Ruthenium-catalyzed propargylation of aromatic compounds with propargylic alcohols

Article abstract of DOI:10.1002/ejoc.200500858

Reactions of propargylic alcohols bearing a terminal alkyne moiety with aromatic compounds in the presence of a catalytic amount of thiolate-bridged diruthenium complexes give the corresponding propargylated aromatic compounds in high yields with complete

Full text of DOI:10.1002/ejoc.200500858

FULL PAPER
DOI: 10.1002/ejoc.200500858
Ruthenium-Catalyzed Propargylation of Aromatic Compounds with
Propargylic Alcohols
Youichi Inada,[a] Masato Yoshikawa,[a] Marilyn Daisy Milton,[a] Yoshiaki Nishibayashi,*[b]
and Sakae Uemura[a]
Keywords: Aromatic substitution / C–C coupling / C–H activation / Ruthenium / Sulfur
Reactions of propargylic alcohols bearing a terminal alkyne
moiety with aromatic compounds in the presence of a cata-
lytic amount of thiolate-bridged diruthenium complexes give
the corresponding propargylated aromatic compounds in
high yields with complete selectivity. Intramolecular reac-
(=C=C=CHPh)]BF4 (Cp* = η5-C5Me5) with 10 equiv. 2-meth-
ylfuran results in the formation of 2-methyl-5-(1-phenyl-2-
propynyl)furan in 34% yield, indicating that these catalytic
reactions proceed via ruthenium–allenylidene intermediates.
The reaction is considered to be an electrophilic substitution
tions of propargylic alcohols bearing an aromatic moiety pro- of aromatic compounds by the ruthenium-stabilized propar-
ceed smoothly to afford the cyclized products in high yields
with complete selectivity. The stoichiometric reaction of the
ruthenium–allenylidene complex [Cp*RuCl(µ2-SMe)2RuCp*-
gyl cation.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
Discovery of the stabilization of reactive intermediates by
transition metals not only stimulated a theoretical interest
remarkably, but also gave a tremendous impact for the ap-
plication of such species in organic synthesis.[4] Introduc-
tion of a transition metal at the γ-position of a propargyl
cation without complexation of the triple bond can realize
the stabilization and conformational fixation of the propar-
gyl cation [Equation (2)].
Introduction
The chemical features of propargyl cations as reactive
intermediates as well as persistent species have attracted
interest in organic and physical chemistry.[1–2] The elec-
tronic ground state of propargyl cations is delineated by
propargylium and allenylium resonance structures, where
the positive charge is distributed over sp2- and sp-hy-
bridized carbon atoms [Equation (1)].
(2)
(1)
The electronic and structural properties of propargyl cat-
ions have been extensively investigated by Olah and co-
workers, who concluded that propargyl cations can be con-
sidered to be alkynyl-substituted carbenium ions, and their
reactivity depends much on the kind of substituents at the
α- and γ-positions,[2] affording either propargyl or allenyl
products by nucleophilic trapping of propargyl cations.[3]
It has been reported that the electrophilic aromatic sub-
stitution reaction of a free propargyl cation gives some
polymers as predominant products together with a small
amount of a mixture of propargylated and allenylated aro-
matic compounds.[5] In contrast, the positive charge at the
γ-position of the metal complex may promote a desirable
electrophilic aromatic substitution reaction. After a detailed
investigation, we have actually succeeded in the selective
propargylation of aromatic compounds with propargylic
alcohols by using a diruthenium complex as a catalyst; the
results are summarized in this paper.[6,7] In this catalytic
reaction, a stabilized propargyl cation assisted by the diru-
thenium complex reacted directly with aromatic com-
pounds.
[a] Department of Energy and Hydrocarbon Chemistry, Graduate
School of Engineering, Kyoto University,
Katsura, Nishikyo-ku, Kyoto, 615–8510, Japan
[b] Institute of Engineering Innovation, The University of Tokyo,
Yayoi, Bunkyo-ku, Tokyo, 113–8656, Japan
Fax: +81-3-5841-1175
E-mail: ynishiba@sogo.t.u-tokyo.ac.jp
Supporting information for this article is available on the
WWW under http://www.eurjoc.org or from the author.
