Reaction of zirconacycles with 3-iodopropenoates and 3-iodocycloenones in the presence of CuCl: A new pathway for the formation of cyclopentadienes and spirocyclic compounds

Article abstract of DOI:10.1021/jo9905975

Formation of cyclic compounds from zirconacycles has been performed by a combination of Michael addition and coupling with an alkenyl iodide moiety in the presence of a stoichiometric amount of CuCl. The reaction of 3- iodopropenoates with various zircona

Full text of DOI:10.1021/jo9905975

J . Org. Chem. 2000, 65, 945-950
945
Rea ction of Zir con a cycles w ith 3-Iod op r op en oa tes a n d
3-Iod ocycloen on es in th e P r esen ce of Cu Cl: A New P a th w a y for
th e F or m a tion of Cyclop en ta d ien es a n d Sp ir ocyclic Com p ou n d s
Chanjuan Xi,† Martin Kotora,† Kiyohiko Nakajima,‡ and Tamotsu Takahashi*,†
Catalysis Research Center and Graduate School of Pharmaceutical Sciences, Hokkaido University,
Kita-ku, Sapporo 060-0811, J apan, CREST, Science and Technology Corporation (J ST),
Sapporo 060-0811, J apan, Aichi University of Education, Igaya, Kariya, Aichi 448-8542, J apan, and
CREST, Science and Technology Corporation (J ST), Kariya, Aichi 448-8542, J apan
Received April 6, 1999
Formation of cyclic compounds from zirconacycles has been performed by a combination of Michael
addition and coupling with an alkenyl iodide moiety in the presence of a stoichiometric amount of
CuCl. The reaction of 3-iodopropenoates with various zirconacyclopentadienes in the presence of a
stoichiometric amount of CuCl afforded penta- and hexasubstituted cyclopentadienes. The reaction
of 3-iodocycloenones with zirconacyclopentadienes, zirconacyclopentenes, or zirconacyclopentanes
gave spirocyclic compounds in good yields.
Sch em e 1
In tr od u ction
Metallacycles, which have two reactive metal-carbon
bonds, are attractive intermediates for the formation of
carbocyclic compounds. In particular, when the metalla-
cycles are readily available such as zirconacycles, devel-
opment of new C-C bond formations is synthetically
useful, especially with regard to the synthesis of car-
bocyclic compounds (Scheme 1).
Sch em e 2
Zirconacycles, in comparison with other metallacycles,
have several advantages: (i) they are easily prepared by
reductive coupling of alkenes and alkynes on reduced
zirconocene, and (ii) under normal conditions they can
be easily handled.1 Recently, we and other groups have
reported several reactions of zirconacycles with a one-
carbon unit building block affording five-membered ring
compounds. These reactions were classified into several
groups such as (i) insertion of carbon monoxide or
isonitriles,2 (ii) reactions with acid chlorides,3 and (iii)
double Michael addition.4 In this paper we report the
details of a novel combination of Michael addition/
coupling with an alkenyl iodide moiety for two new C-C
bond formations (Scheme 2).
penoates 15,6 by cross coupling-Michael addition to give
five-membered ring compounds. Additionally, we as-
(2) For reviews, see: (a) Negishi, E. Comprehensive Organic Syn-
thesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press Ltd: Oxford,
1991; Vol. 5, pp 1163-1184. (b) Broene, R. D. Comprehensive Orga-
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1985, 107, 2568-2569. (e) Negishi, E.; Swanson, D. R.; Cederbaum,
F. E.; Takahashi, T. Tetrahedron Lett. 1987, 28, 917-920. (f) See ref
1b. (g) See ref 1c. (h) Davies, J . M.; Whitby, R. J .; J axa-Chamiec, A.
Tetrahedron Lett. 1987, 28, 5655-5658. (i) Mori, M.; Uesaka, N.;
Shibasaki, M. J . Org. Chem. 1992, 57, 3519-3521. (j) Takahashi, T.;
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4185. (k) Takahashi, T.; Xi, Z.; Nishihara, Y.; Huo, S.; Kasai, K.; Aoyagi,
K.; Denisov, V.; Negishi, E. Tetrahedron 1997, 53, 9123-9134. (l)
Negishi, E.; Pour, M.; Cederbaum, F. E.; Kotora, M. Tetrahedron 1998,
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Our attention was initially turned to (Z)-3-iodoprope-
noate 1,5 which contains a reactive C-I bond suitable to
participate in cross-coupling reactions and also an acti-
vated double bond suitable for Michael addition. We
envisioned that zirconacycles, after transmetalation with
CuCl, would react in tandem reaction with (Z)-3-iodopro-
† Hokkaido University and CREST, Sapporo, J apan.
