Reactions of aroyl chlorides with samarium metal in DMF-controllable syntheses of O-aroylbenzoins, 1,2-diarylethanones, and (z)-α, α′-stilbenediol dibenzoates

Article abstract of DOI:10.1081/SCC-200034825

Reduction of aroyl chlorides carried out in DMF with samarium metal has been studied. Samarium metal, which requires not any intended activation or pretreatment, was found to react with aroyl chloride in a controllable manner. Correspondingly, O-aroylbenzoins, 1,2-diarylethanones, or (Z)-α, α′-stilbenediol dibenzoates were afforded as the major products under controlled conditions.

Full text of DOI:10.1081/SCC-200034825

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Reactions of Aroyl Chlorides
with Samarium Metal in
DMF—Controllable Syntheses
of O‐Aroylbenzoins,
1,2‐Diarylethanones,
and (Z)‐α,α′‐Stilbenediol
Dibenzoates
Yongjun Liu a , Xiaoxia Wang b & Yongmin Zhang a c
a Department of Chemistry , Zhejiang University
(Campus Xixi) , Hangzhou, 310028, P. R. China
b College of Chemistry and Life Sciences , Zhejiang
Normal University , Jinhua, Zhejiang, P. R. China
c State Key Laboratory of Organometallic
Chemistry , Shanghai Institute of Organic
Chemistry, Chinese Academy of Sciences ,
Shanghai, P. R. China
Published online: 12 Jan 2011.
To cite this article: Yongjun Liu , Xiaoxia Wang & Yongmin Zhang (2004) Reactions
of Aroyl Chlorides with Samarium Metal in DMF—Controllable Syntheses of
O‐Aroylbenzoins, 1,2‐Diarylethanones, and (Z)‐α,α′‐Stilbenediol Dibenzoates,
Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 34:21, 4009-4022, DOI: 10.1081/SCC-200034825

To link to this article: http://dx.doi.org/10.1081/SCC-200034825
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SYNTHETIC COMMUNICATIONSw
Vol. 34, No. 21, pp. 4009–4022, 2004
Reactions of Aroyl Chlorides with
Samarium Metal in DMF—Controllable
Syntheses of O-Aroylbenzoins, 1,2-
Diarylethanones, and (Z)-a,a0-Stilbenediol
Dibenzoates
Yongjun Liu,1 Xiaoxia Wang,2 and Yongmin Zhang1,3,
*
1Department of Chemistry, Zhejiang University (Campus Xixi),
Hangzhou, P. R. China
2College of Chemistry and Life Sciences, Zhejiang Normal University,
Jinhua, Zhejiang, P. R. China
3State Key Laboratory of Organometallic Chemistry, Shanghai Institute
of Organic Chemistry, Chinese Academy of Sciences,
Shanghai, P. R. China
ABSTRACT
Reduction of aroyl chlorides carried out in DMF with samarium metal has
been studied. Samarium metal, which requires not any intended activation
or pretreatment, was found to react with aroyl chloride in a controllable
*
Correspondence: Yongmin Zhang, Department of Chemistry, Zhejiang University
(Campus Xixi), Hangzhou 310028, P. R. China; Fax: 86-571-88807077; E-mail:
yminzhang@mail.hz.zj.cn.
4009
DOI: 10.1081/SCC-200034825
0039-7911 (Print); 1532-2432 (Online)
www.dekker.com
Copyright # 2004 by Marcel Dekker, Inc.

4010
Liu, Wang, and Zhang
manner. Correspondingly, O-aroylbenzoins, 1,2-diarylethanones, or (Z)-
a,a0-stilbenediol dibenzoates were afforded as the major products under
controlled conditions.
Key Words: O-Aroylbenzoin; Aroyl chloride; 1,2-diarylethanone;
DMF; Samarium.
1. INTRODUCTION
Thereductionof acylchlorideshas been studiedextensively. Theproducts of
such reactions are highly dependable on the reducing agents used. Besides the
frequent reduction into aldehydes, reduction of aroyl chlorides with zero
valent complexes of nickel or enneacarbonyl diiron leads to the formation of
symmetrical ketones.[1] Reduction of benzoyl chloride with low-valent titanium
species yields tetraphenyl furan.[2] Samarium diiodide in THF can achieve the
coupling of aroyl chlorides into a-diketones, whereas a-hydroxy ketones are
usually obtained from aliphatic acyl chlorides under the same conditions.[3]
Samarium diiodide in CH3CN, however, can promote the coupling of aroyl
chlorides in an alternative manner affording (Z)-a,a0-stilbenediol dibenzoates
in good yields,[4a] though other reducing agent such as sodium amalgam,
lithium amalgam, etc. can realize the same transformation.[4b–f] Another
interesting result is achieved by the reduction of aliphatic acyl chlorides with
samarium diiodide in the presence of samarium and a catalytic amount of
nickel iodide, where three acyl units are incorporated to form carbinols.[5]
Though the use of samarium diiodide is extremely popular in organic syn-
thesis, direct use of samarium metal as a reducing agent has received much
attention of organic chemists in recent years.[6] Usually, the reactions pro-
moted by samarium metal were carried out in THF,[7] where extra efforts
had to be made for the activation of samarium metal. The activating agents
commonly used include iodine, hydrochloric acid, and alkyl halides, etc.[7,8]
Recently, novel and interesting reductions promoted by samarium metal
have been accomplished by our group when we originally exploited DMF
as a solvent.[9] The Sm-DMF system seems to be a promising reducing
agent able to produce versatile results valuable for organic syntheses.
We now wish to report the reduction of aroyl chlorides with samarium
metal in DMF. It is found that the reduction of aroyl chlorides 1 can
provide three different kinds of products, depending upon the reaction con-
ditions applied. As shown in Sch. 1, when the temperature, reaction time, or
the ratio of acyl chlorides to samarium is varied, O-aroylbenzoins, 1,2-diaryl-
ethanones or (Z)-a,a0-stilbenediol dibenzoates are obtained, respectively, as
the major products.

