Cyclic α-Alkoxyphosphonium Salts from (2-(Diphenylphosphino)phenyl)methanol and Aldehydes and Their Application in Synthesis of Vinyl Ethers and Ketones via Wittig Olefination

Article abstract of DOI:10.1021/acs.joc.5b01031

Cyclic α-alkoxyphosphonium salts have been synthesized from (2-(diphenylphosphino)phenyl)methanol and aldehydes in 36-89% yields. These phosphonium salts are bench-stable solids and undergo Wittig olefination with aldehydes under basic conditions (K₂CO₃ or t-BuOK) to form benzylic vinyl ethers, which are readily hydrolyzed to 1,2-disubstituted ethanones under acidic conditions. The formation mechanism of these phosphonium salts via hemiacetal is also proposed.

Full text of DOI:10.1021/acs.joc.5b01031

Article
pubs.acs.org/joc
Cyclic α‑Alkoxyphosphonium Salts from (2-
(Diphenylphosphino)phenyl)methanol and Aldehydes and Their
Application in Synthesis of Vinyl Ethers and Ketones via Wittig
Olefination
Wenhua Huang,* Hong-Ying Rong, and Jie Xu
Department of Chemistry, Tianjin University, 92 Weijin Road, Tianjin 300072, P. R. China
S
* Supporting Information
ABSTRACT: Cyclic α-alkoxyphosphonium salts have been synthesized from
(2-(diphenylphosphino)phenyl)methanol and aldehydes in 36−89% yields.
These phosphonium salts are bench-stable solids and undergo Wittig olefination
with aldehydes under basic conditions (K2CO3 or t-BuOK) to form benzylic
vinyl ethers, which are readily hydrolyzed to 1,2-disubstituted ethanones under
acidic conditions. The formation mechanism of these phosphonium salts via
hemiacetal is also proposed.
chlorodiphenylphosphine with acetal32 or the reaction of
INTRODUCTION
■
diphenylphosphine with aldehyde and alcohol, followed by
Vinyl ethers have been widely used in not only organic
oxidation.33 Four reactions have been utilized to prepare B: (1)
synthesis1−7 but also polymer synthesis8 due to their electron-
chlorophosphite with acetal,12 (2) dimethyl phosphite with
rich double bonds. Although a wide variety of methods are
aldehydes, followed by alkylation,16 (3) trialkyl phosphite with
available for the synthesis of vinyl ethers, each method has its
acetal in the presence of a Lewis acid such as trimethylsilyl
advantage and disadvantage with regard to reaction condition,
chloride17 and TiCl4,18 and (4) dialkyl phosphonate and acetal
stereoselectivity, and availability of starting materials.9 Among
in the presence of BF3.34 The preparation of C is often through
these methods, the Wittig-type olefination of an aldehyde with
the reactions of triphenyl- or trialkylphosphine with α-halo
an α-alkoxyphosphine oxide (A)10,11 or α-alkoxyphosphonate
ethers23,29,35 or acetals20,24−28,36−39 or enol ethers.22,40 The
(B)12−18 or α-alkoxyphosphonium salt (C)19−31 under basic
existing Wittig olefination using A−C presents several
conditions (Scheme 1a) seems to be an attractive way to access
limitations: (1) The use of a strong base such as LDA,
functionalized vinyl ethers. A is usually prepared from the
LHDMS, and NaH to generate the ylides or alkyl phosphonate
hydrolysis of phosphonium salts22 or the reaction of
carbanions makes it difficult to scale up. (2) The preformation
of acetals from aldehydes reduces the efficiency of Wittig
Scheme 1. Synthesis of Vinyl Ethers, Ketones via Wittig-
olefination for synthesis of vinyl ethers. (3) Some α-
Type Reactions
alkoxyphosphonium salts (in particular, when R1 ≠ H for C
in Scheme 1a) are unstable and water-sensitive,19,23 and the
generation of the corresponding ylides from (α-methoxyalkyl)-
triphenylphosphonium salts requires low temperature (< −40
°C).20
To overcome these limitations, we hypothesized that a cyclic
α-alkoxyphosphonium salt from the reaction of (2-(diphenyl-
phosphino)phenyl)methanol (DPPPM) with an aldehyde
should be more stable than the acyclic ones, and thus a weaker
base might be used for subsequent Wittig olefination that
should produce a benzylic vinyl ether and, after further
hydrolysis, a ketone (Scheme 1b). Overall, this reaction
sequence would also provide a more straightforward route to
couple two aldehydes (R1CHO and R2CHO) to produce a
ketone R1COCH2R2 than the similar route using the acyclic α-
Received: April 5, 2015
© XXXX American Chemical Society
A
DOI: 10.1021/acs.joc.5b01031
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Article
alkoxyphosphonium salts prepared from acetals. Herein, we
report our experimental results on testing this hypothesis.
RESULTS AND DISCUSSION
■
DPPPM 1 was readily prepared41 from the commercially
available (2-diphenylphosphino)benzaldehyde by the reduction
using NaBH4. It has been applied in stereoselective Wittig
olefination as a surrogate for triphenylphosphine.42 When a
solution of DPPPM 1 and an equimolar amount of
benzaldehyde 2a in THF were mixed with a nearly saturated
solution of Ph3PHBr in THF, white solids precipitated after the
mixture was stirred at room temperature overnight. The white
solids collected by filtration were identified as the desired
phosphonium salt 3aa by NMR spectra and HRMS, though its
yield was only 24% (Table 1, entry 1). Refluxing the reaction
Table 1. Initial Observations on the Formation of Cyclic α-
Alkoxyphosphonium Salts from DPPPM and Aldehydes
a
Figure 1. Aldehydes used in this work.
entry
YX
Method
A
3a
yield (%)
1
2
3
4
5
6
7
8
HBr
HBr
HBr
Br2
3aa
3aa
3aa
3aa
3ab
3aa
3aa
3ab
24
25
b
Table 2. Synthesis of Cyclic α-Alkoxyphosphonium Salts
from DPPPM and Aldehydes
A
c
A
A
A
17
49
64
74
78
74
HBF4
Br2
d
B
e
Br2
B
e
a
R1
3
yield (%)
HBF4
B
entry
YX
Br2
a
Method A: mixed a solution of 1 (0.86 mmol) and 2 (0.86 mmol) in
1
2
Ph
Ph
3aa
3ab
3ba
3ca
3da
3ea
3fa
78
74
68
57
50
36
53
89
73
75
86
81
89
84
82
87
63
64
2 mL of THF with a saturated solution of Ph3PYX in THF (12 mL for
Ph3PHBr, 5 mL for Ph3HBF4 and Ph3PBr2), rt, overnight. Method B:
mixed 1, 2, and Ph3PYX with a certain amount of THF, rt, overnight.
Refluxing for 9 h. Using 2 equiv of Ph3PHBr in THF (26 mL).
Using 4 mL of THF. Using 1 mL of THF.
HBF4
Br2
3
4-ClC6H4
4
Br2
2-ClC6H4
b
c
d
e
5
Br2
4-O2NC6H4
2-O2NC6H4
3-O2NC6H4
4-FC6H4
6
Br2
7
Br2
8
Br2
3ga
3hb
3ib
9
HBF4
HBF4
HBF4
HBF4
HBF4
HBF4
HBF4
HBF4
Br2
4-BrC6H4
mixture for 9 h led to the almost same yield (entry 2).
Increasing the usage of Ph3PHBr to 2 equiv reduced the yield of
3aa to 17% (entry 3). The yield of 3aa could be improved to
49% when using Ph3PBr2 instead of Ph3PHBr (entry 4).
Further switching to Ph3PHBF4 afforded 3ab in 64% yield
(entry 5). Interestingly, the yield of 3aa was dramatically
increased to 74% by simply reducing the usage of THF (entry
6). Further reducing the usage of THF, 3aa and 3ab were
obtained in 78% and 74% yields, respectively (entries 7 and 8).
We next examined a variety of aldehydes (Figure 1, 2a−2q)
for the formation of phosphonium salts 3, and the results are
summarized in Table 2. In general, electron-rich aromatic
aldehydes gave higher yields of 3 than electron-deficient ones,
except for p-fluorobenzaldehyde, which, surprisingly, gave 3f in
the highest yield (89%, entry 8). o-Nitrobenzaldehyde 2e gave a
lower yield than p-nitrobenzaldehyde 2d and m-nitrobenzalde-
hyde 2f, possibly due to the steric effect of the ortho nitro group
(entries 5−7). The same ortho-steric effect was observed for
chlorobenzaldehyde (entries 3−4). Heteroaromatic 2-furalde-
hyde and aliphatic isobutyraldehyde provided 3qa and 3pa in
moderate yields (entries 17−18). It is noteworthy that these
phosphonium salts are all bench-stable solids and can be
weighed in air without special considerations. In addition, the
10
11
12
13
14
15
16
17
18
1-naphthyl
4-MeC6H4
3jb
4-MeOC6H4
3,4-(MeO)2C6H3
2,4-(MeO)2C6H3
3,4,5-(MeO)2C6H2
(E)-PhCHCH
i-Pr
3kb
3 lb
3mb
3nb
3ob
3pa
3qa
Br2
2-furyl
a
Reaction conditions: 1 (0.7 mmol), 2 (0.70 mmol), Ph3PBr2 (0.38
mmol) or Ph3PHBF4 (0.70 mmol), THF (1 mL), rt, overnight.
preparation of 3 can be easily run on a large scale (20 mmol;
see the Experimental Section).
With cyclic α-alkoxyphosphonium salts 3 in hand, we began
to explore the possibility of their application in Wittig
olefination with aldehydes, and the results are revealed in
Table 3. Initially, we examined the reaction of phosphonium
salt 3aa with a variety of aldehydes using K2CO3 as a base.
When a mixture of phosphonium salt 3aa, aldehyde 2b, and
K2CO3 in DMSO/CH3CN (5/1) was stirred at room
temperature overnight, 4ab was isolated as an inseparable Z/
B
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Table 3. Synthesis of Vinyl Ethers Using Cyclic α-Alkoxyphosphonium Salts
a
b
entry
A/B
R1
R2
4
yield (%)
1
2
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
B
B
B
B
B
B
Ph
Ph
Ph
Ph
Ph
Ph
Ph
4-ClC6H4
4ab
4ad
4ae
4ah
4ao
4aq
4ar
4hg
4gd
4qs
4jt
61 (89:11)
84 (85:15)
75 (40:60)
70 (89:11)
45 (93:7)
80 (94:6)
61 (44:56)
80 (89:11)
68 (95:5)
96 (85:15)
87 (93:7)
80 (48:52)
84 (79:21)
19 (90:10)
4-O2NC6H4
2-O2NC6H4
4-BrC6H4
3
4
5
(E)-PhCHCH
6
2-furyl
c
7
2-pyridyl
8
4-BrC6H4
4-FC6H4
9
4-FC6H4
4-O2NC6H4
4-F3CC6H4
4-MeO2CC6H4
4-O2NC6H4
4-O2NC6H4
Ph
10
11
12
13
14
15
16
17
18
19
20
21
22
2-Furyl
4-MeC6H4
(E)-PhCHCH
4od
4nd
4aa
4aj
3,4,5-(MeO)3C6H2
Ph
Ph
4-MeC6H4
3,4-(MeO)2C6H3
Ph
20 (93:7)
d
Ph
4al
Ph
4aa
4aj
85 (95:5)
87 (96:4)
87 (97:3)
81 (93:7)
68 (91:9)
Ph
4-MeC6H4
4-MeOC6H4
3,4-(MeO)2C6H3
4-MeOC6H4
i-Pr
Ph
4ak
4al
Ph
3,4,5-(MeO)3C6H2
Ph
4nk
4ap
e
28 (93:7)
a
Condition A: 2 (0.31 mmol), 3 (0.37 mmol), K2CO3 (0.44 mmol), DMSO (1 mL), and CH3CN (0.2 mL), rt, overnight. Condition B: 2 (0.25
b
mmol), 3 (0.25 mmol), anhyd THF (5 mL), t-BuOK in THF (1.0 M, 0.3 mL), rt, 3 h. The number in the parentheses is the Z:E ratio determined
by H NMR. Isolated Z:E ratio. 4al was not detected. Using 1.2 equiv of 3aa.
c
d
e
1
E mixture in 61% yield (entry 1). Other aldehydes including
electron-deficient aromatic aldehydes, cinnamyl aldehyde, and
two heteroaromatic aldehydes underwent olefination to give the
corresponding vinyl ethers in moderate to good yields (entries
2−7). A number of combinations of phosphonium salts 3 and
aldehydes 2 also gave the corresponding vinyl ethers in
moderate to good yields (entries 8−13). The configuration of
these vinyl ethers was determined by NOESY spectra, and in
most of cases, the Z/E selectivity is in favor of the (Z)-isomer,
in contrast to that reported19 by Das and McNulty using the
acyclic α-alkoxyphosphonium salts. It seems that the reaction
depends on both the easiness of deprotonation of phospho-
nium salts 3 and the activity of the carbonyl group of aldehydes
2 toward the ylide. The deprotonation to form the ylide for
phosphonium salts 3 formed from electron-deficient aromatic
aldehydes is easier than those from electron-rich ones.
Therefore, phosphonium salt 3 from an electron-rich aldehdye
may react well with an electron-deficient aldehyde (entries 11
and 13). However, combinations of 3aa−2a and 3aa−2j led to
the poor yields of 4aa and 4aj (entries 14 and 15). The
combination of 3aa−2l even did not produce the desired vinyl
ether 4al (entry 16). This is probably due to the superposition
of the low efficiency of deprotonation of phosphonium salt 3
and the low activity of aldehyde 2. Therefore, we switched to a
stronger base (t-BuOK/THF) for the reactions of 3aa with a
number of electron-rich aldehydes, and the results showed that
the corresponding vinyl ethers were obtained in high yields and
with high Z/E ratios (entries 17−21). However, the reaction of
3aa with aliphatic aldehyde 2p led to a low yield of 4ap (28%,
entry 22), probably due to the enolization of 2p. Attempts to
synthesize vinyl ethers from 3pa and 2a or 2p were
unsuccessful.
We further explored the possibility for converting the
obtained benzylic vinyl ethers 4 to the corresponding ketones.
