = 4.8 Hz), 138.3 (d, J = 3.8 Hz), 138.7 (d, J = 3.8 Hz), 139.0, 151.3
(d, J = 8.7 Hz); 31P NMR (162 MHz, CDCl3) δ 27.21; HRMS m/z calcd for C32H22Cl3OP (M+) 558.0474,
found 558.0477.
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(E)-[2-(1,2-Diphenylethenyl)-4-fluorophenyl]bis(4-fluorophenyl)phosphine Oxide (3ea): mp 67-
68oC (colorless powder), 106 mg (83%); 1H NMR (400 MHz, CDCl3) δ 6.77 (d, J = 6.8 Hz, 2H), 6.81 (s,
1H), 6.88-7.17 (m, 14H), 7.34 (ddd, J = 5.9, 8.6, 14.5 Hz, 1H), 7.68 (ddd, J = 5.9, 7.7, 11.3 Hz, 4H); 13C
NMR (100 MHz, CDCl3) δ 113.8 (dd, J = 13.4, 21.0 Hz), 115.8 (dd, J = 13.4, 21.0 Hz), 119.3 (dd, J =
10.5, 21.0 Hz), 127.2, 127.5 (dd, J = 3.8, 106.8 Hz), 127.6, 127.7, 128.1, 129.5 (dd, J = 3.8, 108.7 Hz),
129.6, 130.4, 133.9 (dd, J = 8.6, 10.5 Hz), 134.6, 136.2, 136.9 (dd, J = 8.6, 14.3 Hz), 138.9 (dd, J = 1.9,
3.8 Hz), 139.3, 152.8 (dd, J = 8.6, 8.6 Hz), 164.4 (dd, J = 2.9, 254.6 Hz), 164.7 (dd, J = 2.9, 253.7 Hz);
31P NMR (162 MHz, CDCl3) δ 26.88; HRMS m/z calcd for C32H22F3OP (M+) 510.1360, found 510.1358.
(E)-[2-(1,2-Diphenylethenyl)-4-(trifluoromethyl)phenyl]bis[4-
(trifluoromethyl)phenyl]phosphine Oxide (3fa): mp 70-71oC (pale yellow powder), 131 mg (80%);
1H NMR (400 MHz, CDCl3) δ 6.71-6.74 (m, 3H), 7.03-7.19 (m, 8H), 7.43-7.58 (m, 3H), 7.63 (dd, J =
2.3, 8.3 Hz, 4H), 7.82 (dd, J = 8.3, 11.5 Hz, 4H); 13C NMR (100 MHz, CDCl3) δ 123.2 (q, J = 273.1 Hz),
123.4 (q, J = 273.1 Hz), 123.5 (dq, J = 2.9, 13.4 Hz), 125.5 (dq, J = 2.8, 11.5 Hz), 127.6, 127.8, 128.1,
128.3, 129.1 (dq, J = 2.9, 10.6 Hz), 129.5, 130.4, 131.9 (d, J = 9.6 Hz), 133.8 (dq, J = 2.9, 32.6 Hz),
133.9 (dq, J = 2.9, 33.6 Hz), 134.9 (d, J = 13.4 Hz), 135.3 (d, J = 102.5 Hz), 135.4, 136.8 (d, J = 101.6
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Hz), 137.3 (d, J = 1.9 Hz), 138.6, 138.8 (d, J = 2.8 Hz), 150.8 (d, J = 7.7 Hz); P NMR (162 MHz,
CDCl3) δ 26.45; HRMS m/z calcd for C35H22F9OP (M+) 660.1265, found 660.1259.
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(E)-[2-(1,2-Diphenylethenyl)-5-methylphenyl]bis(3-methylphenyl)phosphine Oxide (3ga): mp
203-204oC (colorless powder), 110 mg (88%); 1H NMR (400 MHz, CDCl3) δ 2.21 (s, 6H), 2.25 (s, 3H),
6.68 (dd, J = 2.2, 7.3 Hz, 2H), 6.91 (s, 1H), 6.99-7.14 (m, 9H), 7.18-7.27 (m, 6H), 7.49 (dd, J = 7.3,
11.8 Hz, 2H), 7.63 (d, J = 11.8 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 21.2, 21.3, 126.5, 127.1, 127.4,
127.8, 128.0 (d, J = 12.4 Hz), 128.5 (d, J = 9.5 Hz), 129.8, 130.6, 131.8 (d, J = 2.9 Hz), 131.9 (d, J = 9.5
Hz), 132.0 (d, J = 2.8 Hz), 132.1 (d, J = 102.0 Hz), 132.3 (d, J = 8.5 Hz), 133.9 (d, J = 103.0 Hz), 134.1,
135.2 (d, J = 12.4 Hz), 136.2 (d, J = 12.4 Hz), 136.9, 138.1 (d, J = 11.4 Hz), 139.7 (d, J = 3.8 Hz), 140.6,
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146.6 (d, J = 7.6 Hz); P NMR (162 MHz, CDCl3) δ 28.81; HRMS m/z calcd for C35H31OP (M+)
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498.2113, found 498.2115.
