Transition metal-catalyzed pentannulation of propargyl acetates via styrylcarbene intermediates

Article abstract of DOI:10.1016/j.tet.2007.09.064

The indene formation from phenyl-substituted sec- and tert-propargyl esters (terminal alkynes) was achieved by platinum or ruthenium catalysis via E-vinylcarbenoid intermediate. Considering the competitive reactions of pentannulation versus cyclopropanati

Full text of DOI:10.1016/j.tet.2007.09.064

Tetrahedron 63 (2007) 12138–12148
Transition metal-catalyzed pentannulation of propargyl
acetates via styrylcarbene intermediates
*
Yusuke Nakanishi, Koji Miki and Kouichi Ohe
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Katsura,
Nishikyo-ku, Kyoto 615-8510, Japan
Received 28 August 2007; revised 20 September 2007; accepted 22 September 2007
Available online 29 September 2007
Dedicated to the heartfelt memory of late Professor Yoshihiko Ito
Abstract—The indene formation from phenyl-substituted sec- and tert-propargyl esters (terminal alkynes) was achieved by platinum or ru-
thenium catalysis via E-vinylcarbenoid intermediate. Considering the competitive reactions of pentannulation versus cyclopropanation, the
equilibrium ratios of E and Z vinylcarbenoid intermediates from sec- and tert-propargyl esters are estimated at ca. 10:90 and 40:60, respec-
tively. Two reaction pathways, Nazarov-type cyclization and/or metallacycle from styrylcarbenoid species, are proposed by considering ratios
of products in the control experiment.
Ó 2007 Elsevier Ltd. All rights reserved.
[M]
1. Introduction
OR
OR [M]
Rs
OR
Rs
O
RL
RL
Vinylcarbene complexes are versatile intermediates in or-
ganic synthesis and widely applicable to stoichiometric and
catalytic annulations.1 Metallatrienes2 including a vinylcar-
bene moiety are the key intermediates for benzannulation re-
CO
Rs
RL
Z-metallatriene
furan
€
actions (Dotz reactions) based on a pentacarbonylchromium
template. Meanwhile, the unique benzannulations are known
to competewith non-CO-incorporated cyclization ofinterme-
diary vinylcarbene complexes to give five-membered rings
such as cyclopentadiene or indene derivatives (Scheme 1).3
OR
OR
OR
Rs
RL
Rs
Rs
[M]
[M] RL
RL
cyclopentadiene
(indene)
E-metallatriene
We have previously developed catalytic reactions via vinyl-
carbene complexes generated from sec- and tert-propargyl
carboxylates with a wide range of transition metals.4 We re-
ported that the intermolecular cyclopropanation and intra-
molecular pentannulation reactions (indene formation) via
vinylcarbene complexes as intermediates are effectively
catalyzed by [RuCl2(CO)3]2.4b The reactions of 1-phenyl-
2-propynyl acetate with several alkenes afforded (Z)-1-
acetoxy-2-phenylvinyl cyclopropanes exclusively, while
1,1-diphenyl-2-propynyl acetate gave 3-phenyl-1H-inden-2-
yl acetate as a major product (Scheme 2). Thus, the distribu-
tion of products was influenced by substituents at a propargyl
position. The proposed mechanism for the generation of
vinylcarbene complexes from propargyl acetates is illustrated
in Scheme 3. The ruthenium vinylcarbene complex gener-
ated from sec-propargyl ester (RL¼Ph, RS¼H) favors a
CO
Dötz reaction
[M] = Cr(CO)5, Mo(CO)5, W(CO)5
Scheme 1. Non-CO-incorporated cyclization or pentannulation of metalla-
trienes.
(Z)-structure A that minimizes sterical repulsion, and thus
the intermolecular cyclopropanation occurs preferentially
rather than pentannulation (indene formation) (Scheme 2).
On the other hand, a tert-propargyl ester (RS¼RL¼Ph)
affords a single intermediate (A¼B), and the carbene center
undergoes a formal insertion into a C–H bond of a proximal
phenyl ring to give 3-phenyl-1H-inden-2-yl acetate. Sarpong
et al. reported that the PtCl2(PPh3)2/PhIO-catalyzed pent-
annulation of tert-propargyl ester having an electron-with-
drawing group at the alkyne terminus (internal alkynes)
affords indenes (Scheme 4).5 Most recently, Wang et al. de-
veloped the Au-catalyzed synthesis of indene derivatives
* Corresponding author. Tel.: +81 75 383 2495; fax: +81 75 383 2499;
e-mail: ohe@scl.kyoto-u.ac.jp
0040–4020/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2007.09.064

Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
12139
OAc
from propargyl sulfides and related dithioacetals (Scheme
5).6 When we reinvestigated pentannulation of several prop-
argyl esters under transition metal catalysis, we found that
steric and electronic modification of propargyl esters affect
the intermediacy, followed by indene formation. We wish
to report herein the scope and limitation of transition
metal-catalyzed indene synthesis using sec- and tert-prop-
argyl acetates (terminal alkynes).
cat. MLn (2.5 mol%)
solvent, 48 h
OAc
Ph
1a
2a
cat.
solvent
DCE
50 °C
trace
0%
60 °C
trace
8%
70 °C
5%
[RuCl2(CO)3]2
PtCl2
toluene
17%
Scheme 6. Ru- and Pt-catalyzed indene formation from 1a.
cat.
OAc
[RuCl2(CO)3]2
Ph
R
R
R1 = H
On the other hand, PtCl2-catalyzed pentannulation of 1a at
60 and 70 ꢀC gave 2a in 8% and 17% yields, respectively, al-
though it was still sluggish at 50 ꢀC. In the same reaction of
1a, PtCl2(PPh3)2/PhIO5 as well as AuCl(PPh3) with/without
OAc
R
Ph
Ph
cat.
R
R1
[RuCl2(CO)3]2
OAc
2b
R1 = Ph
AgSbF6 exhibited marginal catalytic activity, yielding 2a
up to 9% at 70 ꢀC. Based on these preliminary results, we
further investigated the PtCl2-catalyzed pentannulation of
sec-propargyl esters 1b–l having several substituents on
a phenyl ring. Results are summarized in Table 1. sec-Prop-
argyl acetates having para-tolyl or ortho- and para-anisyl
substituents gave low yields of the corresponding indenes
(entries 1–3). In each case, major products were 5- or 7-
substituted 1H-inden-2-yl acetates. meta-Anisyl-substituted
ester 1g gave 6-methoxy-1H-inden-2-yl acetate 2g in 45%
yield (entry 4). As the number of methoxy substituents at
meta- and para-positions increased, yields of indenes were
increased (entries 5 and 6). The reaction of 3,4-methylene-
dioxyphenyl-substituted ester 1j–l resulted in the highest
yield of an indene, giving 2j in 64% yield (entry 7). 3,4-
Methylenedioxyphenyl-substituted benzoic and pivalic es-
ters also gave indenes in excellent yields (entries 8 and 9).
Meanwhile, [RuCl2(CO)3]2 as a catalyst was rather ineffec-
tive for 1j, the yield of 2j being 15%. sec-Propargyl acetates
1d and 1e having a para-chloro and a bromophenyl group
(not shown) were much less reactive under platinum-cata-
lyzed conditions, giving the 5-halogenated 1H-inden-2-yl
acetates in up to 10% yield. These results indicate that sub-
stituents on a phenyl ring influence the nucleophilicity of
a reaction site on the phenyl ring toward a positively charged
carbene carbon more strongly than does the stability of the
allyl cationic intermediates A0 and B0 that participate in
the isomerization of vinylcarbenoids A and B, as shown in
Scheme 3. It is noted that 5-substituted indenes8 obtained
from sec-propargyl esters are different from 6-substituted
indenes obtained in the PtCl2(PPh3)2/PhIO-catalyzed pent-
annulation reported by Sarpong et al.5
Scheme 2. Ru-catalyzed transformation of propargyl acetates.
OAc
OAc
RL
RL
δ+
δ-
RS [M]
A
RS [M]
OAc
0
A
O
O
RL
RS
RL
RS
[M]
OAc
OAc
[M]
RS
RS
δ+
δ-
RL [M]
RL [M]
B0
B
Scheme 3. Generation of vinylcarbene complexes A and B.
10 mol% PtCl2(PPh3)2
20 mol% PhIO
OAc
OAc
Ph
toluene, 100 °C
E = CO2Et
E
E
Scheme 4. Sarpong’s indene synthesis.
SPh
5 mol% AuCl3
SPh
Ph
toluene, 80 °C
Scheme 5. Wang’s indene synthesis.
2. Results and discussion
Because we had noticed that ruthenium and platinum com-
plexes were effective catalysts for the carbene transfer re-
actions using propargyl acetates as a carbene source,4 we
reinvestigated indene synthesis using [RuCl2(CO)3]2 or
PtCl2 and several types of propargyl acetates (Eq. 1).
We began with sec-propargyl esters as the carbene precur-
sor (R¼H). The reaction of 1-phenyl-2-propynyl acetate
(1a) with 2.5 mol % [RuCl2(CO)3]2 in dichloroethane
(DCE) at 50, 60, or 70 ꢀC was almost sluggish, giving
1H-inden-2-yl acetate (2a) in up to 5% yield after 48 h
(Scheme 6).7
Because pentannulation was assumed to require the inter-
vention of the sterically less favored (E)-carbenoids B, a con-
trolled experiment to intercept the intermediates was
attempted by using cyclopropanation reactions with alkenes.
In the presence of a catalytic amount of PtCl2, reactions of
sec-propargyl esters, 1a–e and 1j with 2-ethyl-1-butene
3m (20 equiv) or 1,1-diphenylethene 3n (5 equiv) were car-
ried out in toluene at 50 ꢀC (Eq. 2).9 The results are shown in
Table 2. In most cases, Z-alkene-enriched cyclopropanes
were obtained as major products together with trace amounts
of indenes 2.10 These results indicate that vinylcarbene inter-
mediates can be formed from sec-propargyl esters even at
50 ꢀC, and the Z-vinylcarbene complex A mainly contrib-
utes to the equilibrium between A and B.
R
R'
OAc
cat. MLn
ð1Þ
OAc
Ar
Ar = R'C6H4
R

12140
Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
Table 1. Formation of indenes from sec-propargyl esters 1a
Table 2. Cyclopropanation versus indene formation using sec-propargyl
ester 1 and alkenes 3m or 3n
Entry
1
1
Indene 2 and yieldb
R in 1
Alkene 3
Time (h)
Product and
7
1
yield (Z/E)a
OAc
OAc
6
5
2
OAc
OAc
H (1a)
3m
24
24
8
16
12
48
24
24
40
24
4am 64% (88:12)
4bm 75% (94:6)
4cm 69% (96:4)
4dm 74% (92:8)
4em 73% (94:6)
4an 82% (91:9)
4bn 64% (93:7)
4cn 80% (89:11)
4dn 75% (90:10)
4en 65% (92:8)
Me
3
4
Me (1b)
MeO (1c)
Cl (1d)
Br (1e)
H (1a)
Me (1b)
MeO (1c)
Cl (1d)
Br (1e)
Me
2b 10%
1b
3n
2
MeO
MeO
2c 16%
1c
OAc
MeO
MeO
Ratios of Z and E were determined by 1H NMR.
a
3
4
OAc
2f 9%
1f
amount of an indene 2j in 41% and 21% yields together with
(Z)-vinylcyclopropanes as major products (Eq. 3). These re-
sults imply that both para- and meta-substituents promote
isomerization between (Z)- and (E)-vinylcarbenoids fol-
lowed by the pentannulation, but the equilibrium is other-
wise very slow. We can estimate that the equilibrium ratios
of (Z)- and (E)-vinylcarbenoids from 1 are ca. 9:1 except
for 1j. However, electron-donating para-substituents on
phenyl rings, which should be responsible for the stabiliza-
tion of cationic intermediates, are less effective for indene
formation than meta-substituents.
