Dimerization-carbostannylation of alkynes catalyzed by a palladium-diimine complex: Regioselectivity, stereoselectivity and mechanism

Article abstract of DOI:10.1246/bcsj.74.637

Double insertion of alkynes into the C-Sn bond of an alkynyl-, alkenyl-, allyl- or arylstannane proceeded in the presence of a palladium-diimine complex to afford highly conjugated alkenylstannanes with exclusive syn selectivity. Perfect regioselectivities were observed in the dimerization-carbostannylation of ethyl propiolate with a palladium-1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene complex, which allowed regio- and stereoselective synthesis of stannyl-substituted muconic acid derivatives. The π-conjugation of the dimerization-carbostannylation products was further extended through a cross-coupling or homocoupling reaction. A palladacyclopentadiene is proposed as an intermediate species.

Full text of DOI:10.1246/bcsj.74.637

c. Jpn.
© 2001 The Chemical Society of Japan
Bull. Chem. Soc. Jpn., 74, 637—647 (2001)
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Headline Articles
Dimerization–Carbostannylation of Alkynes Catalyzed by a Palladium–
Diimine Complex: Regioselectivity, Stereoselectivity and Mechanism
01
7
7
SJA8
09-2673
00378
vember
H. Yoshida et al.
Hiroto Yoshida, Eiji Shirakawa,*,† Yoshiaki Nakao, Yuki Honda, and Tamejiro Hiyama*
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501
00
†Graduate School of Materials Science, Japan Advanced Institute of Science and Technology, Asahidai, Tatsunokuchi,
Ishikawa 923-1292
00
.1
(Received November 1, 2000)
Double insertion of alkynes into the C–Sn bond of an alkynyl-, alkenyl-, allyl- or arylstannane proceeded in the
presence of a palladium–diimine complex to afford highly conjugated alkenylstannanes with exclusive syn selectivity.
Perfect regioselectivities were observed in the dimerization–carbostannylation of ethyl propiolate with a palladium–1,2-
bis[(2,6-diisopropylphenyl)imino]acenaphthene complex, which allowed regio- and stereoselective synthesis of stannyl-
substituted muconic acid derivatives. The π-conjugation of the dimerization–carbostannylation products was further ex-
tended through a cross-coupling or homocoupling reaction. A palladacyclopentadiene is proposed as an intermediate
species.
Carbostannylation of alkynes has become a powerful syn-
thetic tool owing to the novel synthetic transformation: C–C
and C–Sn bonds are simultaneously introduced across a triple
bond of alkynes in a syn-manner to give alkenylstannanes,
which can be converted into variously substituted ethenes with
retention of configuration through the Migita–Kosugi–Stille
coupling reaction.1 Furthermore, high chemoselectivity and
mild reactivity of organostannanes as compared with other or-
ganometallic reagents make the carbostannylation and subse-
quent reactions extremely useful and applicable to a wide vari-
ety of substrates. Although allylstannylation of alkynes, in
Scheme 1.
tion of alkynes.
Pd–iminophosphine-catalyzed alkynylstannyla-
particular, has been shown to be mediated by a Lewis acid,2
radical initiator,3 nickel complex4 or palladium complex,5 alky-
nylstannanes and acylstannanes also are demonstrated to par-
ticipate in the carbostannylation of alkynes in the presence of a
nickel4 or palladium6 catalyst.7,8,9,10
In the palladium-catalyzed alkynylstannylation of alkynes,
the nature of a ligand influences significantly the catalytic ac-
tivity. Thus, a palladium complex coordinated by N-(2-di-
phenylphosphinobenzylidene)phenylethylamine (1) efficiently
catalyzes the reaction (Scheme 1), whereas such phosphorus
ligands as triphenylphosphine and 1,3-bis(diphenylphosphi-
no)propane were ineffective, suggesting that the imino moiety
of 1 plays an important role in the catalysis.6 Since then we di-
rected our research to the improvement of the efficiency of the
palladium-catalyzed carbostannylation, and found that a
dimerization–carbostannylation reaction of alkynes was trig-
gered by a palladium complex consisting of a rigid diimine
ligand, i.e., 1,2-bis(arylimino)acenaphthene (2).
We describe herein the scope and limitations of the palladi-
um-catalyzed dimerization–carbostannylation of alkynes,
demonstrating that the novel catalytic process provides a con-
venient method to produce a variety of highly π-conjugated
alkenylstannanes with three to six covalent bonds being gener-
ated in one pot.11
Results and Discussion
Reaction Conditions for Dimerization–Carbostannyla-
tion. First we investigated the reaction of ethyl propiolate
(3a) with tributyl(phenylethynyl)tin (4a) in toluene at 25 ˚C for
1 h using a palladium–1,2-bis(phenylimino)acenaphthene (2a)
complex to observe that diethyl (2E,4Z)-2-(phenylethynyl)-5-
(tributylstannyl)-2,4-hexadienedioate (5a) was produced as the
sole product in 89% conversion (Scheme 2, entry 1 of Table 1).

638 Bull. Chem. Soc. Jpn., 74, No. 4 (2001)
HEADLINE ARTICLES
Table 1.
Palladium-Catalyzed Dimerization–Carbostannylation of Ethyl Propiolate (3a)
with Tributyl(phenylethynyl)tin (4a)a)
Ligand
(Ar in 2)
Conversion
b)
Entry
Solvent
Product(s)
%
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Ph
Ph
Ph
Ph
Ph
Ph
Ph
(2a)
(2a)
(2a)
(2a)
(2a)
(2a)
(2a)
(2b)
toluene
THF
dioxane
CHCl3
DME
89
71
70
70
64
53
< 5
80
49
68
89
< 5
31
84
20
5a
5a
5a
5a
5a
5a
5a
5a
5a
5a
5a
5a
DMF
octane
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
4-CF3C6H4
3,5-(CF3)2C6H3 (2c)
4-MeOC6H4
4-MeC6H4
2,6-(i-Pr)2C6H3 (2f)
(2d)
(2e)
—
—
(2g)
(1)
5a, 6ac)
6ad)
6ae)
none
a) The reaction was carried out in a solvent (3mL) at 25 ˚C using 3a (1.0 mmol) and 4a
(0.34 mmol) for 1 h in the presence of [Pd2Cl2(η3-C3H5)2] (8.2 µmol) and a ligand (16
µmol). b) Determined by 119Sn NMR. c) 5a/6a ꢀ 54/46. d) The regioisomer of 6a was
also detected (6a/isomer ꢀ 4/1). e) Regioisomer was not detected.
Scheme 3.
Dimerization–carbostannylation of alkynes cat-
alyzed by Pd–2a.
Only 1:1 carbostannylation product 6a was obtained with the
palladium–1 catalyst, as we disclosed before (entry 14).6 The
reaction without any ligand was extremely sluggish (entry 15).
Dimerization–Carbostannylation Catalyzed by Pd–2a.
We next examined the dimerization–carbostannylation of vari-
ous organostannanes and alkynes using the Pd–2a catalyst
(Scheme 3, Table 2). As mentioned above, the reaction of 3a
with 4a proceeded smoothly to afford 5a in 77% yield in a pe-
riod of 40 min (entry 1). Tributyl(1-hexynyl)tin (4b) and tribu-
tyl(trimethylsilylethynyl)tin (4c) also reacted effectively with
3a with perfect regioselectivities (entries 2 and 3). Alkenyl-
stannanes 4d, 4e and 4f were more reactive towards 3a than
alkynylstannanes and gave rise to the corresponding conjugat-
Scheme 2.
complexes.
Reaction of 3a with 4a in the presence of Pd–2
The product formation is ascribed to addition of the C–Sn
bond in 4a to 3a accompanied by dimerization of the alkyne.
Results of the reaction of 3a with 4a using other solvents and
ligands are summarized in Table 1. In a polar solvent such as
THF, dioxane, DME or DMF, the reaction using the Pd–2a cat-
alyst was slow (entries 2–6); in octane, the reaction did not
proceed at all, probably due to low solubility of the catalyst
(entry 7). Diimines having an electron-withdrawing or -donat-
ing substituent on Ar did not accelerate the reaction (entries 8–
11). Bulky diimine 2f was totally ineffective (entry 12). Palla-
dium complex with acyclic diimine ligand 2g gave a mixture
of the 2:1 and 1:1 carbostannylation products (entry 13).
′
ed (stannyl)trienes consisting of two regioisomers 5 and 5 (en-
tries 4–6). The reaction of heteroarylstannanes such as tribu-
tyl(2-furyl)tin (4g) and tributyl(2-thienyl)tin (4h) with 3a also
′
proceeded; yields of regioisomer 5 predominated over those
′′
of 5 and 5 (entries 7 and 8). In all cases, the addition of orga-
nostannanes to 3a occurred with exclusive syn selectivity (vide
infra). The reaction was also applicable to dimethyl acetylene-
dicarboxylate (3b), giving 5i–5q12 in a stereoselective manner

H. Yoshida et al.
Bull. Chem. Soc. Jpn., 74, No. 4 (2001) 639
Dimerization–Carbostannylation of Alkynes Catalyzed by Palladium–Diimine 2aa)
Table 2.
