Synthesis of (E)-α,β-Unsaturated ketones by hydrostannylation- Stille tandem reaction of alkylarylacetylenes with acyl chlorides

Article abstract of DOI:10.3184/030823410X12861973220846

(E)-α,β-Unsaturated ketones can be stereoselectively synthesised in one pot under mild conditions, in good yields, by the hydrostannylation of alkylaryl-acetylenes, followed by the Stille cross-coupling with acyl chlorides.

Full text of DOI:10.3184/030823410X12861973220846

JOURNAL OF CHEMICAL RESEARCH 2010
OCTOBER, 559–561
RESEARCH PAPER 559
Synthesis of (E)-a,b-unsaturated ketones by hydrostannylation-Stille
tandem reaction of alkylarylacetylenes with acyl chlorides
a,b
a
a
a
Jianying Li , Yan Yu , Wenyan Hao and Mingzhong Cai *
a
Department of Chemistry, Jiangxi Normal University, Nanchang 330022, P. R. China
bDepartment of Chemistry, Jingdezhen Comprehensive College, Jingdezhen 333000, P. R. China
(
E)-a,b-Unsaturated ketones can be stereoselectively synthesised in one pot under mild conditions, in good yields, by
the hydrostannylation of alkylaryl- acetylenes, followed by the Stille cross-coupling with acyl chlorides.
Keywords: hydrostannylation, (E)-α,β-unsaturated ketone, alkylarylacetylene, Stille coupling, tandem reaction
The synthesis of α,β-unsaturated ketones is of great impor-
tance as this bifunctional unit is one of the main structural
components in various naturally occurring and biologically
temperature was highly regio- and stereoselective, giving
16
(E)-α-arylvinylstannanes in high yields. It is well known that
vinylstannanes can undergo the palladium- catalysed cross-
1
–3
17,18
19
essential substances. The great synthetic value of these
α,β-unsaturated ketones derives from the fact that the positions
α,β and γ to the carbonyl groups can be activated and function-
alised by various means. A variety of synthetic methods for the
synthesis of α,β-unsaturated ketones have been reported. Of
these methods, the direct aldol condensation and the Claisen–
coupling reaction with organic halides.
Labadie and Stille
reported stereospecific cross-coupling of acyl chlorides with
vinyl tin reagents catalysed by palladium. Considering the fact
that both the hydrostannylation and Stille reactions were cata-
lysed by palladium complexes, we tried to combine the two
reactions, in one pot, to synthesise (E)-α,β-unsaturated ketones
stereoselectively (Scheme 1).
4
–6
Schimdt condensation still occupy prominent positions. The
Friedel-Crafts reaction of acyl chlorides, acids, or anhydrides
with olefins is also an important route to the α,β-unsaturated
We found that, after the hydrostannylation reaction of
alkylarylacetylenes 1 with Bu SnH using 3 mol% PdCl (PPh )
3
2
3 2
7
8
ketones. Lee and Oh described one-pot synthesis of α,β-
unsaturated ketones by subsequent treatment of diethyl lithio-
methylphosphonate with nitriles, followed by addition of
in THF at 25 °C for 30 min, solvent removal under reduced
pressure and stirring of the residue with benzene, acyl
chlorides 3 and 75 mol% CuI at reflux temperature for 10 h,
(E)-α,β-unsaturated ketones 4 were obtained in good yields.
The experimental results are summarised in Table 1. It was
found that benzene was the best solvent among those
tested, such as DMF and THF for the Stille coupling of the
intermediates 2 with acyl chlorides. As shown in Table 1, the
9
carbonyl compounds and hydrolysis. Liu et al. reported
the synthesis of acyclic α,β-unsaturated ketones via Pd(II)-
catalysed intermolecular reaction of alkynamides and alkenes.
