Further studies on palladium-catalyzed bismetallative cyclization of enynes in the presence of Bu3SnSiMe3

Article abstract of DOI:10.1016/S0022-328X(03)00601-6

Bismetallative cyclization of enynes with Bu₃SnSiMe ₃ catalyzed by Pd(0) complex was realized for the first time, which gives cyclized products containing a vinylsilane moiety and a homoallyltin moiety in good yield. In this cyclization, Pd₂(dba)₃·CHCl₃ or Pd(OH) ₂ on charcoal is effective as a Pd(0) catalyst and the addition of a phosphine ligand increased the formation of alkyne bismetallation by-product. On the other hand, it was found that a nucleophilic N-heterocyclic carbene could be utilized as a ligand for this cyclization. The utility of the cyclized products obtained from this cyclization in synthetic organic chemistry have been proven by transformation into cyclopropanol derivatives.

Full text of DOI:10.1016/S0022-328X(03)00601-6

Journal of Organometallic Chemistry 687 (2003) 392ꢁ402
/
www.elsevier.com/locate/jorganchem
Further studies on palladium-catalyzed bismetallative cyclization of
enynes in the presence of Bu3SnSiMe3
Yoshihiro Sato *, Noriko Imakuni, Tomohiro Hirose, Hideaki Wakamatsu 1,
Miwako Mori *
Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12, Nishi 6, Kita-ku, Sapporo 060-0812, Japan
Received 28 May 2003; received in revised form 24 June 2003; accepted 24 June 2003
Dedicated to Professor J.P. Geneˆt on the occasion of his 60th birthday
Abstract
Bismetallative cyclization of enynes with Bu3SnSiMe3 catalyzed by Pd(0) complex was realized for the first time, which gives
cyclized products containing a vinylsilane moiety and a homoallyltin moiety in good yield. In this cyclization, Pd2(dba)3×
/CHCl3 or
Pd(OH)2 on charcoal is effective as a Pd(0) catalyst and the addition of a phosphine ligand increased the formation of alkyne
bismetallation by-product. On the other hand, it was found that a nucleophilic N-heterocyclic carbene could be utilized as a ligand
for this cyclization. The utility of the cyclized products obtained from this cyclization in synthetic organic chemistry have been
proven by transformation into cyclopropanol derivatives.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Palladium; Silylstannane; Bismetallation; Enyne; Cyclization; N-heterocyclic carbene
1. Introduction
Bismetallative cyclization between two multiple bonds
might be particularly useful in synthetic organic chem-
istry because a cyclic compound having such an active
Transition metal-catalyzed addition of homo- or
hetero-bimetallic compounds to multiple bonds is of
metalꢀ
/
carbon bond is produced. Indeed, the cyclization
of various substrates (e.g., bis-dienes, diynes, enynes,
interest because new metalꢀ
/
carbon bonds are formed in
the product and these bonds can be utilized in further
transformations as an active bimetal functional group
[1]. We have been interested in the nature and the
allene-yne, allene-aldehyde or -ketone, bis-allene, and
dienal) with a bimetallic reagent (Mꢀ
/
M?, M, M?ꢁ/B, Si,
Ge, Sn, etc.) had been reported [3]. We had been
interested in the bismetallative cyclization of enynes
reactivity of such a bimetallic reagent and/or a metalꢀ
/
carbon bond formed by the reaction of a bimetallic
reagent with a substrate having multiple bonds, and our
continuous interest have led to new findings for the
with a Siꢀ
/
Sn. It is well known that a Siꢀ
/
Sn reagent such
as Bu3SnSiMe3 can react with alkynes in the presence of
the Group 10 metals (i.e., Ni, Pd, Pt) producing the
product having both a vinylsilane group and a vinyl-
stannane group (1) [1,4].
reactivity of compounds having a Siꢀ
SiꢀZr bond [2b]. In this context, we turned our attention
to transition metal-catalyzed bismetallative cyclization.
/Sn bond [2a] or a
/
ð1Þ
* Corresponding authors. Tel.:
7064982.
E-mail
mori@pharm.hokudai.ac.jp (M. Mori).
ꢀ
/
81-11-7063753; fax:
ꢀ
/
81-11-
We speculated that if an enyne 1 could react with a
addresses:
biyo@pharm.hokudai.ac.jp (Y.
Sato),
Siꢀ
insertion of the alkyne part of 1 into the Siꢀ
or the SnꢀPd bond of SiꢀPdꢀSn complex formed by
/
Sn reagent in the presence of a Pd(0) catalyst,
1
/
Pd bond
Present address: Tohoku Pharmaceutical University, 4-4-1
Komatsushima, Aoba-Ku, Sendai 981-8558, Japan.
/
/
/
0022-328X/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00601-6

Y. Sato et al. / Journal of Organometallic Chemistry 687 (2003) 392ꢁ
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402
393
The reaction of 1a was investigated under various
conditions to improve the yield of the desired cyclized
product 3a (Table 1).
It was found that the formation of the alkyne
bismetallation product 4a could be suppressed by using
a palladium catalyst in the absence of a phosphine
ligand, and Pd2(dba)3×
effective catalyst (runs 1ꢁ
and toluene also can be used (runs 6ꢁ
/
CHCl3 seemed to be the most
6). THF was a suitable solvent
8). It is noteworthy
/
/
that heterogeneous Pd catalysts, Pd/C or Pd(OH)2/C [8],
also afforded the desired product 3a in high yield,
although the reaction time was longer than that in the
Scheme 1.
reaction using Pd2(dba)3×
phosphine ligand (runs 9ꢁ
Various enynes, 1bꢁ1h, were reacted with Bu3Sn-
SiMe3 using Pd2dba3×CHCl3 (Method A) or Pd(OH)2/C
(Method B) and the results are summarized in Table 2.