OAc
OAc
MeO
MeO
MeO
MeO
OAc
OAc
2g 45%
1g
5
6
MeO
2h 48%
MeO
MeO
1h
OAc
MeO
MeO
MeO
MeO
OAc
OR
Next, we examined indene formation from tert-propargyl es-
ter 5a having methyl and phenyl groups at a propargyl posi-
tion. Typical results using several catalysts are summarized
in Table 3. [RuCl2(CO)3]2 as a catalyst promoted the pentan-
nulation of 5a at 50 ꢀC to give a mixture of 1-methyl-2-
indene 6a and 3-methyl-2-indene 6a0 in 35% yield with an
83:17 ratio. PtCl2 exhibited prominent catalytic activity in
indene formation from tert-propargyl ester 5a even at
50 ꢀC, giving 6a and 6a0 in 85% yield with a 72:28 ratio. Un-
der Sarpong’s catalytic conditions (PtCl2(PPh3)2/PhIO)5a
mixture of 6a and 6a0 was obtained from 5a in 73% yield
with a 79:21 ratio, while under Toste’s catalytic conditions
(AuCl(PPh3)/AgSbF6),2b the total yield of 6a and 6a0 was
only 9% with reversed selectivity (6a/6a0¼26:74).11 Reac-
tions of tert-propargyl ester 5 having several substituents
on a phenyl ring were carried out under PtCl2 catalysis,
which led to the highest yield of indenes. Results are summa-
rized in Table 4.
MeO
2i 56%
1i
OR
O
O
O
O
7
1j
R¼Ac 2j 64% (15%)c
8
9
1k
1l
R¼Bz 2k 81%d
R¼Piv 2l 65%d
a
Reaction conditions: 1 (0.5 mmol), PtCl2 (2.5 mol %) in toluene (2.5 mL)
at 70 ꢀC for 48 h.
In some cases, <5% of an inseparable indene isomer was detected.
[RuCl2(CO)3]2 (2.5 mol %) in DCE at 50 ꢀC for 72 h.
For 18 h.
b
c
d
OAc
OAc
R
2.5 mol%
PtCl2
1
2
R
Table 3. Transition metal-catalyzed formation of indene from tert-propargyl
ester 5a
+
R'
+
ð2Þ
ð3Þ
toluene
50 °C
R
OAc
7
1
R'
R'
6
R'
2
OAc
3m (R' = Et)
3n (R' = Ph)
5
4
3
4
OAc
6a
cat. MLn
+
Ph
4
toluene
50 °C
3
5
2.5 mol%
PtCl2
1j
+
2
5a
OAc
O
O
6
4
OAc +
1
7
toluene
70 °C, 40 h
6a'
R'
2j
Yield of indenes (6a/6a0)
41%
21%
4jm 43% (only Z)
4jn 58% (only Z)
MLn (2.5 mol %)
Time (h)
R'
3m (R' = Et)
3n (R' = Ph)
[RuCl2(CO3)]2
PtCl2
PtCl2(PPh3)2/PhIO (1/8)
AuCl(PPh3)/AgSbF6 (1/1)
20
14
20
20
35% (83:17)
85% (72:28)
73% (79:21)
9% (26:74)
In contrast, reactions of 3,4-methylenedioxyphenyl-
substituted ester 1j with the same alkenes gave a discernible
Ratios of indenes were determined by 1H NMR.
a

Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
12141
Table 4. PtCl2-catalyzed formation of indenes from tert-propargyl esters 5
Table 5. Cyclopropanation versus indene formation using tert-propargyl
esters 5 and alkenes 3m or 3n
R'
7
1
6
2
OAc
OAc
5
OAc
R'
R
R
2.5 mol%
PtCl2
3
4
R'
R
6
2.5 mol% PtCl2
toluene, 50 °C
6 and 6'
5
+
R'
+
R'
toluene
50 °C, 20 h
4
R
3
OAc
R
5
3m (R' = Et)
3n (R' = Ph)
2
5
R'
R'
OAc
6
1
7
6'
7 (m: R' = Et; n: R' = Ph)
Entry
5
R
R0
Yield of indenes (6/60)a
R in 5
Alkene 3
Products and yields
7 (Z/E)b
6+60 (ratio)a
1
2
3
4
5a
5b
5c
5d
5e
5f
H
Me
Me
Me
Me
Me
Me
Et
85% (72:28)
78% (67:33)
85% (53:47)
82% (49:51)
85% (50:50)
66% (56:44)
86% (78:22)
Me
MeO
Cl
Br
CF3
H
H (5a)
3mc
43% (70:30)
52% (68:32)
67% (50:50)
22% (50:50)
25% (44:56)
41% (71:29)
45% (67:33)
43% (53:47)
14% (50:50)
18% (44:56)
7am 40% (58:42)
7bm 31% (52:48)
7cm 25% (57:43)
7dm 68% (58:42)
7em 65% (55:45)
7an 53% (55:45)
7bn 43% (55:45)
7cn 38% (53:47)
7dn 74% (58:42)
7en 75% (52:48)
Me (5b)
MeO (5c)
Cl (5d)
Br (5e)
H (5a)
Me (5b)
MeO (5c)
Cl (5d)
Br (5e)
5
6
7b
5g
3nd
Ratios of indenes were determined by 1H NMR.
Reaction time: 16 h.
a
b
In most cases, high yields of indenes were obtained, except
with CF3-substituent (entries 1–6). Irrespective of electron-
donating and electron-withdrawing para-substituents of 5,
a mixture of 6 and 60 was obtained more efficiently than
was the case for sec-propargyl esters 1 (vide supra). The re-
action of 3-phenylpent-1-yn-3-yl acetate 5g (R¼H, R0¼Et)
was complete within 16 h, giving a mixture of 6g and 6g0
in 86% yield (78:22) (entry 7). The slight rate enhancement,
which leads to rapid indene formation, is probably caused by
the predominance of E-vinylcarbenoid resulting from an
ethyl group. Platinum-catalyzed reactions of 5 afforded 1-
alkyl-2-acetoxyindenes 6 predominantly with the same
selectivity for sec-propargyl esters 1. The present PtCl2-
catalyzed reaction shows the reverse selectivity in indene
formation reported by Sarpong et al.5
Ratios of 6 and 60 were determined by 1H NMR.
a
Ratios of Z and E in 7 were determined by 1H NMR.
b
c
d
For 2 h.
For 5 h.
In contrast, the [RuCl2(CO)3]2-catalyzed reaction of 5h gave
6h0 predominantly (6h/6h0¼4:96). Because we observed that
no isomerization of indene 6h0 (96% enriched) into 6h oc-
curred under the platinum- or ruthenium-catalyzed condi-
tions, each indene isomer must be produced via different
pathways. Several plausible mechanisms for pentannulation
via vinylcarbenoids or styrylcarbenoids have been postu-
lated.2,5,6,13,14 Because the substituted patterns of indenes re-
ported in this article and our previous paper are completely
different from those reported by Nolan et al.,13b mechanisms
via allene complexes can be excluded. The most plausible
mechanism is shown in Scheme 7.
To gain an insight into indene formation, we again carried
out the competitive reactions of tert-propargyl esters 5 in
the presence of alkenes. The reactions of 5 with 2-ethyl-1-
butene 3m (20 equiv) or 1,1-diphenylethene 3n (5 equiv) af-
forded a mixture of indenes 6/60 and vinylcyclopropanes 7.
The results are summarized in Table 5, and were completely
different from those of sec-propargyl esters 1 (see Table 2).12
Ph
OAc
OAc
6h
2.5 mol% cat.
+
Ph
Ph
Ph
50 °C, 40 h
Electron-donating substituents (R¼Me, MeO) on a phenyl
ring led to the predominant formation of indenes 6/60, while
halogenated phenyl rings (R¼Cl, Br) afforded cyclopro-
panes 7 predominantly. Ratios of Z and E in vinylcyclopro-
panes 7 ranged from ca. 50:50 to 60:40, which were
completely different from ca. 90:10 for sec-propargyl es-
ters.10 This indicates that the higher ratio of an E-vinylcar-
bene intermediate in equilibrium can facilitate the
formation of indenes. The ratios of 6 and 60 were similar
to those for the noncompetitive reactions using 5 (see Table
4). Accordingly, indene formation strongly depends on the
rapid equilibrium as well as the ratio between intermediates
A and B.
ð4Þ
5h
OAc
6h'
PtCl2
[RuCl2(CO)3]2
84% (6h:6h' = 61:39)
71% (6h:6h' = 4:96)
As we mentioned above, E-vinylcarbene complexes in equi-
librium through an allyl cationic intermediate are the first
structural requisite for indene formation. Considering the
competitive reactions of pentannulation versus cyclopropa-
nation, we can estimate that the equilibrium ratios of E
and Z from sec- and tert-propargyl esters 1 and 5 are ca.
10:90 and 40:60, respectively. The enhancement of indene
formation by both para- and meta-substituents in sec-prop-
argyl esters 1 suggests that a Z-platinum–carbene complex
A isomerizes to E-carbene complex B via cationic species
The PtCl2-catalyzed reaction of diphenyl-substituted tert-
propargyl ester 5h afforded a mixture of 1-phenyl-2-acetoxy-
indene 6h and 2-phenyl-2-acetoxyindene 6h0 in 84% yield
(6h/6h0¼61:39) (Eq. 4).

12142
Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
R'
R'
OAc
OAc
+
-
RS [M]
A
RS [M]
OAc
A0
R'
RS
[M]
RS
RS
RS
R'
R'
R'
OAc
OAc
OAc
+
[M]
B0
[M]
-
[M]
F
B
[M]
RS
RS
R'
R'
R'
RS
RS
[1,5]-H
[1,5]-H
a
R'
OAc
OAc
R'
OAc
OAc
OAc
[M]
OAc
H
2' or 6'
RS
a
D
[M]
b
H
b
C
MLn
RS
H
[M] R'
E
2 or 6
Scheme 7. Plausible mechanism of Ru- and Pt-catalyzed indene formation.
