Generation of cycloalkylidene carbenes via exo-type cyclization of alkynyllithiums bearing remote leaving group

Article abstract of DOI:10.1021/jo981411p

The reaction of 5-hexynyl rosylate (3a) with alkynyllithium (RC≡CLi; R = Ph, TMS) gives enynes 5 and 6. The reaction proceeds through a mechanism involving a novel exo-type cyclization of 6-lithio-5-hexynyl tosylate to form cyclopentylidene carbene. Enyne 6 is produced by the addition of RC≡CLi to the carbene, whereas rearrangement of the carbene to cyclohexyne followed by carbolithiation with RC≡CLi gives enyne 5. The formation of cyclopentylidene carbene and cyclohexyne as intermediates is clearly demonstrated by trapping experiments with cyclohexene (and triethylsilane) and with 1,3- diphenylisobenzofuran, respectively. Alkynyllithiums derived from 3-butynyl and 6-heptynyl p-fluorobenzenesulfonates (19a,b) undergo a similar exo-type cyclization to give cyclopropylidene and cyclohexylidene carbenes, respectively.

Full text of DOI:10.1021/jo981411p

J . Org. Chem. 1998, 63, 9007-9012
9007
Gen er a tion of Cycloa lk ylid en e Ca r ben es via Exo-Typ e Cycliza tion
of Alk yn yllith iu m s Bea r in g Rem ote Lea vin g Gr ou p
Toshiro Harada,* Katsuhiro Iwazaki, Takeshi Otani, and Akira Oku
Department of Chemistry, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku 606, J apan
Received J uly 20, 1998
The reaction of 5-hexynyl tosylate (3a ) with alkynyllithium (RCtCLi; R ) Ph, TMS) gives enynes
5 and 6. The reaction proceeds through a mechanism involving a novel exo-type cyclization of
6-lithio-5-hexynyl tosylate to form cyclopentylidene carbene. Enyne 6 is produced by the addition
of RCtCLi to the carbene, whereas rearrangement of the carbene to cyclohexyne followed by
carbolithiation with RCtCLi gives enyne 5. The formation of cyclopentylidene carbene and
cyclohexyne as intermediates is clearly demonstrated by trapping experiments with cyclohexene
(and triethylsilane) and with 1,3-diphenylisobenzofuran, respectively. Alkynyllithiums derived from
3-butynyl and 6-heptynyl p-fluorobenzenesulfonates (19a ,b) undergo a similar exo-type cyclization
to give cyclopropylidene and cyclohexylidene carbenes, respectively.
Sch em e 1
1-Alkynyl organometallics of main group metals have
been frequently used as efficient carbon nucleophiles in
organic syntheses.1 They react with a variety of electro-
philic reagents generally at the carbon R to the metal
atom. Nevertheless, some alkynylmetals, specifically
alkynylboronates2,3 and -zincates,4 are known to react at
the â position.5 It was reported that boronates react with
electrophiles such as haloalkanes and aldehydes at the
â position with 1,2-migration of alkyl ligands (eq 1).2 An
Resu lts a n d Discu ssion
6-Lithio-5-hexynyl tosylate (4a ) was prepared by the
reaction of tosylate 3a with butyllithium (1.0 equiv) in
THF at -85 °C (eq 3). Although 4a was stable at
temperatures up to ca. 0 °C, treatment at room temper-
ature for 2 h gave a 72:28 mixture of enynyl tosylates 5a
and 6a in 32% yield. An improved yield (63%, 5a :6a )
82:18) was obtained when lithiation of 3a was effected
with 0.5 equiv of butyllithium. Reaction of tosylate 3a
with phenylethynyllithium (2.0 equiv) at room temper-
ature for 22 h afforded enynes 5b and 6b (79:21) in 78%
yield together with a minor formation of 5a and 6a (65:
35, 9.1%) (eq 4). Only a small amount (2.2%) of 1-phenyl-
1,7-octadiyne, an R-coupling product of the alkynyllith-
ium, was formed in this reaction. Under similar condi-
tions, reaction of 3a with (trimethylsilyl)ethynyllithium
gave 5c and 6c (83:17) in 62% yield.
intramolecular version of such a reaction leading to exo-
type cyclization products was also reported (eq 2).3,4 We
report herein that alkynyllithiums bearing a remote
leaving group also undergo an exo-type cyclization to give
cycloalkylidene carbenes (Scheme 1). The study demon-
strates a potential reactivity of alkynylmetals other than
alkynylate complexes at the â position.
(1) (a) J a¨ger, V.; Viehe, H. G. In Methoden der Organischen Chemie
(Houben-Weyl); Thieme: Stuttgart, 1977; Vol. 5/2a. (b) Brandsma, L.;
Verkruijsse, H. D. Synthesis of Acetylenes, Allenes and Cumulenes;
Elsevier Scientific Publishing Company: Amsterdam, 1981.
(2) (a) Pelter, A.; Smith, K.; Brown, H. C. Borane Reagents; Academic
Press: London: 1988; 283. (b) Binger, P.; Ko¨ster, R. Tetrahedron Lett.
1965, 1901. (c) Pelter, A.; Harrison, C. R.; Kirkpatrick, D. J . Chem.
Soc., Chem. Commun. 1973, 544. (d) Miyaura, N.; Yoshinari, T.; Itoh,
M.; Suzuki, A. Tetrahedron Lett. 1974, 2961. (e) Pelter, A.; Bentley, T.
W.; Harrison, C. R.; Subrahmanyam, C.; Laub, R. J . J . Chem. Soc.,
Perkin Trans. 1 1976, 2419. (f) Naruse, M.; Utimoto, K.; Nozaki, H.
Tetrahedron 1974, 30, 3037. (g) Pelter, A.; Hughes, L.; Rao, J . M. J .
Chem. Soc., Perkin Trans. 1 1982, 719.
(3) (a) Merril, R. E.; Allen, J . L.; Abramovitch, A.; Negishi, E.
Tetrahedron Lett. 1977, 1019. (b) Corey, E. J .; Seibel, W. L. Tetrahedron
Lett. 1986, 27, 909. (c) Negishi, E.; Nguyen, T.; Boardman, L. D.;
Sawada, H.; Morrison, J . A. Heteroatom Chem. 1992, 3, 293.
(4) (a) Harada, T.; Wada, I.; Oku, A. J . Org. Chem. 1995, 60, 5370.
(b) Harada, T.; Otani, T.; Oku, A. Tetrahedron Lett. 1997, 38, 2855.
(5) Some transition metal acetylides are known to react with
electrophiles at the â position to form vinylidene complexes [RC(E)d
CdM]: Bruce, M. I. Chem. Rev. 1991, 91, 197.
The formation of enynes 6a -c suggests the interme-
diacy of cyclopentylidene carbene 7 (Scheme 2). Thus,
6a -c would be produced through addition of the alky-
nyllithiums to carbene 7. Cycloalkylidene carbenes are
10.1021/jo981411p CCC: $15.00 © 1998 American Chemical Society
Published on Web 11/10/1998

9008 J . Org. Chem., Vol. 63, No. 24, 1998
Harada et al.