‡ Aichi University of Education and CREST, Aichi, J apan.
(3) (a) Takahashi, T.; Kotora, M.; Xi, Z. J . Chem. Soc., Chem.
Commun. 1995, 1503-1504. (b) Takahashi, T.; Xi, Z.; Kotora, M.; Xi,
C. Tetrahedron Lett. 1996, 37, 7521-7524.
(4) Takahashi, T.; Sun, W.-H.; Xi, C.; Kotora, M. Chem. Commun.
1997, 2069-2070.
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10.1021/jo9905975 CCC: $19.00 © 2000 American Chemical Society
Published on Web 01/25/2000

946 J . Org. Chem., Vol. 65, No. 4, 2000
Xi et al.
Sch em e 5
F igu r e 1.
Sch em e 3
cumbersome. On the other hand, we assumed that
zirconacycles could react with 3-iodocycloenones to afford
spirocyclic compounds (Scheme 3). We found the advan-
tage of this approach in the facile access to a variety of
zirconacycles, which are easily prepared by reductive
dimerization of alkynes and alkenes on reduced zir-
conocene.1
Sch em e 4
The initial investigation concerned the reaction of
zirconacyclopentadienes with 3-iodocycloenones, because
we anticipated the reaction to proceed in the same
manner as with 3-iodopropenoates.8 Indeed, the reaction
of zirconacyclopentadienes 3 with 3-iodocycloenones 2 at
(10) Some other representative examples. Lewis acid induced: (a)
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53, 8927-8940. Robinson annulation: (h) Pesaro, M.; Bachmann, J .-
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Takemoto, Y.; Ohra, T.; Yonetoka, Y.; Iwata, C. Chem. Pharm. Bull.
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dron 1997, 53, 8067-8084.
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Muhtadi, F. J . Phytochemistry 1986, 25, 1992-1194. Spirotetrahy-
dronaphthalenes: (b) Filho, R. B.; Diaz, P. P. D.; Gottlieb, O. R.
Phytochemistry 1980, 19, 455-459. Spirojatamol: (c) Baghi, A.;
Oshima, Y.; Hikino, H. Tetrahedron 1990, 46, 1523-1530. Spirolau-
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4995-4998. (e) Suzuki, M.; Kowata, N.; Kurosawa, E. Tetrahedron
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sumed that the reaction of zirconacycles with 3-iodocy-
cloenones 27 could gain access to spirocyclic compounds
(Scheme 3, Figure 1).
Resu lts a n d Discu ssion
F or m a tion of Cyclop en ta d ien es. Our initial interest
was to investigate the reaction of zirconacyclopentadienes
3 with ethyl (Z)-3-iodopropenoate 1 in the presence of a
stoichiometric amount of CuCl. Indeed, the reaction
proceeded as expected, and we were able to get a series
of pentasubstituted cyclopentadienes.8 Further investiga-
tion also showed that (Z)-3-iodo-3-substituted prope-
noates could be used as well and their reaction under
identical conditions afforded hexasubstituted cyclopen-
tadienes (Scheme 4, see Supporting Information).8 The
mechanism of this reaction is based on cross-coupling/
Michael addition.
The structure of cyclopentadienes was unequivocally
confirmed by single-crystal analysis of 4 (R1-5 ) Ph, R6
) Me). These results clearly showed that our concept for
the construction of cyclic compounds based on the reac-
tion with (Z)-3-iodopropenoate was on the right track,
and we were encouraged to follow and expand this
methodology.
Sp ir oa n n u la tion . Our special attention was focused
on the development of a new procedure for the formation
of spirocyclic compounds. A number of synthetic methods
have been developed for the construction of the spirocyclic
framework,9-11 because it is the basic structural unit of
many natural compounds.12 One new procedure for
spiroannulation, developed by Wender et al., is based on
the reaction of bis(nucleophiles), organobis(heterocu-
prates), with haloenones.13 Despite the significant im-
portance of this methodology, the drawback is that
organobis(heterocuprates) are prepared from dilithio-
compounds, whose preparation can be often difficult and
(7) Piers, E.; Grierson, J . R.; Lau, C. K.; Nagakura, N. Can. J . Chem.