Eur. J. Org. Chem. 2006, 881–890
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881

Y. Inada, M. Yoshikawa, M. D. Milton, Y. Nishibayashi, S. Uemura
FULL PAPER
observed by GLC and 1H NMR spectroscopy. The reaction
proceeded smoothly even at room temperature for 1 h, 3a
being obtained in 90% yield. It is noteworthy that only thi-
olate-bridged diruthenium complexes 1a–1d worked as cat-
alysts (Table 1, entries 2–4). The ruthenium–allenylidene
complex [Cp*RuCl(µ2-SMe)2RuCp*(=C=C=CHPh)]BF4
(4a) was also effective in this catalytic reaction (Table 1, en-
try 5). Unfortunately, other conventional mono- and diru-
thenium complexes such as [Cp*RuCl(PPh3)2] (Cp* = η5-
C5Me5), [RuCl2(PPh3)3], [RuCl2(p-cymene)]2, and [(indenyl)
RuCl(PPh3)2], which were known to react with propargylic
alcohols to produce the corresponding allenylidene complexes,
did not work at all as catalysts (Table 1, entries 6–9).
Results and Discussion
As shown in Equation (2), a metal–allenylidene complex
exists as another resonance structure of a metal–alkynyl
complex with a positive charge at the γ-position. At first,
the stoichiometric reaction of the ruthenium–allenylidene
complex with aromatic compounds was investigated. Heat-
ing the allenylidene complex [Cp*RuCl(µ2-SMe)2RuCp*-
(=C=C=CHPh)]BF4 (Cp* = η5-C5Me5; 4a) with 10 equiv.
2-methylfuran in ClCH2CH2Cl at 60 °C for 6 h led to the
formation of 2-methyl-5-(1-phenyl-2-propynyl)furan (3a) in
34% yield as the sole product [Equation (3)].
Reactions of other furans with 1-aryl-, 1-alkenyl-, and 1-
alkyl-substituted propargylic alcohols in the presence of 1a
proceeded smoothly to give the corresponding propar-
gylated furans 3 in high yields with complete selectivity.
Typical results are summarized in Table 2. A slightly lower
yield of 2-(1-phenyl-2-propynyl)furan (3j) was obtained
when furan was used as a substrate (Table 2, entry 10). Pyr-
role, N-methylpyrrole, and 2-methylthiophene can be pro-
pargylated with 2a (Table 2, entries 11–17). In all cases, pro-
pargylation occurred selectively at the α-position of the het-
erocyclic rings, and the reaction of indole with 2a afforded
the β-propargylated indole 3n in 52% yield with complete
selectivity (Scheme 1). These results are exactly in agree-
ment with the regioselectivity of electrophilic substitution
reactions of heterocyclic compounds.[11] Interestingly, the
reaction of indoline with 2a selectively gave N-(1-phenyl-2-
propenyl)indole in 74% yield (Scheme 2).
(3)
This unprecedented result indicates that an electrophilic
aromatic substitution reaction occurs at the γ-carbon of an
allenylidene ligand. Reactions of allenylidene complexes
with various heteroatom- and carbon-centered nucleophiles
at the α- and γ-carbons have already been reported,[8] but
there is no example of the direct reaction of the allenylidene
ligand with aromatic compounds until now.[9]
The result of the stoichiometric reaction above prompted
us to investigate the catalytic reaction of aromatic com-
pounds with propargylic alcohols in the presence of the thi-
olate-bridged diruthenium complex[10] [Cp*RuCl(µ2-SMe)2-