Despite considerable methodological differentiation the
reported procedures in the majority suffer from some draw-
backs such as harsh reaction conditions, expensive and toxic
reagents, moderate yields, and low stereoselectivity. There
is still a need for the development of selective and better
strategies for the one-pot synthesis of α,β-unsaturated
ketones.
hydrostannylation-Stille tandem reaction of Bu SnH with a
3
variety of alkylaryl- acetylenes and aromatic acyl chlorides
proceeded smoothly under mild conditions to afford stereose-
lectively the corresponding (E)-α,β-unsaturated ketones 4.
However, the Stille coupling reaction of the intermediates 2
with aliphatic acyl chlorides did not occur under the same
conditions perhaps due to the presence of the steric barrier
from α-aryl groups. It was reported that the Stille coupling
The tandem reaction has recently been of interest for organic
synthesis because it offers a convenient and economical
1
0–13
method with which to prepare target organic molecules.
2
0
The palladium-catalysed hydrostannylation of alkynes and the
Stille coupling reaction are acknowledged as useful tools for
constructing complex organic molecules. However, to the best
of our knowledge, there have been no reports on palladium-
catalysed tandem hydrostannylation-Stille coupling reaction
of tributyltin hydride with alkylarylacetylenes and acyl chlo-
rides to date. We report here that (E)-α,β-unsaturated ketones
can be stereoselectively synthesised in one pot under mild
conditions, in good yields, by hydrostannylation of alkylary-
lacetylenes, followed by the Stille cross-coupling with acyl
chlorides.
reactions of sterically hindered (E)-α-selanyl- vinylstannanes,
21
(E)-α-arylsulfonylvinylstannanes and (E)-α-arylthiovinyl-
stannanes with aliphatic acyl chlorides was also unsuccess-
ful.
2
2
1
Investigation of the crude products 4 by H NMR spectros-
copy (400 MHz) showed their isomeric purities to be more
than 98%. One olefinic proton signal of compounds 4a–c splits
characteristically into one quartet at δ = 6.37–6.60 with cou-
pling constant J = 6.8–7.2 Hz and one olefinic proton signal of
compounds 4d–l splits characteristically into one triplet at
δ = 6.35–6.46 with coupling constant J = 6.0–7.6 Hz, which
indicated that the hydrostannylation to the alkylarylacetylenes
had taken place with strong preference for the addition of
the tin atom at the carbon adjacent to the aryl group. It is
well documented that the Stille cross-coupling reaction of
Palladium-catalysed hydrostannylation of alkynes provides
1
4,15
a simple, general route for the synthesis of vinylstannanes.
16
Alami et al. reported that the palladium- catalysed hydrostan-
nylation of alkylarylacetylenes with Bu SnH in THF at room
3
Scheme 1
*
Correspondent. E-mail: caimzhong@163.com

5
60 JOURNAL OF CHEMICAL RESEARCH 2010
1
3
vinylstannanes with organic halides in the presence of a palla-
(m, 8H), 6.58 (q, J = 7.2 Hz, 1H), 1.87 (d, J = 7.2 Hz, 3H); C NMR
1
7–19
(100 MHz, CDCl ): δ 197.20, 142.92, 139.58, 138.48, 135.82, 131.89,
29.61, 128.26, 128.14, 127.49, 15.56; MS (EI, 70 eV): m/z 222 (M ,
0), 115 (26), 105 (100), 77 (45). Anal. Calcd for C H O: C, 86.45;
H, 6.35. Found: C, 86.19; H, 6.21%.
E)-1-(4-Chlorobenzoyl)-1-phenylprop-1-ene (4b): Oil. IR (neat):
dium catalyst occurs with retention of configuration.