1982, 60, 210-223.
(8) Kotora, M.; Xi, C.; Takahashi, T. Tetrahedron Lett. 1998, 39,
4321-4324.
(9) Reviews: (a) Krapcho, A. P. Synthesis 1974, 383-319. (b)
Krapcho, A. P. Synthesis 1976, 425-444. (c) Krapcho, A. P. Synthesis
1978, 77-126. (d) Vandevalle, M.; De Clerq, P. Tetrahedron 1985, 41,
1767-1831.
(13) (a) Wender, P. A.; Eck, S. L. Tetrahedron Lett. 1977, 1245-
1249. (b) Wender, P. A.; White, A. W. J . Am. Chem. Soc. 1988, 110,
2218-2223. (c) Wender, P. A.; White, A. W.; McDonald, F. E. Org.
Synth. 1991, 70, 204-214.

Reaction of Zirconacycles
J . Org. Chem., Vol. 65, No. 4, 2000 947
Ta ble 1. Rea ction of Zir con a cyclop en ta d ien e w ith 3-Iod ocycloen on es 2
a
GC yield, Isolated yields are given in parentheses.
room temperature in the presence of a stoichiometric
amount of CuCl proceeded as expected and afforded
spirocyclic cyclopentadienes 5 in moderate to good yields
(Scheme 5). The results are summarized in Table 1. The
reaction of monocyclic zirconacyclopentadienes, sym-
metrically or unsymmetrically substituted, with iodocy-
clohexenone 2a gave the corresponding spirocyclic com-
pounds in good yields. Also the reaction of bicyclic
zirconacyclopentadienes (entry 4) and zirconaindenes
(entries 5 and 6) afforded tricyclic spirocompounds in
good yields. The reaction of zirconacyclopentadiene with
substituted iodocycloenone 2b gave the expected product;
however, the yield was moderate, and completion of the
reaction required longer reaction time (entry 7). The use
of iodocyclopentenone 2c instead of 2a gave similar
results (entries 8 and 9). As far as the nature of the halide
anion in copper(I) salt was concerned, the use of CuCl,
CuBr, and CuI gave 5a in comparable yields (GC) of 96%,
99%, and 98%, respectively. The structure of spirocyclic
compounds was also confirmed by single-crystal X-ray
analysis of compound 5i.
Further investigation was turned to the reactions of
zirconacyclopentenes that are presented in Scheme 6. It
was found that the reaction of zirconacyclopentene 6 with
iodoenones 2 depended on the reaction conditions (tem-
perature) and that the course of the reaction can be easily
controlled by conducting it at 0 or 20 °C. Thus at 0 °C
only cross-coupling took place, and dienone 7a was
obtained as the sole product. It is important to note that
under these conditions we did not detect any formation

948 J . Org. Chem., Vol. 65, No. 4, 2000
Ta ble 2. Rea ction of Zir con a cyclop en ta n es w ith 3-Iod ocycloen on es 2
Xi et al.
a
GC yield, Isolated yields are given in parentheses.
Sch em e 6
Sch em e 8
Sch em e 9
Sch em e 7
Finally, zirconacyclopentanes 8 were the last class of
zirconacycles tested in the reaction with 3-iodoenones
(Scheme 7). As in the previous cases, all reactions
proceeded as expected, and the results are summarized
in Table 2. Both zirconabicyclooctanes and zirconabicy-
clononenes reacted under the standard conditions with
2a (entries 1 and 3) or 2c (entries 2 and 4) to give the
corresponding tricyclic spirocompounds in good yields.
Bimetallic zirconasilabicyclooctane (entry 5) also afforded
a spirocyclic compound albeit in moderate yield.
of the spirocyclic compound 7b. On the other hand, if the
reaction was conducted at 20 °C only spirocyclic com-
pound 7b was obtained in good yield. These results again
showed that it is possible to control the chemoselectivity
of both the Zr-sp2-carbon and Zr-sp3-carbon bonds of
zirconacyclopentenes.14 As expected the reaction with 2c
proceeded at 20 °C and gave a good yield of 7c.
Surprisingly, zirconacyclopentane 8d in the reaction
with 2a afforded only the product of the cross-coupling
reaction 9f (Scheme 8). Despite further efforts to achieve
(14) (a) Kasai, K.; Kotora, M.; Suzuki, N.; Takahashi, T. J . Chem.
