Samarium-promoted michael addition between aroyl chlorides and chalcones

Article abstract of DOI:10.1055/s-0030-1258287

A novel Michael addition type reaction between aroyl chlorides and chalcones was realized in the presence of samarium metal when N,N-dimethylformamide was used as a solvent. A variety of 1,4-diketones were thereby synthesized in moderate to good yields. T

Full text of DOI:10.1055/s-0030-1258287

4188
PAPER
Samarium-Promoted Michael Addition between Aroyl Chlorides and
Chalcones
Yongjun Liu, Yuanying Li, Yan Qi, Jun Wan*
State Key Laboratory Base of Eco-chemical Engineering, College of Chemistry and Molecular Engineering,
Qingdao University of Science and Technology, Qingdao 266042, P. R. of China
Fax +86(532)84023927; E-mail: wanjundz@sohu.com
Received 26 July 2010; revised 6 September 2010
dine, hydrochloric acid, alkyl halides, trimethylsilyl chlo-
ride, etc., which can activate the surface of the samarium
metal so as to improve its reactivity.8 Recently, novel and
interesting reductions promoted by samarium metal have
been developed by our group where we originally exploit-
ed N,N-dimethylformamide (DMF) as a solvent in which
metallic samarium exhibits unusual reactivity.9 In this pa-
per, we wish to present a novel Michael addition of aroyl
chlorides to chalcones promoted by samarium metal in
DMF.
Abstract: A novel Michael addition type reaction between aroyl
chlorides and chalcones was realized in the presence of samarium
metal when N,N-dimethylformamide was used as a solvent. A vari-
ety of 1,4-diketones were thereby synthesized in moderate to good
yields. The possible mechanism is also discussed.
Key words: samarium, Michael addition, aroyl chlorides, chal-
cones, 1,4-diketones
As a well-known synthetic methodology, the Michael ad-
dition and its variants have been widely explored in or-
ganic synthesis for more than 100 years due to their high
efficiency in carbon–carbon bond formations, which are
often the key step involved in a wide range of organic pro-
cesses.1 Among them, several examples of the addition of
acyl anion equivalents to a,b-unsaturated carbonyl com-
pounds have recently appeared as an unusual variation of
the Michael addition, resulting in the formation of 1,4-di-
carbonyl compounds;2 however, the synthetic utility of
the acyl anion is considerably limited because of its insta-
bility, and difficulties in generation and treatment.3 Acyl
metals and their analogues are considered as one of the
most important acyl anion sources; nevertheless, anion
formation is limited to only a few metals such as silica,2a–c
titanium,2d magnesium,2e etc. Excluding the established
catalytic acyl anion addition in the Stetter reaction,4 the
conjugate addition of acyl anions and their equivalents to
a,b-unsaturated carbonyl compounds still stands as one of
the most attractive and challenging methods for the prep-
aration of 1,4-dicarbonyl compounds, which are impor-
tant synthetic intermediates for useful cyclopentenones,
cyclopentane-1,3-diones, butenolides, and furans.5
When chalcone (1a) and benzoyl chloride (2a) were
mixed in DMF in the presence of samarium metal without
any pretreatment or activation, 1,4-diketone 3a was af-
forded smoothly in moderate yield (Scheme 1). This reac-
tion was initially selected as a model reaction to optimize
the reaction conditions.
O
COCl
O
O
Sm
+
DMF
1a
2a
3a
Scheme 1 Samarium-promoted Michael addition between benzoyl
chloride and chalcone
Table 1, which summarizes the influence of the reaction
temperature upon the addition, shows that when the reac-
tion temperature is decreased, a longer reaction time is re-
quired. The addition was incomplete and a quantity of
benzoyl chloride remained unreacted when the reaction
temperature was 0 °C (entry 1). In contrast, higher tem-
peratures resulted in a complicated reaction and the yield
of desired product decreased sharply (entries 4 and 5). The
most suitable reaction temperature is around 25 °C, name-
ly room temperature (entry 3). In addition, further investi-
gation showed that the optimal ratio of reactants benzoyl
chloride–chalcone–samarium is 1:1:1. In contrast, almost
no reaction was observed when the substrates were sub-
jected to similar reaction conditions with tetrahydrofuran
as solvent instead of DMF.