Sch em e 2
ated from tosylates 3b and 3c; under similar conditions,
reactions of the corresponding alkynyllithiums gave
cycloadducts 13b and 13c10 in 54% and 30% yield,
respectively.
To verify that cyclohexyne 8 was formed through the
rearrangement of carbene 7, alkynyl tosylate [6-13C]-3c
in which the terminal acetylenic carbon is labeled with
13C was prepared (Scheme 3) and subjected to the
known to undergo rearrangement to cycloalkynes.6,7
Erickson and Wolinsky7b demonstrated the formation of
reactive cyclohexyne (8) from cyclopentylidene carbene,
generated by the reaction of bromomethylenecyclopen-
tane with t-BuOK, by a trapping experiment with 1,3-
diphenylisobenzofuran. The formation of enynes 5a -c
can be rationalized by rearrangement of carbene 7 and
carbolithiation of the resulting strained alkyne 8 with
the alkynyllithiums.7a,8
Sch em e 3
The reaction of 7 and 8 with an alkynyllithium would
initially produce the corresponding alkenyllithium spe-
cies 9 and 10, respectively. The low yield of 5a and 6a
in the reaction of 3a using 1.0 equiv of butyllithium can
be explained by the instability of the resulting alkenyl-
lithiums with a reactive TsO group [9 and 10; R ) (CH2)4-
OTs]. On the other hand, the use of 0.5 equiv of
butyllithium may improve the products yield because of
a rapid protonation of the alkenyllithiums by alkyne 3a ,
leading to stable products 5a and 6a as well as formation
of alkynyllithium 4a . In the reaction with external
alkynyllithium (RCtCLi; R ) Ph, TMS), both 3a and
RCtCH may serve as a proton donor for 9 and 10.
The intermediacy of cyclopentylidene carbene and
cyclohexyne was confirmed by the following trapping
experiments. Slow addition of butyllithium (1.0 equiv)
to a mixture of 3a and cyclohexene (10 equiv) in THF
during 7 h at room temperature afforded carbene adduct
11a in 18% yield together with 5a and 6a (88:12, 25%).9
Under similar conditions, alkynyl tosylate 3b afforded
adduct 11b in 20% yield. A trapping experiment with
triethylsilane (3.0 equiv) gave the Si-H insertion product
12 in 13% yield together with 5a and 6a (89:11, 59%).
On the other hand, treatment of alkynyllithium 4a in
the presence of 1,3-diphenylisobenzofuran (3.0 equiv) at
room temperature for 3 h afforded [4+2] cycloadduct 13a
in 33% yield. Substituted cyclohexynes were also gener-
reaction with (trimethylsilyl)ethynyllithium. The reac-
tion of [6-13C]-3c (20% 13C content) gave a 32:31:37
mixture of enynes 5d , 5e, and 6d in 37% combined yield
(Scheme 4). Nonselective formation of 5d and 5e is an
Sch em e 4
(6) (a) Hartzler, H. D. Carbenes; Moss, R. A., J ones, M., J r., Eds.;
Wiley: New York, 1975; Vol. II, chapter 2, p 43. (b) Stang, P. J . Chem.
Rev. 1978, 78, 383. (c) Stang, P. J . In Methoden der Organischen
Chemie (Houben-Weyl); Regitz, M., Ed.; Thieme: Stuttgart, 1989; Vol.
E19b. p 84. (d) Kirmse, W. Angew. Chem., Int. Ed. Engl. 1997, 36, 1164.
(7) (a) Meier, H. Adv. Strain Org. Chem. 1991, 1, 215. (b) Erickson,
K. L.; Wolinsky, J . J . Am. Chem. Soc. 1965, 87, 1143. (c) Fitjer, L.;
Kliebisch, U.; Wehle, D.; Modaressi, S. Tetrahedron Lett. 1982, 23,
1661. (d) Gilbert, J . C.; Baze, M. E. J . Am. Chem. Soc. 1983, 105, 664.
(e) Gilbert, J . C.; Baze, M. E. J . Am. Chem. Soc. 1984, 106, 1885. (f)
Tseng, J .; McKee, M. L.; Shevlin, P. B. J . Am. Chem. Soc. 1987, 109,
5474.
(8) (a) Nakagawa, M. Cyclic Acetylenes. In The Chemistry of
Carbon-Carbon Triple Bond; Patai, S., Ed.; J . Wiley & Sons: New
York, 1978, 635. (b) Roberts, J . D. J . Am. Chem. Soc. 1960, 82, 4750.
(c) Wittig, G.; Pohlke, R. Chem. Ber. 1961, 94, 3276. (d) Gassman, P.
G.; Valcho, J . J . J . Am. Chem. Soc. 1975, 97, 4768.
additional support for their formation via carbolithiation
of cyclohexyne intermediate 8′ (Scheme 5). 13C NMR
analyses of 5d and 5e showed the scrambling of the label
between olefinic carbons. For each product, the 13C
content of the olefinic methyne carbon (-CHd) was
determined by 1H NMR integration of the attached
proton. Observation of 13C scrambling at -C(2)Hd of 5e
as well as the loss of 13C label at -C(2)Hd of 5d is
(9) Formation of the [2+2] cycloadduct derived from cyclohexyne was
not detected.
(10) Adduct 13c was obtained as a 1:1 mixture of diastereomers.

Cycloalkylidene Carbene Generation
J . Org. Chem., Vol. 63, No. 24, 1998 9009
Sch em e 5
consistent with the formation of cyclohexyne 8′ through
rearrangement of carbene 7′.
Recently, we reported that related alkynylzincates 1
(M ) Zn, n ) 2, m ) 1, eq 2) undergo direct endo-type
cyclization to form cyclohexyne in competition with exo-
type cyclization to form (cyclopentylidene)alkylzinc 2 (M
) Zn, n ) 2, m ) 1).4b If we assume that carbene 7′
undergoes C(2) and C(5) migration in a 1:1 ratio, the 13C
contents of 5d and 5e will be 10.5% each. Deviation of
the observed 13C contents from the value may imply
preferential migration of C(2), rather than C(5), or
participation of a direct endo-type cyclization pathway
leading to cyclohexyne [2-13C]-8′.
We have shown that alkynyllithiums bearing a remote
leaving group undergo a novel exo-type cyclization to give
cycloalkylidene carbenes. The study not only discloses
a novel reactivity of alkynylmetals at their â position but
also provides a new method for generating alkylidene
carbenes that can be subsequently utilized in construc-
tion of a variety of carbon frameworks.
Exp er im en ta l Section
Gen er a l In for m a tion . Unless otherwise noted, 1H and 13C
NMR spectra were recorded at 300 and 75.6 MHz, respectively,
in CDCl3. All commercially available reagents were used
without further purification unless otherwise noted. Diiso-
propylamine, 1,3-diaminopropane, triethylamine, and DMF
were distilled from CaH2. THF was distilled from sodium
benzophenone ketyl. All reactions were performed under
argon. Unless otherwise noted, organic extracts were dried
over Na2SO4. Flash chromatography was conducted on silica
gel (Wakogel C-300).