Temp
Time
Yield
Ratio
b)
′′c)
Entry
Alkyne
R
Product(s)
′
˚C
50
30
20
50
50
50
50
50
70
90
90
50
50
50
50
50
50
h
0.7
3
0.5
0.7
1
%
5:5 :5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
3a
PhC≡C
BuC≡C
(4a)
(4b)
(4c)
(4d)
(4e)
(4f)
(4g)
(4h)
(4a)
(4b)
(4c)
(4d)
(4e)
(4f)
(4g)
(4i)
77
93
75
72
78
76
81
42
77
32
52
76
75
75
63
75
86
5a
5b
5c
′
5d, 5 d
′
5e, 5 e
100:0:0
100:0:0
100:0:0
79:21:0
89:11:0
71:29:0
30:63:7
13:69:18
—
TMSC≡C
CH2ꢀCH
(E)-PhCHꢀCH
(E)-HexCHꢀCH
2-furyl
′
5f, 5 f
5g, 5 g, 5 g
1
′
′′
14
12
2
19
2
2
1
8
′
′′
2-thienyl
5h, 5 h, 5 h
3b
PhC≡C
5i
5j
5k
5l
5m
5n
5o
5p
5qd)
BuC≡C
—
—
—
—
—
—
—
—
TMSC≡C
CH2ꢀCH
(E)-PhCHꢀCH
(E)-HexCHꢀCH
2-furyl
2-benzofuryl
(E)-PhCHꢀCHCH2
19
26
1
(4j)
a) The reaction was carried out in toluene (3mL) at 50 ˚C using an alkyne (1.0 mmol) and an organostannane (0.34
mmol) in the presence of [Pd2Cl2(η3-C3H5)2] (8.2 µmol) and 2a (16 µmol). b) Isolated yield based on the organostan-
nane is given. c) Determined by 119Sn NMR. d) A 1:1 carbostannylation product (6b) was also obtained in 4% yield.
(1)
Scheme 4. Dimerization–carbostannylation of arylstan-
nanes.
High regioselectivity observed in the reaction of 4n with 3a
compared with alkenylstannanes 4d–4f can be attributed to the
low reactivity of 4n, as discussed later.
(entries 9–16). Tributyl[(E)-cinnamyl]tin (4j) can participate
in the dimerization–carbostannylation with 3b (entry 17). Es-
ter substituent on acetylene seems to be essential for successful
reaction: neither phenylacetylene, 1-octyne, nor 1-butyn-3-one
gave the corresponding carbostannylation product.
Regioselective Synthesis of Stannyl-Substituted Muconic
Acid Derivatives. Although palladium complex coordinat-
ed by bulky diimine ligand, 1,2-bis[(2,6-diisopropylphe-
nyl)imino]acenaphthene (2f), did not catalyze the reaction of
3a with 4a at 25 ˚C as stated above, this complex was found to
promote the reaction at 50 ˚C, giving a single isomer regard-
less of organostannanes employed (Scheme 5).
In contrast to five-membered heteroarylstannanes, tribu-
tyl(phenyl)tin (4k) gave a dimerization–carbostannylation
product with 3a only in 17% conversion after 48 h, and tribu-
tyl(2-pyridyl)tin (4l) was totally unreactive (Scheme 4). Such
an electron-donating group as methoxy on the phenyl in 4k as-
sisted the reaction: with 4m, conversion increased to 43%.
Thus the reactivity scale of arylstannanes is 2-furyl (4g) ꢀ 4-
MeOC6H4 (4m) > Ph (4k) > 2-pyridyl (4l), indicating that
electron-richer arylstannanes are more subject to the reaction.
Application of the dimerization–carbostannylation to an or-
ganostannane containing two C–Sn bonds provided highly
conjugated polyenylstannanes: the reaction of (E)-1,2-
bis(tributylstannyl)ethene (4n) with alkynes 3a and 3b afford-
ed α,ω-distannyldecapentaenes 7a and 7b, respectively, form-
ing six new covalent bonds all in one pot (Eq.1).
Scheme 5.
tion.
Pd–2f-catalyzed dimerization–carbostannyla-

640 Bull. Chem. Soc. Jpn., 74, No. 4 (2001)
HEADLINE ARTICLES
Table 3.
Pd–2f-Catalyzed Dimerization–Carbostannylation of Ethyl Propiolate (3a)a)
Time
Yield
b)
Entry
R
R′
Product
h
%
1
2
3
4
5
6
7
CH2ꢀCH
2-furyl
2-thienyl
2-benzofuryl
3-thienyl
Ph
Bu
Bu
Bu
Bu
Bu
Me
(4d)
(4g)
(4h)
(4i)
1
72
78
68
79
80
42
64
5d
5g
5h
5r
5s
5t
13
22
23
21
27
19
(4o)
′
(4 k)
′
4-MeOC6H4
Me (4 m)
5u
a) The reaction was carried out in toluene (3mL) at 50 ˚C using 3a (1.0 mmol) and an
organostannane (0.34 mmol) in the presence of [Pd2Cl2(η3-C3H5)2] (8.2 µmol) and 2f
(16 µmol). b) Isolated yield based on the organostannane is given.
The dimerization–carbostannylation of 3a in the presence of
neither trimerization–carbostannylation products nor higher
oligomers were produced. Consequently, the present reaction
should be initiated not by oxidative addition of a C–Sn bond of
an organostannane to a Pd(0)–diimine complex,6 but by forma-
tion of palladacyclopentadiene (8 or 9) from a Pd(0)–diimine
complex and 2 mol of an alkyne.14 In order to confirm that the
palladacyclopentadiene would be involved in the dimeriza-
tion–carbostannylation, we monitored the reaction by 1H
NMR, choosing 2e as a ligand, because the methyl substituent
gave distinct information. 1H NMR spectra of the reaction of
3b with 4d showed no other peaks than those of palladacycle
8a in addition to those of the substrate and the expected prod-
uct (Fig. 2). Furthermore, palladacycle 8b was prepared from
Pd(0)–2a and allowed to react with three equimolar amounts
of 4d to give carbostannylation product 5l in a good yield, and
8b was shown to be an equally active catalyst (Scheme 6). All
these observations suggest that the catalytic cycle should be
initiated by formation of the palladacyclopentadiene interme-
diate, followed by reaction with an organostannane, although
subsequent steps of the catalytic cycle remain yet to be stud-
ied.
Pd–2f offers a straightforward method to synthesize variously
substituted trans,trans-muconic acid derivatives. The results
are summarized in Table 3. Tributyl(vinyl)tin (4d) smoothly
reacted to afford 5d as the sole product in 72% yield (entry 1).
It is noteworthy that the Pd–2f catalyst allowed a variety of
five-membered heteroarylstannanes to give 5 exclusively (en-
tries 2–5), whereas with the Pd–2a catalyst and the heteroaryl-
′
stannanes the reactions gave 5 as major products (entries 7
and 8 of Table 2). Phenyl- and p-methoxyphenylstannanes
could participate in the reaction, when –SnBu3 in 4k and 4m
was replaced by –SnMe3, affording desired products 5t and 5u
in moderate yields (entries 6 and 7).
Structure Determination of Dimerization–Carbostanny-
lation Products. Configuration of 5a–5h and 5r–5u was de-
termined based on coupling constants in NMR.13 Products
′
′
′′
′′
5 d–5 h, 5 g and 5 h were confirmed to be regioisomers of
5d–5h, respectively, by the corresponding coupling constants
between olefinic protons as well as between tin and olefinic
proton and/or by NOE experiments. Typical examples of 5a,
′
′′
5 h and 5 h are shown in Fig. 1.
Catalytic Cycle. In the course of the present study, no
trace of a 1:1 carbostannylation product was observed except
for the case of tributyl[(E)-cinnamyl]tin (4j).5,6 Furthermore,
The different regioselectivities observed in the reaction of
ethyl propiolate (3a) can be explained as follows (Scheme 7).
′
′′
Formation of three regioisomeric products 5, 5 and 5 upon
Fig. 1.
Structure determination of dimerization–carbostannylation products.

H. Yoshida et al.
Bull. Chem. Soc. Jpn., 74, No. 4 (2001) 641
Scheme 6.
Reactions using palladacycle 8b.
use of Pd–2a is attributed to palladacycle intermediates, 9a and
9b, which might be equilibrated with each other via a palladi-
um(0)–diimine complex, since product ratios are considerably
influenced by the structure of the organostannane despite use
of an identical catalyst system (see Table 2). Among these pal-
ladacycles, 9a should be thermodynamically stable, because
two electron-withdrawing ester groups are attached to carbons
next to the palladium atom.15 In contrast, formation of 9b
would be kinetically favored due to less steric repulsion be-
tween the aryl groups of the diimine ligand and the ester
groups of 3a. According to this mechanism, an organostan-
nane with low reactivity towards palladacycle 9 should afford
5 predominantly, because kinetically generated palladacycle
9b should isomerize to thermodynamically stable 9a prior to
reaction with the organostannane. Indeed, exclusive formation
of a dimerization–carbostannylation product via 9a (5 or 7a)
was observed using such a less reactive organostannane as
alkynylstannanes 4a–4c or (E)-1,2-bis(tributylstannyl)ethene
(4n) (entries 1–3 of Table 2 or Eq. 1), whereas the reaction of
Fig. 2. 1H NMR (200 MHz) spectrum of the reaction mix-
ture (at ca. 31% conversion) in the reaction of 3b with 4d
in the presence of [Pd2Cl2(η3-C3H5)2]–2e complex (0.2 mol
amt of Pd, Pd/2e = 1) in CDCl3 at 25 ˚C.