In each case, the desired product 3 was obtained in
moderate to good yield. The reaction of enyne 1e which
/
CHCl3 in the absence of the
oxidative addition of a Siꢀ
/
Sn reagent to Pd(0) complex
/
11).
would occur producing the intermediate 2 or 2? (Scheme
/
1). Next insertion of the tethered olefin into Pdꢀ
/C bond
/
in 2 or 2? followed by reductive elimination would give a
cyclized compound 3 or 3?. The cyclized compounds 3 or
3? should be converted to various compounds using the
active Siꢀ
/
C and Snꢀ
/
C bonds. Herein, we report a Pd(0)-
catalyzed bismetallative cyclization of enynes in the
has an electron-withdrawing substituent on the Cꢁ
/C
bond afforded the desired product 3e in moderate yield
[9], while the reaction of 1i with a methyl substituent on
presence of Bu3SnSiMe3 [5].
the Cꢁ/C bond (Fig. 1) under the similar conditions
(Method A) gave 3i in only 7% yield. It is noteworthy
that bicyclic heterocycles 3g or 3h was produced
stereospecifically from the corresponding enynes 1g or
1h, respectively. However, in the reaction of 1g, the
alkyne bismetallation product 4g was also obtained,
which resulted in a lower yield of desired product 3g.
The reaction rate of enyne 1j (Fig. 1), which has a
substituent on the alkyne, was relatively slow, and the
cyclized product 3j was obtained in only 5% yield, and
the starting material 1j was recovered in 76% yield after
46 h (Method A).
2. Results and discussions
2.1. Bismetallative cyclization of enynes using
heterogeneous palladium catalysts [5a]
Initially, we investigated the bismetallative cyclization
of 1a using Bu3SnSiMe3 (5) in the presence of Pd(0)
complex. When a THF solution containing equimolar
quantities of enyne 1a and Bu3SnSiMe3 was stirred at
50 8C in the presence of a catalytic amount of Pd(PPh3)4
for 4 h, a small amount of the cyclized product 3a
containing both a silyl group and a stannane group was
obtained in 14% yield. In this reaction, a bismetallated
product of the alkyne, 4a, was obtained as a main
product in 80% yield (Table 1, run 1). The 119Sn-NMR
The possible mechanism of this cyclization is shown in
Scheme 4. Initially, oxidative addition of Bu3SnSiMe3 to
Pd(0) complex occurs to give Bu3Snꢀ
plex (I) [10]. Insertion of the alkyne moiety in the
substrate 1 into the Pdꢀsilicon bond of I produces
/
Pdꢀ/SiMe3 com-
/
spectrum of 4a showed resonances at ꢂ53.2 ppm,
/
intermediate II. The alkyne bismetallation product 4
should be directly formed from the intermediate II
through reductive elimination. On the other hand, for
the formation of the cyclized product 3 from the
intermediate II, two pathways can be considered.
which was unequivocally assigned as a 119Sn peak of
the vinylstannane moiety in 4a. On the other hand, the
119Sn-NMR spectrum of 3a showed resonances at
ꢂ
15.7 ppm, which seemed to be a 119Sn peak of the
/
alkylstannane moiety. An NOE experiment indicated
that the Z-olefin had been formed in the product 3a or
4a (Scheme 2). To confirm the structure of 3a, destan-
nylation was carried out by treating it with HI in the
presence of [Bu4N]I at 0 8C [6] producing a three-
membered ring compound 5a in good yield (Scheme
3). Probably, protonation occurs at the a-position of
vinylsilane in 3a, and then the iodide anion attacks at a
tin atom to close the three-membered ring [7]. This result
indicates that the structure of the cyclized compound
should be 3a and not 3a?.
Intramolecular insertion of the Cꢁ
/
C bond into the Cꢀ
/
Pd bond of II then occurs (i.e., path a) to give complex
III, and reductive elimination finally affords cyclized
product 3, and Pd(0) is regenerated. On the other hand,
the possibility of the formation of IV [3c] cannot be
excluded in this mechanism (path b). Thus, insertion of
the Cꢁ
/
C bond into the Snꢀ/Pd bond in II could give
complex IV. Reductive elimination from IV should
afford the same cyclized product 3. At present, it is
not clear which pathway is followed in this reaction.

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Table 1
Reaction of 1a with Bu3SnSiMe3 in the presence of Pd(0) a
Run
Catalyst
Solvent
Time (h)
Temperature (8C)
Yield (%)
Recovery of 1a (%)
3a
4a
1
2
Pd(PPh3)4
THF
THF
THF
THF
THF
THF
DMF
toluene
THF
THF
THF
4
6
50
reflux
reflux
rt
14
7
80
ꢁ
ꢁ/
ꢁ/
40
/
PdCl2(PPh3)2
Pd(OAc)2dppb
Pd(cod)Cl2
48
34
3
5
20
30
42
63
10
53
86
88
90
4
16
45
16
16
16
114
42
20
ꢁ/
ꢁ/
ꢁ/
ꢁ/
ꢁ/
ꢁ/
ꢁ/
ꢁ/
b
5
PdCl2
rt
ꢁ/
ꢁ/
6
Pd2(dba)3
Pd2(dba)3
Pd2(dba)3
Pd/C
Pd(OH)2/C c
Pd(OH)2/C d
rt
7
rt
15
8
rt
ꢁ/
10
5
9
rt
10
11
rt
rt
2
a
b
c
All reactions were carried out using 3 mol% of Pd catalyst and 1.1 equivalents of Bu3SnSiMe3.
6 mol% of PdCl2 and 1.5 equivalents of Bu3SnSiMe3 were used.
6 mol% of Pd(OH)2 on charcoal and 1.1 equivalents of Bu3SnSiMe3 were used.
10 mol% of Pd(OH)2 on charcoal and 1.5 equivalents of Bu3SnSiMe3 were used.
d
2.2. Pd(0)-catalyzed bismetallative cyclization of enynes
using N-heterocyclic carbene as a ligand [5b]
As described in the previous section, we succeeded in
developing a Pd(0)-catalyzed bismetallative cyclization
of enynes in the presence of Bu3SnSiMe3, in which
various cyclized products 3 having both a vinylsilane
moiety and a homoallylstannane moiety were produced
from enynes 1. The potential of the cyclized product as a
useful synthon prompted us to try to expand this
cyclization to an asymmetric synthesis by virtue of the
use of a chiral ligand in the reaction. Thus, the
Scheme 2.
cyclization of 1a using Pd2(dba)3×/CHCl3 in the presence
of a phosphine ligand was investigated (Table 3).
However, the addition of any ligands (e.g., electron-
rich or -poor phosphorus ligand, bulky phosphine,
bidentate ligand, and so on) in this cyclization resulted
in a decrease in the yield of the cyclized product 3a, and
the formation of a bismetallative product 4a was
increased. We therefore turned our attention to finding
ligands that could be utilized in this bismetallative
cyclization before the development of this reaction to
an asymmetric version.