When a solution of vinyl ether 4aa in MeOH:6 M HCl (3:1, v/
v) was refluxed for 30 min, TLC showed that 4aa was
completely hydrolyzed and 5a was obtained in 81% yield
(Table 4, entry 1). Other vinyl ethers from a variety of
combinations of phosphonium salt 3 and aldehydes 2 were
readily hydrolyzed to ketones in good to nearly quantitative
yields (entries 2−8). A one-pot synthesis of 5a starting from
3aa and 2a was carried out on a gram scale to afford 5a in 54%
yield (see the Experimental Section for details). 1,2-Diary-
Table 4. Synthesis of Ketones by Hydrolysis of Vinyl Ethers
entry
R1
R2
5
yield (%)
1
2
3
4
5
6
7
8
Ph
Ph
Ph
Ph
5a
5b
5c
5d
5e
5f
81
78
85
73
86
75
78
98
4-MeC6H4
3,4-(MeO)2C6H3
4-O2NC6H4
4-O2NC6H4
4-MeO2CC6H4
4-F3CC6H4
(E)-PhCHCH
3,4,5-(MeO)2C6H2
4-MeC6H4
2-furyl
5g
5h
3,4,5-(MeO)2C6H2
4-MeOC6H4
C
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lethanones are useful building blocks for synthesizing a variety
of heterocycles43 and natural products.44 1,2-Diarylethanones
can be synthesized by Friedel−Crafts acylation of electron-rich
aromatic compounds with aryl acetic acids or chlorides,45 by
hydration of diarylethyne,46 and by transition-metal-catalyzed
carbonylative coupling reaction of benzyl halides with
potassium aryltrifluorborates.47 These methods either suffer
from a lack of regioselectivity or require a noble metal. General
methods for preparation of 1,2-diarylethanones from aromatic
aldehydes including: (1) addition of benzylic Grignard reagents
to aromatic aldehydes, followed by oxidation of the resulting
secondary alcohols,48 which suffers from low yields due to the
coupling aptness of the benzylic Grignard reagent, (2) selective
deoxygenation of benzoins,49 which is limited to symmetrical
benzoins, (3) transformation into carbonyl anion equivalent,
followed by metalation, benzylation, and deprotection, which
usually requires a strong base such as BuLi,50 and (4) synthesis
of vinyl ethers as described in Scheme 1a, followed by
hydrolysis, drawbacks of which we have already analyzed in the
Introduction. Our methodology for synthesis of 1,2-diary-
lethanones has the following advantages: (1) cyclic α-alkoxy
phosphonium salts are readily prepared from aldehydes and
bench-stable solids; (2) two aromatic aldehydes are used as
starting materials, allowing various combinations of two aryl
groups, including deficient-deficient, rich-rich, rich-deficient,
and deficient-rich in the context of electron; and (3) mild
reaction condition without using a strong base such as BuLi and
LDA.
proton may come from HBF4 or HBr) to form hemiacetal 6,
which, after proton-exchange, loses a water and undergoes
intramolecular nucleophilic substitution to produce phospho-
nium salt 3. In path b, phosphine 1 reacts on phosphorus with
protonated aldehyde 2 to form α-hydroxyphosphonium salt 7,
which, after protonation and intramolecular nucleophilic
substitution via 8 and 9, forms phosphonium salt 3. To
distinguish these two pathways, we conducted an 18O-labeling
experiment in which 18O-2a and 1 were treated with Ph3PHBF4
according to the same procedure to prepare 3ab. The resulting
phosphonium salt was analyzed by NMR and HRMS, and none
of them showed the formation of phosphonium salt 18O-3ab
(Scheme 2B). Therefore, the path b via the intermediates 7−9
could be excluded. As for the reactions of 3pa with 2a and 2p in
the presence of t-BuOK, a cyclic phosphine oxide 14 (Scheme
2C) was isolated in 81% and 96% yields, respectively, and is a
mixture of two stereoisomers with ratios of 79:21 and 68:32,
respectively. We reasoned that 14 might form from 3pa via
nucleophilic attack to phosphorus by −OH, which might be
generated in situ from the reaction of t-BuOK with a trace of
water, to produce 12, followed by base-promoted fragmenta-
tion via 13 to lose a phenyl group. Phosphonium salts formed
from aromatic aldehydes have no such problem, which might
be due to the stronger acidity of their α-Hs than that of 3pa,
leading the easier formation of their ylides than that of 3pa.
Alkyltriphenylphosphonium salts have been reported51 to lose a
phenyl group to form alkyldiphenylphosphine oxide in the
presence of t-BuOK or NaH. In addition, the hydrolysis of
alkyltriphenylphosponium salts under basic conditions has also
been used to prepare22 alkyldiphenylphosphine oxide.
There are two possible pathways for the formation of
phosphonium salts 3, as shown in Scheme 2A. In path a,
phosphine 1 reacts on oxygen with protonated aldehyde 2 (the
CONCLUSION
■
Scheme 2. Formation Mechanism of Cyclic α-
Alkoxyphosphonium Salts
In summary, we have synthesized a variety of cylclic α-
alkoxyphosphonium salts from DPPPM and aldehydes. These
phosphonium salts are bench-stable solids and can undergo
Wittig olefination with aromatic aldehydes to provide benzylic
vinyl ethers with the Z/E selectivities mostly favoring the (Z)-
isomer under mild conditions. Furthermore, these vinyl ethers
are readily hydrolyzed to the corresponding ketones. Therefore,
this methodology provides a facile way to couple two aldehydes
to form 1,2-diarylethanones.
EXPERIMENTAL SECTION
■
General. All solvents were freshly distilled before use. All aldehydes
were purified by preparative TLC before use. The olefination reactions
were performed under nitrogen by connecting the flask to a nitrogen
balloon. The melting points were measured on a melting apparatus
with a microscope and hot stage and were uncorrected. PE =
petroleum ether (bp 60−90 °C).
General Procedure for Synthesis of Cyclic α-Alkoxyphos-
phonium Salts. To a test tube (10 mL) were added DPPPM 1
(204.5 mg, 0.70 mmol), Ph3PBr2 (162.5 mg, 0.38 mmol) or Ph3PHBF4
(245.1 mg, 0.70 mmol), aldehyde 2 (0.70 mmol), and THF (1 mL).
After they were stirred at rt overnight, the resulting precipitates were
collected by filtration and dried in vacuo to give phosphonium salt 3.
1,1,2-Triphenyl-2,4-dihydro-1H-benzo[d][1,3]oxaphosphinin-1-
ium Bromide (3aa). A white solid, yield: 250.6 mg, 78%; mp: 217−
218 °C. 1H NMR (400 MHz, DMSO-d6) δ 5.57 (d, 1 H, J = 16.2 Hz),
5.68 (d, 1 H, J = 16.2 Hz), 6.91 (d, 2 H, J = 8.2 Hz), 6.95 (dd, 2 H, J1
= 8.0 Hz, J2C‑P = 12.4 Hz), 7.30 (dd, 2 H, J1 = 7.6 Hz, J2 = 8.2 Hz),
7.40 (dd, 1 H, J1C‑P = 6.8 Hz, J2 = 7.2 Hz), 7.53 (d, 1 H, JC‑P = 3.2 Hz),
7.56−7.67 (m, 4 H), 7.75 (dd, 1 H, J1C‑P = 6.4 Hz, J2 = 6.4 Hz), 7.80−
7.92 (m, 3 H), 7.92−8.04 (m, 2 H), 8.23 (dd, 2 H, J1 = 8.0 Hz, J2C‑P
=
12.0 Hz). 13C NMR (151 MHz, DMSO-d6) δ 70.6, 74.4 (d, JC‑P = 55.6
Hz), 112.9 (d, JC‑P = 80.5 Hz), 113.8 (d, JC‑P = 84.7 Hz), 116.0 (d, JC‑P
D
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= 79.3 Hz), 126.1 (d, JC‑P = 4.5 Hz), 126.6 (d, JC‑P = 8.6 Hz), 128.7 (d,
7.6 Hz, J2 = 8.4 Hz), 8.00 (dd, 1 H, J1C‑P = 6.8 Hz, J2 = 8.0 Hz), 8.16
JC‑P = 2.1 Hz), 129.1 (d, JC‑P = 11.6 Hz), 129.607, 129.609 (d, JC‑P
=
(d, 2 H, J = 8.4 Hz), 8.22 (dd, 2 H, J1 = 7.8 Hz, J2C‑P = 12.6 Hz). 13
C
12.4 Hz), 130.5 (d, JC‑P = 12.4 Hz), 131.0 (d, JC‑P = 2.1 Hz), 134.2 (d,
JC‑P = 6.6 Hz), 134.8 (d, JC‑P = 10.0 Hz), 135.1 (d, JC‑P = 9.5 Hz),
135.2, 135.5, 135.8 (d, JC‑P = 2.0 Hz), 143.1 (d, JC‑P = 3.6 Hz). 31P
NMR (162 MHz, DMSO-d6) δ 2.85. HRMS (MALDI-TOF) m/z [M
− Br−] Calcd for C26H22OP+ 381.1403; Found 381.1405. The
preparation of 3aa was also scaled up using DPPPM (20 mmol),
aldehyde 2a (20 mmol), Ph3PBr2 (11 mmol), and THF (28 mL), and
3aa was obtained in 96% (8.72 g) yield.
NMR (100 MHz, DMSO-d6) δ 71.2, 74.3 (d, JC‑P = 55.5 Hz), 113.0
(d, JC‑P = 81.8 Hz), 113.8 (d, JC‑P = 84.4 Hz), 115.9 (d, JC‑P = 79.4 Hz),
124.4, 127.2 (d, JC‑P = 9.1 Hz), 128.0, 129.8 (d, JC‑P = 11.7 Hz), 130.4
(d, JC‑P = 12.1 Hz), 131.2 (d, JC‑P =12.2 Hz), 134.6 (d, JC‑P = 6.0 Hz),
135.6 (d, JC‑P = 11.3 Hz), 135.7 (d, JC‑P = 10.4 Hz), 135.9, 136.3,
136.6, 138.7, 143.4, 148.5. 31P NMR (162 MHz, DMSO-d6) δ 4.18.
HRMS (MALDI-TOF) m/z [M − Br−] Calcd for C26H21NO3P+
426.1254; Found 426.1252.
1,1,2-Triphenyl-2,4-dihydro-1H-benzo[d][1,3]oxaphosphinin-1-
ium Tetrafluoroborate (3ab). A white solid, yield: 242.1 mg, 74%;
mp: 235−236 °C. 1H NMR (400 MHz, DMSO-d6) δ 5.56 (d, 1 H, J =
16.4 Hz), 5.60 (d, 1 H, J = 16.4 Hz), 6.90 (d, 2 H, J = 7.6 Hz), 6.96
(dd, 2 H, J1 = 7.8 Hz, J2C‑P = 12.2 Hz), 7.27−7.33 (m, 3 H), 7.37−7.43
(m, 1 H), 7.55−7.67 (m, 4 H), 7.71−7.77 (m, 1 H), 7.81−7.91 (m, 3
H), 7.91−8.02 (m, 2 H), 8.17 (dd, 2 H, J1 = 7.6 Hz, J2C‑P = 12.4 Hz).
13C NMR (100 MHz, DMSO-d6) δ 71.3, 75.3 (d, JC‑P = 55.1 Hz),
2-(2-Nitrophenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Bromide (3ea). A pale yellow solid, yield:
127.4 mg, 36%; mp: 260−262 °C. 1H NMR (400 MHz, DMSO-d6) δ
5.51 (dd, 1 H, J1C‑P = 2.0 Hz, J2 = 16.0 Hz), 5.72 (d, 1 H, JC‑P = 16.0
Hz), 7.10 (d, 1 H, JC‑P = 7.6 Hz), 7.18 (d, 2 H, J1 = 7.6 Hz, J2C‑P = 12.4
Hz), 7.50−7.68 (m, 6 H), 7.71−7.79 (m, 4 H), 7.84 (dd, 1 H, J1C‑P
=
7.2 Hz, J2 = 7.6 Hz), 7.87−7.94 (m, 2 H), 8.00 (dd, 1 H, J = 8.0 Hz),
8.11 (dd, 2 H, J1 = 7.6 Hz, J2C‑P = 12.8 Hz). 13C NMR (100 MHz,
DMSO-d6) δ 70.7 (d, JC‑P = 3.8 Hz), 74.2 (d, JC‑P = 52.7 Hz), 113.6 (d,
JC‑P = 56.3 Hz), 114.5 (d, JC‑P = 57.4 Hz), 117.9 (d, JC‑P = 79.0 Hz),
125.6 (d, JC‑P = 2.0 Hz), 127.33 (d, JC‑P = 1.6 Hz), 127.34 (d, JC‑P = 8.4
113.3 (d, JC‑P = 80.1 Hz), 114.2 (d, JC‑P = 84.4 Hz), 116.5 (d, JC‑P
=
78.7 Hz), 126.6 (d, JC‑P = 4.4 Hz), 127.0 (d, JC‑P = 8.6 Hz), 129.2 (d,
JC‑P = 2.9 Hz), 129.7 (d, JC‑P = 11.9 Hz), 130.1 (d, JC‑P = 12.5 Hz),
130.2, 131.1 (d, JC‑P = 12.3 Hz), 131.3 (d, JC‑P = 2.5 Hz), 134.6 (d, JC‑P
= 6.7 Hz), 135.1 (d, JC‑P = 9.7 Hz), 135.6 (d, JC‑P = 9.4 Hz), 135.7,
136.0 (d, JC‑P = 2.5 Hz), 136.3 (d, JC‑P = 2.5 Hz), 143.5 (d, JC‑P = 3.7
Hz). 31P NMR (162 MHz, DMSO-d6) δ 2.81. 11B-NMR (128 MHz,
DMSO-d6) δ −1.20. 19F-NMR (376 MHz, DMSO-d6) δ −148.3,
−148.2. HRMS (MALDI-TOF) m/z [M − F4B−] Calcd for
C26H22OP+ 381.1403; Found 381.1406.
Hz), 129.87 (d, JC‑P = 11.9 Hz), 129.90 (d, J = 4.7 Hz), 130.3 (d, JC‑P
=
12.7 Hz), 130.5 (d, JC‑P = 12.7 Hz), 131.5 (d, JC‑P = 2.9 Hz), 134.5 (d,
JC‑P = 2.7 Hz), 134.8 (d, JC‑P = 4.8 Hz), 134.9 (d, JC‑P = 10.1 Hz),
135.55, 135.60 (d, JC‑P = 9.6 Hz Hz), 135.7 (d, JC‑P = 3.0 Hz), 136.0
(d, JC‑P = 2.9 Hz), 144.0 (d, JC‑P = 3.6 Hz), 146.9 (d, JC‑P = 5.2 Hz). 31
P
NMR (243 MHz, DMSO-d6) δ 4.96. HRMS (MALDI-TOF) m/z [M
− Br−] Calcd for C26H21NO3P+ 426.1254; Found 426.1260.
2-(3-Nitrophenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Bromide (3fa). A white solid, yield: 189.1 mg,
53%; mp: 159−161 °C. 1H NMR (400 MHz, DMSO-d6) δ 5.60 (dd, 1
H, J1C‑P = 2.0 Hz, J2 = 16.4 Hz), 5.86 (d, 1 H, JC‑P = 16.4 Hz), 7.01 (d,
2 H, J1 = 7.8 Hz, J2C‑P = 12.2 Hz), 7.45−7.50 (m, 2 H), 7.56−7.66 (m,
5 H), 7.77 (dd, 1 H, J1C‑P = 6.4 Hz, J2 = 6.8 Hz), 7.80−7.90 (m, 3 H),
7.90−7.95 (m, 1 H), 7.99 (dd, 1 H, J1C‑P = 7.2 Hz, J2 = 7.2 Hz), 8.22
2-(4-Chlorophenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Bromide (3ba). A white solid, yield: 236.0 mg,
68%; mp: 236−237 °C. 1H NMR (400 MHz, DMSO-d6) δ 5.55 (dd, 1
H, J1 = 2.2 Hz, J2 = 16.4 Hz), 5.61 (d, 1 H, J = 16.4 Hz), 6.89 (dd, 2 H,
J1C‑P = 2.2 Hz, J2 = 8.5 Hz), 7.01 (dd, 2 H, J1 = 7.8 Hz, J2C‑P = 12.6
Hz), 7.39 (d, 2 H, J2 = 8.5 Hz), 7.45 (d, 1 H, JC‑P = 3.6 Hz), 7.56−7.67
(m, 4 H), 7.70−7.75 (m, 1 H), 7.80−7.86 (m, 2 H), 7.87−7.95 (m, 2
H), 7.96−8.01 (m, 1 H), 8.20 (dd, 2 H, J1 = 8.0 Hz, J2C‑P = 12.4 Hz).