Reactions of Aroyl Chlorides in DMF
4011
Scheme 1.
2. RESULTS AND DISCUSSION
Research on the reduction of acyl chlorides with samarium diiodide
in THF were well documented,[3] where a side reaction producing
RCO2(CH2)4I via acyl chlorides attack on THF was frequently encoun-
tered.[3b,e] With DMF as the reaction media, the side reaction is obviously
avoided and improved yields of the desirable products are obtained.
2.1 Preparation of O-Aroylbenzoins Promoted by Samarium
Metal in DMF
Reaction of benzoyl chloride 1a with 1 equiv. of samarium metal in
10 mL of newly distilled DMF at room temperature for 1 h led to the formation
of 2a in 94% yield (Table 1, entry 1). A variety of acyl chlorides, including
other aroyl chlorides (1b–1h) and aliphatic acyl chlorides, were used under
the same conditions. Whereas good yields varied from 61–94% of the corres-
ponding O-aroylbenzoins were obtained (Table 1, entries 1–6), the reactions
of aliphatic acyl chlorides (such as phenylacetyl chloride and lauroyl chloride)
were unsuccessful and resulted in a complicated mixture. With ortho and meta

4012
Liu, Wang, and Zhang
Table 1. Preparation of O-aroylbenzoins.
Reaction
time (min)
Temperature
(8C)a
Yield of 2
(%)b
Entry
R in 1
H (1a)
1
2
3
4
5
6
7
8
60
60
25
25
25
25
25
15
15
15
94 (2a)
92 (2b)
83 (2c)
91 (2d)
83 (2e)
61 (2f)c
4-CH3 (1b)
4-Cl (1c)
4-F (1d)
40
40
4-CH3O (1e)
3-CH3 (1f)
3-Cl (1g)
120
40
d
20
20
—
d
—
2-Cl (1h)
aHere 258C indicates room temperature.
bIsolated yields based on aroyl chlorides.
cProduct 4 was formed as a byproduct.
dOnly compounds 3 and 4 were obtained and product 2 was not detected (as shown in
Table 2).
substituted aroyl chlorides (1g and 1h), product 2 was not obtained. Instead,
both 1,2-diarylethanones 3 and di-aroylation products (Z)-a,a0-stilbenediol
dibenzoates 4 were always afforded with excellent total yields (3g þ 4g,
total yield ¼ 94%; 3h þ 4h, total yield ¼ 97%). Attempts to carry out the
reactions at 08C failed to give product 2, only to find that products 3g and
4g, 3h and 4h, formed more slowly than at room temperature. Hardly any
reaction could be observed within 2 hours when the reaction temperature
was adjusted to as low as 2208C.
2.2 Preparation of Desoxybenzoins by Samarium
Metal in DMF
It can be reasoned that products 3g and 3h obtained from ortho and meta
chloro substituted benzoyl chloride (1g and 1h) are further reduction products
of O-aroylbenzoins 2g and 2h, since the reductive elimination of the alkoxy
group at the a-position of the carbonyl group could be easily realized to
afford the type of ketones RCOCH2R.[10] Therefore, we are encouraged to
find out if products 3 can be prepared by the Sm-DMF system, provided
more rigorous conditions are applied. To our delight, the reduction of
benzoyl chloride in DMF with 1 equiv. of Sm at room temperature could
give product 3a in 89% yield with prolonged reaction time (Table 2, entry 1).
Further study found that 91% of 3a could also be obtained when the reaction