Recently, nucleophilic N-heterocyclic carbenes have
attracted considerable attention not only as a stable
isolable carbene species [11] but also as molecules to
coordinate to various transition metals [12]. These
transition metal complexes coordinated by N-hetero-
Scheme 3.

Y. Sato et al. / Journal of Organometallic Chemistry 687 (2003) 392ꢁ
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395
Table 2
Bismetallative cyclization of enynes
Fig. 1. Other saturates and products.
Scheme 4.
Initially, bismetallative cyclization of enyne 1f in the
presence of Bu3SnSiMe3 was investigated using a Pdꢀ
carbene catalyst formed from Pd2dba3×CHCl3 and
Method A: Pd2(dba)3 (3 mol%), Bu3SnSiMe3 (1.1 equivalents),
THF, rt; Method B: Pd(OH)2/C (10 mol%), Bu3SnSiMe3 (1.5
equivalents), THF, rt.
/
/
various imidazolium salts 7 in the presence of Cs2CO3
(Table 4) [13c].
The bismetallative cyclization of 1f in the presence of
Bu3SnSiMe3 (1.1 equivalents) using a catalyst formed
cyclic carbenes were expected to have different reactiv-
ities compared with those coordinated by traditional
ligands such as phosphines. In recent palladium chem-
istry, high catalytic efficiency has been found in a variety
from Pd2dba3×/CHCl3 (3 mol%), imidazolium salt 7a (6
mol%), and Cs2CO3 (12 mol%) gave the desired product
3f in only 5% yield along with many by-products, and
the starting material 1f was recovered in 11% yield (run
1). The reaction using 7b, which has aromatic substi-
tuents on both nitrogen atoms in its imidazole skeleton,
showed a tendency similar to that using 7a, giving 3f in a
low yield (5%) (run 2). On the other hand, the use of 7c
having alkyl groups on the nitrogen atoms improved the
yield of 3f up to 21% yield (run 3). Solvent effects were
carefully examined using 7c as an imidazolium salt.
Polar solvents (DMF, CH3CN) retarded the reaction
(runs 4 and 5) and non-polar solvent (runs 6 and 7) or
of reactions, including Suzukiꢁ
KumadaꢁTamaoꢁCorriu-type
MizorokiꢁHeck reaction [15], amination of aryl halide
[16], Sonogashira coupling [17], and TsujiꢁTrost reac-
/
Miyaura coupling [13],
/
/
coupling [14],
/
/
tion [18] by virtue of using nucleophilic carbene as a
ligand. However, there have been no reports on transi-
tion metal-catalyzed bismetallative cyclization using a
nucleophilic carbene as a ligand [19]. So, we tried to use
a nucleophilic carbene as a ligand in this bismetallative
cyclization of enyne.

396
Y. Sato et al. / Journal of Organometallic Chemistry 687 (2003) 392ꢁ402
/
Table 3
Table 4
aThe reaction was carried out at room temperature.
imidazoline skeleton were tolerated in this imidazoli-
nium salt system, and the bismetallative cyclized pro-
duct 3f was obtained in 62% yield in the reaction using
8d [23].
Table 5
chlorinated solvent (runs 8 and 9) were found to be more
suitable for this reaction, giving 3f in 36% yield (toluene
at room temperature, run 7) or 47% yield (ClCH2CH2Cl
at 40 8C, run 8).
Encouraged by these results, we reinvestigated the
effects of substituents on nitrogen atoms in the imida-
zole skeleton of imidazolium salts in the reaction of 1f in
ClCH2CH2Cl at 40 8C (Table 5). The use of imidazo-
lium salts 7dꢁ7f having alkyl groups on the nitrogen
/
atoms gave good results, and the yield of 3f reached 60%
in the reaction using 7f [20,21].
It was found that imidazolinium salts 8 [22], which are
the saturated analogues of imidazolium salts 7, have an
equal or superior reactivity to that of 7 and that the use
of 8 shortened the reaction time (Table 6). Namely, the
bismetallative cyclization of 1f using imidazolinium salt
8a under similar conditions was completed in only 2.5 h
to give cyclized product 3f in 50% yield (run 1).
Contrary to the imidazolium salt system, it is interesting
that aromatic substituents on the nitrogen atoms in the

Y. Sato et al. / Journal of Organometallic Chemistry 687 (2003) 392ꢁ
/
402
397
Table 6
Bismetallative cyclization of 1f using various imidazolinium salts 8 a
Scheme 5.
attack of the reagent to the less-hindered face of
vinylsilane in 9a (Scheme 5). When the epoxide 9a was
subjected to HClO4 in H2Oꢀ
/
THF, a cyclopropanation
reaction stereoselectively proceeded via intermediate 10
to give cyclopropanol derivative 11a in 74% yield (2
steps from 3a).
a
All reactions were carried out using Pd2(dba)3×CHCl3 (3 mol%),
/
imidazolinium salt 8 (6 mol%), and Cs2CO3 (12 mol%) in the presence
of Bu3SnSiMe3 (1.1 equivalents) in ClCH2CH2Cl at 40 8C.
Similarly, the bismetallative cyclized product 3f could
be stereoselectively converted into epoxy-silane 9f,
which was also transformed into cyclopropanol 11f
(Scheme 6). On the other hand, reduction of 9f with
LiAlH4 proceeded in a regio- and stereoselective man-
ner, giving alcohol 12f in 92% yield. These results prove
the utility of the cyclized products obtained by this
bismetallative cyclization.
Next, the bismetallative cyclizations of 1a were
investigated under similar conditions using imidazolium
salt 7f and imidazolinium salts 8aꢁ
case of substrate 1a, the use of imidazolinium salts 8
(runs 2ꢁ5) was more efficient than was the use of 7f (run
/8d (Table 7). In the
/
1), and the bismetallative cyclization using 8d under
conditions similar to those described above gave bisme-
tallative cyclized product 3a in 68% yield (run 5) [24].