(E)-[5-Chloro-2-(1,2-diphenylethenyl)phenyl]bis(3-chlorophenyl)phosphine Oxide (3ha): mp 73-
74oC (colorless powder), 109 mg (78%); 1H NMR (400 MHz, CDCl3) δ 6.73 (dd, J = 1.8, 7.7 Hz, 2H),
6.89 (s, 1H), 7.03-7.17 (m, 9H), 7.28-7.34 (m, 3H), 7.40-7.44 (m, 3H), 7.57 (dd, J = 7.7, 11.3 Hz, 2H),
7.69 (d, J = 12.2 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 127.2, 127.69, 127.74, 128.1, 129.5 (d, J = 9.5
Hz), 129.6, 130.0 (d, J = 12.4 Hz), 130.5, 131.2 (d, J = 9.6 Hz), 131.97 (d, J = 2.8 Hz), 132.01 (d, J =
3.9 Hz), 132.8 (d, J = 102.0 Hz), 133.0 (d, J = 16.2 Hz), 133.9 (d, J = 8.6 Hz), 134.0 (d, J = 12.4 Hz),
134.90 (d, J = 103.0 Hz), 134.92, 135.1 (d, J = 15.3 Hz), 136.1, 138.7 (d, J = 3.8 Hz), 139.4, 148.1 (d, J
= 6.7 Hz); P NMR (162 MHz, CDCl3) δ 26.02; HRMS m/z calcd for C32H22Cl3OP (M+) 558.0474,
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found 558.0471.
(E)-[2-(1,2-Diphenylethenyl)-6-methylphenyl]bis(2-methylphenyl)phosphine Oxide (3ia): mp 91-
92oC (pale yellow powder), 96 mg (77%); 1H NMR (600 MHz, DMSO-d6, 100 oC) δ 1.83 (s, 3H), 2.37
(s, 6H), 6.08 (s, 1H), 6.79 (dd, J = 1.5, 7.3 Hz, 2H), 6.98-7.02 (m, 3H), 7.07-7.14 (m, 6H), 7.17-7.21 (m,
3H), 7.25 (dd, J = 4.1, 7.6 Hz, 2H), 7.32 (d, J = 6.2 Hz, 2H), 7.40 (tt, J = 1.5, 7.3 Hz, 2H), 7.43 (dt, J =
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1.5, 7.9 Hz, 1H); C NMR (150 MHz, DMSO-d6, 100 C) δ 20.3 (d, J = 4.0 Hz), 22.9 (d, J = 3.9 Hz),
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124.9 (d, J = 12.9 Hz), 125.7, 126.2, 126.8, 126.9, 128.2, 129.2 (d, J = 9.9 Hz), 129.3, 129.7 (d, J =
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102.9 Hz), 130.0 (d, J = 9.9 Hz), 130.07, 130.11 (d, J = 3.0 Hz), 130.8 (d, J = 2.9 Hz), 131.1 (d, J = 9.9
Hz), 131.2 (d, J = 102.9 Hz), 131.4 (d, J = 12.9 Hz), 136.9, 140.0, 140.9 (d, J = 9.9 Hz), 141.9, 142.9 (d,
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J = 4.0 Hz), 150.5 (d, J = 6.9 Hz); P NMR (243 MHz, DMSO-d6) δ 34.64; HRMS m/z calcd for
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(brown powder), 73 mg (74%); H NMR (400 MHz, CDCl3) δ 2.03 (d, J = 12.8 Hz, 3H), 6.57 (s, 1H),
6.89-6.91 (m, 2H), 6.96 (dd, J = 1.8, 8.2 Hz, 2H), 7.09-7.19 (m, 7H), 7.32 (dt, J = 2.8, 7.3 Hz, 2H),
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7.38-7.45 (m, 3H), 7.54-7.59 (m, 2H), 7.96-8.02 (m, 1H); C NMR (100 MHz, CDCl3) δ 17.5 (d, J =
74.8 Hz), 126.9 (d, J = 11.5 Hz), 127.1, 127.5, 127.9, 128.1, 128.3 (d, J = 11.5 Hz), 129.6, 130.3, 130.5
(d, J = 10.5 Hz), 131.1 (d, J = 1.9 Hz), 131.3 (d, J = 1.9 Hz), 131.9 (d, J = 9.6 Hz), 132.6 (d, J = 90.1
Hz), 133.0 (d, J = 10.5 Hz), 135.6 (d, J = 102.5 Hz), 136.4, 139.9, 140.00, 140.04, 148.2 (d, J = 8.6 Hz);
31P NMR (162 MHz, CDCl3) δ 31.54; HRMS m/z calcd for C27H23OP (M+) 394.1487, found 394.1487.