In the past two decades samarium reagents have drawn
much attention due to their particular importance in syn-
thetic chemistry.6 Although the use of samarium diiodide
is extremely popular in organic synthesis, the direct use of
metallic samarium as a reducing agent in organic transfor-
mations is considered more practical and environmentally
friendly than the use of samarium diiodide.7 In these cas-
es, the reactions are often promoted by samarium metal
alone, although an auxiliary is usually added to ensure the
reactions proceed smoothly.7,8 The auxiliaries include io-
A variety of products were synthesized under the opti-
mized reaction conditions, and the results are listed in
Table 2. All reactions proceeded smoothly with moderate
to good yields; however, substituents on the chalcones ex-
SYNTHESIS 2010, No. 24, pp 4188–4192
Advanced online publication: 07.10.2010
DOI: 10.1055/s-0030-1258287; Art ID: F12610SS
x
x.
x
x
.
2
0
1
0
© Georg Thieme Verlag Stuttgart · New York

PAPER
Samarium-Promoted Michael Addition between Aroyl Chlorides and Chalcones
4189
Self-coupling of the chalcones10a or aroyl chlorides10b was
also detected as a side reaction, which generated byprod-
ucts during the reaction process. Due to this reason, at-
tempts to expand the reaction to aliphatic acyl chlorides
were not successful. The byproducts of self-coupling of
the chalcones increased remarkably when aliphatic acyl
chlorides were used instead of aroyl chlorides.
Table 1 Optimization of the Reaction of Chalcone (1a) with Ben-
zoyl Chloride (2a)
Entry
Temp (°C)
Time (h)
Yielda (%)
1
2
3
4
5
0
15
6
43b
72
3
25
1.5
0.5
0.5
75
Although the mechanism of this reaction is not clear
enough yet, we presume that the reaction would involve a
radical mechanism.11 The following reaction pathway is
proposed as one of the most plausible mechanisms
(Scheme 2). An electron transfer from samarium to the
aroyl chloride 2a leads to the corresponding aroyl radical
A. Radical A attacks the b-position of the conjugated car-
bon–carbon double bond, and the radical intermediate B is
formed. Intermediate B immediately captures an electron
from samarium to form the anion C, which is relatively
stable due to the strong oxophilic property of samarium.
After a protonation process, the 1,4-diketone 3a is afford-
ed.
50
18c
c
100
–
a Isolated yield after chromatographic purification.
b Unreacted benzoyl chloride was detected.
c The reaction mixture became very sticky and a complex product was
obtained.
ert a light influence during the addition process on the
yield. Thus, the yields of 1,4-diketones from chalcone
with a para-chloro substituent are slightly lower than
those from chalcones with other substituents (entries 5,
10, and 14). In contrast, no obvious differences in the
yields can be observed when aroyl chlorides with different
substituents are used.
It should be pointed out that, as a solvent with strong po-
larity, and excellent solubility and coordination capability
with lanthanides,12 DMF may play an important role in
Table 2 Samarium-Promoted Michael Addition between Aroyl Chlorides and Chalcones
R3
COCl
O
O
O
Sm
DMF
+
R1
R2
1
R3
R1
R2
3
2
Entry
1
R1
R2
R3
Time (h)
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1
Product
3a
Yielda (%)
H
H
H (2a)
75
80
82
84
71
74
79
81
83
73
79
80
83
71
82
2
Me
H
H
H (2a)
3b
3c
3
Me
H
H (2a)
4
OMe
H
H (2a)
3d
3e
5
Cl
H
H (2a)
6
H
Me (2b)
Me (2b)
Me (2b)
Me (2b)
Me (2b)
Me (2b)
Cl (2c)
Cl (2c)
Cl (2c)
F (2d)
3f
7
Me
H
H
3g
8
Me
H
3h
3i
9
OMe
H
10
11
12
13
14
15
Cl
Me
Me
H
3j
Me
H
3k
3l
OMe
H
1
3m
3n
3o
Cl
H
1
OMe
1
a Isolated yield after chromatographic purification.
