Rhodium-catalyzed convenient synthesis of functionalized tetrahydronaphthalenes

Article abstract of DOI:10.1016/j.tet.2009.12.042

Convenient as well as convergent synthesis of functionalized tetrahydronaphthalenes has been accomplished under mild reaction conditions by the cationic rhodium(I)/H₈-BINAP complex-catalyzed [2+2+2] cycloaddition of 1,7-octadiyne derivatives with functionalized monoynes. The effect of the diyne tether lengths was investigated, which revealed that 1,6-heptadiyne and 1,7-octadiyne exhibit higher reactivity than 1,8-nonadiyne. Mechanistic studies indicated that the present rhodium-catalyzed [2+2+2] cycloaddition proceeds through the rhodacyclopentadiene intermediate generated by oxidative coupling of a diyne with rhodium. On the other hand, in the reactions of diynes and dimethyl acetylenedicarboxylate, the rhodacyclopentadiene intermediate generated by oxidative coupling of a diyne and a monoyne with rhodium would also be involved.

Full text of DOI:10.1016/j.tet.2009.12.042

Tetrahedron 66 (2010) 1563–1569
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Rhodium-catalyzed convenient synthesis of functionalized
tetrahydronaphthalenes
*
Ken Tanaka , Yayoi Sawada, Yusuke Aida, Maliny Thammathevo, Rie Tanaka,
Hiromi Sagae, Yousuke Otake
Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 22 October 2009
Received in revised form 18 December 2009
Accepted 18 December 2009
Available online 28 December 2009
Convenient as well as convergent synthesis of functionalized tetrahydronaphthalenes has been accom-
plished under mild reaction conditions by the cationic rhodium(I)/H8-BINAP complex-catalyzed [2þ2þ2]
cycloaddition of 1,7-octadiyne derivatives with functionalized monoynes. The effect of the diyne tether
lengths was investigated, which revealed that 1,6-heptadiyne and 1,7-octadiyne exhibit higher reactivity
than 1,8-nonadiyne. Mechanistic studies indicated that the present rhodium-catalyzed [2þ2þ2] cyclo-
addition proceeds through the rhodacyclopentadiene intermediate generated by oxidative coupling of
a diyne with rhodium. On the other hand, in the reactions of diynes and dimethyl acetylenedicarboxylate,
the rhodacyclopentadiene intermediate generated by oxidative coupling of a diyne and a monoyne with
rhodium would also be involved.
Ó 2010 Elsevier Ltd. All rights reserved.
2
1. Introduction
R
R
1
4
R
R
+
Tetrahydronaphthalene derivatives are found in several phar-
maceutical ingredients,1 therefore their convenient as well as
convergent synthesis is highly desirable.2,3 Representatively, tet-
rahydronaphthalenes can be synthesized through the hydrogena-
tion of the corresponding naphthalenes2 or the intramolecular
alkylation of the corresponding benzenes3 (Scheme 1). However,
these methods require prior preparation of substituted naphtha-
lene or benzene precursors. On the other hand, the [2þ2þ2] cy-
cloaddition between 1,7-octadiyne derivatives, that can be
obtained from commercial sources or prepared in one-step from
commercially available reagents, with monoynes would be attrac-
tive, because various substituents can be introduced to the benzene
ring in one-step by changing the substituents of two alkyne com-
ponents (Scheme 1).4,5
Despite the potential utility of the [2þ2þ2] cycloaddition be-
tween 1,7-octadiyne derivatives with monoynes for the synthesis
of tetrahydronaphthalene derivatives, successful examples have
been limited in number.6–13 In general, the metal-mediated oxi-
dative cyclization efficiency of 1,7-diynes is lower than that of 1,6-
diynes.14 Especially, the cyclization of 1,7-octadiyne derivatives is
rather difficult due to the lack of the Thorpe–Ingold effect induced
by the tertiary center15 and the heteroatom coordination to the
3
[2 + 2 + 2] cycloaddition
(this work)
1
1
4
1
4
R
R
R
X
R
R
2
3
2
3
2
3
R
R
R
R
R
R
2 H
2
–HX
4
R
alkylation
(ref. 3)
hydrogenation
(ref. 2)
Scheme 1. Synthetic routes for the preparation of tetrahydronaphthalene derivatives.
metals.14a Therefore, a majority of previously reported examples
require the prior formation of metallacyclopentadienes from 1,7-
octadiyne derivatives using a stoichiometric amount of metal
complexes, such as Ta,6 Mo,7 Mg/Mn,8 Co,9 and Ni10 complexes. In
the case of using a catalytic amount of a metal complex, rapid
formation of the metallacyclopentadiene from the 1,7-octadiyne
derivative is necessary. Although several nickel-catalyzed reactions
have been reported, diyne substrates are strictly limited to elec-
tron-deficient 1,7-octadiyne derivatives bearing ester or amide
groups at the terminal positions.11,12 Furthermore, elevated tem-
perature11a or under microwave11b heating are necessary.
In 2003, our research group discovered that cationic rhodium(I)/
biaryl bisphosphine complexes are highly effective catalysts for
* Corresponding author. Tel./fax: þ81 42 388 7037.
E-mail address: tanaka-k@cc.tuat.ac.jp (K. Tanaka).
0040-4020/$ – see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2009.12.042

1564
K. Tanaka et al. / Tetrahedron 66 (2010) 1563–1569
Table 1
the [2þ2þ2] cycloaddition of alkynes, leading to substituted
benzenes.16–18 This new catalyst system could be applicable to the
[2þ2þ2]cycloadditionofnotonly1,6-diynes17 butalso1,9-decadiyne
orlongertethered-terminal1,n-diynes(n¼10–15)withmonoalkynes,
leading to bicyclic benzene derivatives.16 These results prompted our
investigation into the synthesis of functionalized tetrahydronaph-
thalenes by the [2þ2þ2] cycloadditions of 1,7-octadiyne derivatives
with monoynes. Recently, the successful [2þ2þ2] cycloadditions of
1,7-octadiyne with alkynylphosphine sulfides19 and oxides20 using
a cationic rhodium(I)/BINAP complex as a catalyst have been
reported by Oshima, Yorimitsu, and co-workers,19 and Doherty and
co-workers,20 respectively, for the synthesis of phosphine ligands.
However, detailed studies concerning further catalyst tuning and the
substrate scope have not been reported. In this paper, we describe the
cationic rhodium(I)/H8-BINAP complex-catalyzed [2þ2þ2] cyclo-
addition of 1,7-octadiyne derivatives with monoynes for the syn-
thesis of functionalized tetrahydronaphthalenes. Mechanistic insight
of this reaction is also discussed.
Screening of rhodium catalysts for [2þ2þ2] cycloaddition of 1,7-octadiyne (1a) with
ethyl 2-butynoate (2a)a
Entry
Catalyst
Yieldb (%)
1
2
3
4
5
6
7
8
9
[Rh(nbd)2]BF4/dppe
[Rh(cod)2]BF4/dppb
[Rh(cod)2]BF4/dppf
[Rh(cod)2]BF4/BIPHEP
[Rh(cod)2]BF4/BINAP
[Rh(cod)2]BF4/Segphos
[Rh(cod)2]BF4/H8-BINAP
[Rh(cod)Cl]2/2BINAP
[Rh(cod)Cl]2/2AgBF4/2H8-BINAP
5
9
6
42
45
57
69
0
70
a
A (CH2Cl)2 solution of 1a and 2a was added dropwise over 10 min to a (CH2Cl)2
solution of a rhodium catalyst.
b
Isolated yield.