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(E)-Cyclohexyl[2-(1,2-diphenylethenyl)phenyl](phenyl)phosphine Oxide (3ka): mp 71-72 C
(colorless powder), 105 mg (91%); 1H NMR (400 MHz, CDCl3) δ 1.13-1.23 (m, 3H), 1.53-1.81 (m, 7H),
2.25-2.26 (m, 1H), 6.21 (s, 1H), 6.92-6.94 (m, 4H), 7.06-7.15 (m, 7H), 7.26-7.30 (m, 2H), 7.37-7.46 (m,
3H), 7.51-7.56 (m, 2H), 8.06-8.11 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 25.0 (d, J = 2.9 Hz), 25.4 (d,
J = 2.9 Hz), 25.8, 26.3 (d, J = 13.4 Hz), 26.4 (d, J = 14.3 Hz), 36.9 (d, J = 73.5 Hz), 126.7 (d, J = 10.5
Hz), 126.9, 127.2, 127.8, 127.9, 128.1 (d, J = 11.5 Hz), 129.6, 130.4, 130.8 (d, J = 2.8 Hz), 130.9 (d, J =
1.9 Hz), 131.09 (d, J = 90.6 Hz), 131.14 (d, J = 8.5 Hz), 131.9, 132.2 (d, J = 9.5 Hz), 132.9 (d, J = 8.6
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Hz), 133.6 (d, J = 94.4 Hz), 136.7, 139.8, 141.0 (d, J = 2.9 Hz), 148.7 (d, J = 7.6 Hz); P NMR (162
MHz, CDCl3) δ 35.99; HRMS m/z calcd for C32H31OP (M+) 462.2113, found 462.2111.
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(E)-Dicyclohexyl[2-(1,2-diphenylethenyl)phenyl]phosphine Oxide (3la): mp 32-33 C (brown
powder), 96 mg (82%); 1H NMR (400 MHz, CDCl3) δ 0.93-1.36 (m, 10H), 1.55-1.84 (m, 12H), 6.57 (s,
1H), 7.15-7.25 (m, 10H), 7.37 (ddd, J = 1.4, 4.1, 7.3 Hz, 1H), 7.46 (tt, J = 1.4, 7.8 Hz, 1H), 7.51 (tt, J =
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1.4, 7.3 Hz, 1H), 8.06 (ddd, J = 1.4, 7.8, 11.0 Hz, 1H); C NMR (100 MHz, CDCl3) δ 25.6 (d, J = 1.9
Hz), 26.1 (d, J = 3.8 Hz), 26.2 (d, J = 3.8 Hz), 26.3 (d, J = 12.5 Hz), 26.4 (d, J = 12.5 Hz), 37.4 (d, J =
65.1 Hz), 127.1, 127.2 (d, J = 9.6 Hz), 127.8, 128.2, 128.29, 128.33, 130.4, 130.5 (d, J = 78.6 Hz),
130.6 (d, J = 2.9 Hz), 130.8, 132.7 (d, J = 9.6 Hz), 134.6 (d, J = 6.7 Hz), 136.9, 139.0, 142.8 (d, J = 2.9
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Hz), 145.5 (d, J = 8.7 Hz); P NMR (162 MHz, CDCl3) δ 48.28; HRMS m/z calcd for C32H37OP (M+)
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468.2582, found 468.2590.
(E)-Di-tert-butyl[2-(1,2-diphenylethenyl)phenyl]phosphine Oxide (3ma): mp 129-130 oC (brown
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powder), 46 mg (44%); H NMR (400 MHz, CDCl3) δ 1.15 (d, J = 13.1 Hz, 18H), 6.43 (s, 1H), 7.06-
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7.16 (m, 8H), 7.30-7.37 (m, 3H), 7.49-7.60 (m, 3H); C NMR (100 MHz, CDCl3) δ 27.4, 37.2 (d, J =
59.1 Hz), 125.2 (d, J = 11.4 Hz), 126.2, 126.3, 127.0, 127.8, 127.9, 129.0 (d, J = 76.3 Hz), 129.2, 130.2
(d, J = 2.9 Hz), 130.7, 131.6 (d, J = 11.4 Hz), 133.4 (d, J = 8.6 Hz), 137.8, 140.3, 143.2 (d, J = 2.9 Hz),
150.5 (d, J = 3.8 Hz); P NMR (162 MHz, CDCl3) δ 53.48; HRMS m/z calcd for C28H33OP (M+)
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416.2269, found 416.2266.