13C NMR (100 MHz, DMSO-d6) δ 71.2 (d, JC‑P = 1.8 Hz), 74.2 (d,
(d, 1 H, J = 8.0 Hz), 8.29 (s, 1 H), 8.42 (dd, 2 H, J1 = 8.0 Hz, J2C‑P
=
12.0 Hz). 13C NMR (100 MHz, DMSO-d6) δ 71.2, 73.7 (d, JC‑P = 55.0
Hz), 112.9 (d, JC‑P = 81.3 Hz), 114.0 (d, JC‑P = 83.7 Hz), 115.6 (d, JC‑P
= 79.2 Hz), 121.4 (d, JC‑P = 4.4 Hz), 124.9 (d, JC‑P = 2.9 Hz), 127.1 (d,
JC‑P = 8.7 Hz), 129.7 (d, JC‑P = 12.1 Hz), 130.3 (d, JC‑P = 12.6 Hz),
131.1 (overlapped), 131.2 (d, JC‑P = 12.4 Hz), 133.1 (d, JC‑P = 4.2 Hz),
133.6 (d, JC‑P = 2.2 Hz), 134.5 (d, JC‑P = 7.0 Hz), 135.5 (d, JC‑P = 10.1
JC‑P = 54.8 Hz), 113.3 (d, JC‑P = 80.4 Hz), 114.2 (d, JC‑P = 83.8 Hz),
116.2 (d, JC‑P = 78.9 Hz), 127.1 (d, JC‑P = 8.8 Hz), 128.5 (d, JC‑P = 4.6
Hz), 129.3 (d, JC‑P = 2.0 Hz), 129.7 (d, JC‑P = 11.9 Hz), 130.3 (d, JC‑P
=
12.5 Hz), 130.5 (d, JC‑P = 2.5 Hz), 131.1 (d, JC‑P = 12.4 Hz), 134.5 (d,
JC‑P = 6.5 Hz), 134.8 (d, JC‑P = 4.1 Hz), 135.4 (d, JC‑P = 10.0 Hz),
135.66 (d, JC‑P = 9.9 Hz), 135.71, 136.1 (d, JC‑P = 2.2 Hz), 136.4 (d,
JC‑P = 2.6 Hz), 143.5 (d, JC‑P = 3.6 Hz). 31P NMR (162 MHz, DMSO-
d6) δ 3.21. HRMS (MALDI-TOF) m/z [M − Br−] Calcd for
C26H21ClOP+ 415.1013; Found 415.1012.
2-(2-Chlorophenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Bromide (3ca). A white solid, yield: 198.2 mg,
57%; mp: 258−260 °C. 1H NMR (400 MHz, DMSO-d6) δ 5.51 (dd, 1
H, J1 = 2.0 Hz, J2 = 16.0 Hz), 5.89 (d, 1 H, J = 16.0 Hz), 6.66 (dd, 1 H,
J1C‑P = 8.0 Hz), 7.05−7.16 (m, 3 H), 7.39−7.42 (m, 1 H), 7.46−7.57
(m, 3 H), 7.58−7.66 (m, 3 H), 7.71−7.79 (m, 3 H), 7.87−7.95 (m, 3
H), 8.17 (dd, 2 H, J1 = 8.0 Hz, J2C‑P = 12.8 Hz). 13C NMR (151 MHz,
DMSO-d6) δ 70.1, 73.7 (d, JC‑P = 55.1 Hz), 112.95 (d, JC‑P = 83.2 Hz),
Hz), 135.7 (d, JC‑P = 9.6 Hz), 135.8 (d, JC‑P = 1.7 Hz), 136.2 (d, JC‑P
=
2.6 Hz), 136.5 (d, JC‑P = 2.3 Hz), 143.4 (d, JC‑P = 3.6 Hz), 147.9 (d,
JC‑P = 3.3 Hz). 31P NMR (162 MHz, DMSO-d6) δ 4.06. HRMS
(MALDI-TOF) m/z [M − Br−] Calcd for C26H21NO3P+ 426.1254;
Found 426.1255.
2-(4-Fluorophenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Bromide (3ga). A white solid, yield: 297.1 mg,
89%; mp: 216−218 °C. 1H NMR (400 MHz, DMSO-d6) δ 5.54 (dd, 1
H, J1C‑P = 2.0 Hz, J2 = 16.3 Hz), 5.72 (dd, 1 H, J1C‑P = 5.0 Hz, J2 = 16.3
Hz), 6.90−7.02 (m, 4 H), 7.15 (d, 2 H, J1 = 8.6 Hz, J2 = 8.6 Hz),
7.55−7.67 (m, 4 H), 7.70−7.77 (m, 2 H), 7.78−7.85 (m, 2 H), 7.86−
8.00 (m, 3 H), 8.24−8.32 (m, 2 H). 13C NMR (100 MHz, DMSO-d6)
δ 71.2, 74.4 (d, JC‑P = 55.7 Hz), 113.3 (d, JC‑P = 80.1 Hz), 114.2 (d, JC‑P
= 84.0 Hz), 116.27 (d, JC‑P = 79.0 Hz), 116.33 (d, J1C‑P = 2.4 Hz, J2C‑F
= 22.0 Hz), 127.1 (d, JC‑P = 8.8 Hz), 127.7, 129.0 (dd, J1C‑P = 4.7 Hz,
J2C‑F = 8.6 Hz), 129.7 (d, JC‑P = 11.9 Hz), 130.2 (d, JC‑P = 12.6 Hz),
131.1 (d, JC‑P = 12.3 Hz), 134.5 (d, JC‑P = 6.5 Hz), 135.3 (d, JC‑P = 9.9
Hz), 135.7 (d, JC‑P = 9.4 Hz), 135.7 (overlapped), 136.0 (d, JC‑P = 2.8
Hz), 136.3 (d, JC‑P = 2.7 Hz), 143.5 (d, JC‑P = 3.7 Hz), 163.0 (dd, J1C‑P
= 3.8 Hz, J2C‑F = 247.0 Hz). 31P NMR (243 MHz, DMSO-d6) δ 2.94.
HRMS (MALDI-TOF) m/z [M − Br−] Calcd for C26H21FOP+
399.1309; Found 399.1309.
113.02 (d, JC‑P = 81.8 Hz), 116.4 (d, JC‑P = 78.2 Hz), 126.5 (d, JC‑P
=
8.6 Hz), 127.3 (d, JC‑P = 2.6 Hz), 129.2 (d, JC‑P = 12.2 Hz), 129.5 (d,
JC‑P = 2.1 Hz), 129.6 (d, JC‑P = 3.8 Hz), 129.8 (d, JC‑P = 12.7 Hz),
129.9 (d, JC‑P = 1.5 Hz), 130.0 (d, JC‑P = 12.7 Hz), 130.5 (d, JC‑P = 5.6
Hz), 131.5 (d, JC‑P = 3.3 Hz), 134.4 (d, JC‑P = 7.1 Hz), 135.1 (d, JC‑P
=
10.3 Hz), 135.2, 135.3 (d, JC‑P = 9.5 Hz), 135.57, 135.58, 143.6 (d, JC‑P
= 3.5 Hz). 31P NMR (162 MHz, DMSO-d6) δ 3.11. HRMS (MALDI-
TOF) m/z [M − Br−] Calcd for C26H21ClOP+ 415.1013; Found
415.1014.
2-(4-Nitrophenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Bromide (3da). A pale yellow solid, yield:
177.2 mg, 50%; mp: 176−178 °C. 1H NMR (400 MHz, DMSO-d6) δ
5.59 (dd, 1 H, J1C‑P = 2.2 Hz, J2 = 16.5 Hz), 5.66 (d, 1 H, JC‑P = 16.5
2-(4-Bromophenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Tetrafluoroborate (3hb). A white solid, yield:
281.5 mg, 73%; mp: 215−217 °C. 1H NMR (400 MHz, DMSO-d6) δ
5.61 (s, 2 H), 6.86 (d, 2 H, J = 7.6 Hz), 7.01 (dd, 2 H, J1 = 8.0 Hz, J2C‑P
= 12.0 Hz), 7.35 (d, 1 H, JC‑P = 2.8 Hz), 7.54 (d, 2 H, J = 8.0 Hz),
7.60−7.70 (m, 4 H), 7.74−7.79 (m, 1 H), 7.85−8.05 (m, 5 H), 8.21
Hz), 6.99 (d, 2 H, J1 = 7.6 Hz, J2C‑P = 12.4 Hz), 7.15 (d, 2 H, J1C‑P
2.0 Hz, J2 = 8.8 Hz), 7.56−7.65 (m, 4 H), 7.69 (s, 1 H), 7.75 (dd, 1 H,
J1C‑P = 6.4 Hz, J2 = 7.2 Hz), 7.82−7.91 (m, 3 H), 7.95 (dd, 1 H, J1C‑P
=
=
E
DOI: 10.1021/acs.joc.5b01031
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
(dd, 2 H, J1 = 8.0 Hz, J2C‑P = 12.0 Hz). 13C NMR (100 MHz, DMSO-
d6) δ 71.4, 74.7 (d, JC‑P = 55.9 Hz), 113.2 (d, JC‑P = 80.8 Hz), 114.1 (d,
JC‑P = 84.2 Hz), 116.1 (d, JC‑P = 78.8 Hz), 123.6 (d, JC‑P = 4.4 Hz),
127.1 (d, JC‑P = 8.7 Hz), 128.7 (d, JC‑P = 4.6 Hz), 129.7 (d, JC‑P = 11.8
yield: 330.2 mg, 89%; mp: 209−210 °C. 1H NMR (400 MHz, DMSO-
d6) δ 3.28 (s, 3 H), 3.72 (s, 3 H), 5.53 (d, 1 H, J = 16.4 Hz), 5.57 (d, 1
H, J = 16.4 Hz), 6.13 (s, 1 H), 6.62 (d, 1 H, J = 8.2 Hz), 6.91 (d, 1 H, J
= 8.2 Hz), 7.01(dd, 2 H, J1 = 7.4 Hz, J2C‑P = 12.2 Hz), 7.20 (d, 1 H, J =
5.6 Hz), 7.59−7.67 (m, 4 H), 7.69−7.76 (m, 1 H), 7.82 (ddd, 2 H,
J1C‑P = 3.3 Hz, J2 = 7.6 Hz, J3 = 7.8 Hz), 7.87−7.89 (m, 3 H), 8.16 (dd,
2 H, J1 = 7.6 Hz, J2C‑P = 12.4 Hz). 13C NMR (151 MHz, DMSO-d6) δ
54.8, 55.5 (d, JC‑P = 9.7 Hz), 70.1, 74.7 (d, JC‑P = 56.8 Hz), 109.2,
111.5, 113.0 (d, JC‑P = 79.3 Hz), 114.2 (d, JC‑P = 85.0 Hz), 116.0 (d,
Hz), 130.3 (d, JC‑P = 12.7 Hz), 130.7 (d, JC‑P = 2.6 Hz), 131.2 (d, JC‑P
=
12.3 Hz), 132.3 (d, JC‑P = 2.5 Hz), 134.6 (d, JC‑P = 6.7 Hz), 135.2 (d,
JC‑P = 9.9 Hz), 135.7 (d, JC‑P = 9.6 Hz), 135.7 (overlapped), 136.2 (d,
JC‑P = 2.3 Hz), 136.4 (d, JC‑P = 2.9 Hz), 143.5 (d, JC‑P = 3.7 Hz). 31P
NMR (162 MHz, DMSO-d6) δ 2.92. 11B-NMR (128 MHz, DMSO-d6)
δ −1.16. 19F-NMR (376 MHz, DMSO-d6) δ −148.20, −48.15. HRMS
(MALDI-TOF) m/z [M − F4B−] Calcd for C26H21BrOP+ 459.0508;
Found 459.0515.
2-(Naphthalen-1-yl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Tetrafluoroborate (3ib). A white solid, yield:
272.9 mg, 75%; mp: 228−230 °C. 1H NMR (600 MHz, DMSO-d6) δ
5.63 (d, 1 H, J = 16.2 Hz), 5.79 (d, 1 H, JC‑P = 16.2 Hz), 6.81−6.87
(m, 2 H), 6.92−6.99 (m, 1 H), 7.15 (dd, 1 H, J1 = 7.2 Hz, J2 =7.2 Hz),
7.36 (dd, 1 H, J1 = 6.6 Hz, J2 =7.8 Hz), 7.46 (dd, 1 H, J1 = 4.0 Hz, J2
=7.2 Hz), 7.51−7.56 (m, 2 H), 7.56−7.61 (m, 1 H), 7.63−7.75 (m, 4
H), 7.78−7.82 (m, 1 H), 7.83−7.89 (m, 2 H), 7.91 (s, 1 H), 7.95−8.04
(m, 5 H). 13C NMR (100 MHz, DMSO-d6) δ 71.7, 75.1 (d, JC‑P = 54.8
Hz), 113.2 (d, JC‑P = 80.2 Hz), 114.1 (d, JC‑P = 83.1 Hz), 116.9 (d, JC‑P
= 77.1 Hz), 123.6, 125.5 (d, JC‑P = 3.2 Hz), 127.1 (d, JC‑P = 8.5 Hz),
126.5, 126.7, 127.3 (d, JC‑P = 3.0 Hz), 127.4 (d, JC‑P = 6.1 Hz), 129.3,
129.5 (d, JC‑P = 3.8 Hz), 129.7 (d, JC‑P = 12.0 Hz), 130.1 (d, JC‑P = 12.4
JC‑P = 80.0 Hz), 119.2, 122.4, 126.5 (d, JC‑P = 10.0 Hz), 129.1 (d, JC‑P
=
11.3 Hz), 129.7 (d, JC‑P = 12.5 Hz), 130.5 (d, JC‑P = 11.0 Hz), 134.1 (d,
JC‑P = 5.0 Hz), 134.7 (d, JC‑P = 10.0 Hz), 135.2, 135.37 (d, JC‑P = 8.8
Hz), 135.39, 135.7, 143.1 (d, JC‑P = 3.6 Hz), 148.5 (d, JC‑P = 1.8 Hz),
149.7 (d, JC‑P = 3.5 Hz). 31P NMR (162 MHz, DMSO-d6) δ 1.63. 11B-
NMR (128 MHz, DMSO-d6) δ −1.17. 19F-NMR (376 MHz, DMSO-
d6) δ −148.24, −148.19. HRMS (MALDI-TOF) m/z [M − F4B−]
Calcd for C28H26O3P+ 441.1614; Found 441.1613.
2-(2,4-Dimethoxyphenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d]-
[1,3]oxaphosphinin-1-ium Tetrafluoroborate (3mb). A white solid,
yield: 238.8 mg, 84%; mp: 115−117 °C. 1H NMR (400 MHz, DMSO-
d6) δ 3.35 (s, 3 H), 3.74 (s, 3 H), 5.48 (d, 1 H, J = 16.2 Hz), 5.68 (d, 1
H, J = 16.2 Hz), 6.36 (d, 1 H, J = 7.6 Hz), 6.53 (dd, 1 H, J1C‑P = 2.2
Hz, J2 = 8.6 Hz), 6.56 (s, 1 H), 7.06 (dd, 2 H, J1 = 8.0 Hz, J2C‑P = 11.6
Hz), 7.21 (d, 1 H, J = 5.6 Hz), 7.52 (dd, 1 H, J1 = 7.8 Hz, J2C‑P = 13.0
Hz), 7.56−7.65 (m, 3 H), 7.68−7.74 (m, 1 H), 7.75−7.82 (m, 2 H),
Hz), 130.7 (d, JC‑P = 12.7 Hz), 130.8 (d, JC‑P = 5.0 Hz), 133.6 (d, JC‑P
=
7.83−7.95 (m, 3 H), 8.06 (dd, 2 H, J1 = 7.8 Hz, J2C‑P = 12.6 Hz). 13
C
2.0 Hz), 135.09 (d, JC‑P = 5.6 Hz), 135.11 (d, JC‑P = 10.3 Hz), 135.83,
135.84 (d, JC‑P = 9.0 Hz), 135.9, 136.1 (d, JC‑P = 2.4 Hz), 144.2 (d, JC‑P
= 3.6 Hz). 31P NMR (162 MHz, DMSO-d6) δ 3.16. 11B-NMR (128
MHz, DMSO-d6) δ −1.14. 19F-NMR (376 MHz, DMSO-d6) δ
−148.20, −148.14. HRMS (MALDI-TOF) m/z [M − F4B−] Calcd for
C30H24OP+ 431.1559; Found 431.1562.