2. Results and discussion
Table 2. Not only ethyl 2-butynoate (2a) but also ethyl phenyl-
propiolate (2b) reacted with 1a to give the corresponding tetra-
hydronaphthalenes in high yields (entries 1 and 2), while the
cycloadditions of tert-butyl propiolate (2c) and dimethyl acetyle-
nedicarboxylate (2d) with 1a proceeded in moderate yields due to
the formation of homo-[2þ2þ2] cycloaddition products from 2c
and 2d (entries 3 and 4).21 Not only electron-deficient monoynes
2a–d but also electron-rich monoynes (propargylic alcohols) 2e–h
could also participate in this reaction to give the corresponding
tetrahydronaphthalenes in high yields (entries 5–8).22
2.1. Screening of rhodium(I) catalysts for [2D2D2]
cycloaddition of 1,7-octadiyne with ethyl 2-butynoate
We first examined the reaction of commercially available 1,7-
octadiyne (1a) with ethyl 2-butynoate (2a) at room temperature in
the presence of a cationic rhodium(I) complex (5 mol %) with var-
ious bisphosphine ligands (Fig. 1) (Table 1, entries 1–7). In our
previous reports of cationic rhodium(I) complex-catalyzed
[2þ2þ2] cycloadditions of alkynes, cationic rhodium(I) complexes
of biaryl bisphosphine ligands showed significantly higher catalytic
activity than those of conventional mono- and bisphosphine li-
gands (Ph3P, n-Bu3P, dppe, dppb, and dppf), although precise
mechanism is not clear.16,17 Especially, a cationic rhodium(I)/H8-
BINAP complex showed the highest catalytic activity.16 Consistent
with our previous reports, biaryl bisphosphines were found to be
suitable ligands (entries 4–7) and the use of H8-BINAP furnished
the desired tetrahydronaphthalene 3aa in the highest yield (entry
7). Importantly, a cationic character of the catalyst is essential to
promote the desired cycloaddition (entry 8). Not only an isolated
cationic rhodium(I) complex, [Rh(cod)2]BF4, but also a cationic
rhodium(I) complex generated in situ by mixing [Rh(cod)Cl]2 and
AgBF4 could be employed (entry 9).
Table 2
Rhodium-catalyzed [2þ2þ2] cycloadditions of 1,7-octadiyne (1a) with monoynes
2a–ha
Entry
2
R1
R2
2 (equiv)
3
Yieldb (%)
1
2a
2b
2c
2d
2e
2f
Me
Ph
H
CO2Me
Me
Ph
CO2Et
CO2Et
1.1
1.1
2.0
2.0
1.1
1.1
2.0
1.1
3aa
3ab
3ac
3ad
3ae
3af
77
92
52
53
80
90
94
94
2c
3d
4d,e
5
CO2t-Bu
CO2Me
CH2OH
CH2OH
CH2OH
CH2OH
6
7d
8f
2g
2h
H
3ag
3ah
PPh2
PPh2
PPh2
PPh2
PPh2
PPh2
PPh2
CH2OH
Fe
a
A (CH2Cl)2 solution of 1a was added dropwise over 10 min to a (CH2Cl)2 solution
of 2 and Rh catalyst.
PPh2
dppe
dppf
dppb
BIPHEP
b
Isolated yield.
Concentration of 1a: 0.05 M.
A (CH2Cl)2 solution of 1a and 2 was added dropwise over 10 min to a (CH2Cl)2
O
c
d
O
O
PPh2
PPh2
PPh2
PPh2
PPh2
PPh2
solution of Rh catalyst.
e
Ligand: BINAP.
Solvent: THF. For 1 h.
f
O
BINAP
Segphos
H8-BINAP
The scope of monoynes in the reactions with commercially
available 2,8-decadiyne (1b) was also investigated as shown in
Table 3. The cycloadditions of electron-deficient internal monoynes
2a, 2b, and 2d with 1b proceeded in moderate to high yields (en-
tries 1, 2, and 4), while that of electron-deficient terminal monoyne
2c with 1b did not proceed due to the rapid homo-[2þ2þ2] cy-
cloaddition of 2c (entry 3). Interestingly, although electron-rich
monoynes 2e–g could react with 1b in fare to good yields (entries
5–7), 2-butyne-1,4-diol (2h) failed to react with 1b and no con-
versions of both 1b and 2h were observed (entry 8).
Figure 1. Structures of bisphosphine ligands.
2.2. Rhodium-catalyzed [2D2D2] cycloadditions of 1,7-
octadiyne derivatives with monoynes
Thus, the scope of monoynes in the [2þ2þ2] cycloaddition with
1,7-octadiyne (1a) was investigated at room temperature by using
5 mol % of the cationic rhodium(I)/H8-BINAP complex as shown in

K. Tanaka et al. / Tetrahedron 66 (2010) 1563–1569
1565
Table 3
Table 4
Rhodium-catalyzed [2þ2þ2] cycloadditions of 2,8-decadiyne (1b) with monoynes
Rhodium-catalyzed [2þ2þ2] cycloadditions of electron-deficient 1,7-octadiyne de-
2a–ha
rivative 1d with monoynes 2a–ha
Entry
2
R1
R2
2 (equiv)
3
Yieldb (%)
1
2a
2b
2c
2d
2e
2f
Me
Ph
H
CO2Me
Me
Ph
CO2Et
CO2Et
2.0
2.0
2.0
2.0
2.0
2.0
5.0
2.0
3ba
3bb
3bc
3bd
3be
3bf
89
84
0
46
43
76
30
0
2
3c
CO2t-Bu
CO2Me
CH2OH
CH2OH
CH2OH
CH2OH
4c,d,e
5e
6f
Entry
2
R1
R2
2 (equiv)
3
Yieldb (%)
1c
2c
3d
4d,e
5
2a
2b
2c
2d
2e
2f
Me
Ph
H
CO2Me
Me
Ph
CO2Et
CO2Et
2.0
2.0
2.0
2.0
2.0
2.0
5.0
2.0
3da
3db
3dc
3dd
4de
4df
4dg
5
86
96
0
21
98
96
97
0
7c,f
8g
2g
2h
H
3bg
3bh
CH2OH
CO2t-Bu
CO2Me
CH2OH
CH2OH
CH2OH
CH2OH
a
A (CH2Cl)2 solution of 1b was added dropwise over 10 min to a (CH2Cl)2 solution
of 2 and Rh catalyst.
b
Isolated yield.
6f
c
7d
8g
2g
2h
H
A (CH2Cl)2 solution of 1b and 2 was added dropwise over 10 min to a (CH2Cl)2
solution of Rh catalyst.
CH2OH
d
Ligand: BINAP.
a
e
At 80 ꢀC.
A (CH2Cl)2 solution of 1d was added dropwise over 10 min to a (CH2Cl)2 solution
of 2 and Rh catalyst.
f
At 50 ꢀC.
b
g
Isolated yield.
Concentration of 1d: 0.05 M.
A (CH2Cl)2 solution of 1d and 2 was added dropwise over 10 min to a (CH2Cl)2
Solvent: THF.
c
d
Not only 2,8-decadiyne (1b) but also commercially available 3,9-
dodecadiyne (1c) could be equally employed for this reaction
(Scheme 2).
solution of Rh catalyst.
e
Ligand: BINAP.
f
At 40 ꢀC.
g
Solvent: THF.