(E)-Dicyclohexyl[3-(1,2-diphenylethenyl)-[1,1'-biphenyl]-2-yl]phosphine Oxide (3na) (E:Z =
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84:16), 133 mg (98%): H NMR (400 MHz, CDCl3) δ 0.74-1.62 (m, 22H), 6.47 (s, 0.84H, E), 6.74 (s,
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0.16H, Z), 7.06-7.19 (m, 7H), 7.22-7.30 (m, 4H), 7.34-7.47 (m, 7H); C NMR (100 MHz, CDCl3, 40
oC) δ 25.7 (d, J = 1.9 Hz), 26.5 (d, J = 2.9 Hz), 26.6 (d, J = 3.8 Hz), 26.7 (d, J = 13.4 Hz, overlapped),
39.8 (d, J = 66.2 Hz), 126.2, 126.6, 127.4, 127.5 (d, J = 3.8 Hz), 127.7, 127.8, 129.1, 129.3 (d, J = 2.8
Hz), 129.5, 129.7 (d, J = 74.7 Hz), 129.8, 130.9 (d, J = 9.6 Hz), 131.2, 132.5 (d, J = 8.6 Hz), 137.8,
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138.0, 140.7, 143.3 (d, J = 2.9 Hz), 144.6 (d, J = 2.9 Hz), 145.0; P NMR (162 MHz, CDCl3) δ 50.86
(Z), 51.40 (E); HRMS m/z calcd for C38H41OP (M+) 544.2895, found 544.2897.
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(E)-{2-[1,2-Bis(4-methylphenyl)ethenyl]phenyl}diphenylphosphine Oxide (3ab): mp 68-69 C
(colorless powder), 110 mg, 91%); 1H NMR (400 MHz, CDCl3) δ 2.23 (s, 3H), 2.26 (s, 3H), 6.63 (d, J =
7.8 Hz, 2H), 6.80 (s, 1H), 6.83 (d, J = 7.8 Hz, 2H), 6.89-6.94 (m, 4H), 7.14-7.17 (m, 1H), 7.19-7.23 (m,
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1H), 7.31-7.44 (m, 8H), 7.69-7.75 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 21.2 (overlapped), 126.2 (d,
J = 13.4 Hz), 128.18 (d, J = 11.5 Hz), 128.19, 128.6, 129.6, 130.4, 131.1 (d, J = 1.9 Hz), 131.2 (d, J =
2.9 Hz), 131.6 (d, J = 9.6 Hz), 131.8 (d, J = 101.6 Hz), 132.0 (d, J = 9.5 Hz), 133.8, 133.99 (d, J = 103.5
Hz), 134.04, 134.7 (d, J = 12.5 Hz), 136.3, 136.7, 137.5, 139.2 (d, J = 3.8 Hz), 150.0 (d, J = 7.7 Hz); 31P
NMR (162 MHz, CDCl3) δ 28.83; HRMS m/z calcd for C34H29OP (M+) 484.1956, found 484.1960.
(E)-[2-{1,2-Bis[4-(tert-butyl)phenyl] ethenyl}phenyl]diphenylphosphine Oxide (3ac): mp 69-70
oC (colorless powder), 128 mg (90%); 1H NMR (400 MHz, CDCl3) δ 1.25 (s, 9H), 1.28 (s, 9H), 6.69 (d,
J = 8.3 Hz, 2H), 6.75 (s, 1H), 6.99 (d, J = 8.7 Hz, 2H), 7.03 (d, J = 8.7 Hz, 2H), 7.13 (d, J = 8.7 Hz, 2H),
7.17-7.23 (m, 2H), 7.32 (dt, J = 2.8, 7.8 Hz, 4H), 7.37-7.42 (m, 4H), 7.68-7.73 (m, 4H); 13C NMR (100
MHz, CDCl3) δ 31.2, 31.3, 34.4 (overlapped), 124.4, 124.7, 126.1 (d, J = 12.5 Hz), 128.1 (d, J = 11.5
Hz), 129.3, 129.8, 131.1 (d, J = 1.9 Hz), 131.2 (d, J = 2.9 Hz), 131.6 (d, J = 103.5 Hz), 131.7 (d, J = 8.7
Hz), 132.0 (d, J = 8.6 Hz), 133.86, 133.92, 134.0 (d, J = 103.5 Hz), 134.6 (d, J = 12.4 Hz), 137.2, 138.9
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(d, J = 3.8 Hz), 149.6, 149.8, 150.1 (d, J = 7.7 Hz); P NMR (162 MHz, CDCl3) δ 28.93; HRMS m/z
calcd for C40H41OP (M+) 568.2895, found 568.2898.