2.4. Conclusion
2.3. Utilization of the bismetallative cyclized product as a
synthon
Bismetallative cyclization of enynes with Bu3SnSiMe3
catalyzed by Pd(0) complex was realized for the first
time, which gives cyclized products containing a vinylsi-
lane moiety and a homoallyltin moiety in good yield. In
To evaluate the versatility of the cyclized product as a
synthon, transformation using the metalꢀ/carbon bond
this cyclization, Pd2(dba)3×/CHCl3 or Pd(OH)2 on char-
of the product was investigated. Treatment of 3a with
m-CPBA produced epoxy-silane 9a in good yield. In this
reaction, epoxidation stereoselectively proceeded by
coal is effective as a Pd(0) catalyst, and the addition of a
phosphine ligand increased the formation of alkyne
bismetallation by-product. On the other hand, it was
found that a nucleophilic N-heterocyclic carbene could
be utilized as a ligand for this cyclization. It has been
proven that an imidazolium salt having a bulky alkyl
group attached to the nitrogen atoms in its imidazol-2-
Table 7
Bismetallative cyclization of 1a
Run
7 or 8
Time (h)
3a (%)
1
2
3
4
5
7f
36
12
11
16
11
25 a
58
8a
8b
8c
8d
50
59
68
a
1a was recovered in 34% yield.
Scheme 6.

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Y. Sato et al. / Journal of Organometallic Chemistry 687 (2003) 392ꢁ402
/
ylidene skeleton or an imidazolinium salt is suitable as a
ligand precursor. In addition, the utility of the cyclized
products obtained from this cyclization in synthetic
organic chemistry have been proven by transformation
into cyclopropanol derivatives. Although the develop-
ment of this bismetallative reaction to an asymmetric
version has not been achieved yet, the present study is
the first study in which a nucleophilic N-heterocyclic
carbene was used as a ligand of a Pd(0) catalyst for this
type of reaction.
mmol) in ClCH2CH2Cl (0.7 ml) at 0 8C, and the solution
was stirred at 40 8C for 11 h. After removal of the
solvent, the residue was purified by column chromato-
graphy on silica gel (hexane/AcOEtꢃ100/1) to give 3a
/
as a colorless oil (81 mg, 68%).
3.3. Spectral data of cyclized products
3.3.1. 1,1-Bis(ethoxycarbonyl)-3-
(tributylstannyl)methyl-4-(Z)-
(trimethylsilyl)methylidene-cyclopentane (3a)
;
IR (neat) 1734, 1628, 1602, 1266, 1110 cmꢂ1 1H-
3. Experimental
NMR (270 MHz, CDCl3) d 0.06 (s, 9 H), 0.78ꢁ
6H), 0.87 (t, Jꢃ7.5 Hz, 9H), 0.96 (d, Jꢃ12.7 Hz, 1H),
1.06 (dd, Jꢃ12.7, 3.2 Hz, 1H), 1.20 (t, Jꢃ6.7 Hz, 6H),
1.17ꢁ1.32 (m, 6H), 1.40ꢁ1.52 (m, 6H), 1.69 (dd, Jꢃ
13.3, 5.5 Hz, 1H), 2.68 (dd, Jꢃ15.8, 13.3 Hz, 1H), 2.70
(d, Jꢃ16.2 Hz, 1H), 2.75ꢁ2.88 (m, 1H), 3.28 (dt, Jꢃ
16.2, 2.0 Hz, 1H), 4.16 (q, Jꢃ7.5 Hz, 4H), 5.25 (s, 1H)
ppm; 13C-NMR (68 MHz, CDCl3) d ꢂ
0.3, 8.8, 13.2,
13.6, 26.9, 28.8, 39.8, 42.1, 43.9, 58.0, 60.8, 60.9, 119.3,
164.9, 171.2, 171.6 ppm. 119Sn-NMR (C6D6) d ꢂ
15.7
ppm; EI-LRMS m/z 545 [Mꢀ ꢀ
Bu]; EI-HRMS Calcd.
Bu]; Found:
/
0.96 (m,
/
/
All manipulations were performed under an argon
atmosphere unless otherwise mentioned. All solvents
and reagents were purified when necessary using stan-
dard procedures. Column chromatography was per-
/
/
/
/
/
/
/
/
/
formed on silica gel 60 (Merck, 70ꢁ
flash chromatography was performed with silica gel 60
(Merck, 230ꢁ
400 mesh) using the indicated solvent. 1H-
/
230 mesh), and
/
/
/
(270 MHz), 13C- (125 MHz), and 119Sn (100.6 MHz)-
NMR spectra were recorded on a JEOL EX-270 (1H
and 119Sn) and Bruker ARX-500 (13C) spectrometers.
1H and 13C chemical shifts were referenced to internal
Me4Si or internal CHCl3. 119Sn chemical shift was
referenced to external Me4Sn. Mass spectra were
measured on a JEOL JMS 700TZ mass spectrometer.
Pd/C was purchased from N.E. Chemcat and Pd(OH)2/
C was prepared from PdCl2 according to the literature
(W.M. Pearlman, Tetrahedron Lett. (1967) 1663).
/
/
for C24H45O4SiSn 545.2109 [Mꢀ ꢀ
/
545.2106.
3.3.2. 1,1-Bis(benzoyloxymethyl)-3-
(tributylstannyl)methyl-4-(Z)-(trimethylsilyl)-
methylidenecyclopentane (3b)
;
IR (neat) 1724, 1624, 1602, 1266, 1110 cmꢂ1 1H-
NMR (CDCl3) d 0.12 (s, 9H), 0.77ꢁ
(dd, Jꢃ12.9, 13.3 Hz, 1H), 1.19 (dd, Jꢃ
1H), 1.23ꢁ1.30 (m, 6H), 1.40 (dd, Jꢃ5.9, 13.3 Hz, 1H),
1.42ꢁ1.52 (m, 6H), 2.13 (dd, Jꢃ8.9, 13.3 Hz, 1H), 2.37
(d, Jꢃ15.4 Hz, 1H), 2.83 (d, Jꢃ15.4 Hz, 1H), 2.84ꢁ
2.92 (m, 1H), 4.21 (d, Jꢃ11.1 Hz, 1H), 4.28 (d, Jꢃ11.1
Hz, 1H), 4.39 (d, Jꢃ11.0 Hz, 1H), 4.42 (d, Jꢃ11.0 Hz,
1H), 5.34 (s, 1H), 7.42 (dd, Jꢃ7.3, 7.4 Hz, 4H), 7.56 (t,
Jꢃ7.4 Hz, 2H), 8.03 (d, Jꢃ
7.3 Hz, 4H) ppm; 13C-
/0.90 (m, 15H), 1.06
/
/2.7, 12.9 Hz,
3.1. Typical procedure for bismetallative cyclization of
enyne 1a using Pd(OH)2/C
/
/
/
/
/
/
/
A solution of ethyl 2-allyl-2-propargylmalonate 1a
(104.5 mg, 0.44 mmol) and Me3SiSnBu3 (0.23 ml, 0.658
mmol) in THF (2.2 ml) was stirred in the presence of
20% Pd(OH)2/C (30.8 mg, 0.044 mmol) at room
temperature for 20 h. Diethyl ether was added and the
ether layer was washed with brine and dried over
Na2SO4. The organic layer was evaporated, and the
residue was purified by column chromatography on
/
/
/
/
/
/
/
NMR (CDCl3) d 0.2 (CH3), 9.3 (CH2), 13.6 (CH3), 20.3
(CH2), 27.4 (CH2), 29.2 (CH2), 39.6 (CH), 41.0 (CH2),
43.3 (CH2), 44.5 (CH2), 66.7 (CH2), 68.9 (CH2), 120.6
(CH), 128.4 (CH), 129.5 (CH), 129.9 (C), 130.0 (C),
133.0 (CH), 166.5 (C) ppm; 119Sn-NMR (CDCl3) d
silica gel (hexaneꢁdiethyl ether, 10/1) to give 3a as a
colorless oil (236.1 mg, 90%).