NMR (100 MHz, DMSO-d6) δ 55.1, 55.9, 71.2, 72.6 (d, JC‑P = 55.1
Hz), 98.4 (d, JC‑P = 1.3 Hz), 106.1, 111.7 (d, JC‑P = 2.5 Hz), 114.2 (d,
JC‑P = 78.6 Hz), 114.5 (d, JC‑P = 83.3 Hz), 118.1 (d, JC‑P = 78.4 Hz),
127.0 (d, JC‑P = 8.6 Hz), 129.0 (d, JC‑P =4.1 Hz), 129.5 (d, JC‑P = 11.6
Hz), 130.0 (d, JC‑P = 12.3 Hz), 130.2 (d, JC‑P = 12.5 Hz), 134.8 (d, JC‑P
= 6.9 Hz), 134.9 (d, JC‑P = 13.0 Hz), 135.42, 135.45, 135.50 (d, JC‑P
=
1,1-Diphenyl-2-(p-tolyl)-2,4-dihydro-1H-benzo[d][1,3]oxaphos-
9.4 Hz), 135.7 (d, JC‑P = 2.5 Hz), 144.0 (d, JC‑P = 3.7 Hz), 156.6 (d,
JC‑P = 4.2 Hz), 162.0 (d, JC‑P = 3.0 Hz). 31P NMR (162 MHz, DMSO-
d6) δ 1.39. 11B-NMR (128 MHz, DMSO-d6) δ −1.26. 19F-NMR (376
MHz, DMSO-d6) δ −148.30, −148.24. HRMS (MALDI-TOF) m/z
[M − F4B−] Calcd for C28H26O3P+ 441.1614; Found 441.1617.
1,1-Diphenyl-2-(3,4,5-trimethoxyphenyl)-2,4-dihydro-1H-benzo-
[d][1,3]oxaphosphinin-1-ium Tetrafluoroborate (3nb). A white
phinin-1-ium Tetrafluoroborate (3jb). A white solid, yield: 289.5 mg,
1
86%; mp: 214−216 °C. H NMR (600 MHz, DMSO-d6) δ 2.26 (s, 3
H), 5.56 (d, 1 H, J = 16.5 Hz), 5.61 (d, 1 H, J = 16.5 Hz), 6.80 (d, 2 H,
J = 7.0 Hz), 5.98−7.03 (m, 2 H), 7.10 (d, 2 H, J = 7.0 Hz), 7.27 (s, 1
H), 7.58−7.65 (m, 4 H),7.72−7.77 (m, 1 H), 7.82−7.87 (m, 2 H),
7.87−7.91 (m, 1 H), 7.91−7.95 (m, 1 H), 7.96−8.00 (m, 1 H), 8.14−
8.19 (m, 2 H). 13C NMR (151 MHz, DMSO-d6) δ 20.7, 70.9, 74.7 (d,
JC‑P = 56.1 Hz), 112.9 (d, JC‑P = 80.5 Hz), 113.8 (d, JC‑P = 85.0 Hz),
116.0 (d, JC‑P = 79.4 Hz), 126.2, 126.5 (d, JC‑P = 4.8 Hz), 127.7 (d, JC‑P
= 2.3 Hz), 129.1 (d, JC‑P = 11.4 Hz), 129.3, 129.6 (d, JC‑P = 12.5 Hz),
130.6 (d, JC‑P = 12.0 Hz), 134.1, 134.6 (d, JC‑P = 9.4 Hz), 135.18,
135.21 (d, JC‑P = 8.8 Hz), 135.5, 135.7, 139.4 (d, JC‑P = 3.4 Hz), 143.0
(d, JC‑P = 3.8 Hz). 31P NMR (243 MHz, DMSO-d6) δ 2.32. 11B-NMR
(128 MHz, DMSO-d6) δ 1.13. 19F-NMR (376 MHz, DMSO-d6) δ
−148.22, −148.16. HRMS (MALDI-TOF) m/z [M − F4B−] Calcd for
C27H24OP+ 395.1559; Found 395.1560.
1
solid, yield: 320.4 mg, 82%; mp: 213-214 °C. H NMR (400 MHz,
DMSO-d6) δ 3.38 (s, 6 H), 3.64 (s, 3 H), 5.57 (s, 2 H), 6.08 (d, 2 H,
JC‑P = 2.0 Hz), 6.98(dd, 2 H, J1 = 7.8 Hz, J2C‑P = 12.2 Hz), 7.17 (d, 1
H, J = 4.8 Hz), 7.60−7.67 (m, 4 H), 7.68−7.75 (m, 1 H), 7.81−8.01
(m, 5 H), 8.20 (dd, 2 H, J1 = 7.6 Hz, J2C‑P = 12.4 Hz). 13C NMR (151
MHz, DMSO-d6) δ 55.5, 60.3, 70.8 (d, JC‑P = 1.5 Hz), 75.0 (d, JC‑P
=
56.2 Hz), 103.4, 112.6 (d, JC‑P = 79.9 Hz), 114.1 (d, JC‑P = 84.9 Hz),
115.9 (d, JC‑P = 80.3 Hz), 125.9 (d, JC‑P = 2.7 Hz), 126.6 (d, JC‑P = 9.4
Hz), 129.2 (d, JC‑P = 11.2 Hz), 129.6 (d, JC‑P = 12.4 Hz), 130.5 (d, JC‑P
= 12.2 Hz), 134.2 (d, JC‑P = 6.3 Hz), 134.8 (d, JC‑P = 9.8 Hz), 135.2
2-(4-Methoxyphenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Tetrafluoroborate (3kb). A white solid, yield:
281.0 mg, 81%; mp: 224−225 °C. 1H NMR (400 MHz, DMSO-d6) δ
3.76 (s, 3 H), 5.56 (d, 1 H, J = 16.4 Hz), 5.60 (d, 1 H, J = 16.4 Hz),
6.84 (dd, 2 H, J1C‑P = 2.0 Hz, J2 = 8.8 Hz), 6.89 (d, 2 H, J = 8.8 Hz),
7.03 (dd, 2 H, J1 = 7.8 Hz, J2C‑P = 12.2 Hz), 7.24 (d, 1 H, J = 5.6 Hz),
7.59−7.70 (m, 4 H), 7.75 (dd, 1 H, J1C‑P = 6.4 Hz, J2C‑P = 7.2 Hz),
7.83−7.89 (m, 2 H), 7.90−7.83 (m, 3 H), 8.17 (dd, 2 H, J1 = 7.8 Hz,
J2C‑P = 12.2 Hz). 13C NMR (100 MHz, DMSO-d6) δ 55.8, 71.5, 75.1
(d, JC‑P = 56.4 Hz), 113.5 (d, JC‑P = 79.0 Hz), 114.4 (d, JC‑P = 84.5 Hz),
114.7 (d, JC‑P = 1.9 Hz), 116.6 (d, JC‑P = 78.8 Hz), 122.9 (d, JC‑P = 2.5
(overlapped), 135.3 (d, JC‑P = 8.8 Hz), 135.6, 135.7, 138.2 (d, JC‑P =
3.9 Hz), 143.0 (d, JC‑P = 3.2 Hz), 152.9 (d, JC‑P = 3.2 Hz). 31P NMR
(162 MHz, DMSO-d6) δ 2.51. 11B-NMR (128 MHz, DMSO-d6) δ
−1.28. 19F-NMR (376 MHz, DMSO-d6) δ −148.27, −148.21. HRMS
(MALDI-TOF) m/z [M − F4B−] Calcd for C29H28O4P+ 471.1720;
Found 471.1725.
(E)-1,1-Diphenyl-2-styryl-2,4-dihydro-1H-benzo[d][1,3]oxaphos-
phinin-1-ium Tetrafluoroborate (3ob). A white solid, yield: 300.2 mg,
1
87%; mp: 105−106 °C. H NMR (600 MHz, DMSO-d6) δ 5.46 (s, 2
H), 6.36 (ddd, 1 H, J1 = 4.5 Hz, J2 = 5.7 Hz, J3 = 15.9 Hz), 6.65 (dd, 1
H, J1 = 4.5 Hz, J2 = 15.9 Hz), 6.82 (d, 1 H, J = 4.5 Hz), 7.29−7.34 (m,
3 H), 7.36−7.42 (m, 2 H), 7.57 (dd, 2 H, J1C‑P = 8.1 Hz, J2 = 12.2 Hz),
7.61−7.66 (m, 1 H), 7.66−7.76 (m, 4 H), 7.81−7.86 (m, 2 H), 7.87−
Hz), 127.1 (d, JC‑P = 8.7 Hz), 128.3 (d, JC‑P = 4.6 Hz), 129.7 (d, JC‑P
=
11.8 Hz), 130.2 (d, JC‑P = 12.5 Hz), 131.1 (d, JC‑P = 12.2 Hz), 134.6 (d,
JC‑P = 6.0 Hz), 135.1 (d, JC‑P = 9.6 Hz), 135.7, 135.8 (d, JC‑P = 9.4 Hz),
136.0 (d, JC‑P = 2.2 Hz), 136.3 (d, JC‑P = 1.9 Hz), 143.6 (d, JC‑P = 3.7
Hz), 160.7 (d, JC‑P = 3.1 Hz). 31P NMR (162 MHz, DMSO-d6) δ 1.86.
11B-NMR (128 MHz, DMSO-d6) δ 1.26. 19F-NMR (376 MHz,
7.93 (m, 2 H), 7.95−8.00 (m, 1 H), 8.11 (dd, 2 H, J1 = 7.8 Hz, J2C‑P
=
11.4 Hz). 13C NMR (100 MHz, DMSO-d6) δ 70.5 (d, JC‑P = 2.5 Hz),
74.4 (d, JC‑P = 57.8 Hz), 113.2 (d, JC‑P = 79.7 Hz), 115.7 (d, JC‑P = 81.7
Hz), 116.6 (d, JC‑P = 77.2 Hz), 118.3 (d, JC‑P = 4.1 Hz), 127.1 (d, JC‑P
=
8.7 Hz), 127.4 (d, JC‑P = 1.1 Hz), 129.2, 129.4, 129.6 (d, JC‑P = 11.8
Hz), 130.4 (d, JC‑P = 12.6 Hz), 131.0 (d, JC‑P = 12.2 Hz), 134.4 (d, JC‑P
= 6.2 Hz), 134.9 (d, JC‑P = 9.6 Hz), 135.3 (d, JC‑P = 3.4 Hz), 135.6,
135.7(d, JC‑P = 9.9 Hz), 135.9 (d, JC‑P = 2.8 Hz), 136.1 (d, JC‑P = 2.6
DMSO-d6) δ −148.31, −148.25. HRMS (MALDI-TOF) m/z [M −
F4B−] Calcd for C27H24O2P+ 411.1508; Found 411.1511.
2-(3,4-Dimethoxyphenyl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d]-
[1,3]oxaphosphinin-1-ium Tetrafluoroborate (3 lb). A white solid,
F
DOI: 10.1021/acs.joc.5b01031
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
Hz), 136.7 (d, JC‑P = 12.1 Hz), 143.5 (d, JC‑P = 3.9 Hz). 31P NMR (162
MHz, DMSO-d6) δ −0.41. 11B-NMR (128 MHz, DMSO-d6) δ −1.28.
19F-NMR (376 MHz, DMSO-d6) δ −148.27, −148.22. HRMS
JC‑P = 7.1 Hz), 155.2. 31P NMR (162 MHz, DMSO-d6) δ 28.94 (E-
isomer), 29.17 (Z-isomer). HRMS (MALDI-TOF) m/z [M + Na]+
Calcd for C33H26ClNaO2P+ 543.1251; Found 543.1255.
(MALDI-TOF) m/z [M − F4B−] Calcd for C28H24OP+ 407.1559;
Found 407.1558.
(2-(((2-(4-Nitrophenyl)-1-phenylvinyl)oxy)methyl)phenyl)-
diphenylphosphine Oxide (4ad). A yellow solid isolated as an
inseparable Z/E mixture (Z:E = 85:15 based on integrations of two
2-Isopropyl-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]oxaphos-
phinin-1-ium Bromide (3pa). A white solid, yield: 187.1 mg, 63%;
mp: 215−216 °C. 1H NMR (400 MHz, DMSO-d6) δ 0.87 (d, 3 H, J =
6.8 Hz), 1.01 (d, 3 H, J = 6.4 Hz), 1.78−1.91 (m, 1 H), 5.33 (d, 1 H, J
= 17.6 Hz, 1 H), 5.37 (d, 1 H, J = 17.6 Hz), 5.76 (dd, 1 H, J1 = 8.8 Hz,
J2C‑P = 8.8 Hz), 7.46 (dd, 1 H, J1 = 8.0 Hz, J2C‑P = 13.6 Hz), 7.55 (ddd,
1 H, J1C‑P = 1.7 Hz, J2 = 7.2 Hz, J3 = 7.4 Hz), 7.60−7.71 (m, 3 H),
7.76−7.87 (m, 5 H), 7.90−8.00 (m, 2 H), 8.13 (d, 2 H, J = 7.8 Hz,
1
peaks at 6.37 and 5.82 of H NMR), yield: 179.6 mg, 84%; Rf: 0.53
1
(PE:EtOAc 1:1). H NMR (600 MHz, DMSO-d6) δ: Z-isomer, 5.07
(s, 2 H), 6.37 (s, 1 H), 7.04 (dd, 1 H, J1 = 7.8 Hz, J2C‑P = 13.3 Hz),
7.35−7.42 (m, 3 H), 7.43−7.59 (m, 12 H), 7.60−7.68 (m, 1 H), 7.71−
7.75 (m, 1 H), 7.76 (d, 2 H, J = 8.3 Hz), 7.95 (d, 1 H, JC‑P = 5.8 Hz),
8.04 (d, 2 H, J = 8.3 Hz) ; E-isomer (part), 5.36 (s, 2 H), 5.82 (s, 1 H),
6.95 (d, 2 H, J = 8.2 Hz), 7.09−7.16 (m, 3 H), 7.29 (dd, 1 H, J1C‑P
=
7.3 Hz, J2 = 7.3 Hz), 7.92 (d, 2 H, J = 8.4 Hz). 13C NMR (100 MHz,
CDCl3) δ: Z-isomer, 70.1 (d, JC‑P = 4.8 Hz), 111.0, 123.6, 126.9, 127.1
(d, JC‑P = 12.6 Hz), 128.0 (d, JC‑P = 9.7 Hz), 128.5, 128.6, 128.7 (d, JC‑P
= 10.8 Hz), 129.3, 129.6 (d, JC‑P = 100.4 Hz), 131.8 (d, JC‑P = 9.8 Hz),
132.0, 132.1 (d, JC‑P = 102.9 Hz), 132.4, 133.3 (d, JC‑P = 12.2 Hz),
135.2, 142.4 (d, JC‑P = 7.2 Hz), 142.8, 145.3, 159.1; E-isomer (part),
60.4, 101.8, 123.2, 144.7, 144.9, 159.2. 31P NMR (243 MHz, CDCl3) δ
31.44 (Z-isomer), 31.61 (E-isomer). HRMS (QFT-ESI) m/z [M +
Na]+ Calcd for C33H26NNaO4P+ 554.1492; Found 554.1495.