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(E)-{2-[1,2-Bis(4-chlorophenyl)ethenyl]phenyl}diphenylphosphine Oxide (3ad): mp 74-75 C
(colorless powder), 121 mg (92%); 1H NMR (400 MHz, CDCl3) δ 6.64 (s, 1H), 6.70 (d, J = 8.2 Hz, 2H),
7.01-7.07 (m, 6H), 7.17 (dd, J = 4.1, 7.3 Hz, 1H), 7.23-7.38 (m, 6H), 7.41-7.47 (m, 3H), 7.64-7.69 (m,
4H); 13C NMR (100 MHz, CDCl3) δ 126.7 (d, J = 12.4 Hz), 127.9, 128.2, 128.3 (d, J = 11.5 Hz), 130.9,
131.4 (d, J = 2.9 Hz), 131.5 (d, J = 1.9 Hz), 131.6 (d, J = 9.6 Hz), 132.0 (d, J = 8.6 Hz), 132.1, 132.52,
132.54 (d, J = 2.9 Hz), 132.6 (d, J = 108.3 Hz), 133.2, 133.7 (d, J = 104.5 Hz), 134.6 (d, J = 12.4 Hz),
135.1, 138.2, 140.0 (d, J = 3.8 Hz), 148.8 (d, J = 6.7 Hz); 31P NMR (162 MHz, CDCl3) δ 29.31; HRMS
m/z calcd for C32H23Cl2OP (M+) 524.0864, found 524.0859.
(E)-[2-{1,2-Bis[4-(trifluoromethyl)phenyl]ethenyl}phenyl]diphenylphosphine Oxide (3ae): mp
79-80oC (colorless powder), 146 mg (98%); 1H NMR (400 MHz, CDCl3) δ 6.69 (s, 1H), 6.91 (d, J = 8.3
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13
Hz, 2H), 7.19-7.39 (m, 13H), 7.44-7.48 (m, 3H), 7.62-7.67 (m, 4H); C NMR (100 MHz, CDCl3) δ
124.1 (q, J = 272.2 Hz), 124.2 (q, J = 272.2 Hz), 124.8 (q, J = 3.8 Hz), 124.9 (q, J = 3.8 Hz), 127.0 (d, J
= 12.4 Hz), 128.4 (d, J = 11.5 Hz), 128.8 (q, J = 32.6 Hz), 129.3 (q, J = 32.6 Hz), 129.7, 131.0, 131.58
(d, J = 9.6 Hz), 131.62 (d, J = 2.8 Hz), 131.7 (d, J = 2.9 Hz), 132.0 (d, J = 8.6 Hz), 132.1 (d, J = 101.6
Hz), 132.8, 133.5 (d, J = 104.5 Hz), 134.5 (d, J = 12.5 Hz), 140.1 (d, J = 1.9 Hz), 141.5 (d, J = 3.8 Hz),
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143.0, 148.1 (d, J = 7.6 Hz); P NMR (162 MHz, CDCl3) δ 29.36; HRMS m/z calcd for C34H23F6OP
(M+) 592.1391, found 592.1395.
o
(Z)-{2-[1,2-Di(2-thienyl)ethenyl]phenyl}diphenylphosphine Oxide (3af): mp 188-189 C (pale
yellow powder), 24 mg (20%); 1H NMR (400 MHz, CDCl3) δ 6.84 (dd, J = 3.7, 5.0 Hz, 1H), 6.88 (dd, J
= 0.9, 3.7 Hz, 1H), 6.92-6.95 (m, 2H), 7.05 (d, J = 5.0 Hz, 1H), 7.21-7.25 (m, 1H), 7.31-7.47 (m, 11H),
7.71-7.77 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 126.0, 126.6 (d, J = 12.5 Hz), 126.8 (d, J = 13.4 Hz),
127.2, 128.3 (d, J = 12.4 Hz), 129.4, 130.0 (d, J = 3.9 Hz), 130.8, 130.9, 131.26, 131.27 (d, J = 102.6
Hz), 131.36 (d, J = 13.4 Hz), 131.44 (d, J = 3.9 Hz), 131.48 (d, J = 3.8 Hz), 131.51, 133.5 (d, J = 104.5
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Hz), 134.9 (d, J = 13.4 Hz), 139.7, 140.5, 148.0 (d, J = 8.6 Hz); P NMR (162 MHz, CDCl3) δ 29.36;
HRMS m/z calcd for C28H21OPS2 (M+) 468.0771, found 468.0775.