Reactions of Aroyl Chlorides in DMF
Table 2. Formation of desoxybenzoins.
4013
Time (min)/
temp. (8C)
Yield of
3 (%)a
Time (h)/
Temp. (8C)
Yield of
3 (%)a
Entry
R in 1
H (1a)
1
2
3
4
5
6
60/60
60/60
60/50
60/50
120/70
30/50
91 (3a)
93 (3b)
92 (3c)
95 (3d)
78 (3e)
63 (3f)b
16/25
12/25
12/25
12/25
36/25
8/25
89 (3a)
90 (3b)
94 (3c)
91 (3d)
72 (3e)
76 (3f)b
56 (3g)
38 (4g)b
42 (3h)
55 (4h)b
4-CH3 (1b)
4-Cl (1c)
4-F (1d)
4-CH3O (1e)
3-CH3 (1f)
0.5/25
7
8
3-Cl (1g)
2-Cl (1h)
—
—
—
—
0.5/25
aIsolated yields based on aroyl chlorides.
bProducts 3 and 4 were obtained together and the formation of product 4 was
unavoidable.
was carried out for 1 hour with an elevated temperature of 708C (Table 2,
entry 1). Other desoxybenzoins 3 were prepared similarly (Table 2, entries
2–5). Again, for ortho- and meta-chloro substituted benzoyl chloride, the
exclusive formation of the desoxybenzoins 3g and 3h was not observed,
whereas the formation of 4g and 4h was unavoidable (entries 7 and 8).
2.3 Mechanism Consideration
Mechanism for the formation of products 2 and 3 may be depicted as
follows (Sch. 2): Firstly, the aroyl chlorides undergo reductive coupling to
give benzil (a),[3b] which immediately accepts two equiv. of electrons from
samarium metal to form (Z)-enediolate (b).[11] Mono-esterification of (b)
with aroyl chloride affords intermediate (c). Quenching the reaction at this
stage with dilute hydrochloric acid gives product 2 exclusively. On the
other hand, c can also transform to 2 in the reaction system and further
elimination of the acyloxy group in 2 yields product 3.
The proposal that product 2 can be formed in DMF is based on the follow-
ing experiment. After the reaction with equivalent of benzoyl chloride and
samarium metal at room temperature was continued for 1 hour (TLC analysis
showed that benzoyl chlorides had been consumed out), the reaction mixture
was treated with D2O and subsequent workup found no deuterium incorpo-
ration, and afforded product 2 exclusively. The so-called aprotic solvent

4014
Liu, Wang, and Zhang
Scheme 2.
such as THF has been reported to cleave ketolate to afford an analog of
product 2, where THF was actually considered to be a proton source by
Kagan.[3c] In the reaction described here, though DMF as the proton donor
still remains ambiguous, it can be concluded that the proton must come
from the reaction system according to our experimental results mentioned
above.
In order to gain further insight into the mechanism, benzils a or O-aroyl-
benzoins 2 were chosen as starting materials and subjected to the Sm-DMF
system with an expectation to get product 3. If product 3 can be obtained
this way, it is obvious the proposed mechanism will be more persuasive.
Unfortunately, neither benzils a nor O-aroylbenzoins 2 is reactive in the
Sm-DMF system. However, the result does not mean the above mechanism
consideration is unreasonable since the absence of aroyl chloride may
account for the inertia of the reaction. The presence of aroyl chloride is
likely to play a role in activating samarium metal and therefore is indispen-
sable to ensure the reaction proceeding smoothly, which will be discussed
in the latter part of this paper.

Reactions of Aroyl Chlorides in DMF
4015
2.4 Formation of (Z)-a,a0-Stilbenediol Dibenzoates
Promoted by Samarium in DMF
At this point, the formation of products 4g and 4h can be explained to
result from the di-esterification of the (Z)-enediolate b or further esterification
of intermediate c (Sch. 2). Obviously, di-esterification of the (Z)-enediolate b
requires the presence of sufficient amount of aroyl chlorides. Further experi-
ment with 1 mmol of Sm powder and 3 mmol of benzoyl chlorides at room
temperature validated the speculation and afforded product 4a in 76% yield
(Table 3, entry 1). Other (Z)-a,a0-stilbenediol dibenzoates were obtained in
good yields under the similar reaction conditions.
Although the exact function of DMF in this reaction can still not be clari-
fied yet, it must be pointed out that DMF may be crucial to initiate the reaction
since when carried out in THF, this reaction can not occur.[12] Recently, DMF
was confirmed to form a quaternary ammonium analogue with benzoyl
chloride in acetonitrile. Activation of metallic samarium with quaternary
ammonium analogue such as viologen[14a] (N,N-dialkyl-4,40-dipyridinium,
V2þ), which is known to be a one- and two-electron-transfer reagent and
exhibit good redox behavior,[14b] has achieved success. Therefore, it can be
speculated that the quaternary ammonium analogue resulting from benzoyl
chloride and DMF may act as the activator for metallic samarium in the reac-
tion investigated here (Sch. 3). Further, just as HMPA can readily form com-
plexes with samarium salts[15] and therefore promote the reaction to proceed
smoothly, DMF may complex with samarium ion,[16] thus facilitating the
reaction process. Finally, as a solvent with strong polarity and excellent
Table 3. Formation of (Z)-a,a0-stilbenediol dibenzoates.
Reaction
time (min)
Temperature
(8C)
Yield of 4
(%)a
Entry
R in 1
H (1a)
1
2
3
4
5
6
7
8
60
60
25
25
25
25
25
15
15
15
76 (4a)
78 (4b)
81 (4c)
84 (4d)
71 (4e)
82 (4f)
4-CH3 (1b)
4-Cl (1c)
4-F (1d)
40
40
4-CH3O (1e)
3-CH3 (1f)
3-Cl (1g)
120
40
b
30
30
—
b
—
2-Cl (1h)
aIsolated yields based on aroyl chlorides.
bThe result is the same as entries 7 and 8 shown in Table 2.