N,N-Dimethylaniline (5a) reacted with several 1-aryl-2-
RuCp*Cl] (1a) as catalyst, because the ruthenium–allenylid- propyn-1-ols 2 at 60 °C for 2–6 h to give the corresponding
ene complex 4a can be readily prepared from the reaction N,N-dimethyl-4-(1-aryl-2-propynyl)anilines 6a–6f in good
of 1a with 1 equiv. 1-phenyl-2-propyn-1-ol (2a) in the pres- yields with complete regioselectivity. Typical results are
ence of NH4BF4.[10n] Treatment of 2a with 2-methylfuran in summarized in Table 3. In this case, the aryl groups in 2
ClCH2CH2Cl in the presence of 1a (5 mol-%) and NH4BF4 were found to have a strong influence on the catalytic ac-
(10 mol-%) at 60 °C for 1 h afforded the furan 3a in quanti- tivity. Introduction of an electron-withdrawing group such
tative yield (Table 1, entry 1). Typical results are shown in as p-CF3 and p-Cl increased the product yield slightly, while
Table 1. Neither other products nor regioisomers of 3a were the introduction of an electron-releasing group such as p-
Table 1. Propargylation of 2-methylfuran with propargylic alcohol (2a).[a]
Entry
Catalyst
Conv. of 2a [%][b]
Yield of 3a [%][b]
1
2
3
4
5
6
7
8
9
[Cp*RuCl(µ2-SMe)]2 (1a)
[Cp*RuCl(µ2-SnPr)]2 (1b)
[Cp*RuCl(µ2-SiPr)]2 (1c)
100
100
100
100
100
36
18
40
44
Ͼ95 (85)[c]
87
78
Ͼ95
Ͼ95
0
0
0
[Cp*RuCl(µ2-SiPr)2Ru(OH2)Cp*]OTf (1d)[d]
[Cp*RuCl(µ2-SMe)2Ru(=C=C=CHPh)Cp*]BF4 (4a)[d]
[Cp*RuCl(PPh3)2]
[RuCl2(PPh3)3]
[RuCl2(p-cymene)]2
[(indenyl)RuCl(PPh3)2]
0
[a] All reactions of 2-methylfuran (1.0 mmol) with 1-phenyl-2-propyn-1-ol (2a) (0.10 mmol) were carried out in the presence of catalyst
in ClCH2CH2Cl at 60 °C for 1 h. [b] Determined by GLC. [c] Isolated yield. [d] In the absence of NH4BF4.
882
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Ru-Catalyzed Propargylation of Aromatic Compounds with Propargylic Alcohols
Table 2. Propargylation of heterocyclic compounds with propargylic alcohols.[a]
FULL PAPER
Entry
Propargylic alcohol
Heterocyclic compound
Yield of product [%][b]
1
2
3
4
5
6
7
8
2a, R = Ph
X = O, R1 = Me, R2 = H
X = O, R1 = Me, R2 = H
X = O, R1 = Me, R2 = H
X = O, R1 = Me, R2 = H
X = O, R1 = Me, R2 = H
X = O, R1 = Et, R2 = H
X = O, R1 = OMe, R2 = H
X = O, R1 = Me, R2 = H
X = O, R1 = Me, R2 = H
X = O, R1 = H, R2 = H
X = NH, R1 = H, R2 = H
X = NMe, R1 = H, R2 = H
X = S, R1 = Me, R2 = H
X = NMe, R1 = H, R2 = H
X = NMe, R1 = H, R2 = H
X = NMe, R1 = H, R2 = H
X = NMe, R1 = H, R2 = H
X = O, R1 = Me, R2 = Me
X = O, R1 = Me, R2 = H
3a, 85 (Ͼ95)[c]
3b, 83
3c, 70
3d, 77
3e, 84
3f, 75
3g, 51
3h, 59
3i, 61
3j, 68
3k, 67
3l, 94
3m, 86
3o, 95
3p, 92
3q, 92
3r, 90
2b, R = p-MeC6H4
2c, R = p-FC6H4
2d, R = 2,4,6-Me3C6H2
2e, R = 1-naphthyl
2a, R = Ph
2a, R = Ph
2f, R = Ph2C=CH-
2g, R = cyclohexyl
2a, R = Ph
9
10
11
12
13
14
15
16
17
18
19
2a, R = Ph
2a, R = Ph
2a, R = Ph
2g, R = cyclohexyl
2b, R = p-MeC6H4
2c, R = p-FC6H4
2h, R = 2-naphthyl
2a, R = Ph
3s, 91
3t, 79
2h, R = 2-naphthyl
[a] All reactions of 2 (0.60 mmol) with heterocyclic compound (6.0 mmol) were carried out in the presence of 1a (0.03 mmol) and NH4BF4
(0.06 mmol) in ClCH2CH2Cl (15–30 mL) at 60 °C for 1 h. [b] Isolated yield. [c] GLC yield.