1
(E)-Diphenyl[2-(1-phenylprop-1-en-2-yl)phenyl]phosphine Oxide (3ag): oil, 80 mg (81%); H
NMR (400 MHz, CDCl3) δ 1.88 (d, J = 1.4 Hz, 3H), 6.38 (s, 1H), 6.99 (d, J = 7.3 Hz, 2H), 7.15 (t, J =
7.3 Hz, 1H), 7.22-7.53 (m, 12H), 7.69-7.74 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 20.2, 126.0 (d, J =
13.4 Hz), 126.3, 127.7, 128.2 (d, J = 12.4 Hz), 129.0, 129.7 (d, J = 9.6 Hz), 131.1 (d, J = 104.5 Hz),
131.2 (d, J = 1.9 Hz), 131.69 (d, J = 8.7 Hz), 131.72 (d, J = 2.9 Hz), 132.7, 133.7 (d, J = 104.5 Hz),
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134.1 (d, J = 12.5 Hz), 136.8 (d, J = 3.8 Hz), 137.3, 151.3 (d, J = 8.7 Hz); P NMR (162 MHz,
CDCl3) δ 28.77; HRMS m/z calcd for C27H23OP (M+) 394.1487, found 394.1485.
o
(E)-Diphenyl[2-(1-phenylhex-1-en-2-yl)phenyl]phosphine Oxide (3ah): mp 104-105 C (pale
1
yellow powder), 94 mg (86%); H NMR (400 MHz, CDCl3) δ 0.76 (t, J = 6.9 Hz, 3H), 1.13-1.30 (m,
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4H), 2.51 (t, J = 7.3 Hz, 2H), 6.02 (s, 1H), 6.93 (d, J = 7.3 Hz, 2H), 7.13-7.34 (m, 6H), 7.37-7.41 (m,
4H), 7.45-7.53 (m, 3H), 7.69 (dd, J = 7.3, 11.9 Hz, 4H); 13C NMR (100 MHz, CDCl3) δ 13.9, 22.8, 30.5,
32.8, 126.0 (d, J = 12.4 Hz), 126.2, 127.7, 128.2 (d, J = 11.5 Hz), 128.7, 130.6 (d, J = 103.5 Hz), 131.0
(d, J = 9.5 Hz), 131.27, 131.34 (d, J = 2.8 Hz), 131.4 (d, J = 2.9 Hz), 131.9 (d, J = 8.6 Hz), 133.8 (d, J =
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103.5 Hz), 134.0 (d, J = 12.5 Hz), 137.4, 143.2 (d, J = 3.8 Hz), 149.9 (d, J = 7.7 Hz); P NMR (162
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MHz, CDCl3) δ 29.42; HRMS m/z calcd for C30H29OP (M+) 436.1956, found 436.1954.
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(E)-[2-(1-Cyclopropyl-2-phenylethenyl)phenyl]diphenylphosphine Oxide (3ai): mp 26-27 C
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(pale yellow powder), 61ꢀ mg, (58%); H NMR (400 MHz, CDCl3) δ 0.26 (dt, J = 5.8, 5.8 Hz, 2H),
0.55 (dt, J = 5.8, 5.8 Hz, 2H), 1.69 (m, 1H), 6.13 (s, 1H), 7.14-7.19 (m, 2H), 7.22-7.29 (m, 5H), 7.33-
7.49 (m, 8H), 7.65-7.70 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 7.6, 14.7, 126.2 (d, J = 12.4 Hz), 126.3,
127.6, 128.1 (d, J = 12.4 Hz), 129.3, 130.8 (d, J = 9.5 Hz), 131.1 (d, J = 1.9 Hz), 131.29 (d, J = 2.8 Hz),
131.34 (d, J = 104.0 Hz), 132.0 (d, J = 9.6 Hz), 132.5, 133.8 (d, J = 105.0 Hz), 133.0 (d, J = 12.4 Hz),
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137.1, 141.4 (d, J = 3.8 Hz), 147.2 (d, J = 8.6 Hz); P NMR (162 MHz, CDCl3) δ 29.04; HRMS m/z
calcd for C29H25OP (M+) 420.1643, found 420.1640.
(E)-Diphenyl[2-(2-phenylethenyl)phenyl]phosphine Oxide (3aj):16 mp 169-170 C (colorless
o
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powder), 57 mg (50%); H NMR (400 MHz, CDCl3) δ 6.91 (d, J = 16.0 Hz, 1H), 7.17-7.24 (m, 7H),
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7.42-7.54 (m, 7H), 7.68-7.73 (m, 4H), 7.80-7.84 (m, 2H); C NMR (100 MHz, CDCl3) δ 126.6 (d, J =
12.5 Hz), 126.7, 126.8, 127.2 (d, J = 6.8 Hz), 127.8, 128.4, 128.5 (d, J = 12.5 Hz), 130.1 (d, J = 101.6
Hz), 131.3, 131.8 (d, J = 2.9 Hz), 131.9 (d, J = 9.6 Hz), 132.2 (d, J = 2.9 Hz), 132.9 (d, J = 103.5 Hz),
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133.7 (d, J = 12.5 Hz), 137.0, 142.3 (d, J = 6.7 Hz); P NMR (162 MHz, CDCl3) δ 31.73; HRMS m/z
calcd for C26H21OP (M+) 380.1330, found 380.1328.