6-Heptyn-1-ol was prepared according to the literature
procedure.16 Preparation of 4,4-dimethyl-5-hexyn-1-ol, 5-(tert-
butyldimethylsilyloxy)-4-phenyl-1-pentyne (14), 2-phenyl-4-
hexyn-1-ol (16), and 4-(2-phenylethyl)-3-oxa-5-hexyn-1-ol is
described in Supporting Information.
P r ep a r a tion of Alk yn yl Ar en esu lfon a tes. To a solution
of the corresponding alcohol in THF (1 M) at -78 °C was added
an equimolar amount of BuLi (1.6 M in hexane). After being
stirred for 1 h, a THF solution (1 M) of an arenesulfonyl
chloride (1.2 equiv) was added to the mixture at -78 °C. The
reaction mixture was allowed to warm to room temperature
over ca. 2 h, stirred further for 15 h, and then poured into
water. The mixture was extracted twice with ether. The
combined extracts were washed with aqueous NaHCO3, dried,
and concentrated in vacuo. Purification of the residue by flash
chromatography (10% ethyl acetate in hexane) gave the
corresponding arenesulfonates in 77-93% yield. For the
spectral data of alkynyl arenesulfonates 3a ,b,c, 17, and 19a ,b,
see Supporting Information.
6-(Cycloh exen yl)-5-h exyn yl p -Tolu en esu lfon a t e (5a )
a n d 7-(Cyclop en tyliden e)-5-h ep tyn yl p-Tolu en esu lfon a te
(6a ). To a solution of 5-hexynyl tosylate (3a ) (252 mg, 1.0
mmol) in THF (4.5 mL) at -85 °C was added butyllithium (1.6
M in hexane) (0.31 mL, 0.5 mmol). The resulting solution of
alkynyllithium 4a was allowed to warm to room temperature
over 3 h and was stirred for 3.5 h at room temperature. The
mixture was poured into brine and extracted twice with ethyl
acetate. The organic layers were dried and concentrated in
vacuo. Purification of the residue by flash chromatography
(6-10% ethyl acetate in hexane) gave, in the order of elution,
a 82:18 mixture of enynyl tosylates 5a and 6a (106 mg, 63%
combined yield) and the starting tosylate 3a (50.4 mg, 20%).
Separation of the mixture of 5a and 6a by a recycling
preparative HPLC, equipped with a GPC column (J AIGEL-
1H column, J apan Analytical Industry) using CHCl3 as an
eluent, afforded a pure 5a and a 1:1 mixture of 5a and 6a . 5a :
1H NMR δ 1.57 (6H, m), 1.77 (2H, m), 2.05 (4H, m), 2.26 (2H,
Cyclopentylidene carbene can be generated by bromine/
lithium exchange reaction of dibromomethylenecyclopen-
tane. It was demonstrated that the resulting reactive
species is an encumbered carbene (or a carbenoid) in
which LiBr are associated with the carbene.6b,11,12 When
we examined the reaction of dibromomethylenecyclopen-
tane with BuLi in the presence of 1,3-diphenylisobenzo-
furan (3 equiv) (THF, -85 °C, room temperature), only
a small amount (4.4% yield) of cyclohexyne adduct 13a
was formed. Brinker and colleagues13 reported that
cyclopentylidene and cyclohexylidene carbenes, generated
by the ultrasonicated reaction of the corresponding
dibromomethylenecycloalkanes with lithium, were ef-
ficiently trapped with alkenes. Specifically, 67% yield
of 12a was reported when cyclohexene (4 equiv) was used
as an alkene.13 These results imply that carbene 7 gen-
erated from alkynyllithium 4a is more feasible to rear-
rangement to cyclohexyne. The difference in reactivity
might be due to the less encumbered nature6b of carbene
7 in which lithium tosylate is less tightly associated.
Results for related alkynyllithiums bearing a remote
leaving group suggest the generality of carbene formation
via exo-type cyclization. Thus, the reaction of p-fluo-
robenzenesulfonate 17 afforded intramolecular C-H
insertion product 18 in 55% yield as a 93:7 mixture of
diastereomers (eq 5).14 4-Butynyl sulfonate 19a reacted
with phenylethynyllithium at room temperature to give
methylenecyclopropane 20a (56%) without byproduct
formation of cyclobutene derivative (eq 6).14 The result
is in accord with a recent theoretical prediction that
conversion of cyclopropylidene carbene into cyclobutyne
is an endothermic process.15 At room temperature, the
reaction of 6-heptynyl derivative 19b was sluggish. The
reaction at 65 °C, however, afforded exo-cyclization
product 20b selectively (20b:21 ) 75:25, 69%).
(11) Stang, P. J . Acc. Chem. Res. 1978, 11, 107.
(12) (a) Patrick, T. B.; Haynie, E. C.; Probst, W. J .; J . Org. Chem.
1972, 37, 1553. (b) Stang, P. J .; Mangum, M. G. J . Am. Chem. Soc.
1975, 97, 6748.
(13) Xu, L.; Lin, G.; Tao, F., Brinker, U. H. Acta Chem. Scand. 1992,
46, 650.
(14) The reactions shown in eqs 5 and 6 proceeded for tosylate
derivatives as well, albeit with lower efficiency.
(15) J ohnson, R. P.; Daoust, K. J . J . Am. Chem. Soc. 1995, 117, 362.
(16) Reference 1b, p 104.

9010 J . Org. Chem., Vol. 63, No. 24, 1998
Harada et al.
br t, J ) ca. 7 Hz), 2.44 (3H, s), 4.05 (2H, t, J ) 6.3 Hz), 5.97
(1H, br s), 7.33 (2H, m), 7.78 (2H, m); 13C NMR (125.8 MHz)
δ 18.58, 21.52, 21.63, 22.33, 24.63, 25.51, 27.89, 29.50, 70.09,
83.07, 85.96, 120.77, 127.87, 129.81, 133.10, 133.55, 144.69;
IR (liquid film) 2360, 1595 cm-1; MS (CI), m/z (relative
in vacuo. Kugelrohr distillation (80-110 °C/10 mmHg) of the
residue gave 29.6 mg (18%) of 11a .13 Flash chromatography
(20% ethyl acetate in hexane) of the residue gave a 88:12
mixture of 5a and 6a (41.6 mg, 25% combined yield).
7-(2,2-Dim et h ylcyclop en t ylid en e)b icyclo [4.1.0]h ep -
ta n e (11b). The compound was obtained from tosylate 3b in
20% yield by a procedure similar to that described above.