A0 and B0, followed by Nazarov-type cyclization (pentannu-
lation)15 involving an ortho-aromatic carbon and a positively
charged carbene center to give intermediate C. Subse-
quently, elimination of platinum from C affords the interme-
diate D or E, followed by a 1,5-hydrogen shift to give
2-acetoxyindenes. In contrast, low yields of indenes in ruthe-
nium-catalyzed reactions of 1a, 1j, and 5a are probably
caused by the overwhelming sterical requirement that disfa-
vors isomerization from A to B. In the indene formation
from 5h, Ru catalysis gave 2-phenyl-2-acetoxyindene 6h0
predominantly, while Pt catalysis favors the formation of
1-phenyl-2-acetoxyindene 6h. However, the absence of
isomerization of the isolated indene and the catalyst-depen-
dent selectivity of indenes cannot be explained by only
Nazarov-type cyclization mechanism for indene formation.
The absence of enhancement with the meta-substituent of
1j suggests that the nucleophilicity of an ortho-aromatic
carbon is not a crucial factor in ruthenium-catalyzed indene
formation. We therefore propose the reaction pathway via
metallacycle F as an alternative pentannulation mechanism,
particularly in Ru catalysis. Closely related pentannulation
additional carbonyl ligands compared with PtCl2 prefers
the sterical stabilization in intermediates, electronic tuning
by substituents is not effective for indene formation.
4. Experimental
4.1. General
All solvents were dried by the usual methods and distilled
before use. Organic reagents were used as purchased. All
catalytic reactions were carried out under an inert gas atmo-
sphere using standard Schlenk techniques and a glovebox.
Column chromatographies were performed on silica gel
(230–400 mesh). Analytical TLC was performed on ready-
made plates coated with silica gel on glass. The NMR spec-
tra (1H and 13C) were measured for solutions in CDCl3 with
Me4Si as an internal standard at 25 ꢀC.
Preparation of propargyl esters 1 and 5, NOE experiments to
determine the regiochemistry of major products of 2, NOE
experiments to determine the olefin regioisomers of vinylcy-
clopropanes 4 and 7, and NMR Spectra of 2f, 2h, 2i, 4jm,
4cn, 4jn, 5f, 5g, 6c, 6d, 6f, 6g, and 7cn are provided in
Supplementary data.
of styrylcarbene complexes has been proposed for the
€
byproduct formation in the Dotz reaction.
3
3. Conclusion
4.2. Typical procedure for synthesis of indenes 2 and 6
We have demonstrated indene formation from phenyl-
substituted sec- and tert-propargyl esters (terminal alkynes)
in the presence of platinum or ruthenium catalysts. The effi-
ciency of indene formation in platinum catalysis was affected
by electron-donating substituents in propargyl acetates,
whichcan stabilize the intermediary cationic speciesrequired
for indene formation, although the selectivity for indenes
from tert-propargyl acetates was not high. In contrast,
ruthenium catalysis can provide high selectivity for indene
in the reaction of diphenyl-substituted tert-propargyl acetate,
probably because of facile metallacycle formation. Because
the sterically demanding RuCl2(CO)3 moiety having three
A catalytic amount of PtCl2 (0.013 mmol) was placed in
a flame-dried Schlenk flask under N2. A solution of 1 or 5
(0.50 mmol) in anhydrous toluene (2.5 mL) was added to
the flask at room temperature. After the mixture was stirred
at 50 or 70 ꢀC for each appropriate time, the reaction mixture
was cooled to room temperature and then diluted with
EtOAc. The resulting organic solution was filtered through
a short silica gel pad. The filtrate was evaporated under re-
duced pressure and the residue was purified by flash column
chromatography on silica gel (hexane/EtOAc¼10/1) to give
indene 2 or 6. Indene 2a is a known compound.

Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
12143
4.2.1. 5-Methyl-2-indenyl acetate (2b). A colorless oil
(10% yield). IR (neat) nmax cmꢁ1: 2924, 1765 (C]O),
1619, 1371, 1233, 1049, 887. H NMR (400 MHz, CDCl3)
d: 7.21 (d, J¼7.2 Hz, 1H), 7.11 (s, 1H), 6.96 (d, J¼7.2 Hz,
1H), 6.55 (s, 1H), 3.52 (s, 2H), 2.36 (s, 3H), 2.24 (s, 3H).
13C NMR (75.5 MHz, CDCl3) d: 168.0, 155.7, 142.8,
136.2, 134.1, 125.0, 123.0, 121.7, 114.7, 37.5, 21.6, 21.3.
Anal. Calcd for C12H12O2: C, 76.57; H, 6.43. Found: C,
76.85; H, 6.64.
3H), 3.87 (s, 3H), 3.85 (s, 3H), 3.53 (s, 2H), 2.23 (s, 3H).
13C NMR (100 MHz, CDCl3) d: 168.0, 153.0, 151.5,
146.9, 140.8, 133.1, 128.0, 111.4, 104.3, 61.2, 61.1, 56.4,
38.1, 21.2. HRMS (FAB) m/z: Calcd for C14H16O5 (M+)
264.0998. Found: 264.0991.
1
4.2.7. 5H-Indeno[5,6-d][1,3]dioxol-6-yl acetate (2j). A
white solid (64% yield), mp 79.8–80.3 ꢀC. IR (KBr)
nmax cmꢁ1: 3119, 2905, 1761 (C]O), 1618, 1468, 1290,
1199, 1032, 795, 583. 1H NMR (400 MHz, CDCl3) d: 6.84
(s, 1H), 6.78 (s, 1H), 6.47 (s, 1H), 5.91 (s, 2H), 3.46 (s,
2H), 2.22 (s, 3H). 13C NMR (100 MHz, CDCl3) d: 168.0,
154.3, 146.3, 145.0, 136.1, 130.3, 114.6, 105.1, 102.3,
100.6, 37.7, 21.2. Anal. Calcd for C12H10O4: C, 66.05; H,
4.62. Found: C, 66.18; H, 4.57.
4.2.2. 5-Methoxy-2-indenyl acetate (2c). A colorless oil
(16% yield) (ca. 5% of regioisomeric indene 2g was detected
1
by H NMR). IR (neat) nmax cmꢁ1: 2947, 1748 (C]O),
1610, 1478, 1033, 872, 593, 467. 1H NMR (300 MHz,
CDCl3) d: 7.23 (d, J¼8.1 Hz, 1H), 6.86 (d, J¼2.4 Hz, 1H),
6.69 (dd, J¼8.1, 2.4 Hz, 1H), 6.56 (s, 1H), 3.80 (s, 3H),
3.50 (s, 2H), 2.24 (s, 3H). 13C NMR (75.5 MHz, CDCl3) d:
168.0, 159.0, 156.7, 144.1, 129.1, 123.9, 114.8, 110.0,
107.0, 55.4, 37.1, 21.2. Anal. Calcd for C12H12O3: C,
70.57; H, 5.92. Found: C, 70.50; H, 6.00.
4.2.8. 5H-Indeno[5,6-d][1,3]dioxol-6-yl benzoate (2k). A
white solid (81% yield), mp 87.8–88.1 ꢀC. IR (KBr)
nmax cmꢁ1: 2890, 2366, 1730 (C]O), 1621, 1468, 1259,
1120, 1056, 7867, 705. 1H NMR (400 MHz, CDCl3) d: 8.14
(d, J¼7.8 Hz, 2H), 7.62 (dd, J¼7.8, 7.8 Hz, 1H), 7.50 (dd,
J¼7.8, 7.8 Hz, 2H), 6.90 (s, 1H), 6.84 (s, 1H), 6.65 (s, 1H),
5.94 (s, 2H), 3.63 (s, 2H). 13C NMR (100 MHz, CDCl3) d:
163.9, 154.6, 146.5, 145.2, 136.3, 133.6, 130.6, 130.0,
129.4, 128.6, 115.1, 105.3, 102.5, 100.7, 37.9. HRMS (FAB)
m/z: Calcd for C17H12O4 (M+) 280.0736. Found: 280.0728.
4.2.3. 7-Methoxy-2-indenyl acetate (2f). A colorless oil
(9% yield) (a trace amount of regioisomeric indene was de-
tected). IR (neat) nmax cmꢁ1: 2936, 1763 (C]O), 1614,
1
1484, 1263, 1200, 1086, 772. H NMR (400 MHz, CDCl3)
d: 7.23 (dd, J¼8.2, 8.2 Hz, 1H), 6.94 (d, J¼8.2 Hz, 1H),
6.72 (d, J¼8.2 Hz, 1H), 6.58 (s, 1H), 3.87 (s, 3H), 3.51 (s,
2H), 2.25 (s, 3H). 13C NMR (75.5 MHz, CDCl3) d: 168.1,
156.0, 154.8, 144.5, 128.2, 123.7, 114.6, 114.3, 107.2,
55.2, 35.4, 21.2. HRMS (FAB) m/z: Calcd for C12H12O3
(M+) 204.0786. Found: 204.0786.
4.2.9. 5H-Indeno[5,6-d][1,3]dioxol-6-yl pivalate (2l). A
white solid (65% yield), mp 150.0–150.7 ꢀC. IR (KBr)
nmax cmꢁ1: 2977, 2355, 1743 (C]O), 1467, 1278, 1128,
1
857, 671. H NMR (400 MHz, CDCl3) d: 6.85 (s, 1H),
6.78 (s, 1H), 6.46 (s, 1H), 5.91 (s, 2H), 3.47 (s, 2H), 1.30
(s, 9H). 13C NMR (100 MHz, CDCl3) d: 175.8, 154.9,
146.5, 145.0, 136.4, 130.4, 114.4, 105.2, 102.3, 100.6,
39.2, 37.7, 27.1. HRMS (FAB) m/z: Calcd for C15H16O4
(M+) 260.1049. Found: 260.1051.
4.2.4. 6-Methoxy-2-indenyl acetate (2g). A colorless oil
(45% yield) (ca. 5% of regioisomeric indene 2c was detected
by 1H NMR). IR (neat) nmax cmꢁ1: 2939, 2936, 1765
1
(C]O), 1611, 1479, 1370, 1199, 1030, 858, 712, 521. H
NMR (400 MHz, CDCl3) d: 7.17 (d, J¼8.2 Hz, 1H), 6.95
(s, 1H), 6.79 (d, J¼8.2 Hz, 1H), 6.52 (s, 1H), 3.80 (s, 3H),
3.54 (s, 2H), 2.23 (s, 3H). 13C NMR (75.5 MHz, CDCl3) d:
168.2, 157.5, 153.7, 139.0, 135.5, 121.3, 114.4, 111.9,
110.4, 55.5, 37.9, 21.1. Anal. Calcd for C12H12O3: C,
70.57; H, 5.92. Found: C, 70.30; H, 5.80.
4.2.10. 1-Methyl-2-indenyl acetate (6a) and 3-methyl-2-
indenyl acetate (6a0). A colorless oil (85% yield, 6a/
6a0¼72:28) (a mixture of regioisomers). IR (neat)
nmax cmꢁ1: 2973, 1762 (C]O), 1462, 1200, 755. 1H NMR
(400 MHz, CDCl3) d: 7.33–7.13 (m, 8H, 6a+6a0), 6.61 (s,
1H, 6a), 3.56 (s, 2H, 6a0), 3.56 (q, J¼7.2 Hz, 1H, 6a), 2.24
(s, 3H, 6a0), 2.23 (s, 3H, 6a), 1.97 (t, J¼2.2 Hz, 3H, 6a0),
1.31 (d, J¼7.2 Hz, 3H, 6a). 13C NMR (100 MHz, CDCl3)
d: 168.5, 167.8, 159.5, 150.0, 143.8, 142.6, 141.6, 138.0,
126.7, 126.2, 124.4, 124.3, 123.4, 123.2, 122.2, 120.1,
118.7, 112.9, 43.1, 36.7, 21.2, 20.8, 14.8, 8.5. Anal. Calcd
for C12H12O2: C, 76.57; H, 6.43. Found: C, 76.76; H, 6.52.