4016
Liu, Wang, and Zhang
Scheme 3.
dissolubility, DMF may play an important role in stabilizing the intermediates,
dissolving samarium salt, etc.
In conclusion, Sm-promoted versatile reactions of aroyl chlorides can
afford O-aroylbenzoins, 1,2-diarylethanones, or (Z)-a,a0-stilbenediol
dibenzoates in good to excellent yields. With readily available and less-
expensive starting materials, operational simplicity and high yields of the
products, the reactions may have high potential for large-scale preparation.
Furthermore, it offers another example of direct use of samarium metal in
organic syntheses without any intended activation.
3. EXPERIMENTAL
3.1 General
1
All H NMR spectra were measured in CDCl3 and recorded on Brucker
Avance-400 (400 MHz) spectrometer with TMS as the internal standard.
Chemical shifts are expressed in ppm and J values are given in Hz. IR
spectra were run on a Bruck vector 22 spectrometer. EIMS were determined
with a HP5989B mass spectrometer. Melting points are uncorrected. All the
reactions in this paper were performed under nitrogen atmosphere. DMF
was redistilled and dried over molecular sieve before use. All the materials
are commercially available. Metallic samarium (purity . 99.9%) is purchased
from Shanghai Yuelong Non-Ferrous Metals Ltd.
3.2 Typical Procedure for the Synthesis of Compounds 2
A mixture of Sm powder (2 mmol) in freshly distilled DMF (10 mL) was
added to benzoyl chloride (2 mmol, freshly distilled) at room temperature with

Reactions of Aroyl Chlorides in DMF
4017
magnetic stirring under a nitrogen atmosphere. The resulting solution turned
yellow-green within 15 minutes and an exothermic reaction was observed.
After completion of the reaction (about 1 hour, monitored by TLC), a
routine workup of the reaction mixture followed by column chromatography
afforded O-benzoylbenzoin in 94% yield.
3.3 Typical Procedure for the Synthesis of Compounds 3
To a mixture of Sm powder (2 mmol) in freshly distilled DMF (10 mL),
benzoyl chloride (2 mmol, freshly distilled) was added at room temperature
with magnetic stirring under a nitrogen atmosphere. The resulting solution
turned yellow-green within 15 minutes and an exothermic reaction was
observed. The reaction was complete in about 1 hour under 708C (or 16
hours at room temperature) and a routine workup of the reaction mixture
followed by column chromatography afforded 1,2-diphenylethanone in 91%
yield.
3.4 Typical Procedure for the Synthesis of Compounds 4
To a mixture of Sm powder (1 mmol) in freshly distilled DMF (10 mL),
benzoyl chloride (3 mmol, freshly distilled) was added at room temperature
with magnetic stirring under a nitrogen atmosphere. The resulting solution
turned yellow-green within 15 minutes and an exothermic reaction was
observed. After completion of the reaction (about 1 hour, monitored by
TLC), a routine workup of the reaction mixture followed by column chroma-
tography afforded (Z)-a,a0-stilbenediol dibenzoate in 76% yield.
Benzoic acid 2-oxo-1,2-diphenyl-ethyl ester (2a): white solid, yield:
94%, m.p.: 120–1228C. dH: 8.11–8.13 (2H, m), 7.99–8.01 (2H, m), 7.53–
7.59 (4H, m), 7.38–7.46 (7H, m), 7.09 (1H, s). nmax(KBr)/cm21: 3044,
2921, 1708, 1691, 1611, 1514. m/z (%): 316 (Mþ, 0.12), 211 (11.64), 105
(100), 77 (47.77). Anal. C21H16O3. Calcd. C, 79.73; H, 5.10. Found C,
79.61; H, 5.17%.
4-Methyl-benzoic acid 2-oxo-1,2-di-p-tolyl-ethyl ester (2b): white
solid, yield: 92%, m.p.: 140–1428C. dH: 8.01–8.03 (2H, m), 7.91–7.93
(2H, m), 7.45–7.47 (2H, m), 7.22–7.28 (6H, m), 7.05 (1H, s), 2.42 (3H, s),
2.38 (3H, s), 2.35 (3H, s). nmax(KBr)/cm21: 3056, 2875, 1712, 1697, 1599,
1450. m/z (%): 358 (Mþ, 0.31), 239 (9.75), 119 (100), 91 (28.68). Anal.
C24H22O3. Calcd. C, 80.42; H, 6.19. Found C, 80.68; H, 6.16%.
4-Chloro-benzoic acid 1,2-bis-(4-chloro-phenyl)-2-oxo-ethyl ester
(2c): white solid, yield: 83%, m.p.: 195–1988C. dH: 8.04–8.06 (2H, m),