Synthesis 2010, No. 24, 4188–4192 © Thieme Stuttgart · New York

4190
Y. Liu et al.
PAPER
IR (KBr): 3058, 2911, 1676, 1594, 1493, 1446, 1393, 1369, 1332
cm–1.
O
O
O
C
O
C
Sm (+ e)
Ph
Ph
1a
Ph
C
Cl
Ph
Cl
1H NMR: d = 8.04–7.98 (m, 4 H), 7.59–7.55 (m, 1 H), 7.52–7.30
(m, 7 H), 7.28–7.25 (m, 2 H), 7.25–7.22 (m, 1 H), 5.34 (dd,
Jcb = 10.0 Hz, Jca = 3.5 Hz, 1 H, Hc), 4.23 (dd, Jbc = 10.0 Hz,
Jba = 18 Hz, 1 H, Hb), 3.32 (dd, Jab = 18.0 Hz, Jac = 3.5 Hz, 1 H,
Ha).
13C NMR: d = 198.9, 198.0, 138.9, 136.6, 133.3, 132.9, 129.2,
129.0, 128.6, 128.3, 128.2, 127.4, 48.8, 43.9.
Ph
A
2a
Ph
Ph
O
Ph
Ph
O
Ph
Ph
O
O
Sm (+ e)
O
O
protonation
Ph
Ph
Ph
–
Anal. Calcd for C22H18O2: C, 84.05; H, 5.77. Found: C, 83.86; H,
5.76.
B
3a
C
Scheme 2 Possible reaction mechanism
1,2-Diphenyl-4-p-tolylbutane-1,4-dione (3b)
Yield: 0.53 g (80%); yellow solid; mp 78–80 °C.
IR (KBr): 3030, 2922, 1677, 1600 cm–1.
1H NMR: d = 8.06–7.88 (m, 4 H), 7.51–7.48 (m, 1 H), 7.42–7.25
(m, 8 H), 7.25–7.23 (m, 1 H), 5.33 (dd, Jcb = 10.0 Hz, Jca = 4.0 Hz,
1 H, Hc), 4.20 (dd, Jbc = 10.0 Hz, Jba = 18.0 Hz, 1 H, Hb), 3.30
(dd, Jab = 18.0 Hz, Jac = 4.0 Hz, 1 H, Ha), 2.28 (s, 3 H).
stabilizing the intermediates, dissolving samarium salts,
and promoting the reaction to readily proceed, as this re-
action does not occur in tetrahydrofuran in which even the
self-coupling products of the aroyl chloride can hardly be
observed.
In conclusion, a novel Michael addition between aroyl
chlorides and chalcones was realized in the presence of
samarium metal in DMF. This transformation constitutes
a specific method in which 1,4-diketones are formed in
moderate to good yields. Furthermore, with the direct use
of metallic samarium without any activator, simple equip-
13C NMR: d = 199.0, 197.7, 144.0, 138.7, 136.5, 134.0, 132.8,
129.2, 129.1, 128.9, 128.5, 128.3, 127.3, 48.7, 43.8, 21.6.
Anal. Calcd for C23H20O2: C, 84.12; H, 6.14. Found: C, 84.01; H,
6.13.
1,4-Diphenyl-2-p-tolylbutane-1,4-dione (3c)2c
ment and materials, facile operation procedures, and mild Yield: 0.54 g (82%); white solid; mp 88–90 °C (Lit.2c 88.5–90 °C).
reaction conditions, this reaction is also a valuable exam-
ple with a high potential for large-scale preparations pro-
moted by samarium reagents.