11b: 1H NMR δ 1.05-1.35 [11H, m, including two singlets
(3H each) at 1.07 and 1.11], 1.5-1.85 (9H, m), 2.34 (1H, m),
2.49 (1H, m); 13C NMR (125.8 MHz) δ 10.18, 13.36, 21.05,
21.89, 22.25, 23.21, 24.02, 27.70, 28.23, 31.24, 42.28, 42.55,
119.29, 139.47. Anal. calcd for C14H22: C, 88.35; H, 11.65.
Found: C, 88.37; H, 11.91.
(Cyclop en tylid en em eth yl)tr ieth ylsila n e (12). To a so-
lution of tosylate 3a (252 mg, 1.0 mmol) and triethylsilane
(0.48 mL, 3.0 mmol) in THF (4.5 mL) at room temperature
was slowly added butyllithium (1.6 M in hexane) (0.63 mL,
1.0 mmol) during 7 h by using a syringe pump. After being
stirred further for 1 h at room temperature, the mixture was
poured into brine and extracted twice with ether. The yield
of 12 was determined to be 13% by GC analysis of the dried
organic layers using tetradecane (30.1 mg) as an internal
standard. The mixture was concentrated in vacuo. Flash
chromatography (20% ethyl acetate in hexane) of the residue
gave a 89:11 mixture of 5a and 6a (98.4 mg, 59% combined
yield).
An authentic sample of 12 was prepared as follows. Dibro-
momethylenecyclopentane was prepared according to the
literature.20 To a solution of the dibromo compound (1.91 g,
7.96 mmol) in THF (60 mL) at -95 °C was added BuLi (1.6 M
in hexane) (5.0 mL, 8.0 mmol). After being stirred for 20 min
at the same temperature, the reaction was quenched by the
addition of AcOH-THF (1:1). The mixture was poured into
brine and extracted three times with pentane. The combined
extracts were washed with aqueous NaHCO3, dried over K2-
CO3, and concentrated in vacuo. Purification of residue by
Kugelrohr distillation (90 °C/8 mmHg) afforded 1.02 g (80%
yield) of (bromomethylene)cyclopentane: 1H NMR δ 1.73 (4H,
m), 2.28 (4H, m), 5.92 (1H, m).
To a solution of (bromomethylene)cyclopentane (551 mg,
3.43 mmol) in THF (17 mL) at -95 °C was added t-BuLi (1.5
M in pentane) (8 mL, 12 mmol). After being stirred at -95
°C over a period of 6 h, triethylchlorosilane (1.44 mL, 8.6 mmol)
was added to the mixture at the same temperature. After
being stirred further at -95 °C for 2 h, the reaction was
quenched by the addition of MeOH at this temperature. The
mixture was poured into aqueous NH4Cl and extracted three
times with ether. The combined extracts were washed with
aqueous NaHCO3, dried, and concentrated in vacuo. Purifica-
tion of the residue by Kugelrohr distillation (140-150 °C/0.8
mmHg) afforded 245 mg (36% yield) of 12: 1H NMR δ 0.58
(6H, q, J ) 7.8 Hz), 0.93 (9H, t, J ) 7.8 Hz), 1.50-1.75 (4H,
m), 2.24 (2H, br t, J ) ca. 7 Hz), 2.33 (2H, br t, J ) ca. 7 Hz),
5.30 (1H, quint, J ) 2.1 Hz); 13C NMR δ 4.27, 7.59, 25.97,
27.28, 32.85, 37.51, 114.36, 164.01; IR (liquid film) 1620, 1015,
735 cm-1; MS, m/z (relative intensity) 196 (M+, 14), 167 (100),
139 (95); HRMS calcd for C12H24Si 196.1647, found 196.1656.
[4+2] Cycloa d d u ct 13b (Rep r esen ta tive P r oced u r e for
Tr a p p in g Exp er im en t w ith 1,3-Dip h en ylisoben zofu r a n ).
To a solution of tosylate 3b (140 mg, 0.50 mmol) in THF (2.0
mL) at -85 °C was added butyllithium (1.6 M in hexane) (0.31
mL, 0.5 mmol). A solution of 1,3-diphenylisobenzofuran (405
mg, 1.5 mmol) in THF (2.5 mL) was slowly added to the cooled
solution of the resulting alkynyllithium. The mixture was
allowed to warm to room temperature over 2.5 h and stirred
further for 62 h. The mixture was poured into 1N HCl and
extracted twice with ether. The organic layers were washed
with aqueous NaHCO3, dried, and concentrated in vacuo.
Flash chromatography (50% benzene in hexane) of the residue
gave 103 mg (54% yield) of 13b: mp 183-184 °C (recrystallized
from chloroform and hexane); 1H NMR δ 0.82 (3H, s), 0.96 (3H,
s), 1.13 (1H, m), 1.39 (1H, m), 1.58 (2H, m), 2.00 (1H, td, J )
intensity) 333 (MH+, 100), 161 (38); HRMS calcd for C19H24
-
O3S 332.1446, found 332.1457. 6a : 1H NMR (a 1:1 mixture
of 6a and 5a ) δ 1.57 (8H for 6a and 5a , m), 1.66 (2H for 6a ,
m), 1.77 (2H, for 5a , m), 2.05 (4H for 5a , m), 2.2-2.40 (6H for
6a and 2H for 5a , m), 2.44 (3H for 6a and 5a , s), 4.05 (2H for
6a and 5a , t, J ) 6.3 Hz), 5.31 (1H for 6a , br s), 5.97 (1H for
5a , br s), 7.33 (2H for 6a and 5a , m), 7.78 (2H for 6a and 5a ,
m); 13C NMR (125.8 MHz) (a 1:1 mixture of 6a and 5a ) δ 18.58
(5a ), 18.83 (6a ), 21.52 (5a ), 21.63 (6a and 5a ), 22.33 (5a ), 24.63
(5a ), 24.77 (6a ), 25.51 (5a ), 25.98 (6a ), 26.59 (6a ), 27.85 (6a ),
27.89 (5a ), 29.50 (5a ), 31.89 (6a ), 33.54 (6a ), 70.09 (6a and
5a ), 79.56 (6a ), 83.07 (5a ), 85.96 (5a ), 91.09 (6a ), 100.12 (6a ),
120.77 (5a ), 127.87 (6a and 5a ), 129.81 (6a and 5a ), 133.10
(6a and 5a ), 133.55 (5a ), 144.69 (6a and 5a ), 159.61 (6a ); MS
(CI) (a 1:1 mixture of 6a and 5a ), m/z (relative intensity) 333
(MH+, 100), 187 (64), 161 (38); HRMS (a 1:1 mixture of 6a
and 5a ) calcd for C19H24O3S 332.1446, found 332.1455.
The reaction using 1.0 equiv of butyllithium was performed
by a procedure similar to that described above except that the
reaction mixture was stirred for 2 h after being allowed to
warm from -85 °C to room temperature. Purification by flash
chromatography gave a 72:28 mixture of 5a and 6a , and
tosylate 3a (10%).