Et
5 mol % [Rh(cod) ]BF /
Me
2
4
Et
Me
CO Et
H -BINAP
8
+
O
5 mol %
(CH Cl) , rt
R
O
2
2
2
Et
[Rh(cod) ]BF /
16 h
2
4
CO Et
2
R
R
N
Et
3ca 95%
H -BINAP
8
N
+
1c (0.1 M)
2a (2.0 equiv)
O
(CH Cl) , rt
2
2
O
16 h
Scheme 2. Rhodium-catalyzed [2þ2þ2] cycloaddition of internal 3,9-dodecadiyne
(1c) with monoyne 2a.
R
1a (R = H)
2i (2.0 equiv)
3ai 73%
3bi 23%
3di 92%
1b (R = Me)
1d (R = CO Me)
2
Other than electron-rich 1,7-octadiyne derivatives, methoxy car-
bonyl-substituted electron-deficient 1,7-octadiyne 1d, that can be
readily prepared in one-step from commercially available 1a,23 was
employed for this reaction as shown in Table 4. Electron-deficient
internalmonoynes 2a, 2b, and 2dwereabletoreactwith1d(entries1,
2, and 4), while electron-deficientterminalmonoyne 2cfailed toreact
with 1d due to the rapid homo-[2þ2þ2] cycloadditions of both 1d
and 2c (entry 3). In the reactions of 1d and propargylic alcohols 2e–g,
sequential [2þ2þ2] cycloaddition-lactonization24 proceeded to yield
the corresponding lactones in excellent yields (entries 5–7). However,
2-butyne-1,4-diol (2h) failed to react with 1d and no conversions of
both 1d and 2h were observed (entry 8).
Not only propargylic alcohol (2g) but also protected propargyl
amine 2i was able to react with 1,7-diynes 1a, 1b, and 1d to yield
the corresponding protected 2-tetrahydronaphthalenemethyl-
amine derivatives (Scheme 3), while non-protected propargyl
amine could not participate in this reaction.25
(0.1 M)
Scheme 3. Rhodium-catalyzed [2þ2þ2] cycloadditions of 1,7-octadiyne derivatives 1
with protected propargyl amine 2i.
react with 1,8-nonadiyne (1f) to give the corresponding 6–7 fused
bicyclic benzenes in moderate yields (entries 3 and 6). As the
transition-metal-mediated [2þ2þ2] cycloaddition of 1,8-non-
adiyne derivatives with monoynes was scarcely reported, these
successful reactions are worthy of note.13,26,27 However, highly
electron-deficient monoyne 2d reacted with 1,7-diyne 1a in very
low yield (entry 7). The use of BINAP as a ligand instead of H8-BINAP
was found to be effective, and the corresponding 5–6 and 6–6 fused
phthalates were obtained in fair yields (entries 8 and 9), although
less reactive 1,8-diyne 1f failed to react with 2d (entry 10).
2.4. Mechanistic consideration
2.3. Comparison of reactivity of 1,6-heptadiyne, 1,7-
octadiyne, and 1,8-nonadiyne
A plausible mechanism for the rhodium-catalyzed [2þ2þ2]
cycloaddition of terminal diynes 1 with monoynes 2 is shown in
Scheme 4. Bicyclic benzene 3 can be obtained through rhodacy-
clopentadiene intermediate A or B, generated by oxidative coupling
of diyne 1 with rhodium or diyne 1 and monoyne 2 with rhodium,
respectively. In the reactions of terminal diynes 1e, 1a, and 1f with
electron-rich (2e) and moderately electron-deficient monoynes
(2a), homo-[2þ2þ2] cycloaddition products of diynes were gen-
erated as major by-products. Therefore rhodacyclopentadiene A
The effect of the diyne tether lengths on the reactivity toward
the cationic rhodium(I)/H8-BINAP complex-catalyzed [2þ2þ2] cy-
cloaddition was systematically investigated as shown in Table 5.
Electron-rich (2e) and moderately electron-deficient monoynes
(2a) reacted with 1,6-heptadiyne (1e) and 1,7-octadiyne (1a) to give
the corresponding 5–6 and 6–6 fused bicyclic benzenes in high
yields (entries 1, 2, 4, and 5). Monoynes 2e and 2a were also able to
would be
a
major intermediate. Similarly, homo-[2þ2þ2]

1566
K. Tanaka et al. / Tetrahedron 66 (2010) 1563–1569
Table 5
cycloaddition products of diynes were generated as major by-
products in the reactions of internal diynes 1b–d with monoynes
2a–g, and so the rhodacyclopentadiene generated by oxidative
Rhodium-catalyzed [2þ2þ2] cycloadditions of 1,6-heptadiyne (1e), 1,7-octadiyne
(1a), and 1,8-nonadiyne (1f) with monoynes 2a
coupling of diynes 1b–d with rhodium would be
a
major
intermediate.
1
2
R
R
+
Rh
A
Entry
1
2
R1
R2
2 (equiv)
3
Yield (%)b
+
+
Rh(I)
–Rh(I)
Z
1c
1e
1a
1f
1e
1a
1f
1a
1a
1e
1f
2e
2e
2e
2a
2a
2a
2d
2d
2d
2d
Me
Me
Me
Me
Me
Me
CO2Me
CO2Me
CO2Me
CO2Me
CH2OH
CH2OH
CH2OH
CO2Et
CO2Et
CO2Et
CO2Me
CO2Me
CO2Me
CO2Me
1.1
1.1
2.0
1.1
1.1
2.0
2.0
2.0
2.0
2.0
3ee
3ae
3fe
3ea
3aa
3fa
3ad
3ad
3ed
3fd
79
80
39
91
77
45
11
53
29g
dh
2c,d
3e
1
2
R
1
2
Z
R
R
+
+
Rh(I)
2
Rh
R
+
Z
4c
Z
+
5c,d
6e
–Rh(I)
B
R
2
1
3
+
R
1
Rh(I)
7
+
2
Rh
8d,f
9f
R
oligomers derived
from 1 and 2
+
10f
–Rh(I)
1
Z
R
C
a
A (CH2Cl)2 solution of 1 and 2 was added dropwise over 10 min to a (CH2Cl)2
Scheme 4. Plausible mechanism for rhodium-catalyzed [2þ2þ2] cycloaddition of
diynes 1 with monoynes 2.
solution of Rh catalyst.
b
Isolated yield.
c
A (CH2Cl)2 solution of 1 was added dropwise over 10 min to a (CH2Cl)2 solution
of 2 and Rh catalyst.
On the other hand, we previously reported that dialkyl acety-
lenedicarboxylate 5 is an excellent partner for the cationic rho-
dium(I)/H8-BINAP complex-catalyzed chemo- and regioselective
cross-[2þ2þ2] cycloaddition with two terminal monoynes 4 lead-
ing to the corresponding 3,6-disubstituted phthalate 6 (Scheme
5).16 The mechanistic study indicated that this reaction proceeds
through the chemo- and regioselective formation of rhodacyclo-
pentadiene intermediate D.16b
d
Concentration of 1:0.1 M.
e
At 40 ꢀC.
f
Ligand: BINAP.
Determined by 1H NMR using 1,4-dimethoxybenzene as an internal standard.
g
h
A trace amount of 3fd was generated, while that could not be isolated in a pure
form.