Scheme 7.
Plausible catalytic cycle of the dimerization–carbostannylation.

642 Bull. Chem. Soc. Jpn., 74, No. 4 (2001)
HEADLINE ARTICLES
Scheme 8.
Transformation of dimerization–carbostannylation products.
more reactive alkenylstannanes 4d–4f gave mixtures of iso-
mers (entries 4–6 of Table 2). In use of bulky diimine 2f, the
two isopropyl groups would prevent an organostannane from
coordinating to an apical position of the palladacycle as in
Scheme 7,16 leading to slow reaction of the palladacycle with
organostannanes (entry 1 vs 12 of Table 1), which resulted in
the exclusive production of 5 irrespective of the organostan-
nane used (Table 3). Although examples to support the revers-
ibility of 9 remain yet to be found,17 this catalytic cycle ratio-
nally explains the results. At present, the reason why five-
membered heteroarylstannanes 4g and 4h, which react with 3a
most slowly in the presence of Pd–2a catalyst, give three regio-
isomeric products (entries 7 and 8 of Table 2) is unclear.
Transformation of Dimerization–Carbostannylation
Products. Utility of the dimerization–carbostannylation re-
action is demonstrated by transformation to more conjugated
compounds through cross-coupling reaction (Scheme 8).
Thus, cross-coupling reaction of 5a with 4-iodonitrobenzene,
1-bromo-2-phenylethyne or 1,4-diiodobenzene in the presence
of Pd(0)/CuI18 gave 10, 11 or 12, respectively. Moreover, the
π-conjugate system in 5s could be extended by oxidative ho-
mocoupling reaction with CuCl2 to afford 13 in 46% yield. Es-
ter groups in 5s could be reduced with diisobutylaluminum hy-
dride to give stannyl-substituted allylic alcohol 14.
nylation of alkynes and to give highly conjugated (Z)-alkenyl-
stannanes stereoselectively. Furthermore, regio- and stereose-
lective dimerization–carbostannylation of ethyl propiolate has
been achieved in the presence of a palladium complex coordi-
nated by bulky diimine 2f, providing a simple and convenient
approach to stannyl-substituted muconic acid derivatives. The
π-system of the dimerization–carbostannylation products can
be further extended to highly conjugated system through cross-
or homocoupling reaction, proving that the dimerization–car-
bostannylation reaction offers a novel entry to the synthesis of
various π-conjugated molecules.
Experimental
General Remarks. All manipulations of oxygen- and mois-
ture-sensitive materials were conducted with a standard Schlenk
technique under a purified argon atmosphere (deoxygenated by
passing through a BASF-Catalyst R3-11 column at 80 ˚C). Nucle-
ar magnetic resonance spectra were taken on a JEOL EX-270 (1H,
270 MHz; 13C, 67.8 MHz; 119Sn, 101 MHz) spectrometer or a
Varian Mercury 200 (1H, 200 MHz; 13C, 50 MHz) spectrometer
using tetramethylsilane (1H) as an internal standard and tetrameth-
yltin (119Sn) as an external standard. The preparative recycling gel
permeation chromatography was performed with a JAI LC-908
chromatograph equipped with JAIGEL-1H and -2H columns
(chloroform as an eluent). High-resolution mass spectra were ob-
tained with a Bruker Bio APEX 70e spectrometer. All melting
Conclusion. The palladium–diimine complex has been
disclosed to effectively catalyze the dimerization–carbostan-

H. Yoshida et al.
Bull. Chem. Soc. Jpn., 74, No. 4 (2001) 643
points were measured with a Yanagimoto Micro Melting Point ap-
paratus without correction. Rf values were measured by TLC
analyses using Merck Kieselgel 60 F254. Unless otherwise noted,
commercially available reagents were used without purification.
Solvents were distilled from a suitable drying reagent as follows:
sodium/benzophenone ketyl for toluene, THF, dioxane, DME and
octane; diphosphorus pentaoxide for chloroform; calcium hydride
Hz, 2 H), 4.27 (q, J ꢀ 7.1 Hz, 2 H), 5.54 (dd, J ꢀ 11.5, 1.6 Hz, 1
H), 5.74 (dd, J ꢀ 17.6, 1.6 Hz, 1 H), 6.71 (dd, J ꢀ 17.6, 11.5 Hz,
1 H), 7.24 (d, J ꢀ 12.7 Hz, 1 H), 8.15 (d, J ꢀ 12.7 Hz, 1 H); 13
C
NMR (CDCl3) δ 11.8, 13.6, 14.25, 14.29, 27.2, 29.0, 60.9, 61.0,
122.7, 128.9, 134.7, 136.9, 146.6, 149.7, 166.6, 171.4; 119Sn{1H}
NMR (CDCl3) δ ꢁ44.4. Found: C, 56.01; H, 8.24%. Calcd for
C24H42O4Sn: C, 56.16; H, 8.25%.
for DMF.
N-(2-Diphenylphosphinobenzylidene)phenylethyl-
Diethyl 4-[(E)-2-Propenylidene]-2-(tributylstannyl)-(Z)-2-
amine (1),6 1,2-bis(phenylimino)acenaphthene (2a),19 1,2-bis[(4-
trifluoromethylphenyl)imino]acenaphthene (2b),19 1,2-bis{[3,5-
bis(trifluoromethyl)phenyl]imino}acenaphthene (2c),19 1,2-bis[(p-
methoxyphenyl)imino]acenaphthene (2d),19 1,2-bis[(p-tolyl)imi-
no]acenaphthene (2e),19 1,2-bis[(2,6-diisopropylphenyl)imino]-
acenaphthene (2f),19 2,3-bis(phenylimino)butane (2g),20 tributyl-
(phenylethynyl)tin (4a),21 tributyl(1-hexynyl)tin (4b),21 tributyl-
(trimethylsilylethynyl)tin (4c),21 tributyl(vinyl)tin (4d),22 tributyl-
[(E)-styryl]tin (4e),23 tributyl[(E)-1-octenyl]tin (4f),24 tributyl(2-
furyl)tin (4g),25 tributyl(2-thienyl)tin (4h),26 2-benzofuryl(tribu-
tyl)tin (4i),27 tributyl[(E)-cinnamyl]tin (4j),28 tributyl(phenyl)tin
(4k),29 tributyl(2-pyridyl)tin (4l),30 tributyl(p-methoxyphenyl)tin
(4m),31 (E)-1,2-bis(tributylstannyl)ethene (4n),32 tributyl(3-thien-
pentenedioate (5 d). A brown oil, Rf 0.32 (hexane–ethyl acetate
′
1
ꢀ 7:1). H NMR (CDCl3) δ 0.69–1.78 (m, 33 H), 4.22 (q, J ꢀ 7.1
Hz, 2 H), 4.24 (q, J ꢀ 7.1 Hz, 2 H), 5.50 (d, J ꢀ 10.1 Hz, 1 H),
5.67 (d, J ꢀ 17.6, 1 H), 6.63 (ddd, J ꢀ 17.6, 11.2, 10.1 Hz, 1 H),
7.24 (d, J ꢀ 11.2 Hz, 1 H), 7.89 (s, 1 H); 13C NMR (CDCl3) δ
11.3, 13.6, 14.3, 27.3, 29.0, 60.9, 61.0, 126.5, 130.9, 132.9, 141.0,
144.2, 148.1, 166.3, 170.6; 119Sn{1H} NMR (CDCl3) δ ꢁ47.3.
′
Found as a mixture of 5d and 5 d: C, 56.27; H, 8.22%. Calcd for
C24H42O4Sn: C, 56.16; H, 8.25%.
Diethyl 2-[(E)-Styryl]-5-(tributylstannyl)-(2E,4Z)-2,4-hexa-
dienedioate (5e). A brown oil, Rf 0.33 (hexane–ethyl acetate ꢀ
7:1). 1H NMR (CDCl3) δ 0.74–1.76 (m, 33 H), 4.23 (q, J ꢀ 7.1
Hz, 2 H), 4.32 (q, J ꢀ 7.1 Hz, 2 H), 7.15–7.60 (m, 8 H), 8.29 (d, J
ꢀ 11.9 Hz, 1 H); 13C NMR (CDCl3) δ 11.8, 13.7, 14.3, 27.2, 29.0,
60.9, 61.1, 120.5, 127.0, 128.4, 128.6, 134.3, 136.1, 136.5, 137.0,
146.5, 149.3, 166.8, 171.5; 119Sn{1H} NMR (CDCl3) δ ꢁ44.1.
Found: C, 60.87; H, 7.80%. Calcd for C30H46O4Sn: C, 61.13; H,
7.87%.
yl)tin (4o)33 and p-methoxyphenyl(trimethyl)tin (4 m)34 were pre-
′
pared according to literature procedures.