4018
Liu, Wang, and Zhang
7.91–7.94 (2H, m), 7.40–7.50 (8H, m), 7.00 (1H, s). nmax(KBr)/cm21: 3095,
1723, 1696, 1592, 1490. m/z (%): 418 (Mþ, 0.10), 279 (1.98), 141, (32.77),
139 (100), 113 (7.02), 111 (22.40). Anal. C21H13Cl3O3. Calcd. C, 60.10; H,
3.12. Found C, 60.33; H, 3.13%.
4-Fluoro-benzoic acid 1,2-bis-(4-fluoro-phenyl)-2-oxo-ethyl ester
(2d): white solid, yield: 91%, m.p.: 172–1748C. dH: 8.10–8.14 (2H, m),
7.99–8.02 (2H, m), 7.52–7.55 (2H, m), 7.08–7.14 (6H, m), 7.01 (1H, s).
n
max(KBr)/cm21: 2983, 1724, 1698, 1600, 1509. m/z (%): 369 (Mþ 2 1,
0.07), 247 (3.09), 123 (100), 95, (23.53). Anal. C21H13F3O3. Calcd. C,
68.11; H, 3.54. Found C, 68.35; H, 3.51%.
4-Methoxy-benzoic acid 1,2-bis-(4-methoxy-phenyl)-2-oxo-ethyl ester
(2e): white solid, yield: 83%, m.p.: 130–1328C. dH: 8.05–8.08 (2H, m), 7.97–
7.99 (2H, m), 7.47–7.49 (2H, m), 7.00 (1H, s), 6.87–6.92 (6H, m), 3.85 (3H, s),
3.83 (3H, s), 3.79 (3H, s). nmax(KBr)/cm21: 2935, 2838, 1712, 1686, 1605,
1512. m/z (%): 406 (Mþ, 0.53), 271 (10.05), 135 (100), 107 (8.81), 77
(15.65). Anal. C24H22O6. Calcd. C, 70.92; H, 5.46. Found C, 70.68; H, 5.49%.
3-Methyl-benzoic acid 2-oxo-1,2-di-m-tolyl-ethyl ester (2f ): oil, yield:
61%. dH: 7.94–7.96 (2H, m), 7.86–7.88 (2H, m), 7.26–7.41 (8H, m), 7.07
(1H, s), 2.31 (3H, s), 2.26 (3H, s), 2.19 (3H, s). nmax(film)/cm21: 3030, 2922,
1719, 1697, 1605, 1588. m/z (%): 358 (Mþ, 0.21), 239 (8.32), 119 (100), 91
(31.83). Anal. C24H22O3. Calcd. C, 80.42; H, 6.19. Found C, 80.61; H, 6.19%.
1,2-Diphenyl-ethanone (3a):[17a] white solid, yield: 89%, m.p.: 54–558C
(lit. 58–608C). dH: 8.05–8.25 (5H, m), 7.29–7.53 (5H, m), 4.29 (2H, s).
n
max(KBr)/cm21: 3084, 2956, 1685, 1602, 1556, 1498. m/z (%): 196 (Mþ,
1.68), 105 (100), 91 (6.82), 77 (34.87). Anal. C14H12O. Calcd. C, 85.68; H,
6.16. Found C, 85.43; H, 6.19%.
1,2-Di-p-tolyl-ethanone (3b):[17a] white solid, yield: 90%, m.p.: 102–
1048C (lit. 98–1008C). dH: 7.83–7.85 (2H, m), 7.27–7.29 (2H, m), 7.09–
7.14 (4H, m), 4.20 (2H, s), 2.42 (3H, s), 2.38 (3H, s). nmax(KBr)/cm21
:
2920, 1683, 1604. m/z (%): 224 (Mþ, 1.04), 119 (100), 105 (3.43), 91
(36.82). Anal. C16H16O. Calcd. C, 85.68; H, 7.19. Found C, 85.39; H, 7.21%.
1,2-Bis-(4-chloro-phenyl)-ethanone (3c):[17b] white solid, yield: 94%,
m.p.: 111–1138C (lit. 112–1138C). dH: 7.92–7.94 (2H, m), 7.43–7.45 (2H,
m), 7.29–7.31 (2H, m), 7.17–7.19 (2H, m), 4.22 (2H, s). nmax(KBr)/cm21
:
2897, 1690, 1587, 1492. m/z (%): 264 (Mþ, 1.07), 141 (35.31), 139 (100),
127 (2.37), 125 (7.32), 113 (9.24), 111 (27.67). Anal. C14H10Cl2O. Calcd.
C, 63.42; H, 3.80. Found C, 63.51; H, 3.82%.
1,2-Bis-(4-fluoro-phenyl)-ethanone (3d):[17b] white solid, yield: 90%,
m.p.: 95–978C (lit. 96–978C). dH: 8.01–8.03 (2H, m), 6.94–7.39 (6H, m),
4.23 (2H, s). nmax(KBr)/cm21: 2926, 1682, 1602, 1509. m/z (%): 232 (Mþ,
1.21), 123 (100), 109 (13.41), 95 (32.12). Anal. C14H10F2O. Calcd. C, 72.41;
H, 4.34. Found C, 72.69; H, 4.31%.