[Rh(Ligand)]BF
(0.05 equiv)
4
+
E
E
2
R
CH Cl , rt, 1 h
2
2
4a
5a
(E = CO Et)
1
R
(R = n-C
H
)
2
2
1
10 21
2
R
R
CO R
R
+
2
2
2
Rh
2
CO R
+
CO R
2
2
4
Rh(I)
E
E
E
E
E
E
R
R
+
+
+
+
–Rh(I)
1
2
CO R
2
R
CO R
2
R
CO R
2
1
D
R
6
R
6a
1
4 (R = alkyl, Ar, Me Si)
3
8a
7a
Yield of
6a + 7a + 8a 6a / 7a / 8a
2
5 (R = Me, Et, t-Bu)
Ratio of
Scheme 5. Cationic rhodium(I)/H8-BINAP complex-catalyzed cross-[2þ2þ2] cycload-
dition of two terminal monoynes 4 with one dialkyl acetylenedicarboxylate 5.16b
H -BINAP
8
BINAP
93%
84%
92:6:2
54:26:20
Therefore the reactions of diynes 1 with monoyne 2d might
proceed through not only intermediate A but also intermediate B.
Indeed, the use of H8-BINAP as a ligand furnished phthalate 3ad
in low yield along with a large amount of oligomers derived from
1a and 2d presumably through the predominant formation of
intermediate C (Table 5, entry 7). On the other hand, the rho-
dium-catalyzed reaction of 1-dodecyne (4a) with diethyl
acetylenedicarboxylate (5a) by using BINAP as a ligand furnishes
4,5-disubstituted phthalate 8a in significantly higher yield than
that using H8-BINAP as a ligand (Scheme 6).16b In accordance with
this previous observation, the use of BINAP significantly increased
the yield of 4,5-disubstituted phthalate 3ad presumably due to
increased formation of intermediate B (Table 5, entry 8).
Scheme 6. Effect of ligands on regioselectivity of cross-[2þ2þ2] cycloaddition of
monoynes 4 with one dialkyl acetylenedicarboxylate (5).16b
reported nickel-catalyzed reactions are limited to the use of elec-
tron-deficient 1,7-octadiyne derivatives at elevated temperature11a
or under microwave heating,11b allowing use of both electron-rich
and electron-deficient 1,7-octadiyne derivatives under mild re-
action conditions in the present cationic rhodium(I)/H8-BINAP
complex-catalyzed reactions is advantageous than the nickel
catalyses. Furthermore, a variety of electron-rich and deficient
monoynes can alsobe employed as a cycloadditionpartner, although
some limitations exist. Both diynes and monoynes can be obtained
from commercial sources or prepared in one-step from commer-
cially available reagents, and thus this method enables a convenient
synthesis of new functionalized tetrahydronaphthalenes. The effect
of the diyne tether lengths on the reactivity was investigated, which
revealed that 1,6-heptadiyne and 1,7-octadiyne exhibited higher
reactivity than 1,8-nonadiyne. A mechanism of the rhodium-cata-
lyzed [2þ2þ2] cycloaddition is proposedthat the reactions proceeds
through the rhodacyclopentadiene generated by oxidative coupling
of a diyne with rhodium. In the reactions of diynes and dimethyl
acetylenedicarboxylate, the rhodacyclopentadiene generated by
oxidative coupling of a diyne and a monoyne with rhodium would
also be involved.
3. Conclusions
In conclusion, convenient as well as convergent synthesis of
functionalized tetrahydronaphthalenes has been accomplished
under mild reaction conditions by the cationic rhodium(I)/H8-BINAP
complex-catalyzed [2þ2þ2] cycloaddition of 1,7-octadiyne de-
rivatives with functionalized monoynes. Among the bisphosphine
ligands examined, H8-BINAP was the best ligand, which is consistent
with our previously reported cationic rhodium(I) complex-cata-
lyzed [2þ2þ2] cycloadditions of alkynes.16,17 As the previously

K. Tanaka et al. / Tetrahedron 66 (2010) 1563–1569
1567
4. Experimental
7.65 (m, 2H), 7.14–7.04 (m, 1H), 2.87–2.69 (m, 4H), 1.83–1.78 (m,
4H), 1.59 (s, 9H); 13C NMR (CDCl3)
166.1, 142.2, 137.0, 130.2, 129.1,
d
4.1. General
128.9, 126.3, 80.5, 29.5, 29.3, 28.2, 23.0, 22.9.
1H NMR spectra were recorded on 300 MHz (JEOL AL 300). 13
C
4.3.4. 5,6,7,8-Tetrahydronaphthalene-2,3-dicarboxylic acid dimethyl
NMR spectra were obtained with complete proton decoupling on
75 MHz (JEOL AL 300). Infrared spectra were obtained on a JASCO
FT/IR-4100. HRMS data were obtained on a Bruker micrOTOF Focus
II. All reactions were carried out under an atmosphere of argon in
oven-dried glassware with magnetic stirring.
ester (3ad)30,31. Method B (ligand: BINAP); colorless oil; 1H NMR
(CDCl3)
d
7.42 (s, 2H), 3.88 (s, 6H), 2.87–2.70 (m, 4H), 1.82–1.78 (m,
168.3, 140.8, 129.7, 128.9, 52.4, 29.2, 22.6.
4H); 13C NMR (CDCl3)
d
4.3.5. (3-Methyl-5,6,7,8-tetrahydronaphthalen-2-yl)methanol
(3ae). Method A; colorless solid; mp 66.6–67.9 ꢀC; IR (KBr) 3306,
4.2. Materials
2914, 1435, 1006 cmꢁ1; 1H NMR (CDCl3)
d
7.04 (s, 1H), 6.90 (s, 1H),
4.64 (s, 2H), 2.81–2.63 (m, 4H), 2.31 (s, 3H), 1.81–1.77 (m, 4H), 1.51
(s, 1H); 13C NMR (CDCl3)
136.6, 135.9, 134.6, 133.1, 131.0, 128.6,
Anhydrous (CH2Cl)2 (No. 28450-5) and THF (No. 18656-2) were
obtained from Aldrich and used as received. 1,7-Diyne 1d was
prepared according to the literature.21 All other reagents were
obtained from commercial sources and used as received.
d
63.4, 29.0, 28.9, 23.3, 23.2, 18.1; HRMS (ESI) calcd for C12H16ONa
[MþNa]þ 199.1093, found 199.1089.
4.3.6. (3-Phenyl-5,6,7,8-tetrahydronaphthalen-2-yl)methanol
4.3. Representative procedures for the rhodium-catalyzed
[2D2D2] cycloadditions of diynes 1 with monoynes 2
(3af). Method A; pale yellow solid; Mp 61.4–62.5 ꢀC; IR (KBr) 3277,
2932, 1442, 1036, 703 cmꢁ1
;
1H NMR (CDCl3)
d
7.45–7.26 (m, 5H),
7.22 (s,1H), 7.00 (s,1H), 4.54 (s, 2H), 2.92–2.66 (m, 4H),1.93–1.69 (m,
4H),1.78–1.56 (m,1H); 13C NMR (CDCl3)
140.8,138.7,136.70,136.67,
Method A: Table 2, entry 1. H8-BINAP (9.5 mg, 0.015 mmol) and
[Rh(cod)2]BF4 (6.1 mg, 0.015 mmol) were dissolved in CH2Cl2
(3.0 mL), and the reaction mixture was stirred at room temperature
for 5 min. H2 was introduced to the resulting solution in a Schlenk
tube. After stirring at room temperature for 1 h, the resulting so-
lution was concentrated to dryness and the residue was redissolved
in (CH2Cl)2 (0.5 mL) and a (CH2Cl)2 (0.5 mL) solution of 2a (37.0 mg,
0.330 mmol) was added. A (CH2Cl)2 (2.0 mL) solution of 1a
(31.8 mg, 0.300 mmol) was added dropwise to this solution over
10 min at room temperature (concentration of 1a: 0.1 M). The re-
action mixture was stirred at room temperature for 16 h. The
resulting solution was concentrated and purified by a preparative
TLC (n-hexane/ethyl acetate¼20:1), which furnished 3aa (50.4 mg,
0.231 mmol, 77% yield) as a colorless oil.