Dimerization–Carbostannylation of Alkynes. A General
Procedure. A solution of 2 (16 µmol), [Pd2Cl2(η3-C3H5)2] (3.0
mg, 8.2 µmol) and an alkyne (1.0 mmol) in toluene (3 mL) was
degassed by four freeze-thaw cycles. To this solution was added
an organostannane (0.34 mmol); each mixture was stirred at the
specified temperature for the specified period indicated in Table 2
and 3. Concentration in vacuo followed by GPC purification gave
the corresponding dimerization–carbostannylation products.
Yields are listed in Table 2 and 3.
Diethyl (2E,4Z)-2-(Phenylethynyl)-5-(tributylstannyl)-2,4-
hexadienedioate (5a). A brown oil, Rf 0.35 (hexane–ethyl ace-
tate ꢀ 7:1). 1H NMR (CDCl3) δ 0.70–1.83 (m, 33 H), 4.24 (q, J
ꢀ 7.2 Hz, 2 H), 4.32 (q, J ꢀ 7.2 Hz, 2 H), 7.15–7.74 (m, 6 H),
8.30 (d, J ꢀ 12.2 Hz, 1 H); 13C NMR (CDCl3) δ 11.9, 13.6, 14.2,
14.3, 27.2, 28.9, 61.0, 61.8, 83.4, 100.8, 121.3, 122.6, 128.4,
129.0, 131.8, 144.3, 147.8, 153.0, 164.5, 171.3; 119Sn{1H} NMR
(CDCl3) δ ꢁ42.8. Found: C, 61.60; H, 7.60%. Calcd for
C30H44O4Sn: C, 61.34; H, 7.55%.
Diethyl (2E,4Z)-2-(1-Hexynyl)-5-(tributylstannyl)-2,4-hexa-
dienedioate (5b). A brown oil, Rf 0.38 (hexane–ethyl acetate ꢀ
7:1). 1H NMR (CDCl3) δ 0.72–1.72 (m, 40 H), 2.49 (t, J ꢀ 6.9
Hz, 2 H), 4.08–4.36 (m, 4 H), 7.53 (d, J ꢀ 11.9 Hz, 1 H), 8.17 (d,
J ꢀ 11.9 Hz, 1 H); 13C NMR (CDCl3) δ 11.9, 13.59, 13.64, 14.2,
14.3, 19.6, 21.9, 27.2, 28.9, 30.5, 60.9, 61.6, 74.6, 102.8, 121.8,
143.6, 148.0, 151.8, 164.9, 171.4; 119Sn{1H} NMR (CDCl3) δ
ꢁ43.3. Found: C, 59.12; H, 8.31%. Calcd for C28H48O4Sn: C,
59.27; H, 8.53%.
Diethyl (2E,4Z)-5-(Tributylstannyl)-2-(trimethylsilylethyn-
yl)-2,4-hexadienedioate (5c). A brown oil, Rf 0.43 (hexane–eth-
yl acetate ꢀ 7:1). 1H NMR (CDCl3) δ 0.26 (s, 9 H), 0.71–1.73
(m, 33 H), 4.22 (q, J ꢀ 7.1 Hz, 2 H), 4.27 (q, J ꢀ 7.1 Hz, 2 H),
7.59 (d, J ꢀ 12.1 Hz, 1 H), 8.18 (d, J ꢀ 12.1 Hz, 1 H); 13C NMR
(CDCl3) δ ꢁ0.2, 11.9, 13.6, 14.1, 14.3, 27.2, 28.9, 61.0, 61.7,
98.1, 107.1, 121.1, 145.7, 147.7, 153.6, 164.3, 171.2; 119Sn{1H}
NMR (CDCl3) δ ꢁ42.8. Found: C, 55.66; H, 8.55%. Calcd for
C27H48O4SiSn: C, 55.58; H, 8.29%.
Diethyl
4-{(E)-[(E)-Cinnamylidene]}-2-(tributylstannyl)-
′
(Z)-2-pentenedioate (5 e). A brown oil, Rf 0.24 (hexane–ethyl
acetate ꢀ 7:1). 1H NMR (CDCl3) δ 0.68–1.50 (m, 33 H), 4.26 (q,
J ꢀ 7.1 Hz, 4 H), 6.95–7.02 (m, 2 H), 7.28–7.50 (m, 6 H), 8.00 (s,
1 H); 13C NMR (CDCl3) δ 11.4, 13.6, 14.3, 27.3, 29.0, 60.90,
60.95, 124.2, 127.4, 128.7, 129.2, 129.8, 136.0, 141.3, 141.5,
144.0, 148.6, 166.4, 170.7; 119Sn{1H} NMR (CDCl3) δ ꢁ47.3.
′
Found as a mixture of 5e and 5 e: C, 61.35; H, 7.77%. Calcd for
C30H46O4Sn: C, 61.13; H, 7.87%.
Diethyl 2-[(E)-1-Octenyl]-5-(tributylstannyl)-(2E,4Z)-2,4-
hexadienedioate (5f). A brown oil, Rf 0.47 (hexane–ethyl ace-
tate ꢀ 7:1). 1H NMR (CDCl3) δ 0.74–1.77 (m, 44 H), 2.22 (q, J
ꢀ 6.8 Hz, 2 H), 4.21 (q, J ꢀ 7.1 Hz, 2 H), 4.26 (q, J ꢀ 7.1 Hz, 2
H), 6.21 (dt, J ꢀ 15.7, 6.8 Hz, 1 H), 6.40 (d, J ꢀ 15.7 Hz, 1 H),
7.11 (d, J ꢀ 11.9 Hz, 1 H), 8.17 (d, J ꢀ 11.9 Hz, 1 H); 13C NMR
(CDCl3) δ 11.7, 13.6, 14.1, 14.2, 14.3, 22.6, 27.2, 28.89, 28.94,
29.0, 31.6, 33.9, 60.8, 60.9, 122.0, 134.8, 135.1, 140.7, 147.3,
147.7, 167.0, 171.5; 119Sn{1H} NMR (CDCl3) δ ꢁ45.0. Found as
a mixture of 5f and 5'f: C, 60.30; H, 8.93%. Calcd for
C30H54O4Sn: C, 60.31; H, 9.11%.
Diethyl 4-{(E)-[(E)-2-Nonenylidene]}-2-(tributylstannyl)-
(Z)-2-pentenedioate (5 f). A brown oil, Rf 0.32 (hexane–ethyl
acetate ꢀ 7:1). H NMR (CDCl3) δ 0.69–1.75 (m, 44 H), 2.17 ( q,
J ꢀ 6.8 Hz, 2 H), 4.22 (q, J ꢀ 7.2 Hz, 2 H), 4.23 (q, J ꢀ 7.1 Hz, 2
H), 6.18 (dt, J ꢀ 15.2, 6.6 Hz, 1 H), 6.33 (dd, J ꢀ 15.2, 10.3 Hz, 1
H), 7.23 (d, J ꢀ 10.3 Hz, 1 H), 7.91 (s, 1 H); 13C NMR (CDCl3) δ
11.3, 13.6, 14.0, 14.3, 22.6, 27.3, 28.9, 29.0, 31.7, 33.5, 60.8,
126.6, 127.7, 141.7, 143.1, 146.4, 148.8, 166.6, 170.8; 119Sn{1H}
′
1
′
NMR (CDCl3) δ ꢁ47.9. Found as a mixture of 5f and 5 f: C,
60.30; H, 8.93%. Calcd for C30H54O4Sn: C, 60.31; H, 9.11%.
Diethyl (2E,4Z)-2-(2-Furyl)-5-(tributylstannyl)-2,4-hexadi-
enedioate (5g). A brown oil, Rf 0.30 (hexane–ethyl acetateꢀ
7:1). 1H NMR (CDCl3) δ 0.73–1.75 (m, 33 H), 4.22 (q, J ꢀ 7.1
Hz, 2 H), 4.32 (q, J ꢀ 7.1 Hz, 2 H), 6.48 (dd, J ꢀ 3.5, 1.8 Hz, 1
H), 6.90 (d, J ꢀ 3.1 Hz, 1 H), 7.30 (d, J ꢀ 12.1 Hz, 1 H), 7.56 (dd,
J ꢀ 1.8, 0.4 Hz, 1 H), 8.55 (d, J ꢀ 12.1 Hz, 1 H); 13C NMR
Diethyl (2E,4Z)-2-Ethenyl-5-(tributylstannyl)-2,4-hexadi-
enedioate (5d). A brown oil, Rf 0.38 (hexane–ethyl acetate ꢀ
7:1). 1H NMR (CDCl3) δ 0.82–1.74 (m, 33 H), 4.21 (q, J ꢀ 7.1

644 Bull. Chem. Soc. Jpn., 74, No. 4 (2001)
HEADLINE ARTICLES
Tetramethyl
(CDCl3) δ 11.8, 13.7, 14.3, 27.2, 29.0, 60.9, 61.4, 111.5, 114.4,
125.6, 135.6, 143.8, 148.5, 149.4, 151.3, 165.8; 119Sn{1H} NMR
(CDCl3) δ ꢁ45.4. Found: C, 56.26; H, 7.75%. Calcd for
C26H42O5Sn: C, 56.44; H, 7.65%.