J2C‑P = 12.2 Hz). 13C NMR (151 MHz, DMSO-d6) δ 18.3 (dd, J1C‑P
=
2.2 Hz, J2C‑P = 11.4 Hz), 19.2 (d, JC‑P = 1.2 Hz), 30.1 (d, JC‑P = 5.6
Hz), 70.6 (ddd, J1C‑P = 2.3 Hz, J2C‑P = 9.5 Hz, J3C‑P = 10.4 Hz), 78.0
(dd, J1C‑P = 6.4 Hz, J2C‑P = 55.2 Hz), 113.9 (d, JC‑P = 84. Hz), 114.6 (d,
JC‑P = 82.3 Hz), 118.1 (d, JC‑P = 76.0 Hz), 126.2 (d, JC‑P = 4.8 Hz),
129.0 (d, JC‑P = 11.0 Hz), 130.4 (d, JC‑P = 11.6 Hz), 133.6 (d, JC‑P = 5.6
Hz), 134.2 (d, JC‑P = 9.8 Hz), 134.7 (d, JC‑P = 2.1 Hz), 135.1 (d, JC‑P
=
10.1 Hz), 135.4 (d, JC‑P = 2.0 Hz), 143.0 (d, JC‑P = 2.1 Hz). 31P NMR
(162 MHz, DMSO-d6) δ 1.81. HRMS (MALDI-TOF) m/z [M − Br−]
Calcd for C23H24OP+ 347.1559; Found 347.1560.
(2-(((2-(2-Nitrophenyl)-1-phenylvinyl)oxy)methyl)phenyl)-
diphenylphosphine Oxide (4ae). A yellow solid isolated as an
inseparable Z/E mixture (Z:E = 40:60 based on integrations of two
2-(Furan-2-yl)-1,1-diphenyl-2,4-dihydro-1H-benzo[d][1,3]-
oxaphosphinin-1-ium Bromide (3qa). A white solid, yield: 202.3 mg,
64%, mp: 223−224 °C. 1H NMR (400 MHz, DMSO-d6) δ 5.45 (dd, 1
H, J1C‑P = 2.0 Hz, J2 = 16.4 Hz), 5.55 (d, 1 H, JC‑P = 16.4 Hz), 6.40
(dd, 1 H, J1 = 3.2 Hz, J2 = 3.2 Hz), 6.50 (s, 1 H), 7.25 (dd, 2 H, J1 =
7.8 Hz, J2C‑P = 13.0 Hz), 7.49 (s, 1 H), 7.61−7.72 (m, 5 H), 7.73−7.78
(m, 1 H), 7.79−7.85 (m, 2 H), 7.88−8.00 (m, 3 H), 8.11 (dd, 2 H, J1
= 7.8 Hz, J2C‑P = 12.6 Hz). 13C NMR (151 MHz, DMSO-d6) δ 69.6 (d,
JC‑P = 60.6 Hz), 70.2 (d, JC‑P = 2.4 Hz), 111.3, 112.1 (overlapped),
1
peaks at 5.03 and 5.43 of H NMR), yield: 158.7 mg, 75%; Rf: 0.53
(PE:EtOAc 1:1). 1H NMR (600 MHz, CDCl3) δ: E-isomer, 5.43 (s, 2
H), 5.81 (s, 1 H), 7.02 (dd, 1 H, J1 = 7.5 Hz, J2C‑P = 13.1 Hz), 7.10−
7.18 (m, 4 H), 7.19−7.32 (m, 3 H), 7.33−7.40 (m, 3 H), 7.42−7.62
(m, 8 H), 7.67−7.73 (m, 3 H), 7.74−7.81 (m, 1 H), 7.85−7.90 (m, 1
H); Z-isomer (part), 5.03 (s, 2 H), 6.42 (s, 1 H), 6.77 (d, 2 H, J = 6.8
Hz). 13C NMR (151 MHz, CDCl3) δ: E-isomer, 68.4 (d, JC‑P = 4.6
Hz), 99.7, 124.3, 126.9, 127.0 (d, JC‑P = 12.8 Hz), 128.0, 128.4 (d, JC‑P
= 10.1 Hz), 128.5, 128.7 (d, JC‑P = 12.1 Hz), 129.4 (d, JC‑P = 100.9
Hz), 129.5, 130.4, 131.9, 131.9 (overlapped), 132.1 (d, JC‑P = 8.9 Hz),
132.5, 132.7 (d, JC‑P = 100.7 Hz), 133.2 (d, JC‑P = 12.1 Hz), 133.5,
135.0, 141.9 (d, JC‑P = 7.2 Hz), 148.3, 157.4; Z-isomer (part): 70.4 (d,
JC‑P = 4.6 Hz), 106.9, 126.4, 126.82, 126.84 (d, JC‑P = 11.9 Hz), 128.1
(d, JC‑P = 11.0 Hz), 128.6 (d, JC‑P = 12.3 Hz), 128.8, 129.0, 129.6 (d,
112.4 (d, JC‑P = 80.8 Hz), 115.4 (d, JC‑P = 83.7 Hz), 116.1 (d, JC‑P
=
84.0 Hz), 126.7 (d, JC‑P = 8.3 Hz), 129.1 (d, JC‑P = 12.1 Hz), 129.9 (d,
JC‑P = 12.5 Hz), 130.4 (d, JC‑P = 12.2 Hz), 133.9 (d, JC‑P = 6.5 Hz),
134.6 (d, JC‑P = 13.0 Hz), 134.7 (d, JC‑P = 10.7 Hz), 135.2, 135.5,
135.7, 142.9 (d, JC‑P = 3.3 Hz), 143.7 (d, JC‑P = 4.1 Hz), 145.0. 31P
NMR (243 MHz, DMSO-d6) δ −0.71. HRMS (MALDI-TOF) m/z
[M − Br−] Calcd for C24H20O2P+ 371.1195; Found 371.1196.
General Procedure for the Wittig Olefination Using
Phosphonium Salts 3 and K2CO3 as a Base. To a testing tube
(10 mL) were added phosphonium salt 3 (0.35 mmol), aldehyde 2
(0.31 mmol), K2CO3 (58.0 mg, 0.42 mmol), DMSO (1.0 mL), and
CH3CN (0.2 mL). After it was stirred at rt overnight, the reaction
mixture was diluted with water (10 mL), and extracted with CH2Cl2
(10 mL × 2). The combined extract was evaporated, and the residue
was isolated by preparative TLC (silica gel) to afford vinyl ethers 4.
General Procedure for the Wittig Olefination Using
Phosphonium Salts 3 and t-BuOK as a Base. To a mixture of
phosphonium salt 3 (0.3 mmol), aldehyde 2 (0.3 mmol), and anhyd
THF (5 mL) in a round-bottom flask (25 mL) was added t-BuOK (1
M in THF, 0.36 mL) dropwise, and the reaction mixture immediately
turned to dark-red. After it was stirred at rt for 3 h, the mixture was
diluted with CH2Cl2 (10 mL), evaporated, and isolated by preparative
TLC (silica gel) to give vinyl ethers 4.
JC‑P = 100.5 Hz), 129.7, 131.7, 131.8 (d, JC‑P = 9.8 Hz), 132.2 (d, JC‑P
=
103.3 Hz), 132.25, 133.1 (d, JC‑P = 12.2 Hz), 132.34, 135.3, 142.4 (d,
JC‑P = 7.0 Hz), 148.0, 157.5. 31P NMR (162 MHz, CDCl3) δ 31.05 (E-
isomer), 31.09 (Z-isomer). HRMS (QFT-ESI) m/z [M + Na]+ Calcd
for C33H26NNaO4P+ 554.1492; Found 554.1493.
(2-(((2-(4-Bromophenyl)-1-phenylvinyl)oxy)methyl)phenyl)-
diphenylphosphine Oxide (4ah). A white solid isolated as an
inseparable Z/E mixture (Z:E = 89:11 based on integrations of two
1
peaks at 4.99 and 5.28 of H NMR), yield: 158.6 mg, 70%; Rf: 0.58
1
(PE:EtOAc 1:1). H NMR (600 MHz, DMSO-d6) δ: Z-isomer, 4.99
(s, 2 H), 6.32 (s, 1 H), 7.03 (dd, 1 H, J1 = 7.5 Hz, J2C‑P = 13.5 Hz),
7.31−7.36 (m, 3 H), 7.39 (d, 2 H, J = 7.8 Hz), 7.44−7.52 (m, 12 H),
7.54−7.59 (m, 2 H), 7.61−7.68 (m, 1 H), 7.71−7.75 (m, 1 H), 7.99
(d, 1 H, JC‑P = 3.6 Hz); E-isomer (part), 5.28 (s, 2 H), 5.61 (s, 1 H),
6.70 (d, 2 H, J = 7.8 Hz), 7.09−7.13 (m, 3 H), 7.24−7.28 (m, 4 H).
13C NMR (151 MHz, DMSO-d6) δ: Z-isomer, 69.0 (d, JC‑P = 5.1 Hz),
112.0 (d, JC‑P = 4.2 Hz), 119.5, 125.8, 127.3 (d, JC‑P = 12.9 Hz), 127.5
(d, JC‑P = 9.6 Hz), 128.6, 128.7, 128.8 (d, JC‑P = 11.8 Hz), 129.3 (d, JC‑P
(2-(((2-(4-Chlorophenyl)-1-phenylvinyl)oxy)methyl)phenyl)-
diphenylphosphine Oxide (4ab). A white solid isolated as an
inseparable Z/E mixture (Z:E = 89:11 based on integrations of two
= 91.9 Hz), 130.2, 131.2, 131.3 (d, JC‑P = 9.7 Hz), 132.0 (d, JC‑P
=
1
peaks at 5.06 and 5.34 of H NMR), yield: 160.4 mg, 61%; Rf: 0.50
102.4 Hz), 132.1, 132.56 (d, JC‑P = 9.2 Hz), 132.59, 134.4, 135.0, 141.7
(d, JC‑P = 7.4 Hz), 154.8. 31P NMR (243 MHz, DMSO-d6) δ 28.90 (E-
isomer), 29.17 (Z-isomer). HRMS (QFT-ESI) m/z [M + Na]+ Calcd
for C33H26BrNaO2P+ 587.0746; Found 587.0752.
(PE:EtOAc = 1:1). 1H NMR (400 MHz, DMSO-d6) δ: Z-isomer, 5.06
(s, 2 H), 6.37 (s, 1 H), 7.08 (dd, 1 H, J1 = 7.6 Hz, J2C‑P = 13.8 Hz),
7.14−7.18 (m, 1 H), 7.29 (d, 2 H, J = 6.4 Hz), 7.35−7.39 (m, 2 H),
7.41−7.46 (m, 2 H), 7.48−7.55 (m, 8 H), 7.57−7.63 (m, 4 H), 7.64−
7.72 (m, 1 H), 7.73−7.79 (m, 1 H), 8.04 (d, 1 H, J1C‑P = 3.4 Hz, J2 =
7.4 Hz); E-isomer (part), 5.34 (s, 2 H), 5.69 (s, 1 H), 6.80 (d, 2 H, J =
(2-((((3E)-1,4-Diphenylbuta-1,3-dien-1-yl)oxy)methyl)phenyl)-
diphenylphosphine Oxide (4ao). A white solid isolated as an
inseparable Z/E mixture (Z:E = 93:7 based on integrations of two
8.4 Hz). 13C NMR (100 MHz, DMSO-d6) δ: Z-isomer, 69.6 (d, JC‑P
=
peaks at 5.07 and 5.30 of H NMR), yield: 91.4 mg, 45%; Rf: 0.51
1
1
7.1 Hz), 112.4, 126.4, 127.8 (d, JC‑P = 12.1 Hz), 128.1 (d, JC‑P = 9.7
(PE:EtOAc 1:1). H NMR (600 MHz, DMSO-d6) δ: Z-isomer, 5.07
Hz), 128.8, 129.1, 129.2, 129.3 (d, JC‑P = 11.8 Hz), 129.9 (d, JC‑P
90.8 Hz), 130.4, 131.4, 131.8 (d, JC‑P = 9.7 Hz), 132.58, 132.62 (d, JC‑P
= 107.2 Hz), 133.0, 133.1 (d, JC‑P = 6.5 Hz), 134.6, 135.6, 142.3 (d,
=
(s, 2 H), 6.42 (d, 1 H, J = 10.4 Hz), 6.67 (d, 1 H, J = 15.6 Hz), 7.03−
7.09 (m, 1 H), 7.10−7.19 (m, 1 H), 7.20−7.27 (m, 1 H), 7.27−7.35
(m, 5 H), 7.36−7.40 (m, 2 H), 7.41−7.46 (m, 3 H), 7.45−7.67 (m, 10
G
DOI: 10.1021/acs.joc.5b01031
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
H), 7.75−7.80 (m, 1 H), 8.01−8.05 (m, 1 H); E-isomer (part): 5.30
(s, 2 H), 5.58 (d, 1 H, J = 10.2 Hz), 6.36 (d, 1 H, J = 16.4 Hz). 13C
NMR (151 MHz, DMSO-d6) δ: Z-isomer, 70.8 (d, JC‑P = 4.3 Hz),
115.0, 123.2, 125.1, 126.2, 127.38 (d, JC‑P = 10.3 Hz), 127.41, 128.4,
128.5 (d, JC‑P = 9.4 Hz), 128.7, 128.8 (d, JC‑P = 11.9 Hz), 129.6 (d, JC‑P
131.3 (d, JC‑P = 9.4 Hz), 131.4 (d, JC‑F = 2.7 Hz), 131.5, 131.9 (d, JC‑P
= 103.0 Hz), 132.1, 132.5 (d, JC‑P = 11.6 Hz), 132.6, 134.4, 141.6 (d,
JC‑P = 7.0 Hz), 152.4, 160.8 (d, JC‑F = 244.8 Hz). 31P NMR (162 MHz,
CDCl3) δ 31.30 (Z-isomer), 31.44 (E-isomer). HRMS (QFT-ESI) m/
z [M + Na]+ Calcd for C33H25BrFNaO2P+ 605.0652; Found 605.0655.
(2-(((1-(4-Fluorophenyl)-2-(4-nitrophenyl)vinyl)oxy)methyl)-
phenyl)diphenylphosphine Oxide (4gd). A white solid isolated as an
inseparable Z/E mixture (Z:E = 95:5 based on integrations of two
= 99.4 Hz), 131.3 (d, JC‑P = 9.5 Hz), 131.5, 132.1, 132.3 (d, JC‑P
=
102.5 Hz), 132.5, 132.6 (d, JC‑P = 10.8 Hz), 132.7, 134.5, 137.3, 142.0
(d, JC‑P = 7.1 Hz), 154.0. 31P NMR (243 MHz, DMSO-d6) δ 29.08 (E-
isomer), 29.31 (Z-isomer). HRMS (QFT-ESI) m/z [M + Na]+ Calcd
for C35H29NaO2P+ 535.1797; Found 535.1800.
1
peaks at 5.07 and 5.37 of H NMR), yield: 112.9 mg, 68%; Rf: 0.55
1
(PE:EtOAc 1:1). H NMR (600 MHz, DMSO-d6) δ: Z-isomer, 5.07
(s, 2 H), 6.35 (s, 1 H), 7.04 (dd, 1 H, J1 = 7.7 Hz, J2C‑P = 13.6 Hz),
7.19 (dd, 2 H, J1C‑F = 8.5 Hz, J2 = 8.5 Hz), 7.42 (dd, 1 H, J1 = 7.3 Hz,
J2 = 7.3 Hz), 7.44−7.51 (m, 8 H), 7.52−7.57 (m, 4 H), 7.72 (dd, 1 H,
(2-(((2-(Furan-2-yl)-1-phenylvinyl)oxy)methyl)phenyl)diphenyl-
phosphine Oxide (4aq). A pale yellow solid isolated as an inseparable
Z/E mixture (Z:E = 94:6 based on integrations of two peaks at 5.04
and 5.28 of 1H NMR), yield: 152.6 mg, 80%; Rf: 0.47 (PE:EtOAc 1:1).