/
ꢂ
/
15.2 ppm; EI-MS m/z 669 [Mꢀ ꢀ
241, 179, 105; EI-HRMS m/z Calcd. for C37H55O4S-
i120Sn [Mꢀ ꢀ
Meꢀ1] 711.2892; Found: 711.2903.
/
Buꢀ
/
1], 355, 291,
3.2. Typical procedure for bismetallative cyclization of 1a
in the presence of Bu3SnSiMe3 using Pd2(dba)3×
imidazolinium salt 8d/Cs2CO3
/
/
/CHCl3/
3.3.3. 1,1-Bis(benzyloxymethyl)-3-
(tributylstannyl)methyl-4-(Z)-(trimethylsilyl)-
methylidenecyclopentane (3c)
A solution of Pd2(dba)3×
/
CHCl3 (6 mg, 0.006 mmol),
1
imidazolinium salt 8d (7 mg, 0.012 mmol), and Cs2CO3
(8 mg, 0.024 mmol) in degassed ClCH2CH2Cl (0.3 ml)
was stirred at 50 8C for 10 min, and the solution was
cooled to 0 8C. To the solution were added Bu3SnSiMe3
(80 ml, 0.23 mmol) and a solution of 1a (48 mg, 0.20
IR (neat) 1624, 1246, 1110 cmꢂ1; H-NMR (CDCl3)
d 0.00 (s, 9H), 0.82 (t, Jꢃ
6H), 0.95ꢁ1.00 (m, 2H), 1.10ꢁ
(m, 6H), 1.84 (dd, Jꢃ13.4, 8.7 Hz, 1H), 2.07 (d, Jꢃ
15.0 Hz, 2H), 2.54 (d, Jꢃ15.0 Hz, 2H), 2.51ꢁ2.70 (m,
/
7.3 Hz, 9H), 0.74ꢁ
/
0.84 (m,
/
/
1.30 (m, 7H), 1.35ꢁ
/1.46
/
/
/
/

Y. Sato et al. / Journal of Organometallic Chemistry 687 (2003) 392ꢁ
/
402
399
1H), 3.16 (d, Jꢃ
3.36 (d, Jꢃ10.7 Hz, 1H), 3.40 (d, Jꢃ
(s, 2H), 4.46 (s, 2H), 5.12 (s, 1H), 7.19ꢁ
/
9.9 Hz, 1H), 3.19 (d, Jꢃ
10.7 Hz, 1H), 4.42
7.26 (m, 10H)
/
9.9 Hz, 1H),
H, 8.39; N, 2.29; S, 5.23. Found: C, 55.31; H, 8.39, N,
2.33; S, 5.20%.
/
/
/
ppm; 13C-NMR (CDCl3) d 0.3 (CH3), 9.4 (CH2), 11.7
(CH), 13.7 (CH3), 27.5 (CH2), 29.3 (CH2), 39.8 (CH2),
41.1 (C), 43.4 (CH2), 46.0 (CH), 72.4 (CH), 73.1 (CH),
73.2 (CH), 75.1 (CH), 118.8 (CH), 127.3 (CH), 128.2
(CH), 1138.9 (CH), 139.0 (C), 169.0 (C) ppm; EI-MS m/
3.3.7. (1S*,2R*,6S*)-N-p-Toluenesulfonyl-2-
tributylstannyl-9-(E)-trimethylsilylmethylidene-7-
azabicyclo[4.3.0]nonane (3g)
1H-NMR (270 MHz, CDCl3) d 0.03 (s, 9H), 0.88 (t,
Jꢃ
1.85ꢁ
(d, Jꢃ
1H), 7.31 (d, Jꢃ
ppm; 119Sn-NMR (100.55 MHz, C6D6) d ꢂ
IR (neat) 1636, 1350, 1162 cmꢂ1; MS m/z 653 [Mꢀ],
Bu]; HRMS Calcd. for C31H55NO2SSiSn
/
7.1 Hz, 9H), 0.80ꢁ
1.94 (m, 1H), 2.41 (s, 3H), 2.73ꢁ
15.4 Hz, 1H), 4.12 (d, Jꢃ15.4 Hz, 1H), 5.10 (s,
8.1 Hz, 1H), 7.63 (d, Jꢃ8.1 Hz, 1H)
14.2 ppm;
/
1.06 (m, 6H), 1.11ꢁ
/
1.66 (m, 17H),
z
641 [Mꢀ ꢀ
C34H53O2Si120Sn [Mꢀ ꢀ
/
Bu], 91; EI-HRMS m/z Calcd. for
Bu] 641.2848; Found: 641.2865.