IR (KBr): 3024, 2918, 1678, 1595, 1579, 1511, 1447, 1398, 1368,
1335 cm–1.
1H NMR: d = 8.06–7.99 (m, 4 H), 7.59–7.40 (m, 6 H), 7.28–7.25
(m, 2 H), 7.15–7.13 (m, 2 H), 5.30 (dd, Jcb = 10.0 Hz, Jca = 3.5 Hz,
1 H, Hc), 4.22 (dd, Jbc = 10.0 Hz, Jba = 18.0 Hz, 1 H, Hb), 3.30
(dd, Jab = 18.0 Hz, Jac = 3.5 Hz, 1 H, Ha), 2.28 (s, 3 H).
13C NMR: d = 199.1, 198.2, 137.1, 136.7, 135.7, 133.2, 132.8,
129.9, 128.9, 128.6, 128.5, 128.2, 48.4, 43.9, 21.0.
All NMR spectra were measured in CDCl3 and recorded on a Bruk-
er Avance 500 (500 MHz) spectrometer with TMS as the internal
standard. Chemical shifts (d) are expressed in ppm and J values are
given in Hz (see Figure 1 for proton assignments). IR spectra were
recorded on a Bruker Tensor 27 spectrometer. Melting points are
uncorrected. All the reactions described in this paper were per-
formed under a nitrogen atmosphere. The samarium metal was
rubbed into a powder with a steel file and immediately added to the
reaction flask. DMF was refluxed and water removed before use.
Anal. Calcd for C23H20O2: C, 84.12; H, 6.14. Found: C, 84.02; H,
6.13.
4-(4-Methoxyphenyl)-1,2-diphenylbutane-1,4-dione (3d)2c
Yield: 0.58 g (84%); yellow crystals; mp 155–156 °C (Lit.2c 155–
156 °C).
Ar3
Ar2
O
IR (KBr): 3017, 1670, 1594, 1503, 1450, 1386, 1325, 1253, 1167
cm–1.
1H NMR: d = 8.03–7.96 (m, 4 H), 7.51–7.23 (m, 8 H), 6.93–6.91
(m, 2 H), 5.33 (dd, Jcb = 10.0 Hz, Jca = 3.5 Hz, 1 H, Hc), 4.18 (dd,
Jbc = 10.0 Hz, Jba = 18.0 Hz, 1 H, Hb), 3.90 (s, 3 H), 3.28 (dd,
Jab = 18.0 Hz, Jac = 3.5 Hz, 1 H, Ha).
O
Hb
Ar1
Hc
Ha
Figure 1 General structure of the 1,4-diketones
13C NMR: d = 199.9, 199.6, 163.7, 138.9, 136.7, 132.8, 130.5,
1,4-Diketones 3; General Procedure
129.2, 128.9, 128.5, 128.3, 127.3, 114.1, 113.8, 55.5, 48.8, 43.6.
To a mixture of samarium powder (2 mmol) and a chalcone 1 (2
mmol) in freshly distilled DMF (10 mL), freshly distilled benzoyl
chloride (2 mmol) was added at r.t. with magnetic stirring under a
nitrogen atmosphere. The reaction was monitored by thin-layer
chromatography. After completion (about 1 h), the reaction was
quenched with dil HCl (0.1 M, 5 mL), and the mixture was extracted
with EtOAc (3 × 15 mL). The combined organic layer was washed
with sat. brine (15 mL), dried (Na2SO4), and concentrated under re-
duced pressure. The residue was subjected to silica gel chromatog-
raphy (acetone–n-hexane, 1:8).
Anal. Calcd for C23H20O3: C, 80.21; H, 5.85. Found: C, 80.10; H,
5.84.
2-(4-Chlorophenyl)-1,4-diphenylbutane-1,4-dione (3e)2c
Yield: 0.50 g (71%); yellow solid; mp 116–118 °C.