1H NMR (600 MHz, DMSO-d6) δ: Z-isomer, 5.04 (s, 2 H), 6.40−6.45
(m, 3 H), 7.04 (dd, 1 H, J1 = 7.8 Hz, J2C‑P = 12.8 Hz), 7.29−7.34 (m, 3
H), 7.40−7.46 (m, 2 H), 7.46−7.52 (m, 8 H),7.55−7.67 (m, 4 H),
7.72−7.79 (m, 1 H), 8.09 (d, 1 H, JC‑P = 3.1 Hz); E-isomer (part):
5.28 (s, 2 H), 5.52 (s, 1 H), 5.57 (s, 1 H), 6.25 (s. One H), 7.11 (dd, 1
H, JC‑P = 8.1 Hz, J2C‑P = 12.8), 7.20 (d, 2 H, J = 6.7 Hz). 13C NMR
(151 MHz, DMSO-d6) δ: Z-isomer, 68.8, 103.3 (d, JC‑P = 10.0 Hz),
108.9 (d, JC‑P = 12.3 Hz), 112.0 (d, JC‑P = 12.4 Hz), 125.4, 127.2 (d,
J1 = 7.5 Hz, J2 = 7.5 Hz), 7.76 (d, 2 H, J = 8.5 Hz), 7.93 (d, 1 H, JC‑P
=
4.1 Hz), 8.05 (d, 2 H, J = 8.5 Hz); E-isomer (part): 5.37 (s, 2 H), 5.84
(s, 1 H), 6.97 (d, 2 H, J = 8.5 Hz), 7.11−7.15 (m, 2 H). 13C NMR
(151 MHz, DMSO-d6) δ: Z-isomer, 69.6 (d, JC‑P = 4.8 Hz), 110.9,
115.7 (d, JC‑F = 21.8 Hz), 123.5, 127.5 (d, JC‑P = 12.5 Hz), 128.1 (d,
JC‑P = 9.3 Hz), 128.7 (d, JC‑P = 11.3 Hz), 128.8, 128.9, 129.5 (d, JC‑P
=
99.2 Hz), 131.0, 131.3 (d, JC‑P = 9.6 Hz), 132.02 (d, JC‑P = 102.5 Hz),
132.03, 132.6, 132.7 (d, JC‑P = 11.7 Hz), 141.2 (d, JC‑P = 6.8 Hz),
142.3, 145.0, 157.0, 162.6 (d, JC‑F = 247.4 Hz). 31P NMR (243 MHz,
CDCl3) δ 31.51 (Z-isomer), 31.65 (E-isomer). HRMS (QFT-ESI) m/
z [M + Na]+ Calcd for C33H25FNNaO4P+ 572.1397; Found 572.1399.
(2-(((1-(Furan-2-yl)-2-(4-(trifluoromethyl)phenyl)vinyl)oxy)-
methyl)phenyl)diphenylphosphine Oxide (4qs). A white solid
isolated as an inseparable Z/E mixture (Z:E = 85:15 based on
JC‑P = 12.1 Hz), 127.4 (d, JC‑P = 9.8 Hz), 128.5, 128.7, 128.8 (d, JC‑P
=
11.5 Hz), 129.2 (d, JC‑P = 84.1 Hz), 131.3, 132.0 (d, JC‑P = 103.0 Hz),
132.1, 132.56 (d, JC‑P = 9.5 Hz), 132.59, 134.2, 141.5 (d, JC‑P = 7.4
Hz), 141.9 (d, JC‑P = 6.9 Hz), 150.3, 152.2. 31P NMR (243 MHz,
DMSO-d6) δ 29.15 (E-isomer), 29.34 (Z-isomer). HRMS (QFT-ESI)
m/z [M + Na]+ Calcd for C31H25NaO3P+ 499.1434; Found 499.1438.
Diphenyl(2-(((1-phenyl-2-(pyridin-2-yl)vinyl)oxy)methyl)phenyl)-
phosphine Oxide (4ar). Z-isomer: a white solid, yield: 51.8 mg, 27%;
1
integrations of two peaks at 5.18 and 5.30 of H NMR), yield: 162.1
1
mg, 96%; Rf: 0.50 (PE:EtOAc 1:1). H NMR (600 MHz, DMSO-d6)
δ: Z-isomer, 5.18 (s, 2 H), 6.45 (s, 1 H), 6.51 (s, 2 H), 7.04 (dd, 1 H,
J1 = 7.3 Hz, J2C‑P = 13.2 Hz), 7.39−7.44 (m, 1 H), 7.45−7.60 (m, 12
H), 7.61−7.66 (m, 1 H), 7.68−7.75 (m, 3 H), 7.94−7.98 (m, 1 H); E-
isomer (part): 5.30 (s, 2 H), 5.76 (s, 1 H), 6.43 (s, 1 H), 6.49 (s, 1 H),
7.13 (d, 1 H, J1 = 7.7 Hz, J2C‑P = 13.3 Hz),7.76−7.80 (m, 1 H). 13C
NMR (151 MHz, DMSO-d6) δ: Z-isomer, 70.0 (d, JC‑P = 4.4 Hz),
109.5 (d, JC‑P = 10.9 Hz), 110.3 (d, JC‑P = 9.1 Hz), 112.0 (d, JC‑P = 11.2
Hz), 124.2 (q, JC‑F = 271.8 Hz), 125.1 (q, JC‑F = 3.6 Hz), 126.7 (q, JC‑F
= 31.8 Hz), 127.4 (d, JC‑P = 11.9 Hz), 127.8 (d, JC‑P = 9.9 Hz), 128.6,
128.8 (d, JC‑P = 11.3 Hz), 129.3 (d, JC‑P = 99.1 Hz), 131.3 (d, JC‑P = 9.3
Hz), 132.0 (d, JC‑P = 102.7 Hz), 132.1, 132.5, 132.6 (d, JC‑P = 11.1 Hz),
138.5, 141.4 (d, JC‑P = 6.8 Hz), 144.3 (d, JC‑P = 7.4 Hz), 147.5, 148.9.
31P NMR (243 MHz, CDCl3) δ 31.50 (Z-isomer), 31.63 (E-isomer).
1
Rf: 0.25 (PE:EtOAc 2:9); H NMR (600 MHz, CDCl3) δ 5.13 (s, 2
H), 6.27 (s, 1 H), 7.00−7.04 (m, 1 H), 7.07 (dd, 1 H, J1 = 7.4 Hz, J2C‑P
= 13.5 Hz), 7.22−7.30 (m, 4 H), 7.35−7.39 (m, 4 H), 7.41 (d, 2 H, J =
6.8 Hz,), 7.46−7.50 (m, 3 H), 7.51−7.56 (m, 4 H), 7.61 (dd, 1 H, J1C‑P
= 7.4 Hz, J2 = 7.4 Hz), 7.92 (d, 1 H, J = 8.0 Hz), 8.01 (dd, 1 H, J1 = 3.0
Hz, J2C‑P = 3.6 Hz), 8.51 (s, 1 H); 13C NMR (151 MHz, CDCl3) δ
69.8 (d, JC‑P = 4.4 Hz), 114.2, 120.9, 123.4, 126.7, 126.8 (d, JC‑P = 11.7
Hz), 127.9 (d, JC‑P = 9.8 Hz), 128.5, 128.6 (d, JC‑P = 12.2 Hz), 128.8,
129.4 (d, JC‑P = 100.5 Hz), 131.8 (d, JC‑P = 9.9 Hz), 132.0 (d, JC‑P = 1.7
Hz), 132.1 (d, JC‑P = 102.2 Hz), 132.4, 133.2 (d, JC‑P = 12.1 Hz), 135.4,
136.0, 142.8 (d, JC‑P = 7.1 Hz), 149.0, 155.0, 158.1; 31P NMR (243
MHz, CDCl3) δ 31.18; HRMS (ESI-QFT) m/z [M + H+] Calcd for
C32H27NO2P+ 488.1774; Found 488.1778. E-isomer: a white solid,
HRMS (QFT-ESI) m/z [M + Na]+ Calcd for C32H24F3NaO3P+
567.1307; Found 567.1310.
1
yield: 65.8 mg, 34%; Rf: 0.13 (PE:EtOAc 2:9); H NMR (600 MHz,
CDCl3) δ 5.41 (s, 2 H), 5.83 (s, 1 H), 6.59 (d, 1 H, J = 7.8 Hz), 6.89
(s, 1 H), 7.14 (dd, 1 H, J1 = 7.9 Hz, J2C‑P = 13.1 Hz), 7.20−7.25 (m, 4
H), 7.25−7.32 (m, 3 H), 7.43−7.50 (m, 4 H), 7.50−7.60 (m, 3 H),
7.64−7.70 (m, 4 H), 7.77−7.82 (m, 1 H), 8.42 (s, 1 H); 13C NMR
(151 MHz, CDCl3) δ 68.2 (d, JC‑P = 4.5 Hz), 104.2, 119.9, 123.9,
127.0 (d, JC‑P = 12.4 Hz), 128.1, 128.7 (d, JC‑P = 12.1 Hz), 128.8 (d,
JC‑P = 9.9 Hz), 128.9, 129.4, 129.7 (d, JC‑P = 100.6 Hz), 132.01 (d, JC‑P
= 10.0 Hz), 132.04, 132.45 (d, JC‑P = 104.0 Hz), 132.42, 133.3 (d, JC‑P
= 11.9 Hz), 135.2, 135.8, 142.0 (d, JC‑P = 7.2 Hz), 148.9, 156.9, 159.1;
31P NMR (243 MHz, CDCl3) δ 31.38; HRMS (QFT-ESI) m/z [M +
Methyl 4-(2-((2-(Diphenylphosphoryl)benzyl)oxy)-2-(p-tolyl)-
vinyl)benzoate (4jt). A white solid isolated as an inseparable Z/E
mixture (Z:E = 93:7 based on integrations of two peaks at 5.01 and
5.29 of 1H NMR), yield: 121.9 mg, 87%; Rf: 0.50 (PE:EtOAc 1:1). 1H
NMR (600 MHz, DMSO-d6) δ: Z-isomer, 2.34 (s, 3 H), 3.85 (s, 3 H),
5.01 (s, 2 H), 6.29 (s, 1 H), 7.02 (dd, 1 H, J1 = 7.9 Hz, J2C‑P = 13.7
Hz), 7.15 (d, 2 H, J = 7.5 Hz), 7.35 (d, 2 H, J = 7.5 Hz), 7.41−7.50
(m, 9 H), 7.54−7.60 (m, 2 H), 7.66 (d, 2 H, J = 7.9 Hz), 7.74 (dd, 1
H, J1 = 7.1 Hz, J2 = 7.1 Hz), 7.79 (d, 2 H, J = 7.9 Hz), 7.97 (d, 1 H, JC‑P
= 3.8 Hz); E-isomer (part): 2.29 (s, 3 H), 3.79 (s, 3 H), 5.29 (s, 2 H),
5.67 (s, 1 H), 6.88 (d, 2 H, J = 7.3 Hz), 7.08 (d, 2 H, J = 7.3 Hz). 13C
H]+ Calcd for C32H27NO2P+ 488.1774; Found 488.1779. Isolated
ratio: Z:E = 44:56.
NMR (151 MHz, DMSO-d6) δ: Z-isomer, 20.8, 52.0, 69.2 (d, JC‑P
=
4.1 Hz), 111.2 (d, JC‑P = 9.8 Hz), 126.1, 126.9, 127.3 (d, JC‑P = 11.4
Hz), 128.2, 128.8 (d, JC‑P = 11.4 Hz), 128.9 (d, JC‑P = 9.5 Hz), 129.05
(d, JC‑P =99.4 Hz), 129.13, 129.3, 131.2 (d, JC‑P = 9.4 Hz), 131.7 (d,
JC‑P = 103.1 Hz), 131.9, 132.1, 132.61 (d, JC‑P = 10.8 Hz), 132.64,
138.6, 140.2, 141.6 (d, JC‑P = 6.6 Hz), 156.6, 166.0. 31P NMR (243
MHz, CDCl3) δ 31.40 (E-isomer), 31.44 (Z-isomer). IR (KBr, cm−1)
1716 (CO). HRMS (QFT-ESI) m/z [M + Na]+ Calcd for
C36H31NaO4P+ 581.1852; Found 581.1858.
(2-(((1-(4-Bromophenyl)-2-(4-fluorophenyl)vinyl)oxy)methyl)-
phenyl)diphenylphosphine Oxide (4hg). A white solid isolated as an
inseparable Z/E mixture (Z:E = 89:11 based on integrations of two
1
peaks at 4.96 and 5.26 of H NMR), yield: 65.9 mg. 80%; Rf: 0.50
1
(PE:EtOAc 1:1). H NMR (600 MHz, DMSO-d6) δ: Z-isomer, 4.96
(s, 2 H), 6.41 (s, 1 H), 7.02 (dd, 1 H, J1 = 8.0 Hz, J2C‑P = 12.6 Hz),
7.07 (dd, 2 H, J1C‑F = 7.8 Hz, J2 = 7.8 Hz), 7.37 (d, 2 H, J = 7.5 Hz),
7.39−7.44 (m, 1 H), 7.44−7.52 (m, 10 H), 7.53−7.59 (m, 2 H), 7.60−
7.65 (m, 2 H), 7.70−7.76 (m, 1 H), 7.96−8.01 (m, 1 H); E-isomer
(part): 5.26 (s, 2 H), 5.70 (s, 1 H), 5.79−6.84 (m, 1 H), 6.93−6.98
(m, 2 H). 13C NMR (151 MHz, DMSO-d6) δ: Z-isomer, 68.9 (d, JC‑P
= 4.0 Hz), 112.8 (d, JC‑P = 4.1 Hz), 115.2 (d, JC‑F = 21.1 Hz), 121.7,
127.25 (d, JC‑P = 11.7 Hz), 127.30 (d, JC‑P = 7.4 Hz), 127.6, 128.8 (d,
JC‑P = 11.7 Hz), 129.2 (d, JC‑P = 99.2 Hz), 130.3 (d, JC‑F = 7.7 Hz),
(2-((((3E)-1-(4-Nitrophenyl)-4-phenylbuta-1,3-dien-2-yl)oxy)-
methyl)phenyl)diphenylphosphine Oxide (4od). A yellow solid
isolated as an inseparable Z/E mixture (Z:E = 48:52 based on
1
integrations of two peaks at 5.20 and 5.37 of H NMR), yield: 80.2
1
mg, 80%; Rf: 0.57 (PE:EtOAc 1:1). H (600 MHz, DMSO-d6) δ: E-
isomer, 5.37 (s, 2 H), 5.83 (s, 1 H), 6.88 (d, 1 H, J = 15.8 Hz), 7.02 (d,
H
DOI: 10.1021/acs.joc.5b01031
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
1 H, J = 15.8 H), 7.15 (dd, 1 H, J1 = 7.9 Hz, J2C‑P = 12.9 Hz), 7.25−
7.38 (m, 4 H), 7.40−7.60 (m, 11 H), 7.62−7.71 (m, 1 H), 7.72−7.78
(m, 1 H), 7.78−7.83 (m, 1 H), 8.01 (d, 2 H, J = 8.1 Hz), 8.18 (d, 2 H,
J = 8.1 Hz); Z-isomer, 5.20 (s, 2 H), 6.29 (s, 1 H), 6.88 (d, 1 H, J =
15.7 Hz), 6.92 (d, 1 H, J = 15.7 Hz), 7.03−7.07 (m, 1 H), 7.25−7.40
(m, 4 H), 7.40−7.60 (m, 11 H), 7.62−7.72 (m, 6 H), 8.01 (m, 1 H).