Soc., Chem. Commun. 1995, 109-110. (b) See ref 4a. (c) Lipshutz, B.
H.; Segi, M. Tetrahedron 1995, 51, 4407-4420.

Reaction of Zirconacycles
J . Org. Chem., Vol. 65, No. 4, 2000 949
containing the bicyclic zirconacyclopentadiene were added
3-iodo-2-cyclohexen-1-one 2a (244 mg, 1.1 mmol) and CuCl
(198 mg, 2 mmol) at room temperature. The reaction mixture
was quenched with 3 N HCl, extracted with hexane, washed
with a saturated solution of NaCl, dried (MgSO4), and con-
centrated in vacuo, after stirring for 1 h. A colorless solid (170
mg, 48%) was isolated by column chromatography on silica
gel (4/1 hexane/Et2O): mp 118-119 °C; 1H NMR (CDCl3, Me4-
Si) δ 1.47-1.61 (m, 6H), 1.85-1.93 (m, 4H), 2.15-2.33 (m, 4H),
2.53 (s, 2H), 7.13-7.37 (m, 10H); 13C NMR (CDCl3, Me4Si) δ
21.46, 23.36 (2C), 24.33 (2C), 30.06, 39.63, 45.10, 60.96, 126.89
(2C), 128.30 (4C), 129.95 (4C), 137.35 (2C), 137.62 (2C), 146.20
(2C), 211.87; IR(neat) 1710 cm-1; HRMS calcd for C26H26O,
354.1982; found, 354.1990.
1,2,3,4,6-P en ta eth ylsp ir o[4,5]d eca -1,3-d ien -7-on e (5g).
To a solution of tetraethylzirconacyclopentadiene, prepared in
situ from zirconocene dichloride (292 mg, 1 mmol), n-BuLi (2
mol), and 3-hexyne (164 mg, 2 mmol) in THF (5 mL), were
added 3-iodo-2-methyl-2-cyclohexen-1-one 2b (260 mg, 1.1
mmol) and CuCl (198 mg, 2 mmol) at room temperature.
Quenching of the reaction mixture after 1 h of additional
stirring with 3 N HCl, extration with hexane, washing with a
saturated solution of NaCl, drying (MgSO4), and concentration
in vacuo, followed by column chromatography on silica gel (4/1
hexane/Et2O), afforded the title compound as a colorless liquid
(115 mg, 42%): 1H NMR (CDCl3, Me4Si) δ 0.5 (d, J ) 7.5 Hz,
3H), 0.97-1.08 (m, 12H), 1.37 (m, 1H), 1.75 (m, 1H), 2.09-
2.23 (m, 10H), 2.48 (t, J ) 5.7 Hz, 2H), 2.54 (q, J ) 6.4 Hz,
1H); 13C NMR (CDCl3, Me4Si) δ 7.53, 14.58, 14.67, 14.74, 14.91,
17.91, 18.60, 18.78, 19.85, 23.89, 30.86, 41.33, 46.65, 64.81,
141.23, 142.83, 144.36, 144.43, 214.47; HRMS calcd for C19H30O,
274.2295; found, 274.2297.
2,3-Diph en ylin den e-1-spir o-3′-cyclopen tan on e (5i). 3-Io-
do-2-cyclopenten-1-one 2c (229 mg, 1.1 mmol) and CuCl (198
mg, 2 mmol) were added to a solution of 2,3-diphenylzircon-
aindene, prepared in situ from zirconocene dichloride (292 mg,
1 mmol), PhLi (2 mol), and diphenylacetylene (178 mg, 1 mmol)
in THF (5 mL), at 20 °C. The reaction mixture was stirred at
the same temperature for 1 h, quenched with 3 N HCl,
extracted with hexane, washed with a saturated solution of
NaCl, dried (MgSO4), and concentrated in vacuo. The title
compound was obtained as a colorless solid (208 mg, 61%) after
column chromatography on silica gel (4/1 hexane/Et2O): mp
185-186 °C; 1H NMR (CDCl3, Me4Si) δ 2.31-2.40 (m, 3H),
2.53-2.64 (m, 2H), 2.83 (d, J ) 18.3 Hz, 1H), 7.07-7.38 (m,
14H); 13C NMR (CDCl3, Me4Si) δ 31.46, 37.31, 46.26, 58.36,
121.00, 121.25, 125.93, 127.17, 127.19, 127.52, 128.07 (2C),
128.43 (2C), 129.27 (2C), 129.98 (2C), 134.28, 135.72, 139.48,
142.91, 149.28, 150.80, 218.09; IR (neat) 1715 cm-1. Anal.