(E)-Diphenyl[2-(2-phenylethenyl)phenyl]phosphine (4):16 mp 58-59 oC (pale yellow powder), 60
mg (66%); 1H NMR (400 MHz, CDCl3) δ 6.88 (ddd, J = 0.9, 4.5, 7.7 Hz, 1H), 6.96 (d, J = 16.3 Hz, 1H),
7.14-7.37 (m, 17H), 7.71 (dd, J = 4.0, 7.7 Hz, 1H), 7.78 (dd, J = 4.0, 15.8 Hz, 1H); 13C NMR (100 MHz,
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CDCl3) δ 125.4 (d, J = 3.8 Hz), 126.7, 127.2, 127.5 (d, J = 17.2 Hz), 127.6, 128.5 (d, J = 2.9 Hz), 128.7
(d, J = 16.2 Hz), 129.0, 130.4 (d, J = 2.9 Hz), 133.5, 133.9, 134.1, 135.7 (d, J = 13.3 Hz), 136.4 (d, J =
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9.5 Hz), 137.4, 141.9 (d, J = 21.9 Hz); P NMR (162 MHz, CDCl3) δ -13.41; HRMS m/z calcd for
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C26H21P (M+) 364.1381, found 364.1378.
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Butyl 3-[2-(Diphenylphosphoryl)phenyl]propanoate (6): oil, 59 mg (58%); H NMR (400 MHz,
CDCl3) δ 0.90 (t, J = 7.3 Hz, 3H), 1.26-1.35 (m, 2H), 1.50-1.57 (m, 2H), 2.52 (t, J = 7.7 Hz, 2H), 3.19 (t,
J = 7.7 Hz, 2H), 4.00 (t, J = 6.7 Hz, 2H), 7.07 (ddd, J = 1.2, 7.7, 13.9 Hz, 1H), 7.16 (ddt, J = 1.2, 2.6,
7.7 Hz, 1H), 7.36 (ddd, J = 0.7, 4.2, 7.7 Hz, 1H), 7.44-7.49 (m, 5H), 7.55 (dtt, J = 1.4, 1.4, 6.6 Hz, 2H),
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7.65 (ddt, J = 1.4, 6.9, 11.9 Hz, 4H); C NMR (100 MHz, CDCl3) δ 13.7, 19.0, 29.7 (d, J = 5.1 Hz),
30.6, 35.6, 64.1, 125.7 (d, J = 12.4 Hz), 128.5 (d, J = 12.5 Hz), 130.97 (d, J = 10.3 Hz), 131.00 (d, J =
102.0 Hz), 131.8 (d, J = 2.9 Hz), 131.9 (d, J = 9.5 Hz), 132.2 (d, J = 3.0 Hz), 133.0 (d, J = 103.4 Hz),
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133.6 (d, J = 12.5 Hz), 146.1 (d, J = 8.0 Hz), 172.9; P NMR (162 MHz, CDCl3) δ 31.20; HRMS m/z
calcd for C25H28O3P (M+H+) 407.1776, found 407.1770.
Acknowledgment. This work was supported by Grants-in-Aid from MEXT, JSPS, and JST, Japan.
Supporting Information Available: Copies of 1H- and 13C-NMR spectra of products. This material is
available free of charge via the Internet at http://pubs.acs.org.
(1)
For example, see: (a) Zhang, Q.; Adachi, C.; Matsunami, S.; Sakagami, K. Jpn. Kokai Tokkyo
Koho 2013, 120, JP 2013008806. (b) Han, C.; Zhang, Z.; Xu, H.; Xie, G.; Li, J.; Zhao, Y.; Deng,
Z.; Liu, S.; Yan, P. Chem. Eur. J. 2013, 19, 141. (c) Han, C.; Zhang, Z.; Xu, H.; Yue, S.; Li, J.;
Yan, P.; Deng, Z.; Zhao, Y.; Yan, P.; Liu, S. J. Am. Chem. Soc. 2012, 134, 19179. (d) Han, C.;
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2008, 92, 083308. (f) Vecchi, P. A.; Padmaperuma, A. B.; Qiao, H.; Sapochak, L. S.; Burrows, P.
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E. Org. Lett. 2006, 8, 4211. (g) Burrows, P. E.; Padmaperuma, A. B.; Sapochak, L. S.; Djurovich,
P.; Thompson, M. E. Appl. Phys. Lett. 2006, 88, 183503. For a review, see: (h) Xiao, L.; Chen,
Z.; Qu, B.; Luo, J.; Kong, S.; Gong, Q.; Kido, J. Adv. Mater. 2011, 23, 926.