(P h en yleth yn yl)cycloh exen e (5b)17 a n d (3-P h en yl-2-
p r op yn ylid en e)cyclop en ta n e (6b). To a solution of phe-
nylacetylene (204 mg, 2.0 mmol) in THF (32 mL) at -85 °C
was added butyllithium (1.6 M in hexane) (1.25 mL, 2.0 mmol).
The mixture was stirred for 15 min at this temperature. To
the resulting solution of phenylethynyllithium at -85 °C was
added a THF (8 mL) solution of tosylate 3a (252 mg, 1.0 mmol).
The mixture was allowed to warm to room temperature over
2 h and stirred further for 22 h. The mixture was poured into
brine and extracted twice with ether. The organic layers were
dried and concentrated in vacuo. Purification of the residue
by flash chromatography (0-20% ethyl acetate in hexane)
gave, in the order of elution, a 79:21 mixture of 5b17 and 6b
(142 mg, 78% combined yield), 1-phenyl-1,7-octadiyne18 (4.1
mg, 2.2%), and a 65:35 mixture of 5a and 6a (15.1 mg, 9.1%
combined yield). Pure 6b was obtained by separation of the
mixture with a recycling preparative HPLC equipped with a
GPC column (J AIGEL-1H column, J apan Analytical Industry)
using CHCl3 as an eluent. 6b: 1H NMR δ 1.70-1.78 (4H, m),
2.41 (2H, m), 2.54 (2H, m), 5.60 (1H, quintet, J ) 2.3 Hz), 7.28
(3H, m), 7.41 (2H, m); 13C NMR δ 26.02, 26.62, 32.20, 33.90,
88.05, 91.91, 100.16, 124.15, 127.54, 128.20, 131.20, 161.43;
IR (liquid film) 2200, 1595 cm-1; MS, m/z (relative intensity)
182 (M+, 100); 167 (40), 154 (37); HRMS calcd for C14H14
182.1095, found 182.1095. Anal. calcd for C14H14: C, 92.26;
H, 7.74. Found: C, 91.88; H, 7.79.
Reaction of tosylate 3a with trimethylethynyllithium by a
procedure similar to that described above gave a 83:17 mixture
of (cyclohexenylethynyl)trimethylsilane (5c)17 and (3-cyclopen-
tylidene-1-propynyl)trimethylsilane (6c)19 in 62% combined
yield.
7-Cyclop en tylid en ebicyclo[4.1.0]h ep ta n e (11a ).13 To a
solution of tosylate 3a (252 mg, 1.0 mmol) and cyclohexene
(1.01 mL, 10.0 mmol) in THF (4.5 mL) at room temperature
was slowly added butyllithium (1.6 M in hexane) (0.63 mL,
1.0 mmol) during 7 h by using a syringe pump. After being
stirred further for 1.5 h at room temperature, the mixture was
poured into 1N HCl and extracted twice with ether. The
organic layers were washed with brine, dried, and concentrated
(17) Stille, J . K.; Simpson, J . H. J . Am. Chem. Soc. 1987, 109, 2138.
(18) Perchonock, C. D.; Uzinskas, I.; McCarthy, M. E.; Erhard, K.
F.; Gleason, J . G.; Wasserman, M. A.; Muccitelli, R. M.; DeVan, J . F.;
Tucker, S. S.; Vickery, L. M.; Kirchner, T.; Weichman, B. M.; Mong,
S. M.; Scott, M. O.; Chi-Rosso, G.; Wu, H.-L.; Crooke, S. T.; Newton, J .
F. J . Med. Chem. 1986, 29, 1442.
(19) Shen, Y.; Liao, Q. J . Organomet. Chem. 1988, 346, 181.
(20) Hassig, R.; Seebach, D.; Siegel, H. Chem. Ber. 1984, 117, 1877.

Cycloalkylidene Carbene Generation
J . Org. Chem., Vol. 63, No. 24, 1998 9011
7.0 and 17.8 Hz), 2.32 (1H, t, d, J ) 5.3 and 17.8 Hz), 7.02
(1H, t, J ) 7.0 Hz), 7.09 (1H, t, J ) 7.0 Hz), 7.27 (1H, d, J )
6.8 Hz), 7.4-7.6 (6H, m), 7.78 (3H, m), 8.12 (2H, br d, J ) ca.
7 Hz); 13C NMR (125.8 MHz) δ 19.64, 24.38, 25.44, 28.09, 33.49,
40.90, 90.96, 92.64, 119.06, 120.56, 124.36, 124.61, 126.46,
127.61, 127.98, 128.03, 128.27, 135.58, 138.15, 149.43, 151.57,
152.56, 156.30; IR (liquid film) 1600, 740, 700 cm-1; MS, m/z
(relative intensity) 378 (M+, 5), 360 (16), 105 (100); HRMS
calcd for C28H26O 378.1984, found 378.1980. Anal. calcd for
Hz), 2.52 (2H, m), 3.00 (1H, quint, J ) 6.9 Hz), 3.8-4.0 (2H,
m), 7.25 (3H, m), 7.33 (2H, m); IR (liquid film) 3360 (br), 755,
700 cm-1
.
[6-13C]-2-P h en yl-5-h exyn -1-ol (16). To a brown suspen-
sion of potassium 3-aminopropylamide (KAPA)16,22 (23.1 mmol)
in 1,3-diaminopropane (25 mL) at room temperature was
added alcohol 15 (1.34 g, 7.70 mmol). After being stirred for
20 h, the reaction mixture was poured into aqueous NH4Cl
under argon at 0 °C and extracted twice with ether. The
combined organic layers were washed with aqueous NaHCO3
and brine, dried, and concentrated in vacuo. Purification of
the residue by flash chromatography (5-15% ethyl acetate in
hexane) gave 0.230 g (17% yield) of 16: 1H NMR δ 1.40 (1H,
br), 1.74-2.20 [5H, m, including t (J ) 2.4 Hz) and td (J )
2.4 and 247.0 Hz) at 1.96], 2.97 (1H, ddt, J ) 4.5, 6.6, and
11.1 Hz), 3.77 (2H, d, J ) 6.9 Hz), 7.21-7.28 (3H, m), 7.31-
7.37 (2H, m); IR (liquid film) 3400 (br), 3280, 2110, 760, 700
C
28H26O: C, 88.85; H, 6.92. Found: C, 88.90; H, 7.07.
[4+2] Cycloa d d u ct 13c. The compound was obtained as
a mixture of stereoisomers (69:31) in 30% yield by a procedure
similar to that described above. The isomers were separated
by a recycling preparative HPLC, equipped with a GPC column
(J AIGEL-1H column) using CHCl3 as an eluent. Major
isomer: 1H NMR δ 1.56 (1H, m), 1.91 (1H, m), 2.10-2.25 (2H,
m), 2.40 (1H, m), 2.61 (1H, br d, J ) ca. 16 Hz), 2.85 (1H, m),
6.95-7.05 (4H, m), 7.15-7.30 (5H, m), 7.35-7.55 (6H, m), 7.71
(2H, m), 7.79 (2H, m); 13C NMR (125.8 MHz) δ 22.93, 29.68,
31.40, 39.59, 92.22, 92.28, 119.06, 119.38, 124.74, 124.80,
125.96, 126.14, 126.47, 126.83, 127.66, 127.90, 128.34, 128.41,
128.44, 135.12, 135.32, 146.01, 149.69, 150.79, 151.24, 142.02.