Method B: Table 2, entry 3. H8-BINAP (9.5 mg, 0.015 mmol) and
[Rh(cod)2]BF4 (6.1 mg, 0.015 mmol) were dissolved in CH2Cl2
(3.0 mL), and the reaction mixture was stirred at room temperature
for 5 min. H2 was introduced to the resulting solution in a Schlenk
tube. After stirring at room temperature for 1 h, the resulting so-
lution was concentrated to dryness and the residue was redissolved
in (CH2Cl)2 (1.0 mL). To this solution was added a (CH2Cl)2 (2.0 mL)
solution of 1a (31.8 mg, 0.300 mmol) and 2c (75.7 mg, 0.600 mmol)
at room temperature (concentration of 1a: 0.1 M). The reaction
mixture was stirred at room temperature for 16 h. The resulting
solution was concentrated and purified by a preparative TLC (n-
hexane/ethyl acetate¼20:1), which furnished 3ac (35.9 mg,
0.155 mmol, 52% yield) as a colorless oil.
d
135.2,130.8,129.3, 129.2, 128.2, 127.0, 63.1, 29.09, 29.07, 23.2; HRMS
(ESI) calcd for C17H18ONa [MþNa]þ 261.1250, found 261.1259.
4.3.7. (5,6,7,8-Tetrahydronaphthalen-2-yl)methanol
Method B; pale yellow oil; 1H NMR (CDCl3)
7.14–7.01 (m, 3H),
4.62 (d, J¼4.2 Hz, 2H), 2.87–2.66 (m, 4H), 1.82–1.78 (m, 4H),
1.67–1.55 (m, 1H); 13C NMR (CDCl3)
138.0, 137.3, 136.6, 129.3,
127.8, 124.3, 65.2, 29.3, 29.1, 23.2, 23.1.
(3ag)31
.
d
d
4.3.8. (3-Hydroxymethyl-5,6,7,8-tetrahydronaphthalen-2-yl)metha-
nol (3ah). Method A (solvent: THF); colorless solid; mp 105.0–
106.3 ꢀC; IR (KBr) 3420, 2922, 1087, 1001 cmꢁ1 1H NMR (CDCl3)
;
d
7.06 (s, 2H), 4.68 (s, 4H), 2.85–2.64 (m, 4H), 1.81–1.77 (m, 4H), 1.59
(s, 2H); 13C NMR (CDCl3)
d
137.3,136.4, 130.6, 63.9, 29.0, 23.0; HRMS
(ESI) calcd for C12H16O2Na [MþNa]þ 215.1043, found 215.1073.
4.3.9. 1,3,4-Trimethyl-5,6,7,8-tetrahydronaphthalene-2-carboxylic
acid ethyl ester (3ba). Method A; colorless solid; mp 70.8–71.6 ꢀC;
IR (KBr) 2926, 1725, 1433, 1267, 1190 cmꢁ1; 1H NMR (CDCl3)
d 4.40
(q, J¼7.2 Hz, 2H), 2.74–2.52 (m, 4H), 2.20 (s, 3H), 2.13 (s, 6H), 1.80–
1.76 (m, 4H), 1.39 (t, J¼7.2 Hz, 3H); 13C NMR (CDCl3)
d 171.3, 136.5,
133.4, 132.9, 132.7, 129.1, 128.6, 60.7, 28.1, 27.4, 22.9, 22.7, 17.1, 16.1,
14.7, 14.2; HRMS (ESI) calcd for C16H22O2Na [MþNa]þ 269.1512,
found 269.1505.
4.3.10. 1,4-Dimethyl-3-phenyl-5,6,7,8-tetrahydronaphthalene-2-car-
boxylic acid ethyl ester (3bb). Method A; colorless solid; mp 72.9–
74.5 ꢀC; IR (KBr) 2930, 1725, 1286, 1187, 702 cmꢁ1; 1H NMR (CDCl3)
4.3.1. 3-Methyl-5,6,7,8-tetrahydronaphthalene-2-carboxylic
ethyl ester (3aa). Method A; colorless oil; IR (neat) 2931, 1715, 1447,
1264, 1141, 1056 cmꢁ1 1H NMR (CDCl3)
7.64 (s, 1H), 6.93 (s, 1H),
acid
d
7.42–7.11 (m, 5H), 3.89 (q, J¼7.2 Hz, 2H), 2.76–2.55 (m, 4H), 2.19 (s,
;
d
3H), 1.94 (s, 3H), 1.84–1.80 (m, 4H), 0.88 (t, J¼7.2 Hz, 3H); 13C NMR
4.33 (q, J¼7.2 Hz, 2H), 2.85–2.64 (m, 4H), 2.52 (s, 3H), 1.81–1.76 (m,
(CDCl3) d 170.2, 140.1, 137.1, 136.0, 135.2, 132.6, 132.1, 129.8, 129.4,
4H), 1.38 (t, J¼7.2 Hz, 3H); 13C NMR (CDCl3)
d
167.7, 141.5, 136.7,
127.7, 126.8, 60.4, 28.1, 27.5, 22.8, 22.7, 16.3, 16.1, 13.6; HRMS (ESI)
134.4,132.2,131.3,126.9, 60.3, 29.2, 28.7, 23.1, 22.9, 21.2,14.3; HRMS
calcd for C21H24O2Na [MþNa]þ 331.1660, found 331.1512.
(ESI) calcd for C14H18O2Na [MþNa]þ 241.1199, found 241.1225.
4.3.11. 1,4-Dimethyl-5,6,7,8-tetrahydronaphthalene-2,3-dicarboxylic
acid dimethyl ester (3bd). Method B (ligand: BINAP, temperature:
80 ꢀC); colorless solid; mp 63.6–64.9 ꢀC; IR (KBr) 2929, 1725, 1438,
4.3.2. 3-Phenyl-5,6,7,8-tetrahydronaphthalene-2-carboxylic
ethyl ester (3ab)28. Method A (concentration of 1a: 0.05 M); pale
yellow oil; 1H NMR (CDCl3)
7.57 (s, 1H), 7.43–7.20 (m, 5H), 7.05 (s,
acid
d
1265, 1213, 1031 cmꢁ1; 1H NMR (CDCl3)
d
3.85 (s, 6H), 2.73–2.53 (m,
1H), 4.05 (q, J¼7.2 Hz, 2H), 2.90–2.72 (m, 4H),1.85–1.81 (m, 4H), 0.97
4H), 2.21 (s, 6H), 1.88–1.67 (m, 4H); 13C NMR (CDCl3)
d
169.6, 138.7,
(t, J¼7.2 Hz, 3H); 13C NMR (CDCl3)
d
168.8, 141.8, 140.8, 139.7, 136.3,
132.2, 129.4, 52.2, 27.8, 22.5, 16.1; HRMS (ESI) calcd for C16H20O4Na
131.3,130.6,128.4,128.2,127.8,126.7, 60.6, 29.4, 28.9, 23.0, 22.9,13.6.