In
3
+
1
addition, the (E)-configuration of the compound 4i was con-
4
1
16 14
firmed by the NOESY in the H NMR spectrum. An enhance-
ment of the allylic protons was observed as the vinylic proton
(
(
δ = 6.35) of 4i was irradiated. There was no correlation
between the vinylic proton (δ = 6.35) and aromatic protons
δ = 7.38–7.34). Correlation between the allylic protons and
−1
ν (cm ) 3057, 2927, 2855, 1651, 1587, 1494, 1442, 1399, 1266, 1092,
703; H NMR (400 MHz, CDCl ): δ 7.71–7.68 (m, 2H), 7.41–7.22 (m,
7H), 6.60 (q, J = 7.2 Hz, 1H), 1.89 (d, J = 7.2 Hz, 3H); C NMR
(100 MHz, CDCl ): δ 195.97, 142.56, 139.94, 138.27, 136.60, 135.48,
31.04, 129.54, 128.46, 128.35, 127.64, 15.66; MS (EI, 70 eV): m/z
1
3
13
(
aromatic protons (δ = 7.38–7.34) was observed. The NOE
results indicate that compound 4i has the expected (E)-
configuration and the palladium-catalysed cross-coupling
reaction of (E)-α-arylvinylstannanes 2 with acyl chlorides
occurs with retention of the configuration of the starting
intermediates 2.
3
1
2
+
37
+ 35
58 (M , Cl, 10), 256 (M , Cl, 31), 221 (29), 139 (100), 105 (46).
Anal. Calcd for C H OCl: C, 74.85; H, 5.10. Found: C, 74.62; H,
.23%.
E)-1-(4-Nitrobenzoyl)-1-phenylprop-1-ene (4c): Oil. IR (neat): ν
cm ) 3058, 2957, 2855, 1593, 1518, 1495, 1463, 1346, 850, 702; H
16
13
5
(
−1
1
(
In summary, we have developed an efficient and stereose-
lective one-pot method for the synthesis of (E)-α,β-unsaturated
ketones by the tandem hydrostannylation-Stille coupling reac-
tion of alkylarylacetylenes with acyl chlorides. The present
method has the advantages of readily available starting
materials, straightforward and simple procedures, mild reac-
tion conditions and good yields. The procedure should find
wide application to the synthesis of a large array of naturally
occurring substances having the (E)-α,β-unsaturated ketone
system.
NMR (400 MHz, CDCl ): δ 8.11–8.09 (m, 2H), 7.43–7.32 (m, 5H),
3
7
.16–7.13 (m, 2H), 6.37 (q, J = 6.8 Hz, 1H), 1.81 (d, J = 6.8 Hz, 3H);
1
3
C NMR (100 MHz, CDCl ): δ 194.21, 149.25, 141.09, 138.58,
3
130.98, 129.88, 128.56, 128.42, 127.64, 127.52, 123.47, 15.98; MS
+
+
(EI, 70 eV): m/z 269 (M +2, 100), 267 (M , 76), 177 (19), 155 (22), 57
(
19). Anal. Calcd for C H NO : C, 71.90; H, 4.90; N, 5.24. Found: C,
16 13 3
7
1.65; H, 4.71; N, 5.01%.
E)-1-Benzoyl-1-phenylhex-1-ene (4d): Oil. IR (neat): ν (cm )
−
1
(
1
3
057, 2926, 2857, 1657, 1597, 1494, 1445, 1268, 699; H NMR
(
(
(
400 MHz, CDCl ): δ 7.78–7.75 (m, 2H), 7.51–7.24 (m, 8H), 6.46
3
t, J = 7.6 Hz, 1H), 2.28–2.22 (m, 2H), 1.45–1.40 (m, 2H), 1.33–1.25
13
m, 2H), 0.85 (t, J = 7.2 Hz, 3H); C NMR (100 MHz, CDCl ):
3
Experimental
δ 197.35, 145.30, 141.63, 138.51, 136.13, 131.90, 129.65, 129.54,
1
128.22, 128.14, 127.45, 31.26, 29.36, 22.45, 13.85; MS (EI, 70 eV):
H NMR spectra were recorded on a Bruker AC-P400 (400 MHz)
+
m/z 264 (M , 26), 105 (100), 77 (65). Anal. Calcd for C H O: C,
spectrometer with TMS as an internal standard using CDCl as the
19 20
3
13
86.32; H, 7.63. Found: C, 86.54; H, 7.49%.