(1E,3Z)-1-(Tributylstannyl)-1,3-decadien-5-
yne-1,2,3,4-tetracarboxylate (5j). A brown oil, Rf 0.45 (hex-
ane–ethyl acetate ꢀ 2:1). 1H NMR (CDCl3) δ 0.71–1.72 (m, 34
H), 2.32 (t, J ꢀ 7.1 Hz, 2 H), 3.68 (s, 3 H), 3.71 (s, 3 H), 3.77 (s, 3
H), 3.83 (s, 3 H); 13C NMR (CDCl3) δ 12.4, 13.5, 13.7, 19.7, 22.0,
27.2, 28.8, 30.1, 51.4, 52.5, 52.9, 75.3, 105.8, 127.9, 135.8, 136.0,
162.4, 164.9, 165.5, 166.7, 171.2; 119Sn{1H} NMR (CDCl3) δ
ꢁ35.0. Found: C, 55.04; H, 7.46%. Calcd for C30H48O8Sn: C,
54.98; H, 7.38%.
Diethyl 4-[(E)-(2-Furyl)methylene]-2-(tributylstannyl)-(Z)-
′
2-pentenedioate (5 g). A brown oil, Rf 0.28 (hexane–ethyl ace-
tate ꢀ 7:1). 1H NMR (CDCl3) δ 0.67–1.73 (m, 33 H), 4.247 (q, J
ꢀ 7.1 Hz, 2 H), 4.254 (q, J ꢀ 7.1 Hz, 2 H), 6.44–6.54 (m, 1 H),
6.73 (d, J ꢀ 3.5 Hz, 1 H), 7.53 (d, J ꢀ 1.7 Hz, 1 H), 7.56 (d, J ꢀ
1.8 Hz, 1 H), 7.99 (d, J ꢀ 1.8 Hz, 1 H); 13C NMR (CDCl3) δ 11.3,
13.6, 14.29, 14.32, 27.3, 29.0, 60.8, 61.2, 112.7, 117.0, 126.0,
128.1, 143.9, 145.1, 148.1, 151.0, 166.2, 171.3; 119Sn{1H} NMR
(CDCl3) δ ꢁ46.1. Found: C, 56.22; H, 7.41%. Calcd for
C26H42O5Sn: C, 56.44; H, 7.65%.
Tetramethyl
(1E,3Z)-1-(Tributylstannyl)-6-(trimethylsi-
lyl)1,3-hexadien-5-yne-1,2,3,4-tetracarboxylate (5k).
A
brown oil, Rf 0.62 (hexane–ethyl acetate ꢀ 2:1). 1H NMR
(CDCl3) δ 0.19 (s, 9 H), 0.81–1.73 (m, 27 H), 3.70 (s, 3 H), 3.75
(s, 3 H), 3.80 (s, 3 H), 3.88 (s, 3 H); 13C NMR (CDCl3) δ ꢁ0.7,
11.1, 13.6, 27.2, 28.6, 51.4, 52.5, 52.7, 53.1, 97.7, 112.3, 129.0,
134.7, 139.2, 160.6, 162.5, 164.4, 172.3; 119Sn{1H} NMR
(CDCl3) δ ꢁ27.4. Found: C, 51.86; H, 7.00%. Calcd for
C29H48O8SiSn: C, 51.87; H, 7.21%.
Diethyl 2-(2-Furyl)-4-[(E)-(tributylstannyl)methylene]-(E)-
′′
2-pentenedioate (5 g). A brown oil, Rf 0.24 (hexane–ethyl ace-
tate ꢀ 7:1). 1H NMR (CDCl3) δ 0.52–1.66 (m, 33 H), 4.16 (q, J
ꢀ 7.0 Hz, 2 H), 4.18 (q, J ꢀ 7.1 Hz, 2 H), 6.41 (dd, J ꢀ 3.5, 1.8
Hz, 1 H), 6.62 (d, J ꢀ 3.5 Hz, 1 H), 7.44 (d, J ꢀ 1.7 Hz, 1 H), 7.57
(s, 1 H), 7.93 (s, 1 H); 13C NMR (CDCl3) δ 9.7, 13.6, 14.2, 14.3,
27.3, 28.9, 60.8, 61.0, 112.1, 115.8, 127.8, 128.0, 143.2, 144.6,
150.8, 151.8, 164.7, 166.9; 119Sn{1H} NMR (CDCl3) δ ꢁ57.7.
Tetramethyl (1E,3Z)-1-(Tributylstannyl)-1,3,5-hexatriene-
1,2,3,4-tetracarboxylate (5l). A brown oil, Rf 0.42 (hexane–
ethyl acetate ꢀ 2:1). 1H NMR (CDCl3) δ 0.80–1.82 (m, 27 H),
3.70 (s, 3 H), 3.74 (s, 3H ), 3.83 (s, 3 H), 3.92 (s, 3 H), 5.54 (d, J
ꢀ 17.4 Hz, 1 H), 5.60 (d, J ꢀ 10.8 Hz, 1 H), 6.96 (dd, J ꢀ 17.4,
10.8 Hz, 1 H); 13C NMR (CDCl3) δ 10.8, 13.6, 27.2, 28.6, 51.7,
52.5, 52.7, 125.2, 127.6, 130.9, 134.6, 145.5, 161.1, 163.3, 165.2,
167.4, 172.4; 119Sn{1H} NMR (CDCl3) δ ꢁ26.5. Found: C,
51.82; H, 7.11%. Calcd for C26H42O8Sn: C, 51.93; H, 7.04%.
Found: C, 51.82; H, 7.11%.
′
′′
Found as a mixture of 5g, 5 g and 5 g: C, 56.59; H, 7.42%. Calcd
for C26H42O5Sn: C, 56.44; H, 7.65%.
Diethyl (2E,4Z)-2-(2-Thienyl)-5-(tributylstannyl)-2,4-hexa-
dienedioate (5h). A brown oil, Rf 0.35 (hexane–ethyl acetate ꢀ
7:1). 1H NMR (CDCl3) δ 0.73–1.71 (m, 33 H), 4.19 (q, J ꢀ 7.1
Hz, 2 H), 4.32 (q, J ꢀ 7.1 Hz, 2 H), 7.07 (dd, J ꢀ 4.9, 3.5 Hz, 1
H), 7.15 (dd, J ꢀ 3.5, 1.3 Hz, 1 H), 7.46 (dd, J ꢀ 4.9, 1.3 Hz, 1
H), 7.52 (d, J ꢀ 11.6 Hz, 1 H), 8.07 (d, J ꢀ 11.6 Hz, 1 H); 13C
NMR (CDCl3) δ 11.8, 13.7, 14.3, 27.2, 29.0, 60.9, 61.6, 126.6,
128.4, 130.7, 131.0, 134.7, 138.0, 148.0, 150.8, 166.4, 171.4;
119Sn{1H} NMR (CDCl3) δ ꢁ44.0. Found: C, 54.88; H, 7.57%.
Calcd for C26H42O4SSn: C, 54.85; H, 7.43%.
Tetramethyl (1E,3Z,5E)-6-Phenyl-1-(tributylstannyl)-1,3,5-
hexatriene-1,2,3,4-tetracarboxylate (5m).
A brown oil, Rf
1
0.40 (hexane–ethyl acetate ꢀ 2:1). H NMR (CDCl3) δ 0.70–1.58
(m, 27 H), 3.69 (s, 3 H), 3.73 (s, 3 H), 3.85 (s, 3 H), 3.97 (s, 3 H),
6.75 (d, J ꢀ 16.2 Hz, 1 H), 6.96 (d, J ꢀ 16.2 Hz, 1 H), 7.20–7.54
(m, 5 H); 13C NMR (CDCl3) δ 10.8, 13.5, 27.1, 28.6, 51.7, 52.4,
52.6, 52.7, 122.0, 126.4, 127.7, 128.8, 129.7, 134.9, 135.2, 139.5,
145.9, 161.3, 163.5, 165.4, 168.0, 172.6; 119Sn{1H} NMR
(CDCl3) δ ꢁ30.3. Found: C, 56.62; H, 7.04%. Calcd for
C32H46O8Sn: C, 56.74; H, 6.84%.
Diethyl 4-[(E)-(2-Thienyl)methylene]-2-(tributylstannyl)-
′
(Z)-2-pentenedioate (5 h). A brown oil, Rf 0.28 (hexane–ethyl
acetate ꢀ 7:1). 1H NMR (CDCl3) δ 0.65–1.76 (m, 33 H), 4.25 (q,
J ꢀ 7.1 Hz, 2 H), 4.26 (q, J ꢀ 7.1 Hz, 2 H), 7.02–7.14 (m, 1 H),
7.33 (d, J ꢀ 3.3 Hz, 1 H), 7.48 (d, J ꢀ 5.1 Hz, 1 H), 7.87 (d, J ꢀ
1.7 Hz, 1 H), 8.00 (d, J ꢀ 1.7 Hz, 1 H); 13C NMR (CDCl3) δ 11.3,
13.6, 14.3, 27.3, 29.0, 60.8, 61.2, 126.4, 127.5, 131.4, 133.3,
133.7, 138.5, 146.1, 147.9, 166.3, 170.8; 119Sn{1H} NMR
(CDCl3) δ ꢁ45.7. Found: C, 54.95; H, 7.69%. Calcd for
C26H42O4SSn: C, 54.85; H, 7.43%.