13C NMR (151 MHz, DMSO-d6) δ: E-isomer, 67.1 (d, JC‑P = 3.2 Hz),
104.2, 119.5, 123.6, 124.2, 128.5 (d, JC‑P = 7.9 Hz), 128.69, 128.74,
(d, 2 H, J = 7.8 Hz), 6.85 (d, 2 H, J = 7.8 Hz), 7.65−7.7 (m, 4 H),
7.79−7.83 (m, 1 H). 31C NMR (151 MHz, CDCl3) δ: Z-isomer, 21.4,
69.4 (d, JC‑P = 3.9 Hz), 113.5, 126.3, 126.6 (d, JC‑P = 12.7 Hz), 127.7
(d, JC‑P = 9.8 Hz), 128.1, 128.5 (d, JC‑P = 22.8 Hz), 128.6, 129.0, 129.1
(d, JC‑P = 101.2 Hz), 131.9 (d, JC‑P = 9.8 Hz), 132.0 (d, JC‑P = 1.5 Hz),
132.2 (d, JC‑P = 103.6 Hz), 132.4, 132.9, 133.1 (d, JC‑P = 11.9 Hz),
136.1, 136.3, 143.4 (d, JC‑P = 7.2 Hz), 154.2. 31P NMR (243 MHz,
CDCl3) δ 31.33 (Z-isomer), 31.26 (E-isomer). HRMS (QFT-ESI) m/
z [M + Na]+ Calcd for C34H29NaO2P+ 523.1797; Found 523.1800.
(2-(((2-(4-Methoxyphenyl)-1-phenylvinyl)oxy)methyl)phenyl)-
diphenylphosphine Oxide (4ak). A white solid isolated as an
inseparable Z/E mixture (Z:E = 97:3 based on integrations of two
128.8 (d, JC‑P = 11.8 Hz), 129.27 (d, JC‑P = 99.5 Hz), 129.29 (d, JC‑P
=
9.8 Hz), 129.5, 131.4 (d, JC‑P = 9.5 Hz), 132.1, 132.40 (d, JC‑P = 102.8
Hz), 132.6, 132.7 (d, JC‑P = 13.0 Hz), 132.8, 135.9, 140.8 (d, JC‑P = 6.9
Hz), 144.8, 145.0, 157.6; Z-isomer, 70.1 (d, JC‑P = 3.8 Hz), 114.49,
114.52, 123.6, 127.1 (d, JC‑P = 13.8 Hz), 127.4 (d, JC‑P = 12.1 Hz),
1
peaks at 5.09 and 5.32 of H NMR), yield: 112.3 mg, 87%; Rf: 0.40
(PE:EtOAc 1:1). 1H NMR (600 MHz, CDCl3) δ: Z-isomer, 3.76 (s, 3
H), 5.09 (s, 2 H), 6.04 (s, 1 H), 6.74 (d, J = 8.4 Hz, 2 H), 7.03−7.09
(m, 1 H), 7.17−7.21 (m, 3 H), 7.22−7.26 (m, 1 H), 7.31−7.37 (m, 6
H), 7.42−7.47 (m, 2 H), 7.48−7.55 (m, 6 H), 7.58−7.62 (m, 1 H),
8.07−8.11 (m, 1 H); E-isomer (part), 3.68 (s, 3 H), 5.32 (s, 2 H), 5.61
(s, 1 H), 6.61 (d, 2 H, J = 8.4 Hz), 7.78−7.84 (m, 1 H). 13C NMR
(151 MHz, CDCl3) δ: Z-isomer, 55.2, 69.3 (d, JC‑P = 4.4 Hz), 113.2,
113.7, 126.1, 126.6 (d, JC‑P = 12.5 Hz), 127.6 (d, JC‑P = 9.7 Hz), 127.9,
128.5 (d, JC‑P = 23..3 Hz), 128.6, 129.1 (d, JC‑P = 101.0 Hz), 129.9,
127.7 (d, JC‑P = 11.6 Hz), 127.8, 128.67, 128.72, 129.5, 130.4 (d, JC‑P
98.9 Hz), 131.3 (d, JC‑P = 9.4 Hz), 131.6, 132.00, 132.04 (d, JC‑P
=
=
102.6 Hz), 132.6, 132.9 (d, JC‑P = 11.6 Hz), 135.8, 141.6 (d, JC‑P = 6.8
Hz), 142.1, 143.8, 154.8. 31P NMR (243 MHz, DMSO-d6) δ 28.86 (E-
isomer), 29.32 (Z-isomer). HRMS (QFT-ESI) m/z [M + Na]+ Calcd
for C35H28NNaO4P+ 580.1648; Found 580.1652.
(2-(((2-(4-Nitrophenyl)-1-(3,4,5-trimethoxyphenyl)vinyl)oxy)-
methyl)phenyl)diphenylphosphine Oxide (4nd). A yellow solid
isolated as an inseparable Z/E mixture (Z:E = 79:21 based on
1
129.9 (overlapped), 131.8 (d, JC‑P = 9.7 Hz), 132.0, 132.2 (d, JC‑P
=
integrations of two peaks at 5.13 and 5.31 of H NMR), yield: 171.4
1
105.2 Hz), 132.4, 133.1 (d, JC‑P = 12.1 Hz), 136.3, 143.4 (d, JC‑P = 7.1
Hz), 153.2, 158.2. 31P NMR (243 MHz, CDCl3) δ 31.33 (Z-isomer),
31.08 (E-isomer). HRMS (QFT-ESI) m/z [M + Na]+ Calcd for
C34H29NaO3P+ 539.1747; Found 539.1750.
mg, 84%; Rf: 0.25 (PE:EtOAc 1:1). H NMR (600 MHz, DMSO-d6)
δ: Z-isomer, 3.72 (s, 3 H), 3.75 (s, 6 H), 5.13 (s, 2 H), 6.39 (s, 1 H),
6.84 (s, 2 H), 7.06 (dd, 1 H, J1 = 7.9 Hz, J2C‑P = 13.0 Hz), 7.40−7.51
(m, 8 H), 7.51−7.58 (m, 2 H), 7.60−7.70 (m, 1 H), 7.71−7.75 (m, 1
H), 7.76 (d, 2 H, J = 8.4 Hz), 7.95−8.00 (m, 1 H), 8.06 (d, 2 H, J = 8.4
Hz); E-isomer (part): 3.61 (s, 6 H), 3.70 (s, 3 H), 5.31 (s, 2 H), 5.75
(s, 1 H), 6.55 (s, 2 H), 7.02 (d, 2 H, J = 7.8 Hz), 7.14 (dd, 1 H, J1 = 8.0
Hz, J2 = 13.0 Hz). 13C NMR (151 MHz, DMSO-d6) δ: Z-isomer, 55.9,
(2-(((2-(3,4-Dimethoxyphenyl)-1-phenylvinyl)oxy)methyl)phenyl)-
diphenylphosphine Oxide (4al). A white solid isolated as an
inseparable Z/E mixture (Z:E = 93:7 based on integrations of two
1
peaks at 5.00 and 5.25 of H NMR), yield: 109.5 mg, 81%; Rf: 0.33
1
(PE:EtOAc 1:1). H NMR (600 MHz, DMSO-d6) δ: Z-isomer, 3.42
60.1, 69.8 (d, JC‑P = 3.9 Hz), 104.0 (d, JC‑P = 5.1 Hz), 110.3 (d, JC‑P
=
(s, 3 H), 3.75 (s, 3 H), 5.00 (s, 2 H), 6.37 (s, 1 H), 6.83 (d, J = 6.9 Hz,
1 H), 7.00−7.10 (m, 2 H), 7.27−7.37 (m, 4 H), 7.38−7.51 (m, 10 H),
7.51−7.60 (m, 2 H), 7.61−7.70 (m, 1 H), 7.71−7.77 (m, 1 H), 8.10−
18.14 (m, 1 H); E-isomer (part): 3.37 (s, 3 H), 3.65 (s, 3 H), 5.25 (s, 2
H), 5.61 (s, 1 H), 6.70 (d, 2 H, J = 6.9 Hz). 13C NMR (151 MHz,
DMSO-d6) δ: Z-isomer, 54.8, 55.3, 68.7, 111.3, 11.4, 113.4, 121.7,
125.2, 127.1 (d, JC‑P = 11.9 Hz), 127.2 (d, JC‑P = 7.7 Hz), 127.9, 128.1,
8.7 Hz), 123.5, 127.4 (d, JC‑P = 11.4 Hz), 128.1 (d, JC‑P = 9.3 Hz),
128.7, 128.8, 129.5 (d, JC‑P = 99.0 Hz), 130.1, 131.2 (d, JC‑P = 9.2 Hz),
132.0, 132.1 (d, JC‑P = 102.6 Hz), 132.5, 132.7 (d, JC‑P = 11.7 Hz),
138.5, 141.5 (d, JC‑P = 6.8 Hz), 142.6, 144.8, 152.9, 158.3; E-isomer
(part): 55.8, 60.0, 67.8 (d, JC‑P = 3.4 Hz), 101.3, 106.5 (d, JC‑P = 9.1
Hz), 123.2, 128.9, 129.9, 130.4 (d, JC‑P = 99.0 Hz), 131.4 (d, JC‑P
=
10.5 Hz), 132.1, 132.9 (d, JC‑P = 11.8 Hz), 138.5, 140.7 (d, JC‑P = 6.8
Hz), 144.31, 144.35, 152.9, 158.9. 31P NMR (243 MHz, CDCl3) δ
31.57 (E-isomer), 31.57 (Z-isomer, overlapped). HRMS (QFT-ESI)
m/z [M + Na]+ Calcd for C36H32NNaO7P+ 644.1809; Found
644.1812.
128.6, 128.6 (overlapped), 128.7 (d, JC‑P = 11.8 Hz), 129.1 (d, JC‑P
=
89.5 Hz), 131.2 (d, JC‑P = 9.6 Hz), 131.9 (d, JC‑P = 102.5 Hz), 132.1,
132.50, 132.53 (d, JC‑P = 11.0 Hz), 135.5, 142.1 (d, JC‑P = 7.0 Hz),
147.8, 148.2, 151.9. 31P NMR (243 MHz, CDCl3) δ 31.25 (Z-isomer),
31.50 (E-isomer). HRMS (QFT-ESI) m/z [M + Na]+ Calcd for
C35H31NaO4P+ 569.1852; Found 569.1858.
(2-(((1,2-Diphenylvinyl)oxy)methyl)phenyl)diphenylphosphine
Oxide (4aa). A white solid isolated as an inseparable Z/E mixture (Z:E
1
= 95:5 based on integrations of two peaks at 5.10 and 5.35 of H
(2-(((2-(4-Methoxyphenyl)-1-(3,4,5-trimethoxyphenyl)vinyl)oxy)-
methyl)phenyl)diphenylphosphine Oxide (4nk). A white solid
isolated as an inseparable Z/E mixture (Z:E = 91:9 based on
NMR), yield: 124.0 mg, 85%; Rf: 0.20 (PE:EtOAc 1:1). 1H NMR (600
MHz, CDCl3) δ: Z-isomer, 5.10 (s, 2 H), 6.04 (s, 1 H), 7.03−7.09 (m,
1 H), 7.10−7.15 (m, 1 H), 7.16−7.26 (m, 6 H), 7.30−7.38 (m, 6 H),
7.42−7.46 (m, 2 H), 7.49−7.57 (m, 6 H), 7.57−7.61 (m, 1 H), 8.05−
8.10 (m, 1 H); E-isomer (part), 5.35 (s, 2 H), 5.65 (s, 1 H), 6.83 (d, 2
H, J = 7.2 Hz), 6.94−7.00 (m, 1 H), 7.64−7.73 (m, 4 H), 7.79−7.83
1
integrations of two peaks at 5.01 and 5.19 of H NMR), yield: 207.7
1
mg, 68%; Rf: 0.25 (PE:EtOAc 1:1). H NMR (400 MHz, DMSO-d6)
δ: Z-isomer, 3.71 (s, 9 H), 3.75 (s, 3 H), 5.01 (s, 2 H), 6.31 (s, 1 H),
6.76 (s, 2 H), 6.81 (d, 2 H, J = 8.8 Hz), 7.04 (dd, 1 H, J1 = 7.5 Hz, J2 =
13.8 Hz), 7.41 (dd, 1 H, J1 = 7.4 Hz, J2 = 7.5 Hz), 7.44−7.59 (m, 12
H), 7.74 (dd, 1 H, J1 = 7.5 Hz, J2 = 7.5 Hz), 8.07 (dd, 1 H, J1C‑P = 3.3
Hz, J2 = 7.5 Hz); E-isomer (part): 3.59 (s, 6 H), 3.67 (s, 3 H), 3.68 (s,
3 H), 5.19 (s, 2 H), 5.55 (s, 1 H). 13C NMR (151 MHz, DMSO-d6) δ:
(m, 1 H). 13C NMR (151 MHz, CDCl3) δ: Z-isomer, 69.5 (d, JC‑P
4.2 Hz), 113.5, 126.4, 126.5, 126.7 (d, JC‑P = 12.7 Hz), 127.7 (d, JC‑P
=
=
9.7 Hz), 128.3, 128.3 (overlapped), 128.5 (d, JC‑P = 19.0 Hz), 128.6,
128.7, 129.1 (d, JC‑P = 101.5 Hz), 131.8 (d, JC‑P = 9.7 Hz), 132.0 (d,
JC‑P = 1.7 Hz), 132.2 (d, JC‑P = 102.4 Hz), 132.4, 133.1 (d, JC‑P = 12.1
Hz), 135.8, 136.2, 143.3 (d, JC‑P = 7.2 Hz), 155.0. 31P NMR (243
MHz, CDCl3) δ 31.35 (Z-isomer), 31.30 (E-isomer). HRMS (QFT-
ESI) m/z [M + Na]+ Calcd for C33H27NaO2P+ 509.1641; Found
509.1645.
Diphenyl(2-(((1-phenyl-2-(p-tolyl)vinyl)oxy)methyl)phenyl)-
phosphine Oxide (4aj). A white solid isolated as an inseparable Z/E
mixture (Z:E = 96:4 based on integrations of two peaks at 5.09 and
5.33 of 1H NMR), yield: 130.3 mg, 87%; Rf: 0.30 (PE:EtOAc 1:1). 1H
NMR (600 MHz, CDCl3) δ: Z-isomer, 2.29 (s, 3 H), 5.09 (s, 2 H),
6.04 (s, 1 H), 7.01 (d, 2 H, J = 7.8 Hz), 7.03−7.09 (m, 1 H), 7.16−
7.20 (m, 3 H), 7.21−7.25 (m, 1 H), 7.30−7.37 (m, 6 H), 7.41−7.48
(m, 4 H), 7.49−7.55 (m, 4 H), 7.57−7.61 (m, 1 H), 8.06−8.10 (m, 1
H); E-isomer (part): 2.20 (s, 3 H), 5.33 (s, 2 H), 5.63 (s, 1 H), 6.73
Z-isomer, 54.9, 55.7, 60.0, 68.8, 102.8, 112.5, 113.7, 127.06 (d, JC‑P
=
12.5 Hz), 127.07 (d, JC‑P = 9.4 Hz), 127.8, 128.7 (d, JC‑P = 11.7 Hz),
129.0 (d, JC‑P = 102.4 Hz), 129.3, 129.6, 131.2 (d, JC‑P = 9.8 Hz),
131.99 (d, JC‑P = 102.5 Hz), 132.06, 132.52, 132.53 (d, JC‑P = 12.5 Hz),
137.6, 142.3 (d, JC‑P = 6.7 Hz), 152.2, 152.8, 157.9. 31P NMR (162
MHz, DMSO-d6) δ 28.57 (E-isomer), 29.11 (Z-isomer). HRMS
(QFT-ESI) m/z [M + Na]+ Calcd for C37H35NaO6P+ 629.2063;
Found 629.2068.