4.2.5. 4,6-Dimethoxy-2-indenyl acetate (2h) and 5,7-di-
methoxy-2-indenyl acetate (2h0). A colorless oil (48%
yield) (9% of regioisomeric indene 2h0 was detected by 1H
NMR). IR (neat) nmax cmꢁ1: 2943, 1749 (C]O), 1598,
1
1457, 1373, 1227, 1078, 856, 721, 560. 2h (major): H
NMR (400 MHz, CDCl3) d: 6.60 (s, 1H), 6.58 (d,
J¼1.6 Hz, 1H), 6.39 (d, J¼1.6 Hz, 1H), 3.83 (s, 3H), 3.81
(s, 3H), 3.55 (s, 2H), 2.22 (s, 3H). 13C NMR (75.5 MHz,
CDCl3) d: 168.2, 158.9, 153.4, 151.8, 139.8, 123.9, 111.2,
4.2.11. 1,5-Dimethyl-2-indenyl acetate (6b) and 3,6-di-
methyl-2-indenyl acetate (6b0). A colorless oil (78% yield,
6b/6b0¼67:33) (a mixture of regioisomers). IR (neat)
nmax cmꢁ1: 2971, 1764 (C]O), 1619, 1370, 1201, 1052,
1
101.5, 97.1, 55.7, 55.5, 38.4, 21.2. 2h0 (minor): H NMR
(400 MHz, CDCl3) d: 6.54 (s, 1H), 6.52 (d, J¼1.8 Hz,
1H), 6.31 (d, J¼1.8 Hz, 1H), 3.84 (s, 3H), 3.81 (s, 3H),
3.45 (s, 2H), 2.24 (s, 3H). HRMS (FAB) m/z: Calcd for
C13H14O4 (M+) 234.0892. Found: 234.0882.
1
889, 815, 586. H NMR (300 MHz, CDCl3) d: 7.23–6.95
(m, 6H, 6b+6b0), 6.56 (s, 1H, 6b), 3.54 (q, J¼7.2 Hz, 1H,
6b), 3.52 (s, 2H, 6b0), 2.36 (s, 3H, 6b0), 2.35 (s, 3H, 6b),
2.24 (s, 6H, 6b+6b0), 1.96 (s, 3H, 6b0), 1.30 (d, J¼7.2 Hz,
3H, 6b). 13C NMR (75.5 MHz, CDCl3) d: 168.8, 168.0,
159.8, 149.3, 141.8, 141.2, 139.9, 138.3, 136.4, 134.2,
126.9, 125.1, 124.2, 123.4, 122.0, 121.8, 118.5, 113.0,
42.8, 36.6, 21.5, 21.4, 21.2, 20.8, 15.0, 8.5. Anal. Calcd
for C13H14O2: C, 77.20; H, 6.98. Found: C, 77.11; H, 6.99.
4.2.6. 4,5,6-Trimethoxy-2-indenyl acetate (2i). A colorless
oil (56% yield) (ca. 5% of regioisomeric indene was detected
1
by H NMR). IR (KBr) nmax cmꢁ1: 2940, 1764 (C]O),
1601, 1472, 1201, 1115, 1032, 875, 719, 601. H NMR
(400 MHz, CDCl3) d: 6.75 (s, 1H), 6.64 (s, 1H), 3.93 (s,
1

12144
Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
4.2.12. 5-Methoxy-1-methyl-2-indenyl acetate (6c) and
6-methoxy-3-methyl-2-indenyl acetate (6c0). A colorless
oil (85% yield, 6c/6c0¼53:47) (a mixture of regioisomers).
IR (neat) nmax cmꢁ1: 2935, 1763 (C]O), 1615, 1474,
6g/6g0¼78:22) (a mixture of regioisomers). IR (neat)
nmax cmꢁ1: 2967, 1766 (C]O), 1461, 1370, 1195, 1010,
899, 753. H NMR (400 MHz, CDCl3) d: 7.36–7.13 (m,
1
8H), 6.64 (s, 1H), 3.60 (t, J¼5.4 Hz, 1H), 3.57 (s, 2H),
2.48 (q, J¼7.7 Hz, 2H), 2.26 (s, 3H), 2.26 (s, 3H) 2.02–
1.78 (m, 2H), 1.18 (t, J¼7.7 Hz, 3H), 0.76 (t, J¼7.3 Hz,
3H). 13C NMR (75.5 MHz, CDCl3) d: 168.0, 162.6, 158.0,
149.6, 142.5, 141.0, 129.3, 128.1, 127.3, 126.7, 126.3,
124.4, 124.3, 123.5, 122.6, 120.9, 119.1, 114.3, 48.9, 36.8,
22.4, 21.3, 20.9, 17.0, 12.5, 9.3. HRMS (FAB) m/z: Calcd
for C13H14O2 (M+) 202.0994. Found: 202.0995.
1
1370, 1118, 1030, 818, 589. H NMR (300 MHz, CDCl3)
d: 7.23–6.95 (m, 2H, 6c+6c0), 6.95–6.94 (m, 1H, 6c),
6.84–6.80 (m, 2H, 6c), 6.70–6.67 (m, 1H, 6c), 6.57 (s, 1H,
6c), 3.79 (s, 3H, 6c), 3.79 (s, 3H, 6c0), 3.53 (s, 2H, 6c0),
3.50 (q, J¼7.2 Hz, 1H, 6c), 2.25 (s, 3H, 6c), 2.24 (s, 3H,
6c0), 1.94 (t, J¼2.0 Hz, 3H, 6c0), 1.29 (d, J¼7.2 Hz, 3H,
6c). 13C NMR (75.5 MHz, CDCl3) d: 168.9, 167.9, 160.6,
159.1, 157.8, 148.1, 143.0, 139.8, 136.9, 134.9, 123.1,
122.8, 119.2, 113.0, 111.5, 110.4, 109.8, 107.4, 55.5, 55.3,
42.5, 36.8, 21.1, 20.8, 15.1, 8.5. HRMS (FAB) m/z: Calcd
for C13H14O3 (M+) 218.0943. Found: 218.0937.
4.2.17. 1-Phenyl-2-indenyl acetate (6h) and 3-phenyl-
2-indenyl acetate (6h0). A yellow solid (84% yield, 6h/
6h0¼61:39) (a mixture of regioisomers). IR (KBr)
nmax cmꢁ1: 3021, 1762 (C]O), 1597, 1455, 1368, 1217,
1
4.2.13. 5-Chloro-1-methyl-2-indenyl acetate (6d) and
6-chloro-3-methyl-2-indenyl acetate (6d0). A colorless oil
(82% yield, 6d/6d0¼49:51) (a mixture of regioisomers). IR
(neat) nmax cmꢁ1: 2977, 1766 (C]O), 1606, 1371, 1196,
752, 698, 535. H NMR (400 MHz, CDCl3) d: 7.48–7.07
(m, 18H, 6h+6h0), 6.70 (d, J¼1.8 Hz, 1H, 6h), 4.75 (s, 1H,
6h), 3.77 (s, 2H, 6h0), 2.16 (s, 3H, 6h0), 2.06 (s, 3H, 6h).
13C NMR (75.5 MHz, CDCl3) d: 168.9, 168.0, 157.9,
150.7, 142.5, 142.5, 141.8, 138.2, 137.4, 132.2, 128.7,
128.5, 128.5, 128.2, 128.1, 127.6, 127.1, 127.1, 126.4,
125.0, 124.9, 123.7, 123.5, 121.1, 120.1, 115.0, 54.7, 37.3,
21.0, 20.9. Anal. Calcd for C17H14O2: C, 81.58; H, 5.64.
Found: C, 81.76; H, 5.72.
1
1074, 883, 821, 582. H NMR (300 MHz, CDCl3) d: 7.30–
7.10 (m, 6H, 6d+6d0), 6.58 (s, 1H, 6d), 3.57 (s, 2H, 6d0),
3.54 (q, J¼7.5 Hz, 1H, 6d), 2.27 (s, 6H, 6d+6d0), 1.96 (t,
J¼2.0 Hz, 3H, 6d0), 1.31 (d, J¼7.5 Hz, 3H, 6d). 13C NMR
(75.5 MHz, CDCl3) d: 168.6, 167.8, 160.8, 150.2, 143.5,
142.5, 140.8, 139.7, 132.6, 130.4, 126.6, 124.3, 123.8,
123.3, 123.1, 121.2, 119.7, 112.3, 42.9, 36.7, 21.2, 20.8,
14.8, 8.5. HRMS (FAB) m/z: Calcd for C12H11ClO2 (M+)
222.0448. Found: 222.0455.
4.3. Typical procedure for synthesis of styrylcyclo-
propanes
The reactions were carried out with 2-ethylbut-1-ene (3m)
(20 equiv) and 1,1-diphenylethene (3n) (5 equiv) under the
same conditions for the catalytic indene synthesis. A cata-
lytic amount of PtCl2 (0.013 mmol) was placed in a flame-
dried Schlenk flask under N2. A solution of 1 or 5
(0.50 mmol) with alkene in anhydrous toluene (2.5 mL)
was added to the flask at room temperature. After the mix-
ture was stirred at 50 or 70 ꢀC for 2–48 h, the reaction mix-
ture was cooled to room temperature and then diluted with
EtOAc. The resulting organic solution was filtered through
a short silica gel pad. The filtrate was evaporated under re-
duced pressure and the residue was purified by flash column
chromatography on silica gel (hexane/EtOAc¼10/1) to give
styrylcyclopropane 4 or 7 with the corresponding indene.
4.2.14. 5-Bromo-1-methyl-2-indenyl acetate (6e) and
6-bromo-3-methyl-2-indenyl acetate (6e0). A colorless oil
(85% yield, 6e/6e0¼50:50) (a mixture of regioisomers). IR
(neat) nmax cmꢁ1: 2976, 1765 (C]O), 1600, 1370, 1071,
1
885, 818, 577. H NMR (300 MHz, CDCl3) d: 7.44–7.38
(m, 3H, 6e+6e0), 7.26 (dd, J¼7.8, 1.8 Hz, 1H, 6e), 7.13 (d,
J¼7.8 Hz, 1H, 6e), 7.09 (d, J¼7.8 Hz, 1H, 6e), 6.57 (s,
1H, 6e), 3.55 (s, 2H, 6e0), 3.51 (q, J¼7.5 Hz, 1H, 6e), 2.26
(s, 6H, 6e+6e0), 1.95 (t, J¼1.8 Hz, 3H, 6e0), 1.30 (d,
J¼7.5 Hz, 3H, 6e). 13C NMR (75.5 MHz, CDCl3) d:
168.5, 167.8, 160.6, 150.2, 143.9, 142.9, 141.3, 140.0,
129.4, 127.2, 126.5, 124.0, 123.7, 123.1, 120.6, 120.1,
118.2, 112.1, 42.9, 36.7, 21.2, 20.8, 14.7, 8.4. Anal. Calcd
for C12H11BrO2: C, 53.96; H, 4.15. Found: C, 54.13; H, 4.29.