Tetramethyl
(1E,3Z,5E)-1-(Tributylstannyl)-1,3,5-dodec-
atriene-1,2,3,4-tetracarboxylate (5n). A brown oil, Rf 0.46
(hexane–ethyl acetate ꢀ 2:1). 1H NMR (CDCl3) δ 0.78–1.64 (m,
38 H), 2.16 (q, J ꢀ 7.0 Hz, 2 H), 3.67 (s, 3 H), 3.70 (s, 3 H), 3.81
(s, 3 H), 3.89 (s, 3 H), 6.00 (dt, J ꢀ 15.9, 6.8 Hz, 1 H), 6.23 (d, J
ꢀ 15.9 Hz, 1 H); 13C NMR (CDCl3) δ 10.8, 13.6, 14.0, 22.5, 27.2,
28.5, 28.6, 28.9, 31.5, 33.7, 51.6, 52.3, 52.4, 52.6, 124.5, 134.9,
144.6, 146.1, 160.7, 163.5, 165.5, 168.0, 172.5; 119Sn{1H} NMR
(CDCl3) δ ꢁ27.7. Found: C, 55.88; H, 7.98%. Calcd for
C32H54O8Sn: C, 56.07; H, 7.94%.
Diethyl 2-(2-Thienyl)-4-[(E)-(tributylstannyl)methylene]-
′′
(E)-2-pentenedioate (5 h). A brown oil, Rf 0.22 (hexane–ethyl
acetate ꢀ 7:1). 1H NMR (CDCl3) δ 0.53–1.65 (m, 33 H), 4.20 (q,
J ꢀ 7.1 Hz, 2 H), 4.22 (q, J ꢀ 7.1 Hz, 2 H), 6.99–7.07 (m, 1 H),
7.22–7.41 (m, 2 H), 7.93 (d, J ꢀ 0.6 Hz, 1 H), 8.11 (d, J ꢀ 0.6 Hz,
1 H); 13C NMR (CDCl3) δ 9.8, 13.6, 14.2, 14.3, 27.3, 29.0, 60.9,
127.0, 128.1, 130.3, 133.4, 134.0, 138.4, 142.7, 156.0, 164.5,
166.9; 119Sn{1H} NMR (CDCl3) δ ꢁ58.1. Found: C, 54.57; H,
7.18%. Calcd for C26H42O4SSn: C, 54.85; H, 7.43%.
Tetramethyl
(1E,3Z)-1-(2-Furyl)-4-(tributylstannyl)-1,3-
butadiene-1,2,3,4-tetracarboxylate (5o). A brown solid, mp
86–88 ˚C. 1H NMR (CDCl3) δ 0.67–1.49 (m, 27 H), 3.67 (s, 3 H),
3.76 (s, 3 H), 3.85 (s, 3 H), 3.97 (s, 3 H), 6.49 (dd, J ꢀ 3.7, 1.8 Hz,
1 H), 6.79 (dd, J ꢀ 3.7, 0.7 Hz, 1 H), 7.53 (dd, J ꢀ 1.8, 0.7 Hz, 1
H); 13C NMR (CDCl3) δ 10.6, 13.6, 27.2, 28.5, 51.6, 52.6, 52.9,
112.8, 117.6, 122.9, 135.1, 136.0, 145.6, 148.0, 159.5, 163.4,
165.5, 166.6, 172.8; 119Sn{1H} NMR (CDCl3) δ ꢁ29.3. Found:
C, 52.25; H, 6.73%. Calcd for C28H42O9Sn: C, 52.44; H, 6.60%.
Tetramethyl (1E,3Z)-1-(2-Benzofuryl)-4-(tributylstannyl)-
1,3-butadiene-1,2,3,4-tetracarboxylate (5p). A brown oil, Rf
Tetramethyl (1E,3Z)-6-Phenyl-1-(tributylstannyl)-1,3-hexa-
dien-5-yne-1,2,3,4-tetracarboxylate (5i). A brown oil, Rf 0.39
(hexane–ethyl acetate ꢀ 2:1). 1H NMR (CDCl3) δ 0.73–1.83 (m,
27 H), 3.71 (s, 3 H), 3.77 (s, 3 H), 3.86 (s, 3 H), 3.93 (s, 3 H),
7.16–7.65 (m, 5 H); 13C NMR (CDCl3) δ 11.1, 13.5, 27.2, 28.6,
51.6, 52.7, 53.2, 84.1, 104.9, 121.4, 128.4, 129.5, 129.9, 132.0,
132.5, 135.0, 137.1, 161.0, 163.0, 164.7, 172.5; 119Sn{1H} NMR
(CDCl3) δ ꢁ26.1. Found: C, 56.92; H, 6.63%. Calcd for
C32H44O8Sn: C, 56.91; H, 6.57%.
1
0.38 (hexane–ethyl acetate ꢀ 2:1). H NMR (CDCl3) δ 0.64–1.40
(m, 27 H), 3.69 (s, 3 H), 3.79 (s, 3 H), 3.89 (s, 3 H), 4.02 (s, 3 H),
7.07 (d, J ꢀ 0.9 Hz, 1 H), 7.17–7.64 (m, 4 H); 13C NMR (CDCl3)

H. Yoshida et al.
Bull. Chem. Soc. Jpn., 74, No. 4 (2001) 645
1,3,5,7,9-decapentaene-1,4,7,10-tetracarboxylate (7a).
δ 10.6, 13.4, 27.1, 28.5, 51.6, 52.7, 52.8, 53.1, 111.9, 113.5,
122.1, 123.7, 125.9, 127.1, 127.5, 135.2, 136.1, 147.3, 149.4,
155.5, 159.0, 163.4, 165.4, 172.8; 119Sn{1H} NMR (CDCl3) δ
ꢁ28.7. Found: C, 55.30; H, 6.55%. Calcd for C32H44O9Sn: C,
55.59; H, 6.41%.
A
brown oil, Rf 0.69 (hexane–ethyl acetate ꢀ 2:1). 1H NMR
(CDCl3) δ 0.74–1.81 (m, 66 H), 4.20 (q, J ꢀ 7.1 Hz, 4 H), 4.31 (q,
J ꢀ 7.1 Hz, 4 H), 7.26 (d, J ꢀ 12.1 Hz, 2 H), 7.32 (s, 2 H), 8.17
(d, J ꢀ 12.1 Hz, 2 H); 13C NMR (CDCl3) δ 11.8, 13.7, 14.25,
14.29, 27.2, 29.0, 60.9, 61.2, 127.8, 134.0, 138.0, 145.9, 151.0,
166.5, 171.3; 119Sn{1H} NMR (CDCl3) δ ꢁ44.0. Found: C,
55.35; H, 7.88%. Calcd for C46H80O8Sn2: C, 55.33; H, 8.08%.
Tetramethyl (1E,3Z,6E)-7-Phenyl-1-(tributylstannyl)-1,3,6-
heptatriene-1,2,3,4-tetracarboxylate (5q).
A brown oil, Rf
1
0.65 (hexane–ethyl acetate ꢀ 2:1). H NMR (CDCl3) δ 0.82–1.67
(m, 27 H), 3.60 (s, 3 H), 3.73 (s, 3 H), 3.82 (s, 3 H), 3.83 (s, 3 H),
6.04 (dt, J ꢀ 15.7, 7.0 Hz, 1 H), 6.43 (d, J ꢀ 15.7 Hz, 1 H), 7.14–
7.39 (m, 5 H); 13C NMR (CDCl3) δ 11.0, 13.5, 27.2, 28.6, 35.6,
51.6, 52.3, 52.45, 52.54, 122.7, 126.2, 127.5, 128.4, 130.3, 133.5,
135.0, 136.8, 145.4, 159.7, 163.3, 165.4, 168.6, 172.3; 119Sn{1H}
NMR (CDCl3) δ ꢁ28.3. Found: C, 57.07; H, 7.27%. Calcd for
C33H48O8Sn: C, 57.32; H, 7.00%.
Octamethyl
(1E,3Z,5E,7Z,9E)-1,10-Bis(tributylstannyl)-
1,3,5,7,9-decapentaene-1,2,3,4,7,8,9,10-octacarboxylate (7b).
A brown solid, mp 91–92 ˚C. 1H NMR (CDCl3) δ 0.69–1.93 (m,
54 H), 3.67 (s, 6 H), 3.73 (s, 6 H), 3.82 (s, 6 H), 3.94 (s, 6 H), 6.54
(s, 2 H); 13C NMR (CDCl3) δ 10.8, 13.6, 27.1, 28.6, 51.6, 52.6,
52.7, 52.8, 130.7, 131.9, 134.3, 144.5, 162.1, 162.9, 164.8, 166.5,
172.1; 119Sn{1H} NMR (CDCl3) δ ꢁ25.9. Found: C, 50.93; H,
6.89%. Calcd for C50H80O16Sn2: C, 51.13; H, 6.86%.