Reactions of 3,5-dimethoxyacetanilide (5g) and 1,3,5-tri-
methoxybenzene (5h) with 2a proceeded smoothly and se-
lectively, and afforded the corresponding propargylated aro-
matic compounds 6m and 6n in moderate yields (Table 3,
entries 12 and 13). The molecular structure of 6n is unam-
biguously clarified by X-ray analysis (Figure 1). In contrast,
Scheme 1.
no propargylation occurred when acetanilide, 1,3-dimethox-
ybenzene, 1,3,5-trimethylbenzene, p-xylene, and toluene, be-
sides many other aromatic compounds, were used (Fig-
ure 2).[11] Thus, this catalytic propargylation proceeded only
when highly electron-rich arenes[12] were used. Interestingly,
1-propargylated azulenes 6o and 6p were formed in reac-
tions of propargylic alcohols with azulene (Scheme 3).
Next, catalytic intramolecular cyclization reactions were
investigated. Typical results are summarized in Table 4.
Treatment of propargylic alcohols 7a bearing a furan moi-
Scheme 2.
ety in ClCH2CH2Cl at 60 °C for 24 h in the presence of 1a
afforded the corresponding seven-membered tricyclic com-
Me and p-MeO decreased it (Table 3, entries 1–5). It is pound 8a in Ͼ93% yield (GLC, 82% isolated yield)
worth noting that electrophilic substitution reactions oc- (Table 4, entry 1). Noteworthy is that only thiolate- and se-
curred exclusively at the para position of anilines. These re- lenolate-bridged diruthenium complexes worked effectively
sults support a reaction pathway that proceeds by an elec- as catalysts (Table 4, entries 2–5). On the other hand, tellur-
trophilic attack of the cationic γ-carbon of the alkynyl com- olate-bridged diruthenium complexes and other conven-
plex, which is considered to be a resonance structure of the tional mono- and diruthenium complexes such as
allenylidene complex (vide supra). Reactions of 2a with [Cp*RuCl(µ2-TeMe)]2, [CpRuCl(PPh3)2] (Cp = η5-C5H5),
other aniline derivatives proceeded to give the correspond- [RuCl2(PPh3)3], [RuCl2(p-cymene)]2, [(indenyl)RuCl(PPh3)2],
ing propargylated anilines in moderate to good yields. A and [Cp*RuCl2]2 did not work at all as in the case of inter-
mixture of 6j and 6k was obtained in a ratio of 1 to 5 by the molecular reactions of propargylic alcohols with furan
reaction of 2a with N-phenylpyrrole (5e) (Table 3, entry 10).
(Table 4, entries 6–11).
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883

Y. Inada, M. Yoshikawa, M. D. Milton, Y. Nishibayashi, S. Uemura
Table 3. Propargylation of aromatic compounds with propargylic alcohols.[a]
FULL PAPER
Entry
Propargylic alcohol
Aromatic compound
Reaction time [h]
Yield of product [%][b]
1
2
3
4
5
6
7
8
2a, R = Ph
5a
5a
5a
5a
5a
5a
5b
5c
5d
5e
5f
2
2
2
5
3
6
5
3
2
3
1
3
2
6a, 50
6b, 58
6c, 53
6d, 23
6e, –[c]
6f, 30
2i, R = p-CF3C6H4
2j, R = p-ClC6H4
2b, R = p-MeC6H4
2k, R = p-MeOC6H4
2h, R = 2-naphthyl
2a, R = Ph
6g, 23
6h, 49
6i, 63
2a, R = Ph
9
2a, R = Ph
10
11
12
13
2a, R = Ph
6j + 6k, 60[d]
6l, 48
2a, R = Ph
2a, R = Ph
5g
5h
6m, 52
6n, 38
2a, R = Ph
[a] All reactions of 2 (0.60 mmol) with aromatic compound (6.0 mmol) were carried out in the presence of 1a (0.03 mmol) and NH4BF4
(0.060 mmol) in ClCH2CH2Cl (15–30 mL) at 60 °C. [b] Isolated yield. [c] A small amount of 6e was detected by GC–MS. [d] 6j:6k = 1:5.