IR (KBr): 3053, 2918, 1678, 1586 cm–1.
1H NMR: d = 8.01–7.98 (m, 4 H), 7.59–7.41 (m, 6 H), 7.32–7.27
(m, 4 H), 5.33 (dd, Jcb = 10.0 Hz, Jca = 4.0 Hz, 1 H, Hc), 4.18 (dd,
Jbc = 10.0 Hz, Jba = 18 Hz, 1 H, Hb), 3.32 (dd, Jab = 18.0 Hz,
Jac = 4.0 Hz, 1 H, Ha).
13C NMR: d = 198.7, 197.7, 137.2, 136.5, 136.4, 133.3, 133.1,
129.6, 129.4, 128.9, 128.6, 128.2, 48.0, 43.6.
1,2,4-Triphenylbutane-1,4-dione (3a)2c
Yield: 0.47 g (75%); white solid; mp 123–125 °C (Lit.2c 124–
126 °C).
Synthesis 2010, No. 24, 4188–4192 © Thieme Stuttgart · New York

PAPER
Samarium-Promoted Michael Addition between Aroyl Chlorides and Chalcones
4191
Anal. Calcd for C22H17ClO2: C, 75.75; H, 4.91. Found: C, 75.66; H,
4.90.
Jcb = 10.0 Hz, Jca = 4.0 Hz, 1 H, Hc), 4.17 (dd, Jbc = 10.0 Hz,
Jba = 18 Hz, 1 H, Hb), 3.30 (dd, Jab = 18.0 Hz, Jac = 4.0 Hz, 1 H,
Ha), 2.37 (s, 3 H).
13C NMR: d = 198.2, 197.8, 143.9, 137.5, 136.6, 133.8, 133.3,
129.6, 129.3, 129.0, 128.6, 128.2, 47.9, 43.6, 21.6.
2,4-Diphenyl-1-p-tolylbutane-1,4-dione (3f)2c
Yield: 0.49 g (74%); orange solid; mp 113–115 °C.
IR (KBr): 3050, 1672, 1598, 1491, 1445 cm–1.
1H NMR: d = 8.00–7.94 (m, 4 H), 7.57–7.54 (m, 1 H), 7.46–7.43
(m, 2 H), 7.37–7.23 (m, 6 H), 7.22–7.19 (m, 1 H), 5.32 (dd,
Jcb = 9.5 Hz, Jca = 3.5 Hz, 1 H, Hc), 4.21 (dd, Jbc = 9.5 Hz,
Jba = 18 Hz, 1 H, Hb), 3.30 (dd, Jab = 18.0 Hz, Jac = 3.5 Hz, 1 H,
Ha), 2.36 (s, 3 H).
13C NMR: d = 198.5, 198.1, 143.7, 139.0, 136.6, 134.0, 133.2,
129.2, 129.1, 128.6, 128.3, 127.3, 48.6, 43.8, 21.6.
Anal. Calcd for C23H19ClO2: C, 76.13; H, 5.28. Found: C, 75.99; H,
5.27.
1,2,4-Tri-p-tolylbutane-1,4-dione (3k)
Yield: 0.56 g (79%); yellow solid; mp 117–119 °C.
IR (KBr): 2914, 1673, 1604, 1509, 1406 cm–1.
1H NMR: d = 7.95–7.87 (m, 4 H), 7.25–7.23 (m, 4 H), 7.20–7.18
(m, 2 H), 7.12–6.90 (m, 2 H), 5.27 (dd, Jcb = 10.0 Hz, Jca = 3.5 Hz,
1 H, Hc), 4.16 (dd, Jbc = 10.0 Hz, Jba = 18 Hz, 1 H, Hb), 3.25 (dd,
Jab = 18.0 Hz, Jac = 3.5 Hz, 1 H, Ha), 2.40 (s, 3 H), 2.35 (s, 3 H),
2.28 (s, 3 H).