Minor isomer: 1H NMR δ 1.79 (1H, br dt, J ) ca. 5 and 11
Hz), 1.85 (1H, br d, J ) ca. 11 Hz), 2.17 (1H, m), 2.35-2.55
(4H, m), 7.01 (2H, m), 7.10-7.30 (7H, m), 7.35-7.55 (6H, m),
7.70-7.80 (4H, m); 13C NMR (125.8 MHz) δ 24.53, 29.61, 31.53,
41.05, 92.17, 92.22, 118.94, 119.34, 124.74, 124.79, 125.86,
126.28, 126.56, 126.91, 127.65, 127.95, 128.41, 128.42, 128.46,
135.20, 135.24, 146.25, 149.44, 151.14 (2C), 152.20. IR (a
mixture of the stereoisomers) (KBr disk) 995, 965, 740, 700
cm-1; MS (a mixture of the stereoisomers), m/z (relative
intensity) 426 (M+, 12), 408 (8), 105 (100); HRMS (a mixture
cm-1
.
[6-13C]-2-P h en yl-5-h exyn yl p-Tolu en esu lfon a te ([6-13C]-
3c). The tosylate was prepared from alcohol 16 in 81% yield
by a method similar to that described before. The terminal
acetylenic carbon of the 13C labeled tosylate resonated at 1.93
ppm (td, J ) 2.4 and 247.0 Hz).
13C La belin g Exp er im en t. The labeled tosylate (128 mg,
0.39 mmol), whose 13C content was estimated to be 39% as
described above, was mixed with nonlabeled tosylate 3c (122
mg, 0.37 mmol) and the resulting tosylate of 20% 13C content
was used in the reaction with ethynyltrimethylsilane. To a
solution of ethynyltrimethylsilane (147 mg, 1.5 mmol) in THF
(6 mL) at -85 °C was added butyllithium (1.6 M in hexane)
(0.94 mL, 1.5 mmol). The mixture was stirred 10 min at this
temperature. To the resulting solution of (trimethylsilyl)-
ethynyllithium at room temperature was added a THF (2 mL)
solution of the labeled tosylate [6-13C]-3c (249 mg, 0.75 mmol).
After being stirred at room temperature for 24 h, the mixture
was poured into water and extracted twice with ether. The
combined organic layers were dried and concentrated in vacuo.
Purification of the residue by flash chromatography (0-20%
ethyl acetate in hexane) gave, in the order of elution, a 32:31:
37 mixture of enynes 5d , 5e, and 6d (a 19:18 mixture of
geometrical isomers 6d -1 and 6d -2) (71.9 mg, 38% combined
yield), and the starting tosylate [6-13C]-3c (69.7 mg, 28%).
Separation of the mixture of enynes by a recycling preparative
HPLC, equipped with a GPC column (J AIGEL-1H column)
using CHCl3 as an eluent, gave, in the order of elution, 6d -2,
a mixture of 5d and 6d -1, and 5e.
of the stereoisomers) calcd for
426.1973.
C32H26O 426.1984, found
Reaction of Dibr om om eth ylen ecyclopen tan e with Bu Li
in th e P r esen ce of 1,3-Dip h en ylisoben zofu r a n . To a
solution of dibromomethylenecyclopentane (120 mg, 0.50
mmol) and 1,3-diphenylisobenzofuran (406 mg, 1.5 mmol) in
THF (20 mL) at -85 °C was added butyllithium (1.6 M in
hexane) (0.31 mL, 0.5 mmol). The cooling bath was removed
and the mixture was stirred for 5 h at room temperature. The
mixture was poured into water and extracted twice with ether.
The organic layers were dried and concentrated in vacuo.
Flash chromatography (50% benzene in hexane) of the residue
gave 7.7 mg (4.4% yield) of 13a : mp 169-171 °C (recrystallized
from petroleum ether and EtOH) (lit.7b mp 170-171.5 °C); 1H
NMR δ 1.46 (m, 2H), 1.58 (m, 2H), 2.06 (m, 2H), 2.27 (m, 2H),
6.98 (m, 2H), 7.22 (m, 2H), 7.42 (m, 2H), 7.52 (m, 4H), 7.74
(m, 4H); 13C NMR δ 22.44, 23.47, 92.32, 119.01, 124.61, 126.40,
127.72, 128.36, 135.53, 150.22, 151.91.
[6-13C]-2-P h en yl-4-h exyn -1-ol (15). To a stirred suspen-
sion of lithium amide (22 mmol) in liquid ammonia21 (80 mL)
was slowly added a solution of silyl ether 14 (5.06 g, 18.6 mmol)
in THF (40 mL) at -55 °C. The resulting suspension was
stirred for 1 h and then a THF (2.5 mL) solution of [13C]-
iodomethane (3.12 g, 22 mmol, ca. 40% 13C content) was added.
The mixture was stirred for 1 h. The cooling bath was removed
and ammonia was allowed to evaporate. The mixture was
poured into ice water and extracted three times with a mixed
solvent of ethyl acetate and hexane. The combined organic
layers were dried and concentrated in vacuo. The crude
product was then treated with tetrabutylammonium fluoride
(1M in THF) (18.6 mL, 18.6 mmol) in THF (100 mL) at room
temperature for 2 h. The reaction mixture was poured into
water and extracted twice with ether. The combined organic
layers were dried and concentrated in vacuo. Purification of
the residue by flash chromatography (20% ethyl acetate in
hexane) gave 2.78 g (86% yield) of 15. The 13C content of the
product was determined to be 39% on the basis of 1H NMR
integration of the 6-13CH3 (td, J ) 2.4 and 131.0 Hz) and 6-12-
CH3 protons (t, J ) 2.4 Hz). 15: 1H NMR δ 1.60 (1H, br),
1.76 (1.83H, t, J ) 2.4 Hz and 1.27H, td, J ) 2.4 and 131.0
An authentic sample of 5d was prepared from 4-phenylcy-
clohexanone in two steps. Treatment of the ketone with LDA
(1.1 equiv) in THF at -78 °C for 1 h followed by the reaction
of the resulting enolate with N-phenyltrifluoromethanesulfo-
namide (1.1 equiv)19 gave 4-phenylcyclohexenyl trifluorometh-
anesulfonate (91% yield): 1H NMR δ 1.9-2.15 (2H, m), 2.3-
2.65 (4H, m), 2.86 (1H, m), 3.86 (1H, t, J ) 2.7 Hz), 7.24 (3H,
m), 7.33 (2H, m); 13C NMR δ 27.81, 29.64, 31.51, 38.70, 118.04,
118.39 (q, J C-F ) 320 Hz), 126.60, 126.71, 128.59, 144.52,
148.96; 1690, 1210, 1145, 860 660, 700 cm-1; MS, m/z (relative
intensity) 306 (M+, 24), 104 (100); HRMS calcd for C13H13O3-
F3S 306.0537, found 306.0545.