Reactions of Aroyl Chlorides in DMF
4019
1,2-Bis-(4-methoxy-phenyl)-ethanone (3e):[17a] white solid, yield: 72%,
m.p.: 105–1088C (lit. 109–1118C). dH: 7.93–7.96 (2H, m), 7.15–7.59 (6H,
m), 4.17 (2H, s), 3.85 (3H, s), 3.78 (3H, s). nmax(KBr)/cm21: 2954, 1681,
1601. m/z (%): 256 (Mþ, 1.06), 135 (100), 121 (6.35), 107 (12.30). Anal.
C16H16O3. Calcd. C, 74.98; H, 6.29. Found C, 74.83; H, 6.25%.
1,2-Di-m-tolyl-ethanone (3f):[17b] oil, yield: 76%. dH: 7.83–7.85 (2H,
m), 7.36–7.38 (2H, m), 7.21–7.28 (2H, m), 7.07–7.10 (2H, m), 4.25 (2H,
s), 2.42 (3H, s), 2.35 (3H, s). nmax(film)/cm21: 3027, 2922, 1680, 1605,
1586, 1488. m/z (%): 224 (Mþ, 1.67), 119 (100), 105 (6.39), 91 (11.44).
Anal. C16H16O. Calcd. C, 85.68; H, 7.19. Found C, 85.53; H, 7.17%.
1,2-Bis-(3-chloro-phenyl)-ethanone (3g): white solid, yield: 56%, m.p.:
133–1358C. dH: 7.99 (1H, m), 7.87–7.89 (1H, m), 7.16–7.58 (6H, m), 4.26
(2H, s). nmax(KBr)/cm21: 2957, 1688, 1601, 1574, 1478. m/z (%): 264 (Mþ,
1.03), 141 (35.31), 139 (100), 127 (2.08), 125 (6.19), 113 (11.55), 111
(33.84). Anal. C14H10Cl2O. Calcd. C, 63.42; H, 3.80. Found C, 63.55; H, 3.78%.
1,2-Bis-(2-chloro-phenyl)-ethanone (3h): white solid, yield: 42%, m.p.:
61–628C. dH: 7.54–7.56 (1H, m), 7.37–7.41 (3H, m), 7.29–7.31 (2H, m),
7.22–7.24 (2H, m), 4.40 (2H, s). nmax(KBr)/cm21: 3033, 2862, 1710, 1590,
1474. m/z (%): 264 (Mþ, 1.23), 141 (34.30), 139 (100), 127 (2.36), 125
(6.79), 113 (9.92), 111 (26.11). Anal. C14H10Cl2O. Calcd. C, 63.42; H,
3.80. Found C, 63.45; H, 3.79%.
(Z)-1,2-Diphenyl-ethene-1,2-dioldibenzoate (4a):[17c] white solid,
yield: 76%, m.p.: 158–1598C (lit. 1598C). dH: 8.03–8.06 (4H, m), 7.22–
7.46 (16H, m). nmax(KBr)/cm21: 3050, 1735, 1590, 1595, 1575, 1480,
1450. m/z (%): 420 (Mþ, 0.27), 105 (100), 77 (38.48). Anal. C28H20O4.
Calcd. C, 79.98; H, 4.79. Found C, 79.75; H, 4.76%.
(Z)-1,2-Di-p-tolyl-ethene-1,2-diol dibenzoate (4b):[17c] white solid,
yield: 78%, m.p.: 150–1538C (lit. 148–1548C). dH: 7.85–7.88 (4H, m),
7.11–7.24 (12H, m), 2.38 (6H, s) 2.43 (6H, s). nmax(KBr)/cm21: 3030,
2925, 1736, 1590, 1485, 1440. m/z (%): 476 (Mþ, 0.26), 119 (100), 91
(31.83). Anal. C32H28O4. Calcd. C, 80.65; H, 5.92. Found C, 80.47; H, 5.91%.
(Z)-1,2-Bis-(4-chloro-phenyl)-ethene-1,2-diol dibenzoate (4c):[17d]
white solid, yield: 81%, m.p.: 167–1698C (lit. 167–1688C). dH: 7.92–7.95
(4H, m), 7.24–7.36 (12H, m). nmax(KBr)/cm21: 3080, 1740, 1590, 1485.
m/z (%): 560 (Mþ þ 2, 0.16), 558 (Mþ, 0.33), 141 (33.45), 139 (100), 113
(9.44), 111 (29.29). Anal. C28H16Cl4O4. Calcd. C, 60.24; H, 2.89. Found C,
60.51; H, 2.91%.
(Z)-1,2-Bis-(4-fluoro-phenyl)-ethene-1,2-diol dibenzoate (4d): white
solid, yield: 84%, m.p.: 171–1738C. dH: 8.03–8.06 (4H, m), 7.12–7.25
(12H, m). nmax(KBr)/cm21: 3068, 1742, 1591, 1485. m/z (%): 492 (Mþ,
0.35), 123 (100), 95 (23.68). Anal. C28H16F4O4. Calcd. C, 68.30; H, 3.28.
Found C, 68.10; H, 3.26%.