Other intramolecular cyclization reactions of the various
propargylic alcohols 7b–7e bearing a furan moiety were car-
ried out. Cyclized products 8b–8e were obtained in moder-
ate to good yields (Table 4, entries 12–15). The presence of
substituents on a phenyl ring was found to decrease the
product yield. As a further extension of the intramolecular
cyclization reaction, reactions of propargylic alcohols 9a–9c
bearing an electron-rich benzene moiety were investigated
(Scheme 4). Although the reactions proceeded to give the
corresponding cyclized products 10a–10c, their yields were
relatively low. The molecular structure of 10c was unambig-
uously determined by X-ray crystallographic analysis (Fig-
ure 3). Reactions of propargylic alcohols 7f and 9d bearing
a bulky naphthyl moiety also gave the corresponding prod-
ucts 8f and 10d in moderate yields (Scheme 5).
Finally, in order to obtain some mechanistic information,
[D5]pyrrole was allowed to react with 2a under similar reac-
tion conditions (Scheme 6). 2-(1-Phenyl-2-propynyl)pyrrole
(3lЈ) was formed with a high deuterium incorporation
(80%) at the C-3 position, indicating that this catalytic pro-
pargylation of aromatic compounds proceeded via a ruthe-
nium–allenylidene intermediate such as 4a. However, at the
present stage we cannot exclude the possibility that the re-
action proceeded by a charge-transfer mechanism including
radical cation intermediates.
In conclusion, we have found a novel ruthenium-cata-
lyzed inter- and intramolecular propargylation of aromatic
compounds with propargylic alcohols to afford the corre-
sponding propargylated aromatic products in good to high
yields with complete selectivity. The Nicholas reaction has
been known to be effective for propargylation of aromatic
compounds by use of a stoichiometric amount of Co2(CO)8,
where several steps are necessary to obtain propargylated
products from propargylic alcohols via cationic propargyl
complexes [(propargyl)Co2(CO)6]+.[13] The catalytic reac-
tion presented in this paper may be potentially useful for
practical application in organic synthesis, because the selec-
tive propargylation of aromatic compounds is so far known
to be quite difficult.[5,14] It is also noteworthy that some
Figure 1. Crystal structure of 6n.
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Ru-Catalyzed Propargylation of Aromatic Compounds with Propargylic Alcohols
FULL PAPER
Figure 2. Unreactive aromatic compounds for propargylation.
Scheme 3.
Table 4. Intramolecular cyclization of propargylic alcohols bearing a furan moiety (7).[a]
Entry
Propargylic alcohol
Catalyst
Yield of 8 [%][b]
1
2
3
4
5
6
7
8
7a, R = H
7a, R = H
7a, R = H
7a, R = H
7a, R = H
7a, R = H
7a, R = H
7a, R = H
7a, R = H
7a, R = H
7a, R = H
7b, R = 2-Me
7c, R = 2-Cl
7d, R = 4-Me
7e, R = 4-MeO
[Cp*RuCl(µ2-SMe)]2 (1a)
[Cp*RuCl(µ2-SnPr)]2 (1b)
[Cp*RuCl(µ2-SiPr)]2 (1c)
[Cp*RuCl(µ2-SiPr)2Ru(OH2)Cp*]OTf (1d)[d]
[Cp*RuCl(µ2-SeMe)]2
[Cp*RuCl(µ2-TeMe)]2
[CpRuCl(PPh3)2]
8a, Ͼ93 (82)[c]
8a, 92
8a, 84
8a, 25
8a, 38
8a, 0
8a, 0
[RuCl2(PPh3)3]
[RuCl2(p-cymene)]2
8a, 0
9
8a, 0
10
11
12
13
14
15
[(indenyl)RuCl(PPh3)2]
[Cp*RuCl2]2
[Cp*RuCl(µ2-SMe)]2 (1a)
[Cp*RuCl(µ2-SMe)]2 (1a)
[Cp*RuCl(µ2-SMe)]2 (1a)
[Cp*RuCl(µ2-SMe)]2 (1a)
8a, 0
8a, 0
8b, 63[c]
8c, 40[c]
8d, 72[c]
8e, 56[c]
[a] All reactions of 7 (0.10 mmol) were carried out in the presence of catalyst (0.005 mmol) and NH4BF4 (0.01 mmol) in ClCH2CH2Cl
at 60 °C for 24 h. [b] Determined by GLC. [c] Isolated yield. [d] In the absence of NH4BF4.
Scheme 4.