A mixture of Pd(PPh3)2Cl2 (34.9 mg, 0.05 mmol), 4-phenyl-
cyclohexenyl trifluoromethanesulfonate (613 mg, 2.0 mmol),
trimethylsilylacetylene (0.42 mL, 3.0 mmol), and triethylamine
(0.96 mL, 6.9 mmol) in DMF (8 mL) was heated at 75 °C for
1.5 h. The mixture was poured into water and extracted with
a mixed solvent of ether and hexane (1:1). The organic layer
was washed with brine, dried, and concentrated in vacuo.
Purification of the residue by flash chromatography (0-5%
ethyl acetate in hexane) afforded 375 mg (74% yield) of 5d :
1H NMR δ 0.24 (9H, s), 1.80 (1H, m), 1.99 (1H, br d, J ) ca.
12 Hz), 2.18-2.50 (4H, m), 2.79 (1H, m), 6.30 (1H, br s), 7.24
(3H, m), 7.33 (2H, m); 13C NMR δ 0.07, 29.41, 29.73, 33.73,
39.03, 91.54, 106.73, 120.68, 126.16, 126.74, 128.40, 128.42,
135.43, 146.23; IR (liquid film) 2140, 1605 cm-1; MS, m/z
(21) Reference 1b, p 20.
(22) Brown, C. A.; J adhav, P. K. Org. Synth., Coll. Vol. 8 1993, 553.

9012 J . Org. Chem., Vol. 63, No. 24, 1998
Harada et al.
(relative intensity) 254 (M+, 83), 239 (55), 104 (100); HRMS
calcd for C17H22Si 254.1499, found 254.1493. Anal. calcd for
186.1043. Anal. calcd for C13H14O: C, 83.82; H, 7.58. Found:
C, 83.43; H, 7.60.
C
17H22Si: C, 80.25; H, 8.71. Found: C, 80.03; H, 8.69.
Trimethyl[2-(5-phenylcyclohexenyl)ethynyl]silane (5e): 1H
(3-P h en yl-2-p r op yn ylid en e)cyclop r op a n e (20a ). To a
solution of phenylacetylene (204 mg, 2.0 mmol) in THF (32
mL) at -85 °C was added butyllithium (1.6 M in hexane) (1.25
mL, 2.0 mmol). The mixture was stirred for 15 min at this
temperature. To the resulting solution of phenylethynyl-
lithium at -85 °C was a THF (8 mL) solution of p-fluoroben-
zenesulfonate 19a (228 mg, 1.0 mmol). The mixture was
allowed to warm to room temperature over 2 h and stirred
further for 3.5 h at 30 °C. The mixture was poured into brine
and extracted twice with ether. The organic layers were dried
and concentrated in vacuo. Purification of the residue by flash
chromatography (hexane) gave 85.9 mg (56% yield) of 20a : 1H
NMR δ 1.29 (4H, m), 6.15 (1H, br s), 7.30 (3H, m), 7.46 (2H,
m); 13C NMR δ 3.43, 4.14, 87.51, 88.76, 99.69, 123.68, 127.88,
128.22, 131.50, 138.60; IR (liquid film), 1600, 915, 755, 690
cm-1; MS, m/z (relative intensity) 154 (M+, 100); 153 (92), 152
(58); HRMS calcd for C12H10 154.0783, found 154.0789.
(3-P h en yl-2-p r op yn ylid en e)cycloh exa n e (20b ) a n d
2-(P h en yleth yn yl)cycloh ep ten e (21). To a solution of
phenylacetylene (102 mg, 1.0 mmol) in THF (16 mL) at -85
°C was added butyllithium (1.6 M in hexane) (0.63 mL, 1.0
mmol). The mixture was stirred for 15 min at this tempera-
ture. To the resulting solution of phenylethynyllithium at -80
°C was a THF (8 mL) solution of p-fluorobenzenesulfonate 19b
(135 mg, 0.5 mmol). The mixture was allowed to warm to room
temperature over 2.5 h and stirred further at 65 °C for 19 h.
The mixture was poured into brine and extracted twice with
ether. The organic layers were dried and concentrated in
vacuo. Purification of the residue by flash chromatography
(hexane) gave a 75:25 mixture of 20b and 21 (67.8 mg, 69%
combined yield). Pure 20b was isolated by a recycling
preparative HPLC equipped with a GPC column (J AIGEL-1H
column) using CHCl3 as an eluent. 20b: 1H NMR δ 1.60 (6H,
m), 2.22 (2H, m), 2.50 (2H, m), 5.44 (1H, br s), 7.28 (3H, m),
7.43 (2H, m); 13C NMR δ 26.30, 27.55, 28.27, 31.72, 36.05,
87.33, 91.26, 101.62, 124.07, 127.56, 128.19, 131.25, 156.32;
IR (liquid film) 2200, 1595, 830, 755, 690 cm-1; MS, m/z
(relative intensity) 196 (M+, 100); 167 (40), 128 (30); HRMS
NMR (500 MHz) δ 0.21 (9H, s), 1.73 (1H, tt, J ) 8.4 and 12.3
Hz), 1.96 (1H, br d, J ) ca. 12 Hz), 2.26-2.40 (3H, m), 2.46
(1H, br d, J ) ca. 18 Hz), 2.82 (1H, m), 6.28 (1H, br s), 7.26
(3H, m), 7.34 (2H, m); 13C NMR (125.8 MHz) δ 0.04, 26.38,
28.55, 37.03, 39.77, 91.50, 106.59, 120.57, 126.20, 126.79,
128.43, 135.55, 146.12; IR (liquid film) 2140, 1600 cm-1; MS,
m/z (relative intensity) 254 (M+, 62), 239 (100), 226 (18); HRMS
calcd for C17H22Si 254.1499, found 254.1495. Trimethyl-[3-
(3-phenylcyclopentylidene)-1-propynyl]silane (6d ): Minor iso-
mer 6d -2; 1H NMR (500 MHz) δ 0.24 (9H, s), 1.83 (1H, m),
2.26 (1H, m), 2.49-2.64 (2H, m), 2.74-2.92 (2H, m), 3.20 (1H,
tt, J ) 6.9 and 10.5 Hz), 5.52 (1H, quint, J ) 2.1 Hz), 7.24
(3H, m), 7.30 (2H, m); 13C NMR (125.8 MHz) δ 0.16, 31.91,
33.69, 41.44, 45.38, 97.18, 101.09, 103.42, 126.22, 126.90,
128.38, 144.13, 161.36; IR (liquid film) 2130, 1600 cm-1; MS,
m/z (relative intensity) 254 (M+, 57), 239 (100), 180 (40); HRMS
calcd for C17H22Si 254.1499, found 254.1491. Major isomer 6d -
1
1; H NMR (500 MHz) (a mixture of 6d -1 and 5d ) δ 0.21 (9H
of 6d -1, s), 0.24 (9H for 5d , s), 1.74-1.83 (1H for 5d and 6d -1,
m), 2.00 (1H for 5d , br d, J ) ca. 12 Hz), 2.17-2.58 (4H for 5d
and 3H for 6d -1, m), 2.66 (1H for 6d -1, br dd, J ) ca. 5 and 18
Hz), 2.80 (1H for 5d , m), 3.07 (1H for 6d -1, br dd, J ) ca. 7
and 16 Hz), 3.20 (1H for 6d -1, m), 5.50 (1H for 6d -1, quint, J
) 2.1 Hz), 6.30 (1H for 5d , br s), 7.11-7.37 (5H for 5d and
6d -1, m); 13C NMR (125.8 MHz) (a mixture of 6d -1 and 5d ) δ
0.07 (5d ), 0.14 (6d -1), 29.43 (5d ), 29.74 (5d ), 33.30 (6d -1), 33.74
(5d ), 34.43 (6d -1), 39.05 (5d ), 40.26 (6d -1), 45.17 (6d -1), 91.59
(5d ), 96.97 (6d -1), 101.11 (6d -1), 103.34 (6d -1), 106.73 (5d ),
120.67 (5d ), 126.19 (5d ), 126.24 (6d -1), 126.79 (5d ), 127.03
(6d -1), 128.40 (6d -1), 128.42 (5d ), 135.53 (5d ), 144.36 (6d -1),
146.29 (5d ), 161.21 (6d -1); IR (liquid film) (a mixture of 6d -1
and 5d ) 2140, 1605 cm-1; MS (a mixture of 6d -1 and 5d ), m/z
(relative intensity) 254 (M+, 33), 239 (30), 163 (100); HRMS
(a mixture of 6d -1 and 5d ) calcd for C17H22Si 254.1499, found
254.1496.