Calcd for C25H20O: C, 89.25%; H, 5.99%. Found: C, 89.25%;
H, 6.21%.
1,2-Dieth yl-1-bu ten yl-cycloh exa n e-3-on e (7a ). 2,3-Di-
ethylzirconacyclopentene was prepared from zirconocene dichlo-
ride (292 mg, 1 mmol), EtMgBr (2 mol), and 3-hexyne (82 mg,
1 mmol) in THF (5 mL) in situ. To this were added 3-iodo-2-
cyclohexen-1-one 2a (244 mg, 1.1 mmol) and CuCl (198 mg, 2
mmol) at 0 °C. After 1 h, the reaction mixture was quenched
with 3 N HCl, extracted with hexane, washed with a saturated
solution of NaCl, dried (MgSO4), and concentrated in vacuo.
A colorless liquid (97 mg, 47%) of 7a was obtained after column
chromatography on silica gel (4/1 hexane/Et2O): 1H NMR
(CDCl3, Me4Si) δ 0.91-1.01 (m, 9H), 1.94-2.42 (m, 12H), 5.77
(s, 1H); 13C NMR (CDCl3, Me4Si) δ 13.38, 13.43, 13.80, 22.88,
23.03, 23.65, 25.74, 30.27, 37.40, 127.37, 136.00, 137.98,
166.12, 199.83; IR (neat) 1706 cm-1; HRMS calcd for C14H22O,
206.1669; found, 206.1666.
formation of a spirocyclic compound by the use of addi-
tives (HMPA and Me3SiCl),15 the cyclization did not
occur.
With regard to the above presented results, we propose
the following reaction mechanism that is common for all
zirconacycles (zirconacyclopentadiene, -pentene, and -pen-
tane) (Scheme 9). In the first step the transmetalation
of the Zr-C bond in zirconacycle to the Cu-C bond
affords bis(cuprate) 10 that further reacts via cross-
coupling with the C-I bond of iodocycloenone to give the
open-chain intermediate 11. However, the question re-
mains whether this step is a single-step cross-coupling
reaction or a two-step Michael addition followed by
elimination of CuI. Nevertheless, we assume it to be the
cross-coupling reaction on the basis of the comparison of
the reactions with 3-iodo- and 3-bromopropenoate.8 In the
next step 11 undergoes intramolecular Michael reaction
to give spiroenolate 12 that, after hydrolysis, affords a
spirocyclic compound.
Exp er im en ta l Section 16
F or m a tion of Cyclop en ta d ien es. Meth yl 2-(1′,2′,3′,4′,5′-
P en ta p h en yl-1′-cyclop en ta d ien yl)eth a n oa te (4). To a so-
lution of tetraphenylzirconacyclopentadiene, prepared in situ
from zirconocene dichloride (292 mg, 1 mmol), n-BuLi (2 mol),
and diphenylacetylene (356 mg, 2 mmol) in THF (5 mL), were
added methyl (Z)-3-iodo-3-phenylpropenoate (432 mg, 1.5
mmol) and CuCl (198 mg, 2 mmol) at room temperature. The
reaction mixture was stirred at room temperature for 15 min,
quenched with 3 N HCl, extracted with hexane, washed with
a saturated solution of NaCl, dried (MgSO4), and concentrated
in vacuo. Column chromatography on silica gel (9/1 hexane/
Et2O) afforded the title compound as a colorless solid (405 mg,
78%): mp 172.5-173.0 °C; 1H NMR (CDCl3, Me4Si) δ 3.29 (s,
2 H), 3.56 (s, 3 H), 6.28-7.23 (m, 25H); 13C NMR (CDCl3, Me4-
Si) δ 36.56, 51.12, 64.38, 126.11, 126.49 (2C), 126.55 (2C),
126.81 (2C), 127.43 (4C), 127.53 (4C), 128.73 (2C), 129.80 (4C),
129.97 (4C), 135.52 (2C), 135.70 (2C), 138.54, 144.43 (2C),
149.63 (2C), 170.44; IR(neat) 1738 cm-1. Anal. Calcd for
C
38H30O2: C, 88.00; H, 5.83. Found: C, 87.93; H, 5.98.