/
/2.86 (m, 3H), 3.44
/
/
/
/
/
3.3.4. 8,8-Dimethyl-2-(tributylstannyl)methyl-3-(Z)-
(trimethylsilyl)methylidene-7, 9-dioxaspiro[4.5]decane
(3d)
/
596 [Mꢀ ꢀ
/
1
IR (neat) 1624, 1246, 1198 cmꢂ1; H-NMR (CDCl3)
652.6354; Found: 653.2745.
d 0.08 (s, 9H), 0.80ꢁ
13.0 Hz, 1H), 1.00 (dd, Jꢃ
Jꢃ2.8, 12.9 Hz, 1H), 1.25ꢁ
1.42 (s, 3H), 1.44ꢁ1.52 (m, 6H), 1.86 (dd, Jꢃ
Hz, 1H), 2.38 (d, Jꢃ15.3 Hz, 1H), 2.50 (d, Jꢃ
1H), 2.70ꢁ2.74 (m, 1H), 3.48 (d, Jꢃ11.4 Hz, 1H), 3.51
(d, Jꢃ11.4 Hz, 1H), 3.62 (d, Jꢃ11.2 Hz, 1H), 3.73 (d,
Jꢃ
11.2 Hz, 1H) 5.28 (s, 1H) ppm; 13C-NMR (CDCl3) d
/
0.91 (m, 15H), 0.96 (dd, Jꢃ
5.4, 13.3 Hz, 1H), 1.10 (dd,
1.34 (m, 6H), 1.40 (s, 3H),
8.5, 13.3
15.3 Hz,
/12.9,
/
3.3.8. (1S*,2R*,6S*)-N-p-Toluenesulfonyl-2-
tributylstannyl-9-N-diphenylmethyl-2-tributylstannyl-9-
(E)-(trimethylsilyl)methylidene-7-
/
/
/
/
/
/
azabicyclo[4.3.0]nonane (3h)
1H-NMR (270 MHz, CDCl3) d 0.01 (s, 9H), 0.69ꢁ
/
/
/
/
/
1.03 (m, 15H), 1.08ꢁ
2.82 (dd, Jꢃ15.4, 2.2 Hz, 1H) 2.81ꢁ
(br d, Jꢃ15.4 Hz, 1H), 4.62 (s, 1H), 4.99 (br s, 1H),
7.07ꢁ7.35 (m, 8H), 7.38 (d, Jꢃ
6.7 Hz, 2H) ppm; 119Sn-
NMR (100.55 MHz, C6D6) d ꢂ26.0 ppm; IR (neat)
3026, 1636, 1492, 1454, 1352, 1166 cmꢂ1; MS m/z 650
[Mꢀ ꢀMe], 608 [Mꢀ ꢀBu]; HRMS [Mꢀ ꢀ
Bu] Calcd. for
/
1.81 (m, 19H), 2.56ꢁ/2.62 (m, 1H),
/
/
/2.87 (m, 1H), 3.58
0.2 (CH3), 9.3 (CH2), 13.7 (CH3), 20.3 (CH2), 22.1
(CH3), 25.5 (CH3), 27.4 (CH2), 29.3 (CH2), 39.3 (CH),
39.8 (C), 41.9 (CH2), 44.4 (CH2), 67.7 (CH2), 70.1
(CH2), 97.7 (C), 120.0 (CH), 167.4 (C) ppm; 119Sn-NMR
/
/
/
/
(CDCl3) d ꢂ
501, 443, 413, 291, 249, 235, 193, 177; EI-HRMS m/z
Me] 543.2680; Found
/
15.4 ppm; EI-MS m/z 543 [Mꢀ ꢀ
Calcd. for C26H51O2Si120Sn [Mꢀ ꢀ
/
Meꢀ1],
/
/
/
/
C33H50NSiSn 608.2735; Found: 608.2755. Anal. Calcd.
for C37H59NSiSn: C, 66.86; H, 8.95; N, 2.11. Found: C,
67.11; H, 8.98; N, 2.09%.
/
543.2704. Anal. Calcd. for C27H54O2SiSn: C, 58.17; H,
9.76. Found: C, 57.87; H, 9.67%.
3.4. Reaction of the cyclized products
3.3.5. 1,1-Bis(methoxycarbonyl)-3-{1-(tributylstannyl)-
1-(methoxycarbonyl)methyl}-4-(Z)-
(trimethylsilyl)methylidenecyclopentane (3e)
3.4.1. Procedures for transformation of 3a into 5a
(Scheme 2)
1H-NMR (CDCl3) d 0.08 (s, 9H), 0.91 (t, Jꢃ
/
7.3 Hz,
1H)ꢃ25.1
1.72 (m, 6H), 2.51 (dd,
2.94 (m, 4H), 3.51 (d, Jꢃ
2
9H), 1.01 (dd, Jꢃ
Hz), 1.23ꢁ1.40 (m, 6H), 1.44ꢁ
Jꢃ8.6, 10.6 Hz, 1H), 2.62ꢁ
/
7.9, 8.6 Hz, 6H, J(119Snꢀ
/
/
To a solution of 3a (48 mg, 0.08 mmol) in toluene (0.5
ml) was added aqueous HI solution (57%, 0.10 ml, 0.80
mmol) at 0 8C and the solution was stirred at the same
temperature for 1 h. To this solution was added
saturated NaHCO3 solution and the aqueous layer was
extracted with diethyl ether. The organic layer was
washed with brine and dried over Na2SO4. After
removal of the solvent, the residue was purified by
/
/
/
/
/
15.8 Hz, 1H), 3.56 (s, 3H), 3.70 (s, 3H), 3.74 (s, 3H), 5.38
(s, 1H).
3.3.6. N-p-Toluenesulfonyl-4-(tributylstannyl)methyl-3-
(E)-(trimethylsilyl)-methylidenepyrrolidine (3f)
1H-NMR (270 MHz, CDCl3) d 0.04 (s, 9H), 0.71ꢁ
/
column chromatography on silica gel (hexaneꢁ
/
ethyl
acetate, 9/1) to give 5a (18 mg, 72%). H-NMR (270
MHz, CDCl3) d 0.02 (s, 9H), 0.17 (dd, Jꢃ5.5, 4.4 Hz,
1H), 0.26 (dd, Jꢃ7.1, 5.5 Hz, 1H), 0.58 (d, Jꢃ14.6 Hz,
1H), 0.96 (d, Jꢃ14.6 Hz, 1H), 0.94ꢁ
(t, Jꢃ7.1 Hz, 6H), 2.20 (dd, Jꢃ
(d, Jꢃ13.4 Hz, 1H), 2.49 (d, Jꢃ
Jꢃ13.5 Hz, 1H), 4.11ꢁ4.24 (m, 4H) ppm; IR (neat)
1732, 1446 cmꢂ1; MS m/z 312 [Mꢀ], 297 [Mꢀ ꢀ
Me],
239 [Mꢀ ꢀ
SiMe3]; HRMS Calcd. for C16H28O4Si:
312.1757; Found: 312.1769.