[MþNa]þ 299.1254, found 299.1254.
4.3.3. 5,6,7,8-Tetrahydronaphthalene-2-carboxylic acid tert-butyl
4.3.12. (1,3,4-Trimethyl-5,6,7,8-tetrahydronaphthalen-2-yl)methanol
(3be). Method A (temperature: 80 ꢀC); colorless solid; mp 101.5–
ester (3ac)29,30. Method B; colorless oil; 1H NMR (CDCl3)
d
7.75–

1568
K. Tanaka et al. / Tetrahedron 66 (2010) 1563–1569
102.8 ꢀC; IR (KBr) 3335, 2924, 1432, 988 cmꢁ1
;
1H NMR (CDCl3)
21.6, 14.7; HRMS (ESI) calcd for C15H16O4Na [MþNa]þ 283.0941,
d
4.80 (s, 2H), 2.78–2.53 (m, 4H), 2.37 (s, 3H), 2.30 (s, 3H), 2.18 (s,
found 283.0944.
3H), 1.89–1.66 (m, 4H), 1.25 (s, 1H); 13C NMR (CDCl3)
d
135.8, 133.9,
133.6, 133.1, 132.9, 132.7, 59.9, 28.4, 28.1, 23.1, 15.9, 15.3, 14.8; HRMS
4.3.20. 1-Oxo-4-phenyl-1,3,6,7,8,9-hexahydronaphtho[1,2-c]furan-5-
carboxylic acid methyl ester (4df). Method A (temperature: 40 ꢀC);
colorless solid; mp 129.1–131.0 ꢀC; IR (KBr) 2949, 1753, 1452, 1205,
(ESI) calcd for C14H20ONa [MþNa]þ 227.1406, found 227.1408.
4.3.13. (1,4-Dimethyl-3-phenyl-5,6,7,8-tetrahydronaphthalen-2-yl)-
methanol (3bf). Method A (temperature: 50 ꢀC); pale yellow solid;
mp 68.0–69.5 ꢀC; IR (KBr) 3313, 2925,1429, 984, 702 cmꢁ1; 1H NMR
1111, 700 cmꢁ1
;
1H NMR (CDCl3, 300 MHz)
d
7.50–7.33 (m, 3H),
7.20–7.34 (m, 2H), 5.07 (s, 2H), 3.58 (s, 3H), 3.42–3.18 (m, 2H), 2.92–
2.69 (m, 2H), 2.10–1.72 (m, 4H); 13C NMR (CDCl3, 75 MHz)
170.8,
d
(CDCl3)
2.60 (m, 4H), 2.37 (s, 3H), 1.88 (s, 3H), 1.95–1.76 (m, 4H), 1.22 (s, 1H);
13C NMR (CDCl3)
141.4,139.8,135.8,135.6,133.7,133.4,132.1,129.4,
d
7.50–7.32 (m, 3H), 7.22–7.14 (m, 2H), 4.40 (s, 2H), 2.85–
168.8, 143.5, 138.8, 138.6, 135.7, 131.4, 128.8, 128.4, 128.1, 123.5, 68.3,
52.1, 27.0, 25.1, 22.2, 21.5; HRMS (ESI) calcd for C20H18O4Na
[MþNa]þ 345.1097, found 345.1101.
d
128.2, 126.7, 60.6, 28.2, 28.1, 23.0, 22.9, 16.8, 14.8; HRMS (ESI) calcd
for C19H22O [MþH]þ 289.1563, found 289.1572.
4.3.21. 1-Oxo-1,3,6,7,8,9-hexahydronaphtho[1,2-c]furan-5-carboxylic
acid methyl ester (4dg)10b. Method B; colorless solid; mp 129.4–
4.3.14. (1,4-Dimethyl-5,6,7,8-tetrahydronaphthalen-2-yl)methanol
(3bg). Method B (temperature: 50 ꢀC); colorless solid; mp 75.9–
77.4 ꢀC; IR (KBr) 3379, 2925, 1442, 1031, 876 cmꢁ1; 1H NMR (CDCl3)
130.9 ꢀC; 1H NMR (CDCl3)
d
7.60 (s, 1H), 5.20 (s, 2H), 3.89 (s, 3H),
3.30–3.13 (m, 2H), 3.07–2.89 (m, 2H), 1.80–1.76 (m, 4H); 13C NMR
(CDCl3) 170.5, 167.9, 143.9, 140.2, 138.9, 136.2, 125.0, 120.2, 68.4,
d
d
7.00 (s, 1H), 4.67 (s, 2H), 2.76–2.54 (m, 4H), 2.22 (s, 6H), 1.83–1.78
52.4, 27.8, 25.5, 22.3, 21.3.
(m, 4H), 1.46 (s, 1H); 13C NMR (CDCl3)
d
136.2, 135.6, 135.4, 133.8,
132.4, 127.2, 64.3, 27.7, 27.4, 23.1, 22.7, 19.3, 14.0; HRMS (ESI) calcd
4.3.22. 2-(5,6,7,8-Tetrahydronaphthalen-2-ylmethyl)isoindole-1,3-
for C13H18ONa [MþNa]þ 213.1250, found 213.1260.
dione (3ai). Method B; colorless solid; mp 121.6–122.4 ꢀC; IR (neat)
2935, 1713, 1391, 951, 713 cmꢁ1 1H NMR (CDCl3)
; d 7.90–7.75 (m,
4.3.15. 1,4-Diethyl-3-methyl-5,6,7,8-tetrahydronaphthalene-2-car-
2H), 7.77–7.62 (m, 2H), 7.22–7.08 (m, 2H), 7.00 (d, J¼7.8 Hz, 1H),
boxylic acid ethyl ester (3ca). Method A; colorless oil; IR (neat)
4.77 (s, 2H), 2.84–2.61 (m, 4H), 1.85–1.66 (m, 4H); 13C NMR (CDCl3)
2933, 1725, 1451, 1259, 1181, 1056 cmꢁ1; 1H NMR (CDCl3)
d
4.40 (q,
d 168.0, 137.4, 136.8, 133.8, 133.4, 132.1, 129.34, 129.29, 125.8, 123.2,
J¼7.2 Hz, 2H), 2.84–2.65 (m, 4H), 2.64 (q, J¼7.5 Hz, 2H), 2.54 (q,
41.3, 29.3, 29.1, 23.1, 23.0; HRMS (ESI) calcd for C19H17NO2Na
J¼7.5 Hz, 2H), 2.23 (s, 3H), 1.81–1.76 (m, 4H), 1.39 (t, J¼7.2 Hz, 3H),
[MþNa]þ 314.1151, found 314.1172.
1.61 (t, J¼7.5 Hz, 3H), 1.10 (t, J¼7.5 Hz, 3H); 13C NMR (CDCl3)
d 171.4,
138.7, 136.3, 135.3, 133.12, 133.05, 128.4, 60.7, 27.0, 26.3, 23.7, 23.1,
22.8, 21.8, 16.1, 14.6, 14.2, 13.2; HRMS (ESI) calcd for C18H26O2Na
[MþNa]þ 297.1825, found 297.1843.