F or m a tion of Sp ir ocyclic Com p ou n d s. 1,2-Dim eth yl-
3,4-d ip h en ylsp ir o[4,5]d eca -1,3-d ien -7-on e (5c). 3-Iodo-2-
cyclohexen-1-one 2a (244 mg, 1.1 mmol) and CuCl (198 mg, 2
mmol) were added to a solution of 2,3-diphenyl-4,5-dimeth-
ylzirconacyclopentadiene, prepared in situ from zirconocene
dichloride (292 mg, 1 mmol) and n-BuLi (2 mol), followed by
addition of diphenylacetylene (178 mg, 1 mmol) and 2-butyne
(54 mg, 1 mmol) in THF (5 mL) at room temperature. After
stirring at the same temperature for 1 h, the reaction mixture
was quenched with 3 N HCl, extracted with hexane, washed
with a saturated solution of NaCl, dried (MgSO4), and con-
centrated in vacuo. The title compound was obtained as a
colorless oil (158 mg, 48%) by column chromatography on silica
gel (4/1 hexane/Et2O): 1H NMR (CDCl3, Me4Si) δ 1.63-2.00
(m, 10H), 2.13-2.18 (m, 1H), 2.26-2.35 (m, 2H), 2.59 (d, J )
14.8 Hz, 1H), 6.98-7.25 (m, 10H); 13C NMR (CDCl3, Me4Si) δ
12.11 (2C), 22.07, 29.99, 40.10, 45.06, 60.41, 126.35, 126.70,
127.59 (2C), 127.95 (2C), 129.43 (2C), 130.72 (2C), 133.44,
136.11, 137.34, 142.93, 143.04, 148.81, 212.29; IR (neat) 1716
cm-1; HRMS calcd for C24H24O, 328.1826; found, 328.1820.
2H -4,5,6,7-Tet r a h yd r o-1,3-d ip h en ylin d en e-2-sp ir o-3′-
cycloh exa n on e (5d ). 1,8-Diphenylocta-1,7-diyne (258 mg, 1
mmol) was added to dibutylzirconocene prepared in situ by
the reaction of zirconocene dichloride (292 mg, 1 mmol) and
n-BuLi (2 mol) in THF (5 mL). To the reaction mixture
1,2-Dieth ylsp ir o[4,5]d eca -1-en -7-on e (7b). To a solution
of 2,3-diethylzirconacyclopentene (1 mmol), prepared in situ
from zirconocene dichloride (292 mg, 1 mmol), EtMgBr (2 mol),
and 3-hexyne (82 mg, 1 mmol) in THF (5 mL), were added
3-iodo-2-cyclohexen-1-one 2a (244 mg, 1.1 mmol) and CuCl
(198 mg, 2 mmol) at room temperature. After the same workup
described above, column chromatography on silica gel (4/1
hexane/Et2O) afforded 7b as a colorless liquid (83 mg, 40%):
1H NMR (CDCl3, Me4Si) δ 0.97 (q, J ) 7.4 Hz, 6H), 1.45-2.40
(15) Perlmutter, P. Conjugate Addition Reactions; Pergamon
Press: Oxford, 1992; pp 41-43 and references therein.
(16) For general Experimental Section, see our recent paper: Ta-
kahashi, T.; Xi, Z.; Yamazaki, A.; Liu, Y.; Nakajima, K.; Kotora, M. J .
Am. Chem. Soc. 1998, 120, 1672-1680.

950 J . Org. Chem., Vol. 65, No. 4, 2000
Xi et al.
(m, 16H); 13C NMR (CDCl3, Me4Si) δ 12.75, 15.33, 17.65, 21.64,
23.15, 31.49, 33.36, 34.77, 41.13, 50.63, 56.15, 138.36, 141.00,
212.07; IR (neat) 1703 cm-1; HRMS calcd for C14H22O, 206.1669;
found, 206.1666.
143.26 (2C), 211.57; IR(neat) 1726 cm-1; HRMS calcd for
C
26H28O, 356.2139; found, 356.2136.