4.3.1. 1-(2,2-Diethylcyclopropyl)-2-phenylvinyl acetate
(4am). A colorless oil (64% yield, Z/E¼88:12). IR (neat)
nmax cmꢁ1: 2963, 1758 (C]O), 1671, 1204, 1065, 750,
4.2.15. 1-Methyl-5-trifluoromethyl-2-indenyl acetate (6f)
and 3-methyl-6-trifluoromethyl-2-indenyl acetate (6f0). A
colorless oil (66% yield, 6f/6f0¼56:44) (a mixture of re-
gioisomers). IR (neat) nmax cmꢁ1: 2976, 1767 (C]O),
1438, 1322, 1198, 891, 831, 585. 1H NMR (400 MHz,
CDCl3) d: 7.58–7.28 (m, 6H), 6.56 (s, 1H), 3.64 (s, 2H),
3.61 (q, J¼7.3 Hz, 1H), 2.28 (s, 3H), 2.28 (s, 3H), 2.00 (t,
J¼2.0 Hz, 3H), 1.34 (d, J¼7.3 Hz, 3H). 13C NMR
(75.5 MHz, CDCl3) d: 168.5, 167.8, 160.7, 152.4, 147.5,
146.2, 142.5, 142.5, 138.4, 129.4 (q, J¼31.7 Hz), 126.5 (q,
J¼40.7 Hz), 125.0 (q, J¼277.3 Hz), 124.5 (q, J¼266.1 Hz),
123.8 (q, J¼4.1 Hz), 122.5, 121.5 (q, J¼4.1 Hz), 120.1 (q,
J¼3.7 Hz), 118.7, 117.6 (q, J¼3.7 Hz), 112.3, 43.3, 36.9,
21.2, 20.8, 14.5, 8.4. HRMS (FAB) m/z: Calcd for
C13H11F3O2 (M+) 256.0711. Found: 256.0713.
1
695, 520. E-4am: H NMR (400 MHz, CDCl3) d: 7.40–
7.17 (m, 5H), 5.95 (s, 1H), 2.19 (s, 3H), 1.70 (dd, J¼7.4,
5.4 Hz, 1H), 1.59–1.50 (m, 2H), 1.41–1.18 (m, 1H), 1.12–
1.05 (m, 1H), 0.93 (t, J¼7.3 Hz, 3H), 0.90 (t, J¼7.3 Hz,
3H), 0.74 (dd, J¼7.4, 5.4 Hz, 1H), 0.61 (dd, J¼5.4,
5.4 Hz, 1H). 13C NMR (100 MHz, CDCl3) d: 168.4, 149.0,
134.3, 128.2, 128.1, 126.8, 116.9, 29.9, 28.8, 28.0, 22.8,
21.2, 18.1, 10.8, 10.7. Z-4am: 1H NMR (400 MHz,
CDCl3) d: 6.33 (s, 1H) 2.16 (s, 3H), 1.86 (dd, J¼7.4,
5.4 Hz, 1H), 0.31 (dd, J¼5.4, 5.4 Hz, 1H). (Other peaks can-
not be distinguished from major peaks.) Anal. Calcd for
C17H22O2: C, 79.03; H, 8.58. Found: C, 78.92; H, 8.41.
4.3.2. 1-(2,2-Diethylcyclopropyl)-2-(4-methylphenyl)-
vinyl acetate (4bm). A colorless oil (75% yield, Z/E¼
94:6). IR (neat) nmax cmꢁ1: 2963, 2934, 1758 (C]O),
4.2.16. 1-Ethyl-2-indenyl acetate (6g) and 3-ethyl-2-
indenyl acetate (6g0). A colorless oil (86% yield,

Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
12145
1369, 1204, 872, 590. E-4bm: 1H NMR (400 MHz, CDCl3)
d: 7.24 (d, J¼7.9 Hz, 2H), 7.09 (d, J¼7.9 Hz, 2H), 5.91
(s, 1H), 2.31 (s, 3H), 2.18 (s, 3H), 1.68 (dd, J¼8.4, 5.2 Hz,
1H), 1.56–1.50 (m, 2H), 1.25–1.18 (m, 1H), 1.12–1.05
(m, 1H), 0.93 (t, J¼7.2 Hz, 3H), 0.90 (t, J¼7.2 Hz, 3H),
0.73 (dd, J¼8.4, 5.2 Hz, 1H), 0.60 (dd, J¼5.2, 5.2 Hz,
1H). 13C NMR (100 MHz, CDCl3) d: 168.5, 148.3, 136.6,
131.4, 128.9, 128.0, 116.7, 29.8, 28.8, 28.0, 22.8, 21.2,
21.2, 18.1, 10.8, 10.6. Z-4bm: 1H NMR (400 MHz,
CDCl3) d: 7.27 (d, J¼7.9 Hz, 2H), 7.12 (d, J¼7.9 Hz, 1H),
5.91 (s, 1H), 2.33 (s, 3H), 2.15 (s, 3H), 1.83 (dd, J¼8.4,
5.2 Hz, 1H), 0.31 (dd, J¼5.2, 5.2 Hz, 1H). (Other peaks can-
not be distinguished from major peaks.) Anal. Calcd for
C18H24O2: C, 79.37; H, 8.88. Found: C, 79.10; H, 8.72.
peaks cannot be distinguished from major peaks.) Anal. Calcd
for C17H21BrO2: C, 60.54; H, 6.28. Found: C, 60.81; H, 6.36.
4.3.6. 2-(Benzo[d][1,3]dioxol-5-yl)-1-(2,2-diethylcyclo-
propyl)vinyl acetate (4jm). A colorless oil (43% yield, Z
only). IR (neat) nmax cmꢁ1: 2963, 1756 (C]O), 1622,
1
1470, 1208, 1039, 876, 590. H NMR (400 MHz, CDCl3)
d: 6.96 (d, J¼1.2 Hz, 1H), 6.79 (dd, J¼8.4, 1.2 Hz, 1H),
6.73 (d, J¼8.4 Hz, 1H), 5.93 (s, 2H), 5.85 (s, 1H), 2.21 (s,
3H), 1.67 (dd, J¼7.8, 4.8 Hz, 1H), 1.58–1.48 (m, 2H) 1.19
(dq, J¼14.0, 7.6 Hz, 1H), 1.08 (dq, J¼14.0, 7.6 Hz, 1H),
0.93 (t, J¼7.6 Hz, 3H), 0.89 (t, J¼7.6 Hz, 3H), 0.72 (dd,
J¼7.8, 4.8 Hz, 1H), 0.58 (dd, J¼4.8, 4.8 Hz, 1H). 13C
NMR (75.5 MHz, CDCl3) d: 168.4, 147.8, 147.5, 146.3,
128.4, 122.4, 116.5, 108.1, 108.1, 100.9, 29.8, 28.8, 27.9,
22.8, 21.3, 18.1, 10.8, 10.7. HRMS (FAB) m/z: Calcd for
C18H22O4 (M+) 302.1518. Found: 302.1518.
4.3.3. 1-(2,2-Diethylcyclopropyl)-2-(4-methoxyphenyl)-
vinyl acetate (4cm). A colorless oil (69% yield, Z/E¼
96:4). IR (neat) nmax cmꢁ1: 2962, 1752 (C]O), 1608,
1206, 1036, 1036, 871, 830, 538. E-4cm: 1H NMR
(400 MHz, CDCl3) d: 7.31 (d, J¼8.8 Hz, 2H), 6.82 (d,
J¼8.8 Hz, 2H), 5.88 (s, 1H), 3.77 (s, 3H), 2.19 (s, 3H),
1.68 (dd, J¼8.3, 5.2 Hz, 1H), 1.56–1.51 (m, 2H), 1.22–
1.18 (m, 1H), 1.09–1.05 (m, 1H), 0.93 (t, J¼5.2, 5.2 Hz,
3H), 0.90 (t, J¼7.4 Hz, 3H), 0.72 (dd, J¼8.3, 5.2 Hz, 1H),
0.59 (dd, J¼7.4 Hz, 1H). 13C NMR (75.5 MHz, CDCl3) d:
168.6, 158.4, 147.6, 129.4, 127.0, 116.3, 113.7, 55.1, 29.6,
4.3.7. 1-(2,2-Diphenylcyclopropyl)-2-phenylvinyl acetate
(4an). A white solid (82% yield, Z/E¼91:9). IR (KBr)
nmax cmꢁ1: 3024, 1748 (C]O), 1493, 1375, 1204, 1155,
754, 705, 597. E-4an: 1H NMR (400 MHz, CDCl3) d:
7.41–7.09 (m, 15H), 5.82 (s, 1H), 2.63 (dd, J¼8.4, 6.0 Hz,
1H), 2.03 (s, 3H), 1.82 (dd, J¼6.0, 6.0 Hz, 1H), 1.66 (dd,
J¼8.4, 6.0 Hz, 1H). 13C NMR (100 MHz, CDCl3) d:
168.4, 146.5, 145.6, 140.3, 134.1, 130.2, 128.3, 128.1,
128.0, 127.9, 127.4, 126.8, 126.5, 126.1, 117.3, 38.3, 30.7,
1
28.7, 27.8, 22.7, 21.1, 18.0, 10.7, 10.5. Z-4cm: H NMR
1
(400 MHz, CDCl3) d: 7.32 (d, J¼8.8 Hz, 2H), 6.84 (d,
J¼8.8 Hz, 2H), 6.27 (s, 1H), 3.79 (s, 3H), 0.30 (dd, J¼5.2,
5.2 Hz, 1H). (Other peaks cannot be distinguished from ma-
jor peaks.) Anal. Calcd for C18H24O3: C, 74.97; H, 8.39.
Found: C, 74.81; H, 8.27.
21.0, 19.9. Z-4an: H NMR (400 MHz, CDCl3) d: 6.41 (s,
1H), 2.89 (dd, J¼8.4, 6.0 Hz, 1H), 1.58 (dd, J¼8.4,
6.0 Hz, 1H). (Other peaks cannot be distinguished from ma-
jor peaks.) Anal. Calcd for C25H22O2: C, 84.72; H, 6.26.
Found: C, 84.79; H, 6.32.