solvent. C NMR (100 MHz) spectra were also recorded on this
(
E)-1-(4-Methylbenzoyl)-1-phenylhex-1-ene (4e): Oil. IR (neat):
model of spectrometer using CDCl as the solvent. IR spectra were
3
−
1
ν (cm ) 3027, 2957, 2926, 1655, 1606, 1494, 1443, 1269, 1177, 769,
701; H NMR (400 MHz, CDCl
7.20 (m, 7H), 6.41 (t, J = 7.6 Hz, 1H), 2.39 (s, 3H), 2.28–2.22 (m,
2H), 1.45–1.25 (m, 4H), 0.85 (t, J = 7.2 Hz, 3H); C NMR (100 MHz,
CDCl ): δ 197.05, 144.03, 142.67, 141.64, 136.35, 135.70, 129.92,
determined on an FTS-185 instrument as neat films. Mass spectra
were obtained on a Finnigan 8239 mass spectrometer. Microanalyses
were carried out using a Yanaco MT-3 CHN microelemental analyser.
All reactions were carried out in pre-dried glassware (150 °C, 4 h) and
cooled under a stream of dry Ar. THF and benzene were freshly dis-
tilled from sodium-benzophenone prior to use. Alkylarylacetylenes
1
): δ 7.69 (d, J = 8.4 Hz, 2H), 7.39–
3
13
3
129.51, 128.85, 128.19, 127.37, 31.33, 29.24, 22.44, 21.59, 13.85;
23
+
were prepared according to the literature procedure.
MS (EI, 70 eV): m/z 278 (M , 21), 263 (48), 249 (35), 235 (61), 119
(
8
64), 91 (100). Anal. Calcd for C H O: C, 86.29; H, 7.97. Found: C,
20 22
Synthesis of (E)-α,β-unsaturated ketones (4a–l)
A 25 mL, two-necked, round-bottom flask equipped with a magnetic
stir bar and argon was charged sequentially with alkylarylacetylene
5.96; H, 7.78%.
E)-1-(4-Methoxybenzoyl)-1-phenylhex-1-ene (4f): Oil. IR (neat):
(
−1
ν (cm ) 3058, 3021, 2957, 2928, 1651, 1599, 1508, 1255, 1168,
1029, 843, 702; H NMR (400 MHz, CDCl ): δ 7.82–7.80 (m, 2H),
7
(
(
1.0 mmol), THF (2 mL), PdCl (PPh ) (0.03 mmol) and Bu SnH
1.1 mmol) under argon. The mixture was stirred at 25 °C for 30 min,
1
2
3
2
3
3
.37–7.33 (m, 2H), 7.30–7.24 (m, 3H), 6.90-6.87 (m, 2H), 6.35
then the solvent was removed under reduced pressure and the residue
was dissolved in benzene (2 mL). The acyl chloride (1.1 mmol) and
CuI (0.75 mmol) were added and the mixture was stirred for 10 h
(
t, J = 7.6 Hz, 1H), 3.82 (s, 3H), 2.29–2.22 (m, 2H), 1.46–1.25 (m,
13
4
1
1
H), 0.86 (t, J = 7.2 Hz, 3H); C NMR (100 MHz, CDCl ): δ 196.08,
3
62.93, 142.44, 141.52, 136.53, 132.17, 130.82, 129.43, 128.22,
at 80 °C and monitored by TLC (SiO ) for the disappearance of the
2
27.37, 113.45, 55.41, 31.41, 29.12, 22.46, 13.87; MS (EI, 70 eV):
intermediate 2. The reaction mixture was diluted with diethyl ether
+
m/z 294 (M , 66), 251 (30), 212 (26), 135 (100), 77 (37). Anal. Calcd
for C H O : C, 81.60; H, 7.53. Found: C, 81.32; H, 7.33%.