Diethyl
(2E,4Z)-2-(2-Benzofuryl)-5-(tributylstannyl)-2,4-
hexadienedioate (5r). A brown oil, Rf 0.41 (hexane–ethyl ace-
tate ꢀ 7:1). 1H NMR (CDCl3) δ 0.68–1.75 (m, 33 H), 4.23 (q, J
ꢀ 7.1 Hz, 2 H), 4.36 (q, J ꢀ 7.1 Hz, 2 H), 7.15–7.70 (m, 6 H),
8.69 (d, J ꢀ 12.1 Hz, 1 H); 13C NMR (CDCl3) δ 11.9, 13.7, 14.3,
27.2, 29.0, 61.0, 61.6, 110.7, 111.3, 121.7, 123.1, 125.4, 125.7,
128.2, 138.4, 148.1, 153.2, 155.1, 165.6, 165.7, 174.7; 119Sn{1H}
NMR (CDCl3) δ ꢁ45.0. Found: C, 59.98; H, 7.41%. Calcd for
C30H44O5Sn: C, 59.72; H, 7.35%.
Diethyl (2E,4Z)-2-(3-Thienyl)-5-(tributylstannyl)-2,4-hexa-
dienedioate (5s). A brown oil, Rf 0.37 (hexane–ethyl acetate ꢀ
7:1). 1H NMR (CDCl3) δ 0.74–1.67 (m, 33 H), 4.17 (q, J ꢀ 7.1
Hz, 2 H), 4.29 (q, J ꢀ 7.1 Hz, 2 H), 7.13 (dd, J ꢀ 4.5, 1.8 Hz, 1
H), 7.29–7.36 (m, 2 H), 7.50 (d, J ꢀ 11.7 Hz, 1 H), 7.91 (d, J ꢀ
11.7 Hz, 1 H); 13C NMR (CDCl3) δ 11.8, 13.7, 14.3, 27.2, 29.0,
60.9, 61.3, 124.8, 126.9, 129.6, 133.0, 134.1, 138.1, 148.0, 150.1,
166.7, 171.4; 119Sn{1H} NMR (CDCl3) δ ꢁ44.2. Found: C,
54.84; H, 7.72%. Calcd for C26H42O4SSn: C, 54.85; H, 7.43%.
Diethyl (2E,4Z)-2-Phenyl-5-(trimethylstannyl)-2,4-hexadi-
enedioate (5t). A brown oil, Rf 0.26 (hexane–ethyl acetate ꢀ
7:1). 1H NMR (CDCl3) δ 0.38 (s, 9 H), 1.25 (t, J ꢀ 7.1 Hz, 3 H),
1.32 (t, J ꢀ 7.1 Hz, 3 H), 4.14 (q, J ꢀ 7.1 Hz, 2 H), 4.27 (q, J ꢀ
7.1 Hz, 2 H), 7.17–7.45 (m, 5 H), 7.65 (d, J ꢀ 11.9 Hz, 1 H), 7.72
(d, J ꢀ 11.9 Hz, 1 H); 13C NMR (CDCl3) δ ꢁ6.7, 14.2, 60.9, 61.3,
128.0, 128.3, 130.3, 134.0, 137.8, 138.9, 148.1, 149.5, 166.9,
170.7; 119Sn{1H} NMR (CDCl3) δ ꢁ38.1. Found: C, 52.41; H,
6.07%. Calcd for C19H26O4Sn: C, 52.21; H, 6.00%.
Diethyl (2E,4Z)-2-(4-Methoxyphenyl)-5-(trimethylstannyl)-
2,4-hexadienedioate (5u). A brown oil, Rf 0.17 (hexane–ethyl
acetate ꢀ 7:1). 1H NMR (CDCl3) δ 0.37 (s, 9 H), 1.25 (t, J ꢀ 7.1
Hz, 3 H), 1.32 (t, J ꢀ 7.1 Hz, 3 H), 3.83 (s, 3 H), 4.14 (q, J ꢀ 7.1
Hz, 2 H), 4.26 (q, J ꢀ 7.1 Hz, 2 H), 6.91 (d, J ꢀ 8.6 Hz, 2 H), 7.19
(d, J ꢀ 8.6 Hz, 2 H), 7.60 (d, J ꢀ 11.9 Hz, 1 H), 7.77 (d, J ꢀ 11.9
Hz, 1 H); 119C NMR (CDCl3) δ ꢁ6.8, 14.1, 55.2, 60.8, 61.2,
113.4, 126.2, 131.6, 137.0, 138.4, 148.5, 148.6, 159.6, 167.1,
170.7; 119Sn{1H} NMR (CDCl3) δ ꢁ38.5. Found: C, 51.67; H,
6.12%. Calcd for C20H28O5Sn: C, 51.42; H, 6.04%.
Dimerization–Carbostannylation of Alkynes with (E)-1,2-
Bis(tributylstannyl)ethene. A solution of 1,2-bis(phenylimi-
no)acenaphthene (2a) (5.5 mg, 16 µmol), [Pd2Cl2(η3-C3H5)2] (3.0
mg, 8.2 µmol) and an alkyne (1.0 mmol) in toluene (3 mL) was
degassed by four freeze-thaw cycles. To this solution was added
(E)-1,2-bis(tributylstannyl)ethene (4n) (0.10 g, 0.17 mmol), and
the mixture was stirred at 50 ˚C. After the time specified in Eq.1,
the solvent was evaporated. GPC purification of the residue gave
the corresponding dimerization–carbostannylation product.
Cross-Coupling of 5a with 4-Iodonitrobenzene. A solu-
tion of 5a (50 mg, 85 µmol) in DMF (1.5 mL) was degassed by
three freeze-thaw cycles. To this solution was added 4-iodoni-
trobenzene (21 mg, 85 µmol), [Pd(PPh3)4] (9.8 mg, 8.5 µmol) and
CuI (12 mg, 64 µmol). The mixture was stirred at 50 ˚C for 18 h
and then diluted with diethyl ether (25 mL). The organic layer
was separated, washed with water, dried over anhydrous magne-
sium sulfate and concentrated in vacuo. The residue was diluted
with diethyl ether (10 mL) and stirred for 30 min with a 1 M (ꢀ 1
mol dmꢁ3) KF aqueous solution (2 mL). Filtration through a
Celite plug was followed by extraction with diethyl ether (20 mL).
The organic layer was washed successively with water and brine,
and dried over anhydrous magnesium sulfate. Evaporation of the
solvent followed by GPC gave diethyl (2E,4E)-2-(4-nitrophenyl)-
5-(phenylethynyl)-2,4-hexadienedioate (10) (25 mg, 70% yield) as
a yellow solid: mp 147–149 ˚C. 1H NMR (CDCl3) δ 1.26 (t, J ꢀ
7.1 Hz, 3 H), 1.27 (t, J ꢀ 7.1 Hz, 3 H), 4.21 (q, J ꢀ 7.1 Hz, 2 H),
4.24 (q, J ꢀ 7.1 Hz, 2 H), 7.09–7.75 (m, 8 H), 8.11 (d, J ꢀ 12.3
Hz, 1 H), 8.22 (d, J ꢀ 8.4 Hz, 2 H); 13C NMR (CDCl3) δ 14.09,
14.13, 61.9, 62.1, 83.4, 102.1, 122.2, 123.3, 123.5, 128.5, 129.4,
131.3, 131.9, 136.5, 137.5, 138.9, 140.9, 147.8, 164.0, 165.6.
HRMS (ESI) Found: m/z 442.1261. Calcd for C24H21NO6Na:
MꢂꢂNa, 442.1261.
Cross-Coupling of 5a with 1-Bromo-2-phenylethyne.
A
solution of 5a (65 mg, 0.11 mmol) in DMF (1.5 mL) was degassed
by three freeze-thaw cycles. To this solution was added 1-bromo-
2-phenylethyne (20 mg, 0.11 mmol), [Pd(PPh3)4] (13 mg, 11
µmol) and CuI (2.1 mg, 11 µmol). The mixture was stirred at 50
˚C for 5 h and then diluted with diethyl ether (25 mL). The organ-
ic layer was washed with water and dried over anhydrous magne-
sium sulfate; then it was concentrated in vacuo. The residue was
diluted with diethyl ether (10 mL) and stirred for 30 min with a 1
M KF aqueous solution (2 mL). Filtration through a Celite plug
was followed by extraction with diethyl ether (20 mL). The or-
ganic layer was washed successively with water and brine and
dried over anhydrous magnesium sulfate. Evaporation of the sol-
vent followed by GPC gave diethyl (2E,4E)-2,5-Bis(phenylethy-
nyl)-2,4-hexadienedioate (11) (24 mg, 54% yield) as a red solid:
mp 112–114 ˚C. 1H NMR (CDCl3) δ 0.91 (t, J ꢀ 7.1 Hz, 6 H),
4.02 (q, J ꢀ 7.1 Hz, 4 H), 6.82 (s, 2 H), 7.13–7.45 (m, 10 H); 13
C
NMR (CDCl3) δ 13.8, 60.5, 117.3, 125.4, 127.8, 129.2, 131.2,
154.4, 154.8, 165.1. HRMS (ESI) Found: m/z 421.1414. Calcd
for C26H22O4Na: MꢂꢂNa, 421.1410.