In the 1H NMR analysis of 5d , the olefinic proton H(2)
appeared at 6.30 ppm as a br s along with 13C satellites (J C-H
) 160 Hz). The 13C content of 5d at C(2) was estimated to be
15% on the basis of the integration of the signals. Similarly,
the olefinic proton H(2) of 5e appeared at 6.28 ppm as a br s
with 13C satellites (J C-H ) 160 Hz) and the 13C content of 5e
was estimated to be 7%. The olefinic protons H(1′) of 6d -1
and 6d -2 appeared at 5.50 and 5.52 ppm with 13C satellites
(J C-H ) 162 and 163 Hz), respectively, and the 13C contents of
6d -1 and 6d -2 were estimated to be 20% and 21%, respectively.
In 13C NMR analyses, enhancement of the following resonances
were observed: 5d , 120.67 (C-2) and 135.53 ppm (C-1); 5e,
120.57 (C-2) and 135.55 ppm (C-1); 6d -1, 101.11 ppm (C-1′);
6d -2, 101.09 ppm (C-1′).
calcd for C15H16 196.1252, found 196.1260. Anal. calcd for C15
16: C, 91.78; H, 8.22. Found: C, 91.41; H, 8.26.
An authentic sample of 21 was prepared by a palladium-
-
H
(0)-catalyzed cross-coupling reaction of cycloheptenyl trifluo-
romethanesulfonate and phenylacetylene in 49% yield.23 21:
1H NMR δ 1.50-1.67 (4H, m), 1. 78 (2H, m), 2.25 (2H, m),
2.45 (2H, m), 6.42 (1H, br t, J ) ca. 6.5 Hz), 7.28 (3H, m), 7.41
(2H, m); 13C NMR δ 26.53, 26.60, 29.26, 32.14, 34.28, 86.77,
92.93, 123.86, 126.89, 127.57, 128.15, 131.30, 140.20; IR (liquid
film) 2200, 1595, 850, 755, 690 cm-1; MS, m/z (relative
intensity) 196 (M+, 100); 168 (40), 167 (52); HRMS calcd for
C
15H16 196.1252, found 196.1254. Anal. calcd for C15H16: C,
91.78; H, 8.22. Found: C, 91.46; H, 8.21.
7-P h en yl-2-oxa bicyclo[3.3.0]oct-6-en e (18): To a solution
of p-fluorobenzenesulfonate 17 (462 mg, 1.0 mmol) in THF (4.5
mL) at room temperature was slowly added butyllithium (1.6
M in hexane) (0.63 mL, 1.0 mmol) during 7 h by using a
syringe pump. After being stirred further for 0.5 h at room
temperature, the mixture was poured into brine and extracted
twice with ether. The organic layers were dried and concen-
trated in vacuo. Flash chromatography of the residue (5-20%
ethyl acetate in hexane) gave, in the order of elution, 18 (a
93:7 mixture of stereoisomers) (102 mg, 55% yield) and the
recovery of 17 (17%). 18: 1H NMR (500 MHz) δ 1.72 (1H, ddd,
J ) 7.8, 9.6, and 12.2 Hz), 2.45-2.65 (2H, m), 2.72 (1H, td, J
) 6.0 and 12.2 Hz), 4.13-4.30 (3H, m), 4.80 (1H, br t, J ) ca.
6.5 Hz), 5.54 (1H, br s), 7.20-7.27 (3H, m), 7.32 (2H, m) [minor
stereoisomer resonated at 5.00 (1H, br t, J ) ca. 6 Hz) and
5.67 (1H, br s)]; 13C NMR δ 25.74, 44.19, 54.87, 71.26, 88.14,
124.88, 126.38, 127.21, 128.41, 144.98, 148.67 (minor stereo-
isomer resonated at 25.52, 41.01, 36.56, 71.67, 87.68, 124.56,
126.08, 126.95, 128.41, 144.81, 148.67); IR (liquid film) 1600,
970, 760, 700 cm-1; MS, m/z (relative intensity) 186 (M+, 100);
155 (19), 129 (28); HRMS calcd for C13H14O 186.1045, found
Ack n ow led gm en t. This work was supported par-
tially by the Grant-in-Aid for Scientific Research on
Priority Area of Reactive Organometallics from the
Ministry of Education, Science and Culture, J apan.
Su p p or tin g In for m a tion Ava ila ble: Preparation of 14,
16, 4,4-dimethyl-5-hexyn-1-ol, and 4-(2-phenylethyl)-3-oxa-5-
hexyn-1-ol as well as spectral data of 3a ,b,c, 17, and 19a ,b
and 1H or 13C NMR spectra of new compounds not accompanied
by elemental analyses (32 pages). This material is contained
in many libraries on microfiche, immediately follows this
article in the microfilm version of the journal, can be ordered
from the ACS, and can be downloaded from the Internet; see
any current masthead page for ordering information and
Internet access instructions.
J O981411P
(23) Scott, W. J .; Pen˜a, M. R.; Swa¨rd, K.; Stoessel, S. J .; Stille, J . K.
J . Org. Chem. 1985, 50, 2302.