4.3.23. 2-(1,4-Dimethyl-5,6,7,8-tetrahydronaphthalen-2-ylmethyl)-
isoindole-1,3-dione (3bi). Method B; colorless solid; ꢁm1 p 153.8–
155.6 ꢀC; IR (KBr) 2924, 1712, 1391, 1109, 952, 714 cm
;
1H NMR
(CDCl3)
2H), 2.73–2.51 (m, 4H), 2.31 (s, 3H), 2.15 (s, 3H), 1.85–1.79 (m, 4H);
13C NMR (CDCl3)
168.3, 136.0, 135.4, 133.9, 133.8, 132.2, 132.0,
d 7.92–7.79 (m, 2H), 7.78–7.65 (m, 2H), 7.00 (s, 1H), 4.87 (s,
4.3.16. 3-Methyl-5,6,7,8-tetrahydronaphthalene-1,2,4-tricarboxylic
acid 2-ethyl ester 1,4-dimethyl ester (3da). Method A (concentration
of 1d: 0.05 M); colorless solid; mp 55.4–57.0 ꢀC; IR (KBr) 2944,1727,
d
130.7, 127.4, 123.3, 39.8, 27.9, 27.3, 23.1, 22.6, 19.5, 14.4; HRMS (ESI)
1439, 1231, 1066 cmꢁ1
;
1H NMR (CDCl3)
d
4.30 (q, J¼7.2 Hz, 2H),
calcd for C21H21NO2Na [MþNa]þ 342.1465, found 342.1450.
3.90 (s, 3H), 3.84 (s, 3H), 2.85–2.65 (m, 2H), 2.75–2.60 (m, 2H), 2.27
(s, 3H), 1.77–1.73 (m, 4H), 1.33 (t, J¼7.2 Hz, 3H); 13C NMR (CDCl3)
4.3.24. 2-(1,3-Dioxo-1,3-dihydroisoindol-2-ylmethyl)-5,6,7,8-
tetrahydronaphthalene-1,4-dicarboxylic acid dimethyl ester
(3di)10b. Method B; colorless solid; mp 162.3–164.1 ꢀC; 1H NMR
d
169.6, 168.5, 167.6, 137.2, 136.5, 133.4, 133.3, 130.2, 129.7, 61.5,
52.21, 52.19, 27.2, 26.9, 22.2, 21.9, 17.0, 14.0; HRMS (ESI) calcd for
C18H22O6Na [MþNa]þ 357.1309, found 357.1312.
(CDCl3)
2H), 3.96 (s, 3H), 3.85 (s, 3H), 3.14–2.85 (m, 2H), 2.85–2.55 (m, 2H),
1.85–1.59 (m, 4H); 13C NMR (CDCl3)
169.0, 167.74, 167.69, 138.7,
d 7.92–7.74 (m, 2H), 7.78–7.60 (m, 2H), 7.77 (s, 1H), 4.84 (s,
4.3.17. 3-Phenyl-5,6,7,8-tetrahydronaphthalene-1,2,4-tricarboxylic
acid 2-ethyl ester 1,4-dimethyl ester (3db). Method A (concentration
of 1d: 0.05 M); colorless solid; mp 85.0–86.8 ꢀC; IR (KBr) 2929,
d
136.8, 135.5, 134.0, 131.9, 131.6, 129.7, 129.1, 123.3, 52.5, 52.0, 39.0,
27.8, 27.5, 22.2, 22.0.
1728, 1434, 1208, 1020, 708 cmꢁ1 1H NMR (CDCl3)
; d 7.37–7.26 (m,
3H), 7.26–7.16 (m, 2H), 3.90 (q, J¼7.2 Hz, 2H), 3.86 (s, 3H), 3.46 (s,
4.3.25. (6-Methylindan-5-yl)-methanol (3ee). Method A (concen-
tration of 1e: 0.05 M); colorless solid; mp 65.9–67.0 ꢀC; IR (KBr)
3H), 2.91–2.77 (m, 2H), 2.83–2.68 (m, 2H), 1.83–1.78 (m, 4H), 0.85
(t, J¼7.2 Hz, 3H); 13C NMR (CDCl3)
d
168.7, 168.4, 167.5, 137.8, 136.62,
3348, 2913, 2841, 1454, 1063 cmꢁ1 1H NMR (CDCl3)
; d 7.22 (s, 1H),
136.56, 135.6, 134.9, 133.4, 130.0, 128.8, 127.7, 127.6, 61.2, 52.4, 51.8,
27.3, 27.1, 22.1, 21.9, 13.4; HRMS (ESI) calcd for C23H24O6Na
[MþNa]þ 419.1465, found 419.1465.
7.08 (s, 1H), 4.66 (s, 2H), 2.89 (t, J¼7.5 Hz, 4H), 2.12 (s, 3H), 2.07
(quint, J¼7.5 Hz, 2H), 1.61 (s, 1H); 13C NMR (CDCl3)
d 144.0, 141.9,
136.5, 133.9, 126.3, 123.9, 63.7, 32.6, 32.4, 25.5, 18.6; HRMS (ESI)
calcd for C11H14ONa [MþNa]þ 185.0937, found 185.0948.
4.3.18. 5,6,7,8-Tetrahydronaphthalene-1,2,3,4-tetracarboxylic
acid
tetramethyl ester (3dd)32. Method B (ligand: BINAP); colorless
4.3.26. (3-Methyl-6,7,8,9-tetrahydro-5H-benzocyclohepten-2-yl)-
methanol (3fe). Method A (temperature: 40 ꢀC, concentration of 1f:
0.05 M); colorless solid; mp 107.0–108.8 ꢀC; IR (KBr) 3330, 2909,
solid; mp 147.8–149.3 ꢀC; 1H NMR (CDCl3)
d 3.88 (s, 6H), 3.83 (s,
6H), 2.88–2.70 (m, 4H), 1.80–1.76 (m, 4H); 13C NMR (CDCl3)
166.6, 138.8, 134.7, 128.3, 52.9, 52.6, 27.5, 21.7.
d 167.7,
1442, 1075, 1033 cmꢁ1; 1H NMR (CDCl3)
d
7.08 (s, 1H), 6.94 (s, 1H),
4.64 (s, 2H), 2.85–2.69 (m, 4H), 2.31 (s, 3H), 1.92–1.75 (m, 2H), 1.74–
1.50 (m, 5H); 13C NMR (CDCl3)
143.0, 141.0, 135.9, 133.4, 131.3,
4.3.19. 4-Methyl-1-oxo-1,3,6,7,8,9-hexahydronaphtho[1,2-c]furan-5-
d
carboxylic acid methyl ester (4de). Method A; colorleꢁss1 solid; mp
128.8, 63.3, 36.24, 36.18, 32.7, 28.44, 28.35, 18.0; HRMS (ESI) calcd
>280.0 ꢀC; IR (KBr) 2952, 1761, 1722, 1213, 1016 cm
;
1H NMR
for C13H18ONa [MþNa]þ 213.1250, found 213.1258.