Anal. Calcd for C23H20O2: C, 84.12; H, 6.14. Found: C, 83.89; H,
6.13.
2-Phenyl-1,4-di-p-tolylbutane-1,4-dione (3g)
Yield: 0.54 g (79%); white solid; mp 132–134 °C.
IR (KBr): 3029, 2914, 1672, 1602 cm–1.
13C NMR: d = 198.6, 197.7, 143.7, 143.3, 136.7, 135.9, 134.0,
129.7, 129.1, 128.9, 128.7, 128.1, 127.6, 124.8, 48.2, 43.5, 21.4,
20.9, 20.8.
1H NMR: d = 7.95–7.87 (m, 4 H), 7.37–7.35 (m, 2 H), 7.31–7.28
(m, 2 H), 7.24–7.18 (m, 5 H), 5.31 (dd, Jcb = 9.5 Hz, Jca = 3.5 Hz,
1 H, Hc), 4.18 (dd, Jbc = 9.5 Hz, Jba = 18 Hz, 1 H, Hb), 3.28 (dd,
Jab = 18.0 Hz, Jac = 3.5 Hz, 1 H, Ha), 2.40 (s, 3 H), 2.36 (s, 3 H).
Anal. Calcd for C25H24O2: C, 84.24; H, 6.79. Found: C, 84.13; H,
6.78.
1-(4-Chlorophenyl)-4-phenyl-2-p-tolylbutane-1,4-dione (3l)
Yield: 0.58 g (80%); light yellow solid; mp 106–108 °C.
IR (KBr): 2912, 1730, 1675, 1584, 1501, 1446, 1396 cm–1.
1H NMR: d = 7.99–7.96 (m, 4 H), 7.57–7.55 (m, 1 H), 7.47–7.44
(m, 2 H), 7.38–7.36 (m, 2 H), 7.23–7.12 (m, 4 H), 5.23 (dd,
Jcb = 10.0 Hz, Jca = 3.5 Hz, 1 H, Hc), 4.19 (dd, Jbc = 10.0 Hz,
Jba = 18 Hz, 1 H, Hb), 3.29 (dd, Jab = 18.0 Hz, Jac = 3.5 Hz, 1 H,
Ha), 2.23 (s, 3 H).
13C NMR: d = 198.6, 197.7, 143.9, 143.6, 139.1, 134.1, 130.2,
129.2, 129.1, 128.6, 128.3, 127.7, 127.2, 124.9, 48.7, 43.7, 21.6,
21.6.
Anal. Calcd for C24H22O2: C, 84.18; H, 6.48. Found: C, 84.01; H,
6.46.
4-Phenyl-1,2-di-p-tolylbutane-1,4-dione (3h)
Yield: 0.55 g (81%); yellow solid; mp 144–146 °C.
IR (KBr): 2914, 1672, 1602, 1507, 1446, 1398, 1331 cm–1.
13C NMR: d = 198.1, 197.9, 139.2, 137.3, 136.5, 135.3, 134.9,
133.3, 130.3, 130.0, 128.8, 128.6, 128.2, 128.1, 48.4, 43.9, 21.0.
1H NMR: d = 7.98–7.97 (m, 2 H), 7.94–7.92 (m, 2 H), 7.55–7.53
(m, 1 H), 7.46–7.42 (m, 2 H), 7.26–7.23 (m, 2 H), 7.20–7.18 (m, 2
H), 7.12–7.10 (m, 2 H), 5.28 (dd, Jcb = 10.0 Hz, Jca = 4.0 Hz, 1 H,
Hc), 4.18 (dd, Jbc = 10.0 Hz, Jba = 18 Hz, 1 H, Hb), 3.26 (dd,
Jab = 18.0 Hz, Jac = 4.0 Hz, 1 H, Ha), 2.35 (s, 3 H), 2.28 (s, 3 H).
Anal. Calcd for C23H19ClO2: C, 76.13; H, 5.28. Found: C, 76.01; H,
5.27.