1
1.21 (m, 8H), 0.88 (t, Jꢃ
6H), 1.39ꢁ1.59 (m, 6H), 2.40 (s, 3H), 2.79ꢁ
3.02 (dd, Jꢃ9.3, 1.8 Hz, 1H), 3.15 (dd, Jꢃ
1H), 3.54 (dd, Jꢃ14.1, 1.6 Hz, 1H), 4.03 (d, Jꢃ
Hz, 1H), 5.18 (br s, 1H), 7.29 (d, Jꢃ8.4 Hz, 2H), 7.68
(d, Jꢃ
8.4 Hz, 2H) ppm; 119Sn-NMR (100.55 MHz,
C6D6) d ꢂ
15.8 ppm; IR (neat) 1630, 1376, 1166 cmꢂ1
MS m/z 598 [Mꢀ ꢀMe], 556 [Mꢀ ꢀBu]; HRMS (Mꢀ-
/
7.1 Hz, 9H), 1.24ꢁ
2.86 (m, 1H),
9.3, 7.2 Hz,
14.1
/
1.36 (m,
/
/
/
/
/
/
/
/
/
/
/
1.01 (m, 1H), 1.22
/
/
/13.5, 1.4 Hz, 1H), 2.44
/
/
/
13.4 Hz, 1H), 2.57 (d,
/
;
/
/
/
/
/
Bu) Calcd. for C24H42NO2SSiSn: 556.1727; Found:
556.1733. Anal. Calcd. for C28H51NO2SSiSn: C, 54.90;
/

400
Y. Sato et al. / Journal of Organometallic Chemistry 687 (2003) 392ꢁ402
/
3.4.2. Procedures for transformation of 3a into 11a via 9a
(Scheme 5)
3.4.4. Procedures for transformation of 9f into 11f
(Scheme 6)
To a solution of 9f (16 mg, 0.03 mmol) in THF (1 ml)
To a solution of 3a (20 mg, 0.03 mmol) in CH2Cl2 (0.7
ml) was added m-CPBA (9 mg, 0.05 mmol) at 0 8C, and
the mixture was stirred at room temperature for 1 h. To
the mixture was added 10% Na2S2O3 aqueous solution,
and the aqueous layer was extracted with CH2Cl2. The
combined organic layer was washed with saturated
NaHCO3 aqueous solution, brined, and dried over
MgSO4. After removal of the solvent, the residual crude
product 9a was dissolved in THF (1 ml). To the solution
was added 7% HClO4 in THFꢁH2O (9:1) solution (0.5
/
ml), and the mixture was stirred at 30 8C for 1 h. To the
mixture was added saturated NaHCO3 aqueous solution
at 0 8C, and the aqueous layer was extracted with
EtOAc. The combined organic layer was washed with
brine and dried over Na2SO4. After removal of the
solvent, the residue was purified by column chromato-
graphy on silica gel (hexaneꢁ
(7 mg, 77%) as a colorless oil. 1H-NMR (270 MHz,
CDCl3) d ꢂ0.07 (s, 9H), 0.61 (dd, Jꢃ7.1, 5.1 Hz, 1H),
0.59ꢁ0.64 (m, 1H), 1.32 (ddd, Jꢃ7.1, 4.0, 4.0 Hz, 1H),
1.43 (bs, 1H), 2.42 (s, 3H), 2.96 (d, Jꢃ9.5 Hz, 1H), 3.51
(d, Jꢃ9.5 Hz, 1H), 7.31 (d, Jꢃ8.1 Hz, 2H), 7.66 (d,
Jꢃ
8.1 Hz, 2H) ppm; 13C-NMR (100 MHz, CDCl3) d
2.74, 9.97, 13.4, 20.5, 21.6, 32.3, 49.8, 51.9, 68.7,
/
Et2O, 4/1ꢁ1/1) to give 11f
/
was added 7% HClO4 in THFꢁH2O (9:1) solution (0.7
/
ml), and the mixture was stirred at room temperature
for 30 min. To the mixture was added saturated
NaHCO3 aqueous solution at 0 8C, and the aqueous
layer was extracted with EtOAc. The combined organic
layer was washed with brine and dried over Na2SO4.
After removal of the solvent, the residue was purified by
/
/
/
/
/
/
/
/
ꢂ
/
column chromatography on silica gel (hexaneꢁEtOAc,
/
127.6, 129.5, 132.8, 143.5 ppm; IR (neat) 3518, 1341,
1164 cmꢂ1; EI-LRMS m/z 324 [Mꢀ], 309, 279, 252.
10/1) to give 11a (8 mg, 74%, 2 steps) as a colorless oil.
1H-NMR (400 MHz, CDCl3) d 0.11 (s, 9H), 0.28 (dd,
Jꢃ
(t, Jꢃ
(m, 1H), 1.36 (bs, 1H), 2.38 (dd, Jꢃ
2.42 (d, Jꢃ13.5 Hz, 1H), 2.59 (d, Jꢃ
(d, Jꢃ13.8 Hz, 1H), 3.04 (s, 1H), 4.14 (q, Jꢃ
2H), 4.15 (q, Jꢃ
7.3 Hz, 2H) ppm; 13C-NMR (100
MHz, CDCl3) d ꢂ2.18, 14.4, 15.0, 22.7, 34.1, 36.2,
/
5.3, 4.7 Hz, 1H), 0.50 (dd, Jꢃ
7.3 Hz, 3H), 1.23 (t, Jꢃ7.3 Hz, 3H), 1.26ꢁ
13.8, 5.0 Hz, 1H),
13.5 Hz, 1H), 2.61
7.3 Hz,
/
6.5, 5.3 Hz, 1H), 1.20
/
/
/
1.32
3.4.5. Procedures for transformation of 9f into 12f
(Scheme 6)
/
/
/
To a solution of 9f (17 mg, 0.03 mmol) in THF (1.5
ml) was added LiAlH4 (3 mg, 0.08 mmol) at 0 8C and
the mixture was stirred at room temperature for 40 min.