4.3.4. 1-(2,2-Diethylcyclopropyl)-2-(4-chlorophenyl)-
vinyl acetate (4dm). A colorless oil (74% yield, Z/E¼
92:8). IR (neat) nmax cmꢁ1: 2963, 2934, 1759 (C]O),
1492, 1370, 1201, 1013, 870, 589. E-4dm: 1H NMR
(400 MHz, CDCl3) d: 7.31–7.23 (m, 4H), 5.90 (s, 1H),
2.18 (s, 3H), 1.68 (dd, J¼8.3, 5.4 Hz, 1H), 1.57–1.50 (m,
2H), 1.25–1.17 (m, 1H), 1.12–1.05 (m, 1H), 0.93 (t,
J¼7.2 Hz, 3H), 0.90 (t, J¼7.2 Hz, 3H), 0.74 (dd, J¼8.3,
5.4 Hz, 1H), 0.60 (dd, J¼5.4, 5.4 Hz, 1H). 13C NMR
(100 MHz, CDCl3) d: 168.2, 149.7, 132.8, 132.3, 129.3,
128.4, 115.7, 30.0, 28.8, 27.9, 22.8, 21.1, 18.1, 10.8, 10.8.
4.3.8. 1-(2,2-Diphenylcyclopropyl)-2-(4-methylphenyl)-
vinyl acetate (4bn). A white solid (64% yield, Z/E¼93:7).
IR (KBr) nmax cmꢁ1: 3022, 1748 (C]O), 1494, 1204,
1
1151, 701, 550. E-4bn: H NMR (400 MHz, CDCl3) d:
7.39–7.00 (m, 14H), 5.78 (s, 1H), 2.60 (dd, J¼8.8, 5.9 Hz,
1H), 2.25 (s, 3H), 2.03 (s, 3H), 1.79 (dd, J¼5.9, 5.9 Hz,
1H), 1.64 (dd, J¼8.8, 5.9 Hz, 1H). 13C NMR (100 MHz,
CDCl3) d: 168.4, 145.9, 145.6, 140.4, 136.5, 131.2, 130.2,
128.9, 128.8, 128.2, 127.9, 127.4, 126.5, 126.0, 117.1,
1
38.1, 30.8, 21.2, 21.0, 19.9. Z-4bn: H NMR (400 MHz,
CDCl3) d: 6.35 (s, 1H), 2.87 (dd, J¼8.8, 5.9 Hz, 1H), 2.30
(s, 3H), 2.01 (s, 3H). (Other peaks cannot be distinguished
from major peaks.) Anal. Calcd for C26H24O2: C, 84.75;
H, 6.57. Found: C, 84.55; H, 6.67.
1
Z-4dm: H NMR (400 MHz, CDCl3) d: 6.28 (s, 1H), 0.29
(dd, J¼5.4, 5.4 Hz, 1H). (Other peaks cannot be distin-
guished from major peaks.) Anal. Calcd for C17H21ClO2:
C, 69.73; H, 7.23. Found: C, 70.02; H, 7.31.
4.3.9. 1-(2,2-Diphenylcyclopropyl)-2-(4-methoxyphenyl)-
vinyl acetate (4cn). A white solid (80% yield, Z/E¼89:11).
IR (KBr) nmax cmꢁ1: 3064, 1749 (C]O), 1509, 1204, 1154,
1026, 702, 591. E-4cn: 1H NMR (400 MHz, CDCl3) d: 7.39–
7.37 (m, 2H), 7.25–7.21 (m, 6H), 7.15–7.10 (m, 2H), 7.05–
7.03 (m, 2H), 6.74–6.72 (m, 2H), 5.76 (s, 1H), 3.87 (s, 3H),
2.61 (dd, J¼8.0, 5.6 Hz, 1H), 2.03 (s, 3H), 1.78 (dd, J¼5.6,
5.6 Hz, 1H), 1.63 (dd, J¼8.0, 5.6 Hz, 1H). 13C NMR
(100 MHz, CDCl3) d: 168.4, 158.2, 145.6, 145.1, 140.4,
130.2, 129.2, 128.2, 127.8, 127.4, 126.7, 126.4, 126.0,
4.3.5. 1-(2,2-Diethylcyclopropyl)-2-(4-bromophenyl)-
vinyl acetate (4em). A colorless oil (73% yield, Z/E¼
94:6). IR (neat) nmax cmꢁ1: 2963, 1759 (C]O), 1488,
1
1201, 1010, 870, 708, 589. E-4em: H NMR (400 MHz,
CDCl3) d: 7.32 (d, J¼8.3 Hz, 2H), 7.14 (d, J¼8.3 Hz, 2H),
5.80 (s, 1H), 2.09 (s, 3H), 1.59 (dd, J¼8.5, 5.4 Hz, 1H),
1.49–1.41 (m, 2H), 1.15–1.09 (m, 1H), 1.04–0.98 (m, 1H),
0.85 (t, J¼7.4 Hz, 3H), 0.81 (t, J¼7.4 Hz, 3H), 0.67 (dd,
J¼8.5, 5.4 Hz, 1H), 0.52 (dd, J¼5.4, 5.4 Hz, 1H). 13C
NMR (100 MHz, CDCl3) d: 168.1, 149.8, 133.2, 131.3,
129.6, 120.5, 115.8, 30.0, 28.7, 28.0, 22.8, 21.1, 18.1, 10.8,
10.6. Z-4em: 1H NMR (400 MHz, CDCl3) d: 7.34 (d,
J¼8.3 Hz, 2H), 7.17 (d, J¼8.3 Hz, 1H), 6.18 (s, 1H), 1.61
(dd, J¼8.5, 5.4 Hz, 1H), 0.22 (dd, J¼5.4, 5.4 Hz, 1H). (Other
1
116.8, 113.5, 55.0, 38.1, 30.7, 21.0, 19.8. Z-4cn: H NMR
(400 MHz, CDCl3) d: 6.33 (s, 1H), 3.70 (s, 1H), 1.98 (s,
3H), 0.88 (dd, J¼8.0, 5.6 Hz, 1H). (Other peaks cannot be
distinguished from major peaks.) HRMS (FAB) m/z: Calcd
for C26H24O3 (M+) 384.1725. Found: 384.1720.

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Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
4.3.10. 1-(2,2-Diphenylcyclopropyl)-2-(4-chlorophenyl)-
vinyl acetate (4dn). A white solid (75% yield, Z/E¼
90:10). IR (KBr) nmax cmꢁ1: 3030, 1755 (C]O), 1492,
1198, 1013, 876, 748, 703, 551. E-4dn: 1H NMR
(400 MHz, CDCl3) d: 7.38–7.36 (m, 2H), 7.29–7.14 (m,
10H), 7.01–6.99 (m, 2H), 5.74 (s, 1H), 2.59 (dd, J¼8.9,
5.9 Hz, 1H), 2.03 (s, 3H), 1.80 (dd, J¼5.9, 5.9 Hz, 1H),
1.66 (dd, J¼8.9, 5.9 Hz, 1H). 13C NMR (100 MHz,
CDCl3) d: 168.2, 147.2, 145.4, 140.2, 132.6, 132.4, 130.2,
129.2, 128.3, 128.3, 127.9, 127.4, 126.6, 126.1, 116.1,
38.5, 30.6, 21.0, 19.9. Z-4dn: 1H NMR (400 MHz, CDCl3)
d: 6.34 (s, 1H), 2.79 (dd, J¼8.9, 5.9 Hz, 1H). (Other peaks
cannot be distinguished from major peaks.) Anal. Calcd
for C25H21ClO2: C, 77.21; H, 5.44. Found: C, 77.07; H, 5.57.
dr¼52:48) (a mixture of E and Z isomers). IR (neat)
nmax cmꢁ1: 2963, 1753 (C]O), 1513, 1458, 1367, 1223,
1191, 1055, 819. H NMR (300 MHz, CDCl3) d: 7.25–
1
7.08 (m, 8H), 2.34 (s, 3H), 2.31 (s, 3H), 2.18 (s, 3H), 2.08
(s, 3H), 1.89 (s, 3H), 1.89 (s, 3H), 1.76 (dd, J¼5.3, 8.8 Hz,
1H), 1.62–1.01 (m, 9H), 0.94 (t, J¼7.9 Hz, 3H), 0.93 (t,
J¼7.9 Hz, 3H), 0.88 (t, J¼7.9 Hz, 3H), 0.68 (dd, J¼5.3,
8.8 Hz, 1H), 0.65 (t, J¼7.9 Hz, 3H), 0.43 (dd, J¼5.3,
8.8 Hz, 1H), 0.42 (dd, J¼5.3, 5.3 Hz, 1H), 0.04 (dd,
J¼5.3, 5.3 Hz, 1H). 13C NMR (75.5 MHz, CDCl3) d:
169.4, 168.7, 143.7, 141.9, 137.8, 137.6, 136.2, 136.1,
128.6, 128.5, 128.5, 127.4, 126.4, 125.9, 29.4, 29.3, 28.6,
28.4, 25.7, 25.5, 23.8, 23.6, 21.1, 21.1, 20.8, 20.6, 19.1,
18.6, 18.4, 17.6, 10.8, 10.6, 10.5, 10.0. Anal. Calcd for
C19H26O2: C, 79.68; H, 9.15. Found: C, 79.67; H, 9.11.
4.3.11. 1-(2,2-Diphenylcyclopropyl)-2-(4-bromophenyl)-
vinyl acetate (4en). A white solid, (65% yield, Z/E¼92:8).
IR (KBr) nmax cmꢁ1: 3026, 1750 (C]O), 1487, 1200,
4.3.15. 1-(2,2-Diethylcyclopropyl)-2-(4-methoxyphenyl)-
prop-1-enyl acetate (7cm). A colorless oil (25% yield,
dr¼57:43) (a mixture of E and Z isomers). IR (neat)
nmax cmꢁ1: 2962, 1752 (C]O), 1609, 1511, 1246, 1193,
1
1151, 1011, 853, 705, 547. E-4en: H NMR (400 MHz,
CDCl3) d: 7.38–7.36 (m, 2H), 7.31–7.21 (m, 8H), 7.18–
7.13 (m, 2H), 6.94–6.92 (m, 2H), 5.71 (s, 1H), 2.59 (dd,
J¼9.0, 5.8 Hz, 1H), 2.02 (s, 3H), 1.80 (dd, J¼5.8, 5.8 Hz,
1H), 1.65 (dd, J¼9.0, 5.8 Hz, 1H). 13C NMR (100 MHz,
CDCl3) d: 168.1, 147.3, 145.3, 140.2, 133.0, 131.2, 130.2,
129.5, 128.4, 127.9, 127.4, 126.6, 126.1, 120.5, 116.1,
1
1036, 833, 556. H NMR (300 MHz, CDCl3) d: 7.25 (d,
J¼8.8 Hz, 2H), 7.13 (d, J¼8.8 Hz, 2H), 6.85 (d, J¼8.8 Hz,
2H), 6.82 (d, J¼8.8 Hz, 2H), 3.81 (s, 3H), 3.79 (s, 3H),
2.18 (s, 3H), 2.08 (s, 3H), 1.90 (s, 3H), 1.89 (s, 3H), 1.75
(dd, J¼8.7, 5.4 Hz, 1H), 1.60–1.00 (m, 9H), 0.96 (t,
J¼7.5 Hz, 3H), 0.94 (t, J¼7.5 Hz, 3H), 0.88 (t, J¼7.5 Hz,
3H), 0.69 (dd, J¼8.7, 5.4 Hz, 1H), 0.67 (t, J¼7.5 Hz, 3H),
0.43 (dd, J¼8.7, 5.4 Hz, 1H), 0.42 (dd, J¼5.4, 5.4 Hz,
1H), 0.04 (dd, J¼5.4, 5.4 Hz, 1H). 13C NMR (75.5 MHz,
CDCl3) d: 169.3, 168.8, 158.3, 158.2, 143.6, 141.8, 133.1,
132.9, 129.7, 128.7, 126.0, 125.6, 113.3, 113.3, 55.2, 55.2,
29.5, 29.3, 28.6, 28.4, 25.7, 25.5, 23.8, 23.7, 20.8, 20.6,
19.2, 18.6, 18.4, 17.7, 10.8, 10.6, 10.5, 10.0. Anal. Calcd
for C19H26O3: C, 75.46; H, 8.67. Found: C, 75.42; H, 8.67.