1-(4-Chlorophenyl)-4-(4-methoxyphenyl)-2-phenylbutane-1,4-
dione (3m)
Yield: 0.63 g (83%); light yellow solid; mp 159–161 °C.
IR (KBr): 2949, 1674, 1592, 1499, 1403 cm–1.
1H NMR: d = 7.98–7.95 (m, 4 H), 7.39–7.27 (m, 7 H), 6.93–6.91
(m, 2 H), 5.25 (dd, Jcb = 10.0 Hz, Jca = 3.5 Hz, 1 H, Hc), 4.17 (dd,
Jbc = 10.0 Hz, Jba = 17.5 Hz, 1 H, Hb), 3.87 (s, 3 H), 3.27 (dd,
Jab = 17.5 Hz, Jac = 3.5 Hz, 1 H, Ha).
13C NMR: d = 198.7, 198.3, 143.6, 137.0, 136.7, 136.0, 133.2,
130.3, 129.9, 129.2, 129.1, 128.6, 128.2, 128.1, 48.3, 43.8, 21.6,
21.0.
Anal. Calcd for C24H22O2: C, 84.18; H, 6.48. Found: C, 83.99; H,
6.47.
4-(4-Methoxyphenyl)-2-phenyl-1-p-tolylbutane-1,4-dione (3i)
Yield: 0.60 g (83%); yellow solid; mp 145–147 °C.
IR (KBr): 2917, 1735, 1670, 1596 cm–1.
1H NMR: d = 8.00–7.95 (m, 4 H), 7.38–7.20 (m, 7 H), 6.96–6.92
(m, 2 H), 5.32 (dd, Jcb = 10.0 Hz, Jca = 3.5 Hz, 1 H, Hc), 4.17 (dd,
Jbc = 10.0 Hz, Jba = 18 Hz, 1 H, Hb), 3.83 (s, 3 H), 3.27 (dd,
Jab = 18.0 Hz, Jac = 3.5 Hz, 1 H, Ha), 2.37 (s, 3 H).
13C NMR: d = 198.0, 196.5, 163.7, 139.3, 138.5, 135.0, 130.5,
130.3, 129.6, 129.3, 128.8, 128.2, 127.5, 113.8, 55.5, 48.9, 43.6.
Anal. Calcd for C23H19ClO3: C, 72.92; H, 5.05. Found: C, 72.78; H,
5.04.
1,2-Bis(4-chlorophenyl)-4-phenylbutane-1,4-dione (3n)
Yield: 0.55 g (71%); light yellow solid; mp 139–141 °C.
13C NMR: d = 198.6, 196.6, 163.6, 143.6, 139.2, 134.1, 130.5,
IR (KBr): 3066, 2910, 1671, 1584 cm–1.
129.8, 129.2, 129.1, 128.3, 127.2, 113.7, 55.5, 48.7, 43.5, 21.6.
1H NMR: d = 7.98–7.94 (m, 4 H), 7.59–7.56 (m, 1 H), 7.48–7.39
(m, 4 H), 7.31–7.27 (m, 4 H), 5.25 (dd, Jcb = 10.0 Hz, Jca = 4.0 Hz,
1 H, Hc), 4.17 (dd, Jbc = 10.0 Hz, Jba = 18 Hz, 1 H, Hb), 3.30 (dd,
Jab = 18 Hz, Jac = 4 Hz, 1 H, Ha).
Anal. Calcd for C24H22O3: C, 80.42; H, 6.19. Found: C, 80.30; H,
6.18.
2-(4-Chlorophenyl)-4-phenyl-1-p-tolylbutane-1,4-dione (3j)
Yield: 0.53 g (73%); white solid; mp 174–176 °C.
IR (KBr): 3058, 2915, 1727, 1672, 1602 cm–1.