(
3
30 mL), filtered and then treated with 20% aqueous KF (10 mL) for
0 min before being dried and concentrated. The residue was purified
2
0
22
2
−
1
(
E)-1-Benzoyl-1-phenyloct-1-ene (4g): Oil. IR (neat): ν (cm )
1
by column chromatography on silica gel, eluting with a mixture of
ethyl acetate and light petroleum.
3
057, 3025, 2926, 2856, 1658, 1597, 1494, 1446, 1275, 760, 699; H
NMR (400 MHz, CDCl ): δ 7.78–7.76 (m, 2H), 7.54–7.24 (m, 8H),
.46 (t, J = 7.6 Hz, 1H), 2.27–2.21 (m, 2H), 1.46–1.40 (m, 2H), 1.30–
−1
3
(
E)-1-Benzoyl-1-phenylprop-1-ene (4a): Oil. IR (neat): ν (cm )
6
3
027, 2957, 2857, 1651, 1606, 1494, 1443, 1270, 1178, 769, 701;
H NMR (400 MHz, CDCl ): δ 7.75 (d, J = 8.4 Hz, 2H), 7.51–7.24
13
1
1.18 (m, 6H), 0.87 (t, J = 7.2 Hz, 3H); C NMR (100 MHz, CDCl
δ 197.36, 145.37, 141.61, 138.52, 136.14, 131.90, 129.66, 129.55,
28.21, 128.14, 127.45, 31.54, 29.63, 29.07, 29.00, 22.51, 14.02; MS
3
):
3
1
+
(
EI, 70 eV): m/z 292 (M , 19), 105 (100), 77 (47). Anal. Calcd for
Table 1 Synthesis of (E)-α,β-unsaturated ketones (4a–l)
C H O: C, 86.26; H, 8.27. Found: C, 86.03; H, 8.39%.
21
24
R1
Product Yield /%
a
Entry R
Ar
(E)-1-(4-Methylbenzoyl)-1-phenyloct-1-ene (4h): Oil. IR (neat):
1
−
ν (cm ) 3027, 2927, 2856, 1655, 1606, 1494, 1443, 1273, 1176, 701;
1
2
3
4
5
6
7
8
9
Me
Ph
Ph
4a
4b
4c
4d
4e
4f
4g
4h
4i
71
78
81
76
70
75
73
70
74
68
75
80
1
H NMR (400 MHz, CDCl ): δ 7.70 (d, J = 8.4 Hz, 2H), 7.36–7.18
Me
Me
n-C
n-C
n-C
n-C
n-C
n-C
Ph
4-ClC
6
H
4
3
(
m, 7H), 6.41 (t, J = 7.6 Hz, 1H), 2.38 (s, 3H), 2.27–2.21 (m, 2H),
Ph
4-O
Ph
4-MeC
4-MeOC
Ph
4-MeC
4-MeOC
Ph
4-MeC
4-O NC
2 6 4
NC H
13
1
.47–1.38 (m, 2H), 1.29–1.16 (m, 6H), 0.85 (t, J = 7.2 Hz, 3H); C
4
4
4
6
6
6
H
H
H
H
H
H
9
Ph
9
Ph
6
H
4
NMR (100 MHz, CDCl ): δ 197.05, 144.07, 142.69, 141.65, 136.39,
135.72, 129.95, 129.52, 128.87, 128.20, 127.39, 31.57, 29.53, 29.15,
29.02, 22.54, 21.59, 14.04; MS (EI, 70 eV): m/z 306 (M , 41), 235
(32), 210 (73), 119 (100), 91 (86). Anal. Calcd for C H O: C, 86.23;
H, 8.55. Found: C, 86.41; H, 8.37%.
E)-1-(4-Methoxybenzoyl)-1-phenyloct-1-ene (4i): Oil. IR (neat):
ν (cm ) 3056, 2927, 2856, 1649, 1600, 1508, 1495, 1464, 1256, 1168,
3
9
Ph
6
H
4
+
13
13
13
Ph
Ph
6
H
4
22
26
Ph
6
H
4
1
0
1
2
MeOCH
MeOCH
MeOCH
2
2
2
2-MeOC
2-MeOC
2-MeOC
6
H
6
H
6
H
4
4
4
4j
4k
4l
(
1
1
6
H
4
−1
2
6
H
4
1
1
029, 844, 702; H NMR (400 MHz, CDCl ): δ 7.82–7.79 (m, 2H),
3
a
Isolated yield based on alkylarylacetylene 1 used.