3-Bu tylcycloh exen on e (9f). To a solution of zirconacyclo-
pentane, prepared in situ from zirconocene dichloride (292 mg,
1 mmol), n-BuLi (2 mol), and ethylene in THF (5 mL), were
added 3-iodo-2-cyclohexen-1-one 2a (244 mg, 1.1 mmol) and
CuCl (198 mg, 2 mmol) at 20 °C. Quenching of the reaction
mixture with 3 N HCl, extraction with hexane, washing with
a saturated solution of NaCl, drying (MgSO4), and concentra-
tion in vacuo after additional stirring at the same temperature
for 1 h was followed up by column chromatography on silica
gel (4/1 hexane/Et2O) that afforded the title compound as a
colorless liquid (76 mg, 50%): 1H NMR (CDCl3, Me4Si) δ 0.87
(t, J ) 7.2 Hz, 3H), 1.29 (q, J ) 7.4 Hz, 2H), 1.43 (q, J ) 7.4
Hz, 2H), 1.93 (m, 2H), 2.16 (t, J ) 7.5 Hz, 2H), 2.24 (t, J ) 6.0
Hz, 2H), 2.30 (t, J ) 6.6 Hz, 2H), 5.82 (s, 1H); 13C NMR (CDCl3,
Me4Si) δ 13.70, 22.23, 22.65, 28.97, 29.58, 37.26, 37.65, 125.54,
166.56, 199.74; HRMS calcd for C10H16O, 152.1200; found,
152.1206.
(1R*,4R*)-Sp ir o[bicyclo[3.3.0]octa n e-3,1′-cycloh exa n -
3′-on e] (9a ). 3-Iodo-2-cyclohexen-1-one 2a (244 mg, 1.1 mmol)
and CuCl (198 mg, 2 mmol) were sequentially added to a
reaction mixture at 20 °C contaning 3-zirconabicyclo[3.3.0]-
octane, prepared in situ from zirconocene dichloride (292 mg,
1 mmol), n-BuLi (2 mol), and 1,6-heptadiene (96 mg, 1 mmol)
(1 mmol) in THF (5 mL). After the same workup, the title
compound was isolated by column chromatography on silica
gel (4/1 hexane/Et2O) as a colorless liquid (155 mg, 80%): 1H
NMR (CDCl3, Me4Si) δ 0.94-1.09 (m, 4H), 1.54-2.02 (m, 12H),
2.24-2.32 (m, 4H); 13C NMR (CDCl3, Me4Si) δ 23.14, 26.20
(2C), 28.91, 39.08, 39.95, 41.01, 41.22, 52.25, 52.52, 54.13,
55.60, 211.50; IR(neat) 1725 cm-1. Anal. Calcd for C13H20O:
C, 81.20%; H, 10.48%. Found: C, 81.09%; H, 10.48%.
(1′R*,6′S*)-Sp ir o[3-cycloh exa n on e-1,8′-(3′,4′-d ip h en yl-
bicyclo[4.3.0]-n on -3-en e)] (9c). To a solution of 3,4-diphenyl-
8-zirconabicyclo[4.3.0]non-3-ene in situ prepared from zir-
conocene dichloride (292 mg, 1 mmol), n-BuLi (2 mol), and 4,5-
diphenyl-1,4,7-octatriene (260 mg, 1 mmol) in THF (5 mL)
were added 3-iodo-2-cyclohexen-1-one 2a (244 mg, 1.1 mmol)
and CuCl (198 mg, 2 mmol) at 20 °C. After stirring at the same
temperature for 1 h, the reaction mixture was quenched with
3 N HCl. After the same workup, a colorless solid of 9c (200
mg, 56%) was obtained by column chromatography on silica
gel (4/1 hexane/Et2O): mp 148-149 °C; 1H NMR (CDCl3, Me4-
Si) δ 1.25-1.30 (m, 2H), 1.69-1.93 (m, 6H), 2.28-2.34 (m, 6H),
2.53-2.68 (m, 4H), 6.98-7.14 (m, 10H); 13C NMR (CDCl3, Me4-
Si) δ 23.00, 34.55, 35.80 (2C), 36.35 (2C), 41.19, 44.65 (2C),
46.87, 54.67, 125.75 (2C), 127.68 (4C), 128.82 (4C), 135.87 (2C),
Ack n ow led gm en t. We thank the Ministry of Edu-
cation, Science, Sport and Culture, J apan, for support
of a part of this study (09440212).
Su p p or tin g In for m a tion Ava ila ble: Characterization of
a series of derivatives of 4; experimental details, structures,
tables of crystallographic data, atomic coordinates, thermal
1
parameters, and bond lengths and angles for 4 and 5i; and H
and 13C NMR spectra of new compounds. This material is
available free of charge via the Internet at http://pubs.acs.org.
J O9905975