(2-(((3-Methyl-1-phenylbut-1-en-1-yl)oxy)methyl)phenyl)-
diphenylphosphine Oxide (4ap). 1.2 equiv of phosphonium salt 3aa
was used. A colorless gum isolated as an inseparable Z/E mixture (Z:E
1
= 93:7 based on integrations of two peaks at 4.89 and 5.00 of H
1
NMR), yield: 37.8 mg, 28%; Rf: 0.31 (PE:EtOAc 2.5:1). H NMR
(600 MHz, DMSO-d6) δ: Z-isomer, 0.83 (d, 6 H, J = 6.7 Hz), 2.54−
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2.61 (m, 1 H), 4.89 (s, 2 H), 5.30 (d, 1 H, J = 9.4 Hz), 7.01 (dd, 1 H,
J1 = 7.7 Hz, J2C‑P = 13.7 Hz), 7.24−7.29 (m, 3 H), 7.30−7.34 (m, 2 H),
7.36−7.41 (m, 1 H), 7.48−7.55 (m, 8 H), 7.60−7.64 (m, 2 H), 7.70−
7.75 (m, 1 H), 7.96−7.99 (m, 1 H); E-isomer (part): 4.20 (d, 1 H, J =
10.1 Hz), 5.00 (s, 2 H). 13C NMR (151 MHz, DMSO-d6) δ: Z-isomer,
7.43−748 (m, 2 H), 7.53−7.57 (m, 1 H), 8.01 (d, 2 H, J = 7.8 Hz).
13C NMR (151 MHz, CDCl3) δ 45.1, 55.86, 55.88, 111.3, 112.5, 121.6,
127.0, 128.6, 128.7, 133.2, 136.6, 148.0, 149.0, 197.9. IR (KBr, cm−1)
1677 (CO).
(E)-1-(4-nitrophenyl)-4-phenylbut-3-en-2-one (5d).54 A pale
yellow solid, yield: 40.6 mg, 73%; Rf: 0.48 (PE:EtOAc 3:1). 1H
NMR (600 MHz, CDCl3) δ 4.09 (s, 2 H), 6.80 (d, 1 H, J = 16.1 Hz),
7.39−7.45 (m, 5 H), 7.55 (d, 2 H, J = 8.3 Hz), 7.66 (d, 1 H, J = 16.1
Hz), 8.21 (d, 2 H, J = 8.3 Hz). 13C NMR (151 MHz, CDCl3) δ 47.4,
123.8, 124.9, 128.5, 129.0, 130.5, 131.0, 134.0, 141.9, 144.3, 147.0,
195.5. IR (KBr, cm−1) 1693 (CO).
23.0, 24.8 (d, JC‑P = 9.0 Hz), 69.8 (d, JC‑P = 4.5 Hz), 122.7 (d, JC‑P
=
12.5 Hz), 124.9, 127.1 (d, JC‑P = 11.7 Hz), 127.67 (d, JC‑P = 8.9 Hz),
127.75, 128.5, 128.8 (d, JC‑P = 11.2 Hz), 129.2 (d, JC‑P = 100.0 Hz),
131.3 (d, JC‑P = 9.0 Hz), 132.1, 132.2 (d, JC‑P = 102.4 Hz), 132.5 (d,
JC‑P = 15.3 Hz), 132.6, 135.0, 142.3 (d, JC‑P = 7.1 Hz), 150.8. 31P NMR
(243 MHz, DMSO-d6) δ 28.40 (E-isomer), 29.23 (Z-isomer). HRMS
(QFT-ESI) m/z [M + Na]+ Calcd for C30H29NaO2P+ 475.1797;
Found 475.1793.
2-(4-Nitrophenyl)-1-(3,4,5-trimethoxyphenyl)ethanone (5e).55
A
1
white solid, yield: 39.7 mg, 86%; Rf: 0.24 (PE:EtOAc 3:1). H NMR
(600 MHz, CDCl3) δ 3.92 (s, 6 H), 3.94 (s, 3 H), 4.40 (s, 2 H), 7.26
(s, 2 H), 7.43 (d, 2 H, J = 8.1 Hz), 8.20 (d, 2 H, J = 8.1 Hz). 13C NMR
(151 MHz, CDCl3) δ 44.8, 56.3, 61.0, 106.0, 123.7, 130.5, 131.2,
142.2, 143.1, 147.0, 153.1, 194.8. IR (KBr, cm−1) 1685 (CO).
Methyl 4-(2-Oxo-2-(p-tolyl)ethyl)benzoate (5f). A white solid,
2-Isopropyl-1-phenyl-2,4-dihydro-1H-benzo[d][1,3]oxaphos-
phinine 1-Oxide (14). The reaction of 3pa with 2a using t-BuOK as
base did not produce the corresponding vinyl ether, and instead 14
was isolated in 81% (83.4 mg) yield as a mixture of two stereoisomers
(79:21 determined by 1H NMR based on integrations of two peaks at
3.72 and 3.62). The reaction of 3pa with 2p afforded 14 in 96% (115.8
mg) yield as a mixture of two stereoisomers (68:32 determined by 1H
NMR based on integrations of two peaks at 3.74 and 3.63). By
developing four times using PE:EtOAc 1:1.5 as eluate, these two
stereoisomers could be partly separated by preparative TLC (silica
1
yield: 48.5 mg, 75%; Rf: 0.52 (PE:EtOAc 3:1). H NMR (600 MHz,
CDCl3) δ 2.40 (s, 3 H), 3.89 (s, 3 H), 4.31 (s, 2 H), 7.25 (d, 2 H, J =
7.5 Hz), 7.33 (d, 2 H, J = 7.5 Hz), 7.90 (d, 2 H, J = 7.8 Hz), 7.99 (d, 2
H, J = 7.8 Hz). 13C NMR (151 MHz, CDCl3) δ 21.7, 45.3, 52.1, 128.7,
128.8, 129.4, 129.6, 129.9, 133.9, 140.1, 144.3, 166.9, 196.5. IR (KBr,
cm−1) 1715 (CO of ester), 1678 (CO of ketone). HRMS (QFT-
1
gel). Rf: 0.29 (minor stereoisomer), 0.24 (major stereoisomer). H
+
+
NMR (600 MHz, CDCl3) δ: major stereoisomer, 0.91 (d, 3 H, J = 6.3
Hz), 1.06 (d, 3 H, J = 6.6 Hz), 1.52−1.58 (m, 1 H), 3.67 (d, 1 H, J =
9.8 Hz), 4.83 (d, 1 H, J = 15.7 Hz), 5.00 (d, 1 H, J = 15.7 Hz), 7.06−
7.10 (m, 1 H), 7.24−7.29 (m, 1 H), 7.33−7.40 (m, 3 H), 7.41−7.45
(m, 1 H), 7.67 (dd, 1 H, J1 = 8.0 Hz, J2C‑P = 12.0 Hz), 7.70−7.75 (m, 2
H); minor stereoisomer, 0.85 (d, 3 H, J = 6.6 Hz), 1.15 (d, 3 H, J = 6.4
Hz), 2.43−2.52 (m, 1 H), 3.63 (dd, 1 H, J1 = 9.1 Hz, J2C‑P = 13.6 Hz),
4.86 (d, 1 H, J = 15.6 Hz), 5.15 (d, 1 H, J = 15.6 Hz), 7.18−7.22 (m, 1
H), 7.26−7.32 (m, 1 H), 7.43−7.55 (m, 5 H), 7.65−7.79 (m, 2 H).
13C NMR (151 MHz, CDCl3) δ: major stereoisomer, 18.6, 19.8 (d,
JC‑P = 11.1 Hz), 29.9, 71.6 (d, JC‑P = 1.9 Hz), 84.0 (d, JC‑P = 84.4 Hz),
123.8 (d, JC‑P = 8.0 Hz), 127.9 (d, JC‑P = 11.2 Hz), 128.2 (d, JC‑P = 11.9
Hz), 129.0 (d, JC‑P = 93.2 Hz), 130.8 (d, JC‑P = 96.1 Hz), 131.5 (d, JC‑P
= 5.8 Hz), 131.7, 131.9 (d, JC‑P = 1.8 Hz), 132.4 (d, JC‑P = 9.4 Hz),
142.1 (d, JC‑P = 1.8 Hz); minor stereoisomer, 19.5 (d, JC‑P = 9.2 Hz),
ESI) m/z [M + Na] Calcd for C17H16NaO3 291.0992; Found
291.0995.
1-(Furan-2-yl)-2-(4-(trifluoromethyl)phenyl)ethanone (5g). A
1
white solid, yield: 59.8 mg, 78%; Rf: 0.50 (PE:EtOAc 3:1). H NMR
(600 MHz, CDCl3) δ 4.19 (s, 2 H), 6.56 (s, 1 H), 7.26 (s, 1 H), 7.42
(d, J = 7.8 Hz, 2 H), 7.58 (d, J = 7.8 Hz, 2 H), 7.61 (s, 1 H). 13C NMR
(151 MHz, CDCl3) δ 44.9, 112.6, 118.1, 124.2 (q, JC‑F = 272.1 Hz),
125.5 (q, JC‑F = 3.6 Hz), 129.3 (q, JC‑F = 32.3 Hz), 130.0, 138.0, 146.9,
152.2, 185.6. IR (KBr, cm−1) 1674 (CO). HRMS (QFT-ESI) m/z
+
[M + Na]+ Calcd for C13H9F3NaO2 277.0447; Found 277.0450.
2-(4-Methoxyphenyl)-1-(3,4,5-trimethoxyphenyl)ethanone
(5h).55 A white solid, yield: 52.6 mg, 98%; Rf: 0.50 (PE:EtOAc 3:1).
1H NMR (400 MHz, CDCl3) δ 3.79 (s, 3 H), 3.90 (s, 6 H), 3.92 (s, 3
H), 4.20 (s, 2 H), 6.88 (d, 2 H, J = 8.6 Hz), 7.20 (d, 2 H, J = 8.6 Hz),
7.27 (s, 2 H). 13C NMR (100 MHz, CDCl3) δ 44.7, 55.2, 56.2, 60.9,
106.3, 114.2, 126.8, 130.2, 131.7, 142.6, 153.0, 158.5, 196.7. IR (KBr,
cm−1) 1677.
19.6 (d, JC‑P = 3.2 Hz), 29.3, 71.2 (d, JC‑P = 2.9 Hz), 85.3 (d, JC‑P
=
82.4 Hz), 124.3 (d, JC‑P = 8.1 Hz), 127.8 (d, JC‑P = 11.4 Hz), 128.5 (d,
JC‑P = 11.7 Hz), 128.7 (d, JC‑P = 128.5 Hz), 131.6 (d, JC‑P = 9.5 Hz),
131.8, 131.9, 132.5 (d, JC‑P = 94.6 Hz), 132.6 (d, JC‑P = 6.6 Hz), 142.0
(d, JC‑P = 3.4 Hz). 31P NMR (243 MHz, CDCl3) δ 19.53 (major
stereoisomer), 12.74 (minor stereoisomer). HRMS (QFT-ESI) m/z
[M + Na]+ Calcd for C17H19NaO2P+ 309.1015; Found 309.1018
(major stereoisomer), 309.1016 (minor stereoisomer).
The One-Pot Synthesis of 5a on a Gram Scale. To a mixture of
phosphonium salt 3aa (3.045 g, 6.6 mmol), aldehyde 2a (0.584 g, 5.5
mmol), and anhyd THF (100 mL) in a round-bottom flask (250 mL)
was added t-BuOK (1 M in THF, 7.9 mL, 7.9 mmol) dropwise. After it
was stirred at rt for 3 h, the mixture was evaporated and the residue
was mixed with 6 M HCl (33 mL) and MeOH (99 mL). The mixture
was refluxed for 30 min, evaporated to remove MeOH, and then
extracted with PE (70 mL × 5) and EtOAc (70 mL × 2). The
combined extract was evaporated and isolated by flash column
chromatography (silica gel) eluted with PE:EtOAc (10:1) to give 5a
(0.581 g) in 54% yield based on aldehyde 2a.
General Procedure for the Hydrolysis of Vinyl Ethers 4. A
mixture of vinyl ether 4 (0.22 mmol), MeOH (4.5 mL), and 6 M HCl
(1.5 mL) in a round-bottom flask (25 mL) was refluxed for 30 min.
After it cooled down to rt, the mixture was evaporated to remove
MeOH and extracted with CH2Cl2 (10 mL × 2). The combined
extract was dried over anhyd MgSO4 and after evaporation isolated by
preparative TLC (silica gel) to give ketone 5.
The 18O-Labeling Experiment. 18O-2a was prepared according to
the literature procedure.56 The phosphonium salt prepared from 18O-
2a, DPPPM 1, and Ph3PHBF4 using the same procedure for 3ab was
analyzed by 1H and 13C NMR and HRMS, and none of them showed
the formation of 18O-3ab.
1,2-Diphenylethanone (5a).52 A white solid, yield: 40.5 mg, 81%;
Rf: 0.77 (PE:EtOAc 3:1). 1H NMR (600 MHz, CDCl3) δ 4.27 (s, 2 H,
CH2), 7.21−7.28 (m, 3 H), 7.29−7.34 (m, 2 H), 7.41−7.46 (m, 2 H),
7.51−7.56 (m, 1 H), 8.00 (d, 2 H, J = 7.2 Hz). 13C NMR (151 MHz,
CDCl3) δ 45.5, 126.9, 128.66, 128.70, 128.73, 129.5, 133.2, 134.6,
136.6, 197.7. IR (KBr, cm−1) 1686 (CO).
ASSOCIATED CONTENT
■
1-Phenyl-2-(p-tolyl)ethanone (5b).53 A white solid, yield: 42.6 mg,
78%; Rf: 0.77 (PE:EtOAc 3:1). 1H NMR (600 MHz, CDCl3) δ 2.30 (s,
3 H), 4.23 (s, 2 H), 7.12 (d, 2 H, J = 6.9 Hz), 7.15 (d, 2 H, J = 6.9 Hz),
7.41−7.45 (m, 2 H), 7.50−7.55 (m, 1 H), 8.00 (d, 2 H, J = 7.2 Hz).
13C NMR (151 MHz, CDCl3) δ 21.1, 45.2, 128.7, 128.7 (overlapped),
129.4, 129.5, 131.5, 133.1, 136.5, 136.7, 197.9. IR (KBr, cm−1) 1687
(CO).
S
* Supporting Information
NMR spectra of all cyclic α-alkoxyphosphonium salts, vinyl
ethers, and ketones. The Supporting Information is available
free of charge on the ACS Publications website at DOI:
10.1021/acs.joc.5b01031.
AUTHOR INFORMATION
2-(3,4-Dimethoxyphenyl)-1-phenylethanone (5c).53 A white solid,
■
1
Corresponding Author
*E-mail: huangwh@tju.edu.cn.
yield: 43.5 mg, 85%; Rf: 0.44 (PE:EtOAc 3:1). H NMR (600 MHz,
CDCl3) δ 3.85 (s, 6 H), 4.23 (s, 2 H), 6.79 (s, 1 H), 6.82 (s, 2 H),
J
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Article
(36) Dunkel, R.; Treu, J.; Martin, H.; Hoffmann, R. Tetrahedron:
Asymmetry 1999, 10, 1539.
Notes
The authors declare no competing financial interest.
(37) Fujioka, H.; Goto, A.; Otake, K.; Kubo, O.; Sawama, Y.;
Maegawa, T. Chem. Commun. (Cambridge, U.K.) 2011, 47, 9894.
(38) Goto, A.; Otake, K.; Kubo, O.; Sawama, Y.; Maegawa, T.;
Fujioka, H. Chem.Eur. J. 2012, 18, 11423.
ACKNOWLEDGMENTS
■
We thank the National Natural Science Foundation of China
for their financial support of our program (Grant No.
21272170).
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