/
/
/
/
38.8, 60.6, 62.1, 71.4, 172.3, 172.9 ppm; IR (neat) 3528,
1732 cmꢂ1; EI-LRMS m/z 328 [Mꢀ], 313, 254.
To the solution was added Na2SO4×10H2O at 0 8C, and
/
the mixture was stirred at room temperature for 3 h. The
mixture was filtered through a pad of celite, and the
filtrate was concentrated. The residue was purified by
3.4.3. Procedures for transformation of 3f into 9f
(Scheme 6)
column chromatography on silica gel (hexaneꢁEt2O, 3/
/
1
To a solution of 3f (101 mg, 0.16 mmol) in CH2Cl2 (3
ml) was added m-CPBA (53 mg, 0.24 mmol) at 0 8C and
the mixture was stirred at room temperature for 5 h. To
the mixture was added 10% Na2S2O3 aqueous solution
and the aqueous layer was extracted with CH2Cl2. The
combined organic layer was washed with saturated
NaHCO3 aqueous solution, brined, and dried over
MgSO4. After removal of the solvent, the residue was
purified by column chromatography on silica gel
1) to give 12f (15 mg, 92%) as a colorless oil. H-NMR
(270 MHz, CDCl3) d 0.09 (s, 9H), 0.47 (dd, Jꢃ12.9,
11.1 Hz, 1H), 0.81 (t, Jꢃ7.9 Hz, 6H), 0.88 (t, Jꢃ7.9
Hz, 9H), 0.91 (d, Jꢃ11.1 Hz, 1H), 1.20ꢁ1.35 (m, 6H),
1.40ꢁ1.51 (m, 6H), 2.23 (dd, Jꢃ11.1, 4.0 Hz, 1H), 2.41
(s, 3H), 2.96 (d, Jꢃ8.7 Hz, 1H), 3.13 (d, Jꢃ8.5 Hz,
1H), 3.17 (d, Jꢃ8.5 Hz, 1H), 3.47 (dd, Jꢃ8.7, 4.0 Hz,
1H), 3.59 (s, 1H), 7.29 (d, Jꢃ8.0 Hz, 2H), 7.76 (d, Jꢃ
/
/
/
/
/
/
/
/
/
/
/
/
/
8.0 Hz, 2H) ppm; 13C-NMR (100 MHz, CDCl3) d 0.7,
9.0, 9.6, 14.1, 21.9, 22.1, 27.8, 29.5, 49.5, 54.2, 59.0, 82.8,
127.7, 129.9, 134.2, 143.6 ppm; IR (neat) 3510, 1341,
1162 cmꢂ1; EI-LRMS m/z 630 [Mꢀ], 614, 574, 558. EI-
(hexaneꢁ
a colorless oil. H-NMR (270 MHz, CDCl3) d 0.09 (s,
9H), 0.69 (dd, Jꢃ13.7, 13.3 Hz, 1H), 0.85 (t, Jꢃ7.1 Hz,
6H), 0.88 (t, Jꢃ7.1 Hz, 9H), 0.99 (d, Jꢃ13.3 Hz, 1H),
1.21ꢁ1.35 (m, 6H), 1.38ꢁ1.50 (m, 6H), 1.91 (dd, Jꢃ
13.7, 4.4 Hz, 1H), 2.25 (s, 1H), 2.39 (s, 3H), 2.85 (d, Jꢃ
11.5 Hz, 1H), 3.19 (d, Jꢃ9.1 Hz, 1H), 3.32 (dd, Jꢃ9.1,
4.4 Hz, 1H), 3.95 (d, Jꢃ11.5 Hz, 1H), 7.25 (d, Jꢃ8.3
Hz, 2H), 7.68 (d, Jꢃ
8.3 Hz, 2H) ppm; 13C-NMR (68
/
EtOAc, 15/1ꢁ13/1) to give 9f (90 mg, 89%) as
/
1
/
/
/
/
HRMS Calcd. for C28H52NO2SSiSn [Mꢀ ꢀ
/
OH]:
/
/
/
614.2487; Found: 614.2510.
/
/
/
/
/
/
Acknowledgements
MHz, CDCl3) d 9.27, 11.6, 13.6, 21.5, 27.4, 29.1, 40.9,
52.9, 53.1, 54.3, 73.3, 127.5, 129.7, 133.9, 143.4 ppm; IR
(neat) 1350, 1250, 1164, 842 cmꢂ1; EI-LRMS m/z 628
[Mꢀ], 572, 458, 416. EI-HRMS Calcd. for
C28H51NO3SSiSn: 628.2327; Found: 628.2366.
This work was financially supported by a Grand-in-
Aid for Scientific Research from the Japan Society of
the Promotion of Science (No. 14703031).

Y. Sato et al. / Journal of Organometallic Chemistry 687 (2003) 392ꢁ
/
402
401
(b) M. Hada, Y. Tanaka, M. Ito, M. Murakami, H. Amii, Y. Ito,
H. Nakatsuji, J. Am. Chem. Soc. 116 (1994) 8754.
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[5] Portions of this work have previously been communicated: (a) M.
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[21] In the reaction using a chiral imidazolium salt 7f, the cyclized
product 3f was obtained in 2% ee, which was determined by the
1H-NMR spectrum of MPTA ester of 11f after derivation of 3f by
the procedure shown in Scheme 6.
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Tetrahedron: Asymmetry 12 (2001) 2083;
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whose stereochemistry has not been determined yet.
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402
Y. Sato et al. / Journal of Organometallic Chemistry 687 (2003) 392ꢁ402
/
(d) A novel imidazolinium salt 8d was synthesized by the similar
procedure reported in Ref. [22c].
[24] The cyclized products 3a in Table 7 were obtained with a low
enantiomeric excess (e.g., 7f0not determined, 8a01% ee, 8b0
2% ee, 8c06% ee, 8d0
8% ee), which was determined by the 1H-
/
/
/
[23] The cyclized products 3f in the reaction using imidazolinium salts
8aꢁ8d were obtained with a low enantiomeric excess (e.g., 8a0
1% ee, 8b0
/
/
/
/
NMR spectrum of MPTA ester of 11a after derivation of 3a by
/
3% ee, 8c0
/
2% ee, 8d01% ee), which was also
/
the procedure shown in Scheme 5.
determined by the 1H-NMR spectrum of MPTA ester of 11f
derived from 3f.