1
38.5, 30.6, 21.0, 19.9. Z-4en: H NMR (400 MHz, CDCl3)
d: 6.31 (s, 1H), 2.78 (dd, J¼9.0, 5.8 Hz, 1H). (Other peaks
cannot be distinguished from major peaks.) Anal. Calcd
for C25H21BrO2: C, 69.29; H, 4.88. Found: C, 68.99; H, 4.95.
4.3.12. 2-(Benzo[d][1,3]dioxol-5-yl)-1-(2,2-diphenylcy-
clopropyl)vinyl acetate (4jn). A white solid (58% yield, Z
only), mp 113.2–113.6 ꢀC. IR (KBr) nmax cmꢁ1: 3025,
1
1749 (C]O), 1490, 1160, 1038, 842, 734, 698. H NMR
(400 MHz, CDCl3) d: 7.38–7.36 (m, 2H), 7.28–7.16 (m,
8H), 6.67–6.64 (m, 2H), 6.55 (d, J¼8.4 Hz, 1H), 5.88 (s,
2H), 5.73 (s, 1H), 2.58 (dd, J¼8.8, 6.4 Hz, 1H), 2.07 (s,
3H), 1.79 (dd, J¼6.4, 6.4 Hz, 1H), 1.65 (dd, J¼8.8,
6.4 Hz, 1H). 13C NMR (75.5 MHz, CDCl3) d: 168.5,
147.3, 146.3, 145.6, 145.4, 140.4, 130.3, 128.3, 128.2,
128.0, 127.5, 126.5, 126.1, 122.3, 117.0, 108.1, 108.0,
100.8, 38.2, 30.8, 21.2, 19.9. HRMS (FAB) m/z: Calcd for
C18H22O4 (M+) 398.1518. Found: 398.1518.
4.3.16. 1-(2,2-Diethylcyclopropyl)-2-(4-chlorophenyl)-
prop-1-enyl acetate (7dm). A colorless oil (68% yield,
dr¼58:42) (a mixture of E and Z mixture). IR (neat)
nmax cmꢁ1: 2963, 2934, 1756 (C]O), 1490, 1368, 1222,
1
1192, 832, 597. H NMR (300 MHz, CDCl3) d: 7.30–7.23
(m, 6H), 7.14–7.11 (m, 2H), 2.19 (s, 3H), 2.07 (s, 3H),
2.07 (s, 3H), 1.89 (s, 3H), 1.74 (dd, J¼8.7, 5.4 Hz, 1H),
1.60–1.01 (m, 9H), 0.96 (t, J¼7.5 Hz, 3H), 0.95 (t,
J¼7.5 Hz, 3H), 0.85 (t, J¼7.5 Hz, 3H), 0.70 (dd, J¼8.7,
5.4 Hz, 1H), 0.66 (t, J¼7.5 Hz, 3H), 0.45 (dd, J¼8.7,
5.4 Hz, 1H), 0.43 (dd, J¼5.4, 5.4 Hz, 1H), 0.03 (dd,
J¼5.4, 5.4 Hz, 1H). 13C NMR (75.5 MHz, CDCl3) d:
169.1, 168.6, 144.5, 142.8, 139.2, 139.0, 132.5, 132.3,
130.0, 129.0, 128.1, 128.1, 125.5, 125.0, 29.7, 29.5, 28.6,
28.4, 25.6, 25.4, 23.8, 23.7, 20.7, 20.5, 19.0, 18.8, 18.2,
17.7, 10.8, 10.6, 10.4, 10.0. Anal. Calcd for C18H23ClO2:
C, 70.46; H, 7.56. Found: C, 70.27; H, 7.57.
4.3.13. 1-(2,2-Diethylcyclopropyl)-2-phenylprop-1-enyl
acetate (7am). A colorless oil (40% yield, dr¼58:42) (a
mixture of E and Z isomers). IR (neat) nmax cmꢁ1: 2963,
1
2934, 1755 (C]O), 1223, 1191, 1056, 766, 701. H NMR
(300 MHz, CDCl3) d: 7.32–7.17 (m, 10H), 2.19 (s, 3H),
2.10 (s, 3H), 1.91 (s, 3H), 1.87 (s, 3H), 1.76 (dd, J¼8.4,
4.6 Hz, 1H), 1.61–1.03 (m, 9H), 0.96 (t, J¼7.2 Hz, 3H),
0.88 (t, J¼7.2 Hz, 3H), 0.88 (t, J¼7.2 Hz, 3H), 0.70 (dd,
J¼8.4, 4.6 Hz, 1H), 0.62 (t, J¼7.2 Hz, 3H), 0.43 (dd,
J¼4.6, 4.6 Hz, 1H), 0.42 (dd, J¼8.4, 4.6 Hz, 1H), 0.04
(dd, J¼4.6, 4.6 Hz, 1H). 13C NMR (75.5 MHz, CDCl3) d:
169.2, 168.6, 143.8, 142.1, 140.7, 140.6, 128.6, 128.2,
127.9, 127.8, 127.4, 126.6, 126.5, 126.5, 29.5, 29.4, 28.7,
28.5, 25.7, 25.5, 23.9, 23.7, 20.8, 20.6, 19.2, 18.6, 18.5,
17.7, 10.9, 10.7, 10.6, 10.0. Anal. Calcd for C18H24O2: C,
79.37; H, 8.88. Found: C, 79.27; H, 8.84.
4.3.17. 1-(2,2-Diethylcyclopropyl)-2-(4-bromophenyl)-
prop-1-enyl acetate (7em). A colorless oil (65% yield,
dr¼55:45) (a mixture of E and Z isomers). IR (neat)
nmax cmꢁ1: 2963, 1754 (C]O), 1668, 1487, 1368, 1220,
1
1192, 1071, 827, 597. H NMR (300 MHz, CDCl3) d: 7.44
(d, J¼8.0 Hz, 2H), 7.40 (d, J¼8.0 Hz, 2H), 7.19 (d,
J¼8.0 Hz, 2H), 7.06 (d, J¼8.0 Hz, 2H), 2.18 (s, 3H), 2.07
(s, 3H), 1.89 (s, 3H), 1.88 (s, 3H), 1.73 (dd, J¼7.4, 5.2 Hz,
1H), 1.59–1.02 (m, 9H), 0.95 (t, J¼7.0 Hz, 3H), 0.93 (t,
J¼7.0 Hz, 3H), 0.87 (t, J¼7.0 Hz, 3H), 0.70 (dd, J¼7.4,
4.3.14. 1-(2,2-Diethylcyclopropyl)-2-(4-methylphenyl)-
prop-1-enyl acetate (7bm). A colorless oil (31% yield,

Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
12147
5.2 Hz, 1H), 0.66 (t, J¼7.0 Hz, 3H), 0.45 (dd, J¼7.4, 5.2 Hz,
1H), 0.44 (dd, J¼5.2, 5.2 Hz, 1H), 0.03 (dd, J¼5.2, 5.2 Hz,
1H). 13C NMR (75.5 MHz, CDCl3) d: 168.9, 168.3, 144.4,
142.6, 139.6, 139.4, 131.0, 130.9, 130.3, 129.2, 125.4,
124.9, 120.5, 120.3, 29.7, 29.5, 28.6, 28.4, 25.6, 25.5,
23.9, 23.7, 20.7, 20.6, 18.9, 18.9, 18.2, 17.7, 10.8, 10.6,
10.5, 10.1. Anal. Calcd for C18H23BrO2: C, 61.54; H, 6.60.
Found: C, 61.30; H, 6.55.
4.3.21. 1-(2,2-Diphenylcyclopropyl)-2-(4-chlorophenyl)-
prop-1-enyl acetate (7dn). A colorless oil (74% yield,
dr¼58:42) (a mixture of E and Z isomers). IR (neat)
nmax cmꢁ1: 2963, 2934, 1756 (C]O), 1490, 1368, 1222,
1
1192, 832, 597. H NMR (300 MHz, CDCl3) d: 7.32–7.07
(m, 24H), 6.94–6.84 (m, 4H), 2.84 (dd, J¼8.7, 6.3 Hz,
1H), 2.59 (dd, J¼8.7, 6.3 Hz, 1H), 2.14 (s, 3H), 1.90 (s,
3H), 1.75 (s, 3H), 1.72 (dd, J¼6.3, 6.3 Hz, 1H), 1.67 (s,
3H), 1.56 (dd, J¼8.7, 6.3 Hz, 1H), 1.47 (dd, J¼6.3,
6.3 Hz, 1H), 1.35 (dd, J¼8.7, 6.3 Hz, 1H). 13C NMR
(75.5 MHz, CDCl3) d: 168.8, 168.2, 145.4, 145.4, 142.0,
141.1, 140.7, 140.7, 139.1, 138.7, 132.8, 132.3, 130.0,
129.5, 129.4, 128.8, 128.4, 128.4, 128.2, 128.0, 127.9,
127.9, 127.8, 127.6, 126.7, 126.5, 126.2, 126.2, 126.0,
126.0, 37.2, 37.2, 28.4, 28.0, 20.3, 20.2, 20.2, 20.0, 19.2,
18.6. Anal. Calcd for C26H23ClO2: C, 77.51; H, 5.75. Found:
C, 77.47; H, 5.75.
4.3.18. 1-(2,2-Diphenylcyclopropyl)-2-phenylprop-1-enyl
acetate (7an). A colorless oil (53% yield, dr¼55:45) (a mix-
ture of E and Z isomers). IR (neat) nmax cmꢁ1: 3057, 3024,
1
1753 (C]O), 1495, 1195, 1067, 766, 701, 550. H NMR
(400 MHz, CDCl3) d: 7.34–7.07 (m, 26H), 6.96–6.91 (m,
4H), 2.86 (dd, J¼9.2, 5.6 Hz, 1H), 2.63 (dd, J¼9.2, 5.6 Hz,
1H), 2.16 (s, 3H), 1.90 (s, 3H), 1.78 (s, 3H), 1.71 (dd,
J¼5.6, 5.6 Hz, 1H), 1.65 (s, 3H), 1.57 (dd, J¼9.2, 5.6 Hz,
1H), 1.47 (dd, J¼5.6, 5.6 Hz, 1H), 1.32 (dd, J¼9.2, 5.6 Hz,
1H). 13C NMR (100 MHz, CDCl3) d: 169.0, 168.1, 145.6,
145.5, 141.4, 141.2, 140.7, 140.6, 140.3, 140.0, 129.5,
129.4, 128.6, 128.4, 128.2, 128.1, 127.9, 127.8, 127.8,
127.6, 127.4, 127.1, 126.9, 126.5, 126.4, 126.1, 125.9, 37.2,
37.1, 28.2, 28.2, 20.4, 20.3, 20.1, 20.0, 19.5, 18.9. (Three
peaks (Ar or vinyl) are included in others.) Anal. Calcd for
C26H24O2: C, 84.75; H, 6.57. Found: C, 84.84; H, 6.50.