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Lam, K.-H.; Chui, C.-H.; Gambari, R.; Wong, R. S.-M.; Cheng, G. Y.-M.; Lau, F.-Y.; Lai, P. B.-
S.; Tong, S.-W.; Chan, K.-W.; Wong, W.-Y.; Chan, A. S.-C.; Tang, J. C.-O. Eur. J. Med. Chem.
2010, 45, 5527.
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(a) Aoki, S.; Kotani, S.; Sugiura, M.; Nakajima, M. Chem. Commun. 2012, 48, 5524. (b)
Shimoda, Y.; Kotani, S.; Sugiura, M.; Nakajima, M. Chem. Eur. J. 2011, 17, 7992. (c) Kotani, S.;
Hashimoto, S.; Nakajima, M. Tetrahedron 2007, 63, 3122. (d) Ogawa, C.; Sugiura, M.;
Kobayashi, S. Angew. Chem. Int. Ed. 2004, 43, 6491.
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(4)
Selected examples: (a) Busacca, C. A.; Raju, R.; Grinberg, N.; Haddad, N.; James-Jones, P.; Lee,
H.; Lorenz, J. C.; Saha, A.; Senanayake, C. H. J. Org. Chem. 2008, 73, 1524. (b) Xie, J.-H.; Duan,
H.-F.; Fan, B.-M;. Cheng, X.; Wang, L.-X.; Zhou, Q.-L. Adv. Synth. Catal. 2004, 346, 625. (c)
RajanBabu, T. V.; Nomura, N.; Jin, J.; Nandi, M.; Park, H.; Sun, X. J. Org. Chem. 2003, 68,
8431. (d) Baillie, C.; Xiao, J. Tetrahedron 2004, 60, 4159. (e) Imamoto, T.; Kikuchi, S.-I.; Miura,
T.; Wada, Y. Org. Lett. 2001, 3, 87. (f) Yin, J.; Buchwald, S. L. J. Am. Chem. Soc. 2000, 122,
12051. (g) Imamoto, T.; Oshiki, T.; Onozawa, T.; Kusumoto, T.; Sato, K. J. Am. Chem. Soc.
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(5)
Selected recent reviews for C–H functionalization: (a) Kozhushkov, S. I.; Ackermann, L. Chem.
Sci. 2013, 4, 886. (b) Arockiam, P. B.; Bruneau, C.; Dixneuf, P. H. Chem. Rev. 2012, 112, 5879.
(c) Colby, D. A.; Tsai, A. S.; Bergman, R. G.; Ellman, J. A. Acc. Chem. Res. 2012, 45, 814. (d)
Engle, K. M.; Mei, T.-S.; Wasa, M.; Yu, J.-Q. Acc. Chem. Res. 2012, 45, 788. (e) Mitchell, E. A.;
Peschiulli, A.; Lefevre, N.; Meerpoel, L.; Maes, B. U. W. Chem. Eur. J. 2012, 18, 10092. (f)
Song, G.; Wang, F.; Li, X. Chem. Soc. Rev. 2012, 41, 3651. (g) Patureau, F. W.; Wencel-Delord,
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Soc. Rev. 2011, 40, 5068. (i) Wencel-Delord, J.; Droge, T.; Liu, F.; Glorius, F. Chem. Soc. Rev.
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Shi, W.; Lei, A. Chem. Rev. 2011, 111, 1780. (l) Ackermann, L. Chem. Rev. 2011, 111, 1315. (m)
Le Bras, J.; Muzart, J. Chem. Rev. 2011, 111, 1170. (n) Lyons, T. W.; Sanford, M. S. Chem. Rev.
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Sun, C.-L.; Li, B.-J.; Shi, Z.-J. Chem. Commun. 2010, 46, 677. (q) Satoh, T.; Miura, M. Chem.
Eur. J. 2010, 16, 11212. (r) Karimi, B.; Behzadnia, H.; Elhamifar, D.; Akhavan, P. F.; Esfahani,
F. K.; Zamani, A. Synthesis 2010, 1399. (s) Chen, X.; Engle, K. M.; Wang, D.-H.; Yu, J.-Q.
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efficiency: (a) Takebayashi, S.; Shibata, T. Organometallics 2012, 31, 4114. During the
preparation of this manuscript, related oxidative coupling reactions involving P–OH directed C–
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(8)
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Lett. 2008, 10, 5309. (e) Kakiuchi, F.; Yamamoto, Y.; Chatani, N.; Murai, S. Chem. Lett. 1995,
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For reviews, see: (a) Kakiuchi, F.; Kochi, T. Synthesis 2008, 3013. (b) Kakiuchi, F.; Chatani, N.
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(12) It was recently reported that AcOH promotes the C–H bond activation of 2-phenylpyridine: (a)
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(15) Liao, H.-H.; Liu, R.-S. Chem. Commun. 2011, 47, 1339.
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