7.38–7.34 (m, 2H), 7.31–7.25 (m, 3H), 6.90–6.87 (m, 2H), 6.35

JOURNAL OF CHEMICAL RESEARCH 2010 561
(
(
t, J = 7.6 Hz, 1H), 3.84 (s, 3H), 2.28–2.22 (m, 2H), 1.47–1.20
We thank the National Natural Science Foundation of China
(Project No. 20862008) and the Natural Science Foundation
of Jiangxi Province of China (2008GQH0034) for financial
support.
13
m, 8H), 0.86 (t, J = 7.2 Hz, 3H); C NMR (100 MHz, CDCl ):
3
δ 196.08, 162.91, 142.50, 141.48, 136.53, 132.17, 130.84, 129.42,
1
1
28.21, 127.35, 113.43, 55.41, 31.57, 29.39, 29.21, 29.01, 22.53,
+
4.03; MS (EI, 70 eV): m/z 322 (M , 16), 212 (67), 135 (100), 77 (36).
Anal. Calcd for C H O : C, 81.95; H, 8.13. Found: C, 81.71; H,
22
26
2
Received 29 July 2010; accepted 7 August 2010
Paper 1000273 doi: 10.3184/030823410X12861973220846
Published online: 22 October 2010
7
.95%.
E)-1-Benzoyl-1-(2-methoxyphenyl)-3-methoxyprop-1-ene (4j): Oil.
(
−1
IR (neat): ν (cm ) 3058, 2930, 1661, 1599, 1490, 1450, 1247, 1123,
1
1
7
025, 757; H NMR (400 MHz, CDCl ): δ 7.83 (d, J = 7.2 Hz, 2H),
.50–7.31 (m, 4H), 7.19–6.95 (m, 3H), 6.46 (t, J = 6.0 Hz, 1H), 4.12
3
References
13
(
d, J = 6.0 Hz, 2H), 3.66 (s, 3H), 3.33 (s, 3H); C NMR (100 MHz,
1
E.J. Corey, W. Li and T. Nagamitsu, Angew. Chem. Int. Ed., 1998, 37,
1676.
CDCl ): δ 197.13, 156.62, 140.18, 139.20, 137.97, 131.08, 130.16,
3
1
29.92, 129.67, 128.05, 124.86, 120.51, 111.00, 69.77, 58.52, 55.40;
+
2
3
J.S. Panek and C.E. Masse, Angew. Chem. Int. Ed., 1999, 38, 1093.
S.K. Kumar, E. Hager, C. Pettit, N. Gurulinappa, N.E. Davidson and S.R.
Khan, J. Med. Chem., 2003, 46, 2813.
MS (EI, 70 eV): m/z 282 (M , 37), 252 (38), 178 (55), 91 (100), 77
(
68). Anal. Calcd for C H O : C, 76.57; H, 6.43. Found: C, 76.30; H,
18 18 3
4
5
A.T. Nielsen and W. Houlihan, Org. React., 1968, 16, 15.
B.D. Chong,Y.I. Ji, S.S. Oh, J.D.Yang, W. Baik and S. Koo, J. Org. Chem.,
6
.18%.
E)-1-(2-Methoxyphenyl)-1-(4-methylbenzoyl)-3-methoxyprop-1-ene
(
1
997, 62, 9323.
−
1
(
4k): Oil. IR (neat): ν (cm ) 3058, 2926, 1657, 1606, 1490, 1463,
6
7
U.P. Kreher, A.E. Rosamilia, C.L. Raston, J.L. Scott and C.R. Strauss, Org.
Lett., 2003, 5, 3107.