4.3.22. 1-(2,2-Diphenylcyclopropyl)-2-(4-bromophenyl)-
prop-1-enyl acetate (7en). A colorless oil (75% yield,
dr¼52:48) (a mixture of E and Z isomers). IR (neat)
nmax cmꢁ1: 3025, 1748 (C]O), 1488, 1368, 1224, 1071,
1
828, 698, 548. H NMR (300 MHz, CDCl3) d: 7.46–7.42
(m, 2H), 7.33–7.06 (m, 22H), 6.93–6.90 (m, 2H), 6.83–
6.78 (m, 2H), 2.84 (dd, J¼9.3, 6.3 Hz, 1H), 2.58 (dd,
J¼9.3, 6.3 Hz, 1H), 2.13 (s, 3H), 1.89 (s, 3H), 1.75 (s,
3H), 1.72 (dd, J¼6.3, 6.3 Hz, 1H), 1.66 (s, 3H), 1.56 (dd,
J¼9.3, 6.3 Hz, 1H), 1.47 (dd, J¼6.3, 6.3 Hz, 1H), 1.35
(dd, J¼9.3, 6.3 Hz, 1H). 13C NMR (75.5 MHz, CDCl3) d:
168.7, 168.1, 145.3, 145.3, 141.9, 141.0, 140.6, 140.6,
139.5, 139.2, 131.3, 131.0, 130.3, 129.5, 129.3, 129.2,
128.4, 128.2, 127.9, 127.8, 127.8, 127.6, 126.7, 126.4,
126.2, 126.2, 126.0, 126.0, 120.9, 120.4, 37.2, 27.2, 28.3,
28.0, 20.3, 20.2, 20.1, 19.9, 19.1, 18.5. Anal. Calcd for
C26H23BrO2: C, 69.80; H, 5.18. Found: C, 69.59; H, 5.27.
4.3.19. 1-(2,2-Diphenylcyclopropyl)-2-(4-methylphenyl)-
prop-1-enyl acetate (7bn). A colorless oil (43% yield,
dr¼55:45) (a mixture of E and Z isomers). IR (neat)
nmax cmꢁ1: 3024, 2919, 1754 (C]O), 1663, 1195, 1061,
1
701, 548. H NMR (300 MHz, CDCl3) d: 7.29–7.08 (m,
22H), 7.02–7.00 (m, 2H), 6.95–6.93 (m, 2H), 6.87–6.84
(m, 2H), 2.86 (dd, J¼9.3, 6.3 Hz, 1H), 2.64 (dd, J¼9.3,
6.3 Hz, 1H), 2.36 (s, 3H), 2.27 (s, 3H), 2.15 (s, 3H), 1.89
(s, 3H), 1.77 (s, 3H), 1.71 (dd, J¼6.3, 6.3 Hz, 1H), 1.68 (s,
3H), 1.56 (dd, J¼9.3, 6.3 Hz, 1H), 1.47 (dd, J¼6.3,
6.3 Hz, 1H), 1.33 (dd, J¼9.3, 6.3 Hz, 1H). 13C NMR
(75.5 MHz, CDCl3) d: 169.1, 168.3, 145.7, 145.6, 141.4,
141.2, 140.9, 139.8, 137.7, 137.4, 136.6, 136.2, 129.6,
129.5, 128.9, 128.6, 128.5, 128.5, 128.4, 128.1, 128.0,
128.0, 127.9, 127.8, 127.7, 127.3, 126.7, 126.4, 126.1,
125.9, 37.1, 37.0, 28.3, 28.2, 21.1, 21.1, 20.3, 20.3, 20.1,
20.0, 19.4, 18.8. Anal. Calcd for C27H26O2: C, 84.78; H,
6.85. Found: C, 85.04; H, 6.98.
Acknowledgements
This work is supported by Grant-in-Aid for Scientific Re-
search (B, 19350093) and Scientific Research on Priority
Areas ‘Advanced Molecular Transformations of Carbon Re-
sources’, from the Ministry of Education, Culture, Sports,
Science and Technology, Japan. Financial support from
Shorai Foundation for Science and Technology is gratefully
acknowledged.
4.3.20. 1-(2,2-Diphenylcyclopropyl)-2-(4-methoxyphe-
nyl)prop-1-enyl acetate (7cn). A colorless oil (38% yield,
dr¼53:47) (a mixture of E and Z isomers). IR (neat)
nmax cmꢁ1: 3025, 1752 (C]O), 1510, 1245, 1032, 910,
Supplementary data
1
Supplementary data associated with this article can be found
in the online version, at doi:10.1016/j.tet.2007.09.064.
833, 701, 587. H NMR (300 MHz, CDCl3) d: 7.29–7.09
(m, 20H), 6.97–6.86 (m, 6H), 6.76–6.73 (m, 2H), 3.82 (s,
3H), 3.75 (s, 3H), 2.85 (dd, J¼9.0, 6.3 Hz, 1H), 2.65 (dd,
J¼9.0, 6.3 Hz, 1H), 2.15 (s, 3H), 1.90 (s, 3H), 1.76 (s,
3H), 1.71 (dd, J¼6.3, 6.3 Hz, 1H), 1.69 (s, 3H), 1.56 (dd,
J¼9.0, 6.3 Hz, 1H), 1.47 (dd, J¼6.3, 6.3 Hz, 1H), 1.34
(dd, J¼9.0, 6.3 Hz, 1H). 13C NMR (75.5 MHz, CDCl3) d:
169.1, 168.4, 158.6, 158.1, 145.7, 145.7, 141.3, 141.2,
140.9, 139.8, 132.9, 132.7, 129.8, 129.6, 129.5, 128.6,
128.4, 128.2, 127.9, 127.9, 127.9, 127.7, 127.3, 126.6,
126.4, 126.2, 126.1, 125.9, 113.6, 113.3, 55.3, 55.1, 37.1,
37.0, 28.4, 28.2, 20.4, 20.3, 20.2, 20.0, 19.4, 18.8. HRMS
(FAB) m/z: Calcd for C27H26O3 (M+) 398.1882. Found:
398.1873.
References and notes
€
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Chem. 2004, 13, 123; (b) Echavarren, A. M.; Nevado, C. Chem.
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2007, 46, 3410 and references therein.
2. For cyclopentenone formation via metallatrienes, see: (a)
Rautenstrauch, V. J. Org. Chem. 1984, 49, 950; (b) Shi, X.;

12148
Y. Nakanishi et al. / Tetrahedron 63 (2007) 12138–12148
Gorin, D. J.; Toste, F. D. J. Am. Chem. Soc. 2005, 127, 5802; (c)
ꢀ
Nieto Faza, O.; Silva Lopez, C.; Alvarez, R.; de Lera, A. R.
10. E and Z structures of vinylcyclopropanes 4 and 7 were deter-
mined by NOE studies (see Supplementary data).
ꢀ
J. Am. Chem. Soc. 2006, 128, 2434.
11. Comparing these results with Sarpong’s shown in Scheme 4,5
the terminal substituents might play one of the most important
roles affecting the olefin regioselectivity in platinum catalysis.
However, the difference in selectivity of indenes resulting from
terminal alkynes is not clear at present.
3. For selected examples, see: (a) Wulff, W. D.; Bax, B. M.;
Brandvold, T. A.; Chan, K. S.; Gilbert, A. M.; Hsung, R. P.;
Mitchell, J.; Clardy, J. Organometallics 1994, 13, 102; (b)
Waters, M. L.; Bos, M. E.; Wulff, W. D. J. Am. Chem. Soc.
ꢀ
1999, 121, 6403; (c) Barluenga, J.; Aznar, F.; Gutierrez, I.;
Martın, A.; Garcıa-Granda, S.; Llorca-Baragano, M. A.
J. Am. Chem. Soc. 2000, 122, 1314; (d) Herndon, J. W.
12. When the reactions of 5 were carried out with smaller amount
of alkene or under diluted conditions, the yields of indenes 6/60
were increased. See Supplementary data.
ꢀ
ꢀ
ꢀ
Tetrahedron 2000, 56, 1257; (e) Barluenga, J.; Lopez, L. A.;
Martınez, S.; Tomas, M. Tetrahedron 2000, 56, 4967; (f)
Zhang, L.; Herndon, J. W. Organometallics 2004, 23, 1231;
13. (a) Soriano, E.; Marco-Contelles, J. J. Org. Chem. 2007, 72,
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
1443; (b) Marion, N.; Dıez-Gonzalez, S.; de Fremont, P.;
Noble, A. R.; Nolan, S. P. Angew. Chem., Int. Ed. 2006, 45,
3647; (c) Zhang, L.; Wang, S. J. Am. Chem. Soc. 2006, 128,
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ꢀ
(g) Barluenga, J.; Barrio, P.; Riesgo, L.; Lopez, L. A.; Tomas,
ꢀ
M. Tetrahedron 2006, 62, 7547.
4. (a) Miki, K.; Ohe, K.; Uemura, S. Tetrahedron Lett. 2003, 44,
2019; (b) Miki, K.; Ohe, K.; Uemura, S. J. Org. Chem. 2003,
68, 8505; (c) Miki, K.; Fujita, M.; Uemura, S.; Ohe, K. Org.
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14. Although the intermediary tricyclic compound seems to be un-
stable, Buchner-type mechanism cannot be excluded for the
present indene formation. For an example, see: Maguire,
A. R.; O’Leary, P.; Harrington, F.; Lawrence, S. E.; Blake,
A. J. J. Org. Chem. 2001, 66, 7166.
RS
R'
RS
RS
a
b
OAc
a
R'
R'
OAc
OAc
H
[M]
D
b
[M]
B
RS
H
H
R'
7. Starting material 1a was fully consumed, however only indene
2a could be determined.
OAc
8. Regiochemistries of 2b–i were determined by NOE studies (see
Supplementary data).
E
Alternative reaction pathway via Buchner mechanism.
9. When the platinum-catalyzed reaction of 1a with 3n was carried
outat70 ꢀCfor14 h, 4anwasobtainedin70%yield(Z/E¼91:9),
with a trace amount of 2a. Since no significant difference in
selectivity of products and an isomeric ratio of cyclopropanes
was observed, we employed the milder reaction conditions.
15. For reviews, see: (a) Habermas, K. L.; Denmark, S. E.; Jones,
T. K. Org. React. 1994, 45, 1; (b) Pellissier, H. Tetrahedron
2005, 61, 6479; (c) Frontier, A. J.; Collison, C. Tetrahedron
2005, 61, 7577.