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Liu, Wang, and Zhang
(Z)-1,2-Bis-(4-methoxy-phenyl)-ethene-1,2-diol dibenzoate (4e):[17c]
white solid, yield: 71%, m.p.: 185–1878C (lit. 1878C). dH: 7.91–7.94
(4H, m), 6.92–7.16 (12H, m), 3.71 (6H, s), 3.75 (6H, s). nmax(KBr)/
cm21: 3040, 2995, 1730, 1590, 1485, 1460. m/z (%): 540 (Mþ, 0.28),
135 (100), 107 (11.40). Anal. C32H28O8. Calcd. C, 71.10; H, 5.22. Found
C, 70.97; H, 5.19%.
(Z)-1,2-Di-m-tolyl-ethene-1,2-diol dibenzoate (4f): oil, yield: 82%.
dH: 7.83–7.86 (4H, m), 7.04–7.35 (12H, m), 2.24 (6H, s), 2.29 (6H, s).
n
max(film)/cm21: 3031, 2921, 1741, 1605, 1589, 1487, 1454. m/z (%): 476
(Mþ, 0.31), 119 (100), 91 (22.80). Anal. C32H28O4. Calcd. C, 80.65; H,
5.92. Found C, 80.57; H, 6.90%.
(Z)-1,2-Bis-(3-chloro-phenyl)-ethene-1,2-diol dibenzoate (4g): oil,
yield: 38%. dH: 7.95–8.01 (4H, m), 7.29–7.44 (12H, m). nmax(film)/cm21
:
3071, 1748, 1595, 1568, 1476, 1425. m/z (%):560 (Mþ þ 2, 0.25), 558
(Mþ, 0.49), 141 (34.82), 139 (100), 113 (8.13), 111 (25.44). Anal.
C28H16Cl4O4. Calcd. C, 60.24; H, 2.89. Found C, 60.39; H, 2.90%.
(Z)-1,2-Bis-(2-chloro-phenyl)-ethene-1,2-diol dibenzoate (4h): oil,
yield: 55%. dH: 8.03–8.05 (2H, m), 7.10–7.51 (14H, m). nmax(film)/cm21
:
3044, 1754, 1590, 1474. m/z (%): 560 (Mþ þ 2, 0.16), 558 (Mþ, 0.34), 141
(35.39), 139 (100), 113 (7.04), 111 (21.59). Anal. C28H16Cl4O4. Calcd. C,
60.24; H, 2.89. Found C, 60.34; H, 2.87%.
ACKNOWLEDGMENT
We are grateful to the National Natural Science Foundation of China
(Project No. 20072033) and Specialized Research Fund for the Doctoral
Program of Higher Education of China.
REFERENCES
1. Flood, T.C. Tetrahedron Lett. 1977, 3861–3864.
2. Dams, R.; Malinowski, M.; Westdorp, I.; Geise, H.J. J. Org. Chem. 1981,
46, 2406–2407.
3. (a) Girard, P.; Couffignal, R.; Kagan, H.B. Tetrahedron Lett. 1981, 22,
3959–3960; (b) Souppe, J.; Namy, J.-L.; Kagan, H.B. Tetrahedron Lett.
1984, 25, 2869–2872; (c) Collin, J.; Namy, J.-L.; Dallemer, F.;
Kagan, H.B. J. Org. Chem. 1991, 56, 3118–3122; (d) Machrouhi, F.;
Hamann, B.; Namy, J.-L.; Kagan, H.B. Synlett 1996, 633–634;
(e) Namy, J.-L.; Colomb, M.; Kagan, H.B. Tetrahedron Lett. 1994, 35,
1723–1726.