1H NMR: d = 8.00–7.92 (m, 4 H), 7.59–7.56 (m, 1 H), 7.48–7.45
(m, 2 H), 7.33–7.28 (m, 4 H), 7.24–7.22 (m, 2 H), 5.32 (dd,
13C NMR: d = 197.7, 197.5, 139.6, 136.8, 136.3, 134.7, 133.6,
133.4, 130.3, 129.53, 129.48, 128.9, 128.6, 128.2, 48.0, 43.7.
Anal. Calcd for C22H16Cl2O2: C, 68.94; H, 4.21. Found: C, 68.81; H,
4.20.
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Y. Liu et al.
PAPER
1-(4-Fluorophenyl)-4-(4-methoxyphenyl)-2-phenylbutane-1,4-
dione (3o)
Yield: 0.59 g (82%); light yellow solid; mp 146–148 °C.
IR (KBr): 2950, 1674, 1594, 1504 cm–1.
1H NMR: d = 8.08–8.05 (m, 2 H), 7.97–7.95 (m, 2 H), 7.36–7.24
(m, 5 H), 7.09–7.05 (m, 2 H), 6.93–6.91 (m, 2 H), 5.27 (dd,
Jcb = 10.5 Hz, Jca = 3.5 Hz, 1 H, Hc), 4.17 (dd, Jbc = 10.5 Hz,
Jba = 18 Hz, 1 H, Hb), 3.83 (s, 3 H), 3.27 (dd, Jab = 18.0 Hz,
Jac = 3.5 Hz, 1 H, Ha).
13C NMR: d = 197.5, 196.5, 166.6, 164.2, 163.7, 138.7, 133.1,
131.6, 131.5, 130.5 129.7, 129.3, 128.2, 127.4, 115.7, 115.5, 113.8,
55.5, 48.8, 43.6.
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(c) Hashimoto, T.; Hirose, M.; Maruoka, K. J. Am. Chem.
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273. (b) Sánchez-Larios, E.; Gravel, M. J. Org. Chem. 2009,
74, 7536. (c) DiRocco, D. A.; Oberg, K. M.; Dalton, D. M.;
Rovis, T. J. Am. Chem. Soc. 2009, 131, 10872. (d) Liu, Q.;
Rovis, T. Org. Lett. 2009, 11, 2856. (e) Christmann, M.
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(5) Hassner, A. In Comprehensive Organic Synthesis, Vol. 1;
Trost, B. M., Ed.; Pergamon Press: Oxford, 1991, 541–577.
(6) (a) Nicolaou, K. C.; Ellery, S. P.; Chen, J. S. Angew. Chem.
Int. Ed. 2009, 48, 7140. (b) Procter, D. J.; Flowers, R. A. II;
Skrydstrup, T. Organic Synthesis Using Samarium
Diiodide: A Practical Guide; Royal Society of Chemistry
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Anal. Calcd for C23H19FO3: C, 76.23; H, 5.28. Found: C, 76.13; H,
5.27.
Acknowledgment
This project was supported by the National Natural Science Found-
ation of China (Project No. 20701023) and the Scientific Research
Foundation for the Returned Overseas Chinese Scholars, State Edu-
cation Ministry (20071108).
(7) For a review of the use of metallic samarium, see: Banik, B.
K. Eur. J. Org. Chem. 2002, 2431.
(8) (a) Ghatak, A.; Becker, F. F.; Banik, B. K. Tetrahedron Lett.
2000, 41, 3793. (b) Talukdar, S.; Fang, J.-M. J. Org. Chem.
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Zhang, S. Eur. J. Org. Chem. 2008, 5470. (b) Liu, Y.; Xu,
X.; Zhang, Y. Synlett 2004, 445. (c) Liu, Y.; Zhang, Y.
Tetrahedron Lett. 2004, 45, 1295. (d) Liu, Y.; Zhang, Y.
Tetrahedron 2003, 59, 8429.
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Synthesis 2010, No. 24, 4188–4192 © Thieme Stuttgart · New York