C.D. Nenitzescu and A.T. Balaban, Friedel-Crafts and related reactions,
G.A. Olah, ed.; Interscience: New York, NY, 1964, Vol. 3; p. 1033.
K. Lee and D.Y. Oh, Synthesis, 1991, 213.
1
1
246, 1123, 911, 735; H NMR (400 MHz, CDCl ): δ 7.75 (d,
3
J = 8.0 Hz, 2H), 7.33–7.16 (m, 4H), 7.00–6.96 (m, 1H), 6.85 (d,
J = 8.0 Hz, 1H), 6.42 (t, J = 6.0 Hz, 1H), 4.10 (d, J = 6.0 Hz, 2H),
13
3
.64 (s, 3H), 3.31 (s, 3H), 2.38 (s, 3H); C NMR (100 MHz, CDCl ):
8
9
3
N. Momiyama, M.W. Kanan and D.R. Liu, J. Am. Chem. Soc., 2007, 129,
δ 197.56, 156.62, 142.68, 140.25, 138.45, 135.24, 131.10, 129.93,
29.86, 128.74, 125.07, 120.48, 111.00, 69.82, 58.50, 55.35, 21.63;
2
230.
10 G.H. Posner, Chem. Rev., 1986, 86, 831.
L.F. Tietze and U. Beifuss, Angew. Chem. Int. Ed., 1993, 32, 131.
12 L.F. Tietze, Chem. Rev., 1996, 96, 115.
X. Huang and M. Xia, Org. Lett., 2002, 4, 1331.
1
+
MS (EI, 70 eV): m/z 296 (M , 100), 282 (20), 147 (51), 91 (82). Anal.
Calcd for C H O : C, 77.00; H, 6.80. Found: C, 76.71; H, 6.65%.
1
1
19
20
3
(
E)-1-(2-Methoxyphenyl)-1-(4-nitrobenzoyl)-3-methoxyprop-1-ene
1
3
−
1
(
4l): Oil. IR (neat): ν (cm ) 2925, 1598, 1515, 1490, 1342, 1243,
109, 850, 753; H NMR (400 MHz, CDCl ): δ 8.11 (d, J = 9.2 Hz,
H), 7.41–7.37 (m, 3H), 7.11–6.95 (m, 3H), 6.43 (t, J = 6.4 Hz, 1H),
.93 (d, J = 6.4 Hz, 2H), 3.67 (s, 3H), 3.31 (s, 3H); C NMR
14 B.M. Trost and C.J. Li, Synthesis, 1994, 1267.
15 N.D. Smith, J. Mancuso and M. Lautens, Chem. Rev., 2000, 100, 3257.
1
1
2
3
3
1
6
F. Liron, P.L. Garrec and M. Alami, Synlett, 1999, 246.
13
17 J.K. Stille, Angew. Chem. Int. Ed., 1986, 25, 508.
18
19
20
21
T.N. Mitchell, J. Organomet. Chem., 1986, 304, 1.
(
100 MHz, CDCl ): δ 197.68, 156.88, 147.79, 146.78, 138.93, 131.11,
3
J.W. Labadie and J.K. Stille, J. Am. Chem. Soc., 1983, 105, 669.
Y. Ma, B. Li and X. Huang, J. Organomet. Chem., 1999, 590, 234.
S. You, Y. Li and M. Cai, Tetrahedron, 2009, 65, 6863.
1
5
30.33, 127.15, 127.07, 126.35, 123.53, 120.73, 111.23, 70.39, 58.32,
5.49; MS (EI, 70 eV): m/z 328 (M +1, 34), 147 (48), 73 (100). Anal.
+
Calcd for C H NO : C, 66.05; H, 5.23; N, 4.28. Found: C, 65.77; H,
22 F. Yao, S. You and M. Cai, Heteroatom Chem., 2009, 20, 218.
18
17
5
5
.38; N, 3.99%.
23 M. Alami, F. Ferri and G. Linstrumelle, Tetrahedron Lett., 1993, 34, 6403.

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