Reactions of Aroyl Chlorides in DMF
4021
4. (a) Li, Z.F.; Zhang, Y.M. Chin. J. Chem. 2001, 19, 634–636;
(b) Wu, T.Ch.; Rieke, R.D. J. Org. Chem. 1988, 53, 2381–2383;
(c) Bauld, N.L. J. Am. Chem. Soc. 1962, 84, 4345–4347;
(d) Cantrell, T.S.; Silverton, J.V. J. Org. Chem. 1979, 44, 4477–4481;
(e) Bauld, N.L. Tetrahedron Lett. 1963, 1841–1845; (f) Horner, L.;
Dickerhof, K. Chem. Ber. 1983, 116, 1603–1614.
¨
5. Clausen, C.; Weidner, I.; Butenschon, H. Eur. J. Org. Chem. 2000, 65,
3799–3806.
6. Banik, B.K. Eur. J. Org. Chem. 2002, 2431–2444 (and references cited
therein).
7. (a) Ogawa, A.; Nanke, T.; Takami, N.; Sumino, Y.; Ryu, I.; Sonoda, N.
Chem. Lett. 1994, 379–380; (b) Molander, G.A.; Etter, J.B. J. Org.
Chem. 1986, 51, 1778–1786; (c) Imamoto, T.; Takeyam, T.; Koto, H.
Tetrahedron Lett. 1986, 27, 3243–3246; (d) Hou, Z.; Fujiwara, Y.;
Taniguchi, H. J. Org. Chem. 1988, 53, 3118–3120; (e) Yanada, R.;
Negoro, N. Tetrahedron Lett. 1996, 37, 9313–9316.
8. (a) Banik, B.K.; Mukhopadhyay, C.; Venkatraman, M.S.; Becker, F.F.
Tetrahedron Lett. 1998, 39, 7243–7246; (b) Yanada, R.; Negora, N.;
Yanada, K.; Fujita, T. Tetrahedron Lett. 1997, 38, 3271–3274;
(c) Komachi, Y.; Kudo, T. Chem. Pharm. Bull. 1994, 42, 402–404;
(d) Ogawa, A.; Takami, N.; Sckiguchi, M.; Ryu, I.; Kambe, N.;
Sonoda, N. J. Am. Chem. Soc. 1992, 114, 8729–8730; (e) Wang, L.;
Zhang, Y. Tetrahedron 1998, 54, 11129–11140; (f) Ghatak, A.;
Becker, F.F.; Banik, B.K. Tetrahedron Lett. 2000, 41, 3793–3796;
(g) Talukdar, S.; Fang, J.-M. J. Org. Chem. 2001, 66, 330–333.
9. (a) Liu, Y.; Liu, X.; Zhang, Y. Tetrahedron Lett. 2003, 44, 1667–1670;
(b) Liu, Y.; Zhang, Y. Tetrahedron Lett. 2003, 44, 4291–4294;
(c) Liu, Y.; Zhang, Y. Tetrahedron 2003, 59, 8429–8437; (d) Liu, Y.;
Xu, X.; Zhang, Y. Synlett 2004, 445–448; (e) Liu, Y.; Zhang, Y.
J. Chem. Res. (S); 2003, 317–319; J. Chem. Res. (M) 2003, 0621–0635.
10. (a) Tumer, S.U.; Herndon, J.W.; Mcmullen, L.A. J. Am. Chem. Soc.
1992, 114, 8394–8404; (b) Smith, A.B., III; Dunlap, N.K.;
Sulikowski, G.A. Tetrahedron Lett. 1988, 29, 439–442.
11. (a) Farcas, S.; Namy, J.-L. Tetrahedron 2001, 57, 4881–4888;
(b) Takeuchi, S.; Miyoshi, N.; Hirata, K.; Hayashida, H.; Ohgo, Y.
Bull. Chem. Soc. Jpn. 1992, 65, 2001–2003.
12. Liu, Y.S.; Jiang, T.; Bei, M.Z. Chem. J. Chin. Univer. 1993, 14, 54–55.
13. Popov, A.F.; Savelova, V.A.; Sadovskii, Yu.S.; Solomoichenko, T.N.;
Piskunova, Zh.P.; Lobanova, O.V. Russ. J. Org. Chem. 2001, 37,
1176–1182.
14. (a) Yu, C.; Liu, B.; Hu, L. J. Org. Chem. 2001, 66, 919–924;
(b) Moffett, R.B. Organic Synthesis 1967, 2, 64.

4022
Liu, Wang, and Zhang
15. (a) Prasad, E.; Flower, R.A., II. J. Am. Chem. Soc. 2002, 124,
6895–6899; (b) Shabangi, M.; Kuhlman, M.L.; Flowers, R.A., II. Org.
Lett. 1999, 1, 2133–2135.
16. For complexing of DMF with metallic ions see: (a) Elias, H.;
Schumacher, R.; Schwamberger, J.; Wittekopf, T. Inorg. Chem. 2000,
39, 1721–1727; (b) Ishiguro, S.; Takahashi, R.; Ozutsumi, K. Kidorui
1994, 24, 96–97; (c) Hanawa, H.; Kii, S.; Asao, N.; Maruoka, K. Tetra-
hedron Lett. 2000, 41, 5543–5546.
17. (a) Ho, T.-L.; Wong, C.M. Synthesis 1975, 161; (b) Krepski, L.R.;
Heilmann, M.S.; Rasmussen, J.K.; Tumey, M.L.; Smith, H.K., II.
Synth. Commun. 1986, 16, 377–386; (c) Horner, L.; Dickerhof, K.
Chem. Ber. 1983, 116, 1603; (d) Wu, T.Ch.; Rieke, R.D. J. Org. Chem.
1988, 53, 2381–2383.
Received in Japan May 24, 2004