(CDCl3)
2H), 2.19 (s, 3H), 1.83–1.79 (m, 4H); 13C NMR (CDCl3)
144.0, 139.3, 136.8, 135.2, 125.5, 123.1, 68.1, 52.3, 26.9, 24.8, 22.2,
d
5.16 (s, 2H), 3.95 (s, 3H), 3.28–3.12 (m, 2H), 2.80–2.63 (m,
d
171.1, 169.4,
4.3.27. 6-Methylindan-5-carboxylic ethyl ester (3ea). Method A;
colorless oil; IR (neat) 2956, 2360, 1716, 1251, 1112 cmꢁ1 1H NMR
;

K. Tanaka et al. / Tetrahedron 66 (2010) 1563–1569
1569
Huang, I.; Cheng, C.-H. Org. Lett. 2002, 4, 807 Under microwave heating, see: (b)
Teske, J. A.; Deiters, A. J. Org. Chem. 2008, 73, 342.
12. Although a single example of the nickel-catalyzed reaction between 1,7-octa-
diyne (1a) and a monoyne was reported, the yield was extremely low (13%);
see: Turek, P.; Nova´k, P.; Pohl, R.; Hocek, M.; Kotora, M. J. Org. Chem. 2006, 71,
8978.
13. Palladium-catalyzed [2þ2þ2] cycloadditions of 1,7-octadiyne derivatives and
3,11-tridecadiyne with allylic compounds leading to substituted benzenes were
reported; see: Tsukada, N.; Sugawara, S.; Nakaoka, K.; Inoue, Y. J. Org. Chem.
2003, 68, 5961.
14. For related discussions, see: (a) Yamamoto, Y.; Arakawa, T.; Ogawa, R.; Itoh, K.
J. Am. Chem. Soc. 2003, 125, 12143; (b) Grigg, R.; Scott, R.; Stevenson, P. J.
Chem. Soc., Perkin Trans. 1 1988, 1357.
15. (a) Beesley, R. M.; Ingold, C. K.; Thorpe, J. F. J. Chem. Soc. 1915, 107, 1080; (b) Jung,
M. E.; Gervay, J. J. Am. Chem. Soc. 1991, 113, 224.
16. (a) Tanaka, K.; Shirasaka, K. Org. Lett. 2003, 5, 4697; (b) Tanaka, K.; Toyoda, K.;
Wada, A.; Shirasaka, K.; Hirano, M. Chem.d Eur. J. 2005, 11, 1145.
17. For our accounts, see: (a) Tanaka, K. Synlett 2007, 1977; (b) Tanaka, K.; Nishida,
G.; Suda, T. J. Synth. Org. Chem. Jpn. 2007, 65, 862.
18. For a review of rhodium-catalyzed cyclotrimerization reactions, see: Fujiwara,
M.; Ojima, I. In Modern Rhodium-Catalyzed Organic Reactions; Evans, P. A., Ed.;
Wiley-VCH: Weinheim, 2005; p 129.
19. Kondoh, A.; Yorimitsu, H.; Oshima, K. J. Am. Chem. Soc. 2007, 129, 6996.
20. (a) Doherty, S.; Knight, J. G.; Smyth, C. H.; Harrington, R. W.; Clegg, W. Org. Lett.
2007, 9, 4925; (b) Doherty, S.; Smyth, C. H.; Harrington, R. W.; Clegg, W. Or-
ganometallics 2008, 27, 4837.
21. 2-Tetrahydronaphthoyl derivatives are found in various pharmaceutical in-
gredients.For selected examples see: (a) Ujihara, K.; Ujita, S.; Manabe, A.;
Takaishi, M. WO 2,009,075,250 A1, 2009; Chem. Abstr. 2009, 151, 50508; (b)
Umemiya, H.; Takahashi, M.; Bohno, M.; Kawabe, K.; Shirokawa, S.; Nagatsuka,
T.; Sasako, S.; Satou, R.; Itoh, S.; Shimizu, T. WO 2,009,011,285 A1, 2009; Chem.
Abstr. 2009, 150, 168384; (c) Ogino, M.; Nakada, Y.; Shimada, M.; Asano, K.;
Tamura, N.; Masago, M. WO 2,006,082,952 A1, 2006; Chem. Abstr. 2006, 145,
230632.
22. 2-Tetrahydronaphthalenemethanol derivatives are found in various pharma-
ceutical ingredients.For selected examples see: (a) Brown, S.P.; Dransfield, P.;
Houze, J.B.; Liu, J.; Liu, J.; Ma, Z.; Medina, J.C.; Pattaropong, V.; Schmitt, M.J.;
Sharma, R.; Wang, Y. WO 2,008,030,618 A1, 2008; Chem. Abstr. 2008, 148,
355798; (b) Salama, I.; Hocke, C.; Utz, W.; Prante, O.; Boeckler, F.; Huebner, H.;
Kuwert, T.; Gmeiner, P. J. Med. Chem. 2007, 50, 489; (c) Stolle, A.; Antonicek, H.-
P.; Lensky, S.; Voerste, A.; Muller, T.; Baumgarten, J.; Von Dem Bruch, K.; Muller,
G.; Stropp, U.; Horvath, E.; De Vry, J.-M.-V.; Schreiber, R. WO 2,001,004,107 A1,
2001; Chem. Abstr. 2001, 134, 115845.
(CDCl3)
d
7.78 (s, 1H), 7.10 (s, 1H), 4.34 (q, J¼7.2 Hz, 2H), 2.90 (t,
J¼7.5 Hz, 4H), 2.57 (s, 3H), 2.08 (quint, J¼7.5 Hz, 2H), 1.39 (t,
J¼7.2 Hz, 3H); 13C NMR (CDCl3)
d 168.0, 148.8, 141.6, 138.1, 127.7,
127.5, 126.2, 60.4, 32.8, 32.2, 25.4, 21.7, 14.3; HRMS (ESI) calcd for
C13H16O2Na [MþNa]þ 227.1043, found 227.1048.
4.3.28. 3-Methyl-6,7,8,9-tetrahydro-5H-benzocycloheptene-2-car-
boxylic acid ethyl ester (3fa). Method B (temperature: 40 ꢀC, con-
centration of 1f: 0.05 M); colorless oil; IR (neat) 2924, 1716, 1448,
1269, 1050 cmꢁ1; 1H NMR (CDCl3)
d 7.66 (s, 1H), 6.97 (s, 1H), 4.33 (q,
J¼7.2 Hz, 2H), 2.79 (t, J¼5.4 Hz, 2H), 2.77 (t, J¼5.4 Hz, 2H), 2.53 (s,
3H), 1.90–1.75 (m, 2H), 1.71–1.52 (m, 4H), 1.38 (t, J¼7.2 Hz, 3H); 13C
NMR (CDCl3)
d 167.8, 147.8, 140.7, 137.8, 132.6, 131.0, 127.0, 60.4,
36.5, 36.0, 32.6, 28.3, 28.1, 21.2, 14.4; HRMS (ESI) calcd for
C15H20O2Na [MþNa]þ 255.1356, found 255.1382.
4.3.29. Indan-5,8-dicarboxylic acid dimethyl ester (3ed)33. Method
B (concentration of 1e: 0.05 M, ligand: BINAP); 1H NMR (CDCl3)
d
7.55 (s, 2H), 3.88 (s, 6H), 2.94 (t, J¼7.5 Hz, 4H), 2.12 (quint,
J¼7.5 Hz, 2H); 13C NMR (CDCl3)
d 168.6, 147.9, 130.2, 124.8, 52.5,
32.7, 25.2.
Acknowledgements
This work was supported partly by a Grant-in-Aid for Scientific
Research (No. 20675002) from MEXT, Japan. We are grateful to
Takasago International Corporation for the gift of Segphos and H8-
BINAP, and Umicore for generous support in supplying rhodium
complexes.
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