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885

Y. Inada, M. Yoshikawa, M. D. Milton, Y. Nishibayashi, S. Uemura
FULL PAPER
Scheme 5.
perature. After the addition of 2a (79 mg, 0.60 mmol) and 2-meth-
ylfuran (492 mg, 6.00 mmol), the reaction flask was kept at 60 °C
for 1 h. The solvent was concentrated under reduced pressure main-
tained by an aspirator, and then the residue was purified by TLC
(SiO2) with EtOAc/n-hexane (1:9) to give 2-methyl-5-(1-phenyl-2-
propynyl)furan (3a) as a pale yellow oil (100 mg, 0.51 mmol; 85%
yield).
1
3a: H NMR δ = 2.23 (s, 3 H), 2.41 (d, J = 3.0 Hz, 1 H), 5.00 (s,
1 H), 5.88 (s, 1 H), 6.06 (d, J = 3.0 Hz, 1 H), 7.25–7.43 (m, 5 H)
ppm. 13C NMR δ = 13.6, 37.0, 71.8, 82.3, 106.2, 107.4, 127.3,
127.7, 128.6, 138.5, 151.3, 152.0 ppm. C14H12O (196.24): calcd. C
85.68, H 6.16; found C 85.41, H 5.88.
3b: Yield 83% (105 mg). Pale yellow oil. 1H NMR δ = 2.22 (s, 3
H), 2.33 (s, 3 H), 2.39 (s, 1 H), 4.96 (s, 1 H), 5.86 (s, 1 H), 6.06 (s,
1 H), 7.13 (d, J = 7.5 Hz, 2 H), 7.29 (d, J = 7.5 Hz, 2 H) ppm. 13C
NMR δ = 13.6, 21.0, 36.7, 71.6, 82.5, 106.2, 107.3, 127.6, 129.3,
135.6, 137.0, 151.5, 151.9 ppm. C15H14O (210.27): calcd. C 85.68,
H 6.71; found C 85.44, H 6.59.
Figure 3. Crystal structure of 10c.
3c: Yield 70% (90 mg). Pale yellow oil. 1H NMR δ = 2.23 (s, 3 H),
2.42 (d, J = 2.4 Hz, 1 H), 4.98 (s, 1 H), 5.88 (s, 1 H), 6.06 (d, J =
2.4 Hz, 1 H), 7.01 (t, J = 8.8 Hz, 2 H), 7.38 (dd, J = 8.8 and 5.4 Hz,
2 H) ppm. 13C NMR δ = 13.6, 36.3, 72.0, 82.0, 106.2, 107.5, 115.3
(d, J = 22 Hz), 129.3 (d, J = 9 Hz), 134.2 (d, J = 4 Hz), 151.0,
152.1, 162.0 (d, J = 246 Hz) ppm. C14H11FO (214.23): calcd. C
78.49, H 5.18; found C 78.30, H 5.07.
Scheme 6.
propargylated aromatic products are useful monomers in
the field of material science.
3d: Yield 77% (110 mg). Pale yellow oil. 1H NMR δ = 2.21 (s, 3
H), 2.26 (s, 3 H), 2.29 (d, J = 2.7 Hz, 1 H), 2.35 (s, 6 H), 5.43 (s,
1 H), 5.86 (s, 1 H), 6.03 (s, 1 H), 6.85 (s, 2 H) ppm. 13C NMR δ =
13.6, 20.4, 20.8, 31.7, 70.6, 81.7, 106.0, 107.3, 129.9, 131.5, 136.8,
136.9, 150.3, 151.5 ppm. C17H18O (238.32): calcd. C 85.67, H 7.61;
found C 85.45, H 7.28.
Experimental Section
General Methods: 1H NMR (400, 300, and 270 MHz) and 13C
NMR (100, 75, and 67.8 MHz) spectra were recorded using CDCl3
as solvent. Quantitative GLC analyses were performed with a Shi-
madzu GC-14A instrument equipped with a flame ionization detec-
tor using a 25 m×0.25 mm CBP10 fused silica capillary column.
GC–MS analyses were carried out with a Shimadzu GC–MS QP-
5000 spectrometer. Elemental analyses were performed at the Mi-
croanalytical Center of Kyoto University. Mass spectra were mea-
sured with a JEOL JMS600H mass spectrometer. All reactions
were carried out under dry nitrogen. Solvents were dried by the
usual methods and distilled before use.