Cross-Coupling of 5a with 1,4-Diiodobenzene.
A solution
of 5a (48 mg, 81 µmol) in DMF (1.5 mL) was degassed by three
freeze-thaw cycles. To this solution was added 1,4-diiodobenzene
Tetraethyl
(1Z,3E,5E,7E,9Z)-1,10-Bis(tributylstannyl)-

646 Bull. Chem. Soc. Jpn., 74, No. 4 (2001)
HEADLINE ARTICLES
(13 mg, 41 µmol), [Pd(PPh3)4] (9.4 mg, 8.1 µmol) and CuI (7.7
mg, 41 µmol). The mixture was stirred at 50 ˚C for 8 h and then
diluted with diethyl ether (25 mL). The organic layer was washed
with water, dried over anhydrous magnesium sulfate; then it was
concentrated in vacuo. The residue was diluted with diethyl ether
(10 mL) and stirred for 30 min with a 1 M KF aqueous solution (2
mL). Filtration through a Celite plug was followed by extraction
with diethyl ether (20 mL). The organic layer was washed succes-
sively with water and brine and dried over anhydrous magnesium
sulfate. Evaporation of the solvent followed by GPC gave 2,2′-(p-
phenylene)bis[diethyl(2E,4E)-5-phenylethynyl-2,4-hexadienedio-
ate] (12) (17 mg, 62% yield) as an orange solid: mp 164–167 ˚C.
1H NMR (CDCl3) δ 1.33 (t, J ꢀ 7.2 Hz, 6 H), 1.36 (t, J ꢀ 7.1 Hz,
6 H), 4.29 (q, J ꢀ 7.2 Hz, 4 H), 4.33 (q, J ꢀ 7.1 Hz, 4 H), 7.15–
7.73 (m, 16 H), 8.12 (d, J ꢀ 12.2 Hz, 2 H); 13C NMR (CDCl3) δ
14.1, 14.2, 61.6, 61.9, 83.8, 101.3, 122.1, 122.5, 128.4, 129.1,
130.1, 131.8, 134.5, 135.2, 139.2, 140.6, 164.3, 166.6. HRMS
(ESI) Found: m/z 693.2464. Calcd for C42H38O8Na: MꢂꢂNa,
693.2459.
4
E. Shirakawa, K. Yamasaki, H. Yoshida, and T. Hiyama, J.
Am. Chem. Soc., 121, 10221 (1999).
E. Shirakawa, H. Yoshida, Y. Nakao, and T. Hiyama, Org.
Lett., 2, 2209 (2000).
5
6
a) E. Shirakawa, H. Yoshida, T. Kurahashi, Y. Nakao, and
T. Hiyama, J. Am. Chem. Soc., 120, 2973 (1998). b) H. Yoshida,
E. Shirakawa, T. Kurahashi, Y. Nakao, and T. Hiyama, Orgamo-
metallics, 19, 5671 (2000).
7
Carbostannylation of alkynes using a combination of (stan-
nylethynyl)amines and dimethyl acetylenedicarboxylate, is report-
ed. G. Himbert, J. Chem. Res. (S), 1979, 88.
8
Alkenylation of ketones or phenols using terminal alkynes
and SnCl4 is considered to proceed through carbostannylation of
stannylacetylenes. a) A. Hayashi, M. Yamaguchi, M. Hirama, C.
Kabuto, and M. Ueno, Chem. Lett., 1993, 1881. b) M. Yamaguchi,
A. Hayashi, and M. Hirama, J. Am. Chem. Soc., 115, 3362 (1993).
c) M. Yamaguchi, A. Hayashi, and M. Hirama, J. Am. Chem. Soc.,
117, 1151 (1994).
9
Carbostannylation may alternatively be accomplished by
Homocoupling of 5s. To a solution of 5s (29 mg, 52 µmol) in
DMF (1.0 mL) was added CuCl2 (6.9 mg, 52 µmol), and the mix-
ture was stirred at 0 ˚C for 3 h. Saturated aqueous NH4Cl–NH3
(pH 8, 2 mL) was added, and the mixture was stirred under an
aerial atmosphere until the color became deep blue. The mixture
was extracted with diethyl ether (10 mL). The ethereal layer was
washed with water and dried over anhydrous magnesium sulfate.
Evaporation of the solvent followed by GPC gave tetraethyl
(1E,3E,5E,7E)-1,8-di(3-thienyl)-1,3,5,7-octatetraene-1,4,5,8-tet-
racarboxylate (13) (6.6 mg, 46% yield) as a yellow oil: Rf 0.37
(hexane–ethyl acetate ꢀ 2:1). 1H NMR (CDCl3) δ 1.24 (t, J ꢀ
7.1 Hz, 12 H), 4.22 (q, J ꢀ 7.1 Hz, 8 H), 7.12–7.48 (m, 8 H), 7.67
(d, J ꢀ 11.5 Hz, 2 H); 13C NMR (CDCl3) δ 14.1, 14.2, 61.4, 61.5,
125.2, 127.6, 129.5, 132.5, 133.5, 134.1, 135.0, 138.2, 165.8,
166.2. Found: C, 60.04; H, 5.65%. Calcd for C28H30O8S2: C,
60.20; H, 5.41%.
Reduction of 5s. To a solution of 5s (19 mg, 33 µmol) in tol-
uene (1.0 mL) was added diisobutylaluminum hydride (0.9 M in
hexanes, 0.15 mL, 0.13 mmol); then the mixture was stirred at
ꢁ20 ˚C for 30 min. Saturated aqueous NH4Cl (3 mL) was added,
and the resulting mixture was extracted with ethyl acetate (10
mL). The organic layer was separated, dried over anhydrous mag-
nesium sulfate; then it was concentrated in vacuo. GPC purifica-
tion of the residue gave (2E,4E)-2-(3-thienyl)-5-(tributylstannyl)-
2,4-hexadiene-1,6-diol (14) (12 mg, 77%) as a yellow oil: Rf 0.51
(hexane–ethyl acetate ꢀ 2:1). 1H NMR (CDCl3) δ 0.74–1.75 (m,
27 H), 4.28 (d, J ꢀ 4.8 Hz, 2 H), 4.41 (d, J ꢀ 5.5 Hz, 2 H), 6.32
(d, J ꢀ 11.0 Hz, 1 H), 7.00–7.44 (m, 4 H); 13C NMR (CDCl3) δ
10.5, 13.7, 27.3, 29.2, 67.7, 70.3, 123.8, 125.4, 128.2, 135.9,
136.7, 138.1, 152.6; 119Sn{1H} NMR (CDCl3) δ ꢁ52.3. Found:
C, 54.43; H, 7.61%. Calcd for C22H38O2SSn: C, 54.45; H, 7.89%.
carbocupration of alkynes followed by quenching with tin halides/
triflate. H. Westmijze, J. Meijer, and P. Vermeer, Recl. Trav. Chim.
Pays-Bas, 96, 194 (1997).
10 Kosugi and his co-workers reported the palladium-cata-
lyzed carbostannylation of norbornene using organotin trichlo-
rides. a) K. Fugami, T. Enokido, K. Kawata, M. Kameyama, and
M. Kosugi, Main Group Met. Chem., 22, 511 (1999). b) K.
Fugami, Y. Mishiba, S. Hagiwara, D. Koyama, M. Kameyama,
and M. Kosugi, Synlett, 2000, 553.
11 A part of this work has been reported. E. Shirakawa, H.
Yoshida, Y. Nakao, and T. Hiyama, J. Am. Chem. Soc., 121, 4290
(1999).
12 No isomer was obtained in the reaction of 3b. Syn-addition
in use of 3a led us to the conclusion that carbostannylation prod-
ucts 5i–5q are also syn-adducts.
13 For the coupling constants between an allylic carbon and
an olefinic proton in an enyne, see: E. Breitmaier and W. Voelter,
“Carbon-13 NMR Spectroscopy,” 3rd ed, VCH, New York (1987),
Chapter 3.2. For those between a tin and an olefinic proton in an
alkenylstannane, see: A. J. Leusink, H. A. Budding, and J. W.
Marsman, J. Organomet. Chem., 9, 285 (1967).
14 Elsevier and his co-workers recently reported three compo-
nent coupling of acetylenedicarboxylate, organic halide and tet-
ramethyltin, using palladium–diimine 2e complex as a catalyst.
The catalytic cycle is considered to involve reaction of palladacy-
clopentadiene 8a (cf. Fig. 2), derived from Pd(0)–2e and dimethyl
acetylenedicarboxylate (3b), with an organic halide followed by
transmetalation with tetramethyltin. a) R. van Belzen, H. Hoff-
mann, and C. J. Elsevier, Angew. Chem., Int. Ed. Engl., 36, 1743
(1997). b) R. van Belzen, R. A. Klein, H. Kooijman, N. Veldman,
A. L. Spek, and C. J. Elsevier, Organometallics, 17, 1812 (1998).
15 J. P. Collmann, L. S. Hegedus, J. R. Norton, and R. G.
Finke, “Principles and Applications of Organotransition Metal
Chemistry,” University Science Books, Mill Valley (1987), Chap-
ter 3.5.
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