3e: Yield 84% (124 mg). Pale yellow oil. 1H NMR δ = 2.24 (s, 3
H), 2.45 (d, J = 3.0 Hz, 1 H), 5.71 (s, 1 H), 5.88 (s, 1 H), 6.04 (d,
J = 3.0 Hz, 1 H), 7.50 (m, 3 H), 7.62 (d, J = 7.0 Hz, 1 H), 7.80 (d,
J = 8.0 Hz, 1 H), 7.87 (d, J = 7.0 Hz, 1 H), 8.12 (d, J = 8.0 Hz, 1
H) ppm. 13C NMR δ = 13.6, 37.2, 72.1, 82.2, 106.2, 107.6, 125.9,
125.9, 126.2, 126.4, 127.6, 127.9, 128.4, 132.7, 133.4, 135.8, 151.2,
152.1 ppm. C18H14O (246.3): calcd. C 87.78, H 5.73; found C 87.53,
H 5.64.
1
Ruthenium-Catalyzed Propargylation of Aromatic Compounds with
Propargylic Alcohols: A typical experimental procedure for the re-
action of 2-methylfuran with 1-phenyl-2-propyn-1-ol (2a) catalyzed
by [Cp*RuCl(µ2-SMe)2RuCp*Cl] (1a) is described below. In a 20-
mL flask were placed 1a (19 mg, 0.03 mmol) and NH4BF4 (6 mg,
0.06 mmol) under nitrogen. Anhydrous ClCH2CH2Cl (15 mL) was
added, and then the mixture was magnetically stirred at room tem-
3f: Yield 75% (95 mg). Pale yellow oil. H NMR δ = 1.17 (t, J =
7.5 Hz, 3 H), 2.40 (d, J = 2.5 Hz, 1 H), 2.58 (q, J = 7.5 Hz, 2 H),
5.00 (d, J = 2.5 Hz, 1 H), 5.88 (d, J = 3.0 Hz, 1 H), 6.07 (d, J =
3.0 Hz, 1 H), 7.23–7.42 (m, 5 H) ppm. 13C NMR δ = 12.0, 21.3,
37.0, 71.7, 82.2, 104.5, 107.2, 127.3, 127.7, 128.6, 138.5, 151.1,
157.7 ppm. C15H14O (210.27): calcd. C 85.68, H 6.71; found C
85.43, H 6.69.
886
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2006, 881–890

Ru-Catalyzed Propargylation of Aromatic Compounds with Propargylic Alcohols
FULL PAPER
1
3g: Yield 51% (65 mg). Pale yellow oil. H NMR δ = 2.40 (d, J =
136.7 ppm. C15H15N (209.29): calcd. C 86.08, H 7.22, N 6.69;
1.2 Hz, 1 H), 3.75 (s, 3 H), 4.93 (s, 1 H), 5.04 (d, J = 3.0 Hz), 6.07 found C 85.85, H 7.19, N 6.61.
(d, J = 3.0 Hz, 1 H), 7.25–7.42 (m, 5 H) ppm. 13C NMR δ = 36.9,
57.6, 71.9, 79.8, 81.9, 107.6, 127.3, 127.7, 128.6, 138.2, 142.8,
161.3 ppm. C14H12O2 (212.24): calcd. C 79.22, H 5.70; found C
78.99, H 5.51.
3q: Yield 92% (118 mg). Yellow oil. 1H NMR δ = 2.45 (d, J =
2.0 Hz, 1 H), 3.44 (s, 3 H), 5.04 (s, 1 H), 5.98 (d, J = 2.0 Hz, 1 H),
6.06 (t, J = 3.0 Hz, 1 H), 6.57 (s, 1 H), 7.01 (dd, J = 8.7 and 8.7 Hz,
2 H), 7.32 (dd, J = 8.7 and 8.7 Hz) ppm. 13C NMR δ = 34.1, 34.7,
72.4, 82.8, 100.5, 106.7, 108.5, 115.3 (d, J = 21 Hz), 123.1, 129.1
(d, J = 8 Hz), 130.2, 134.7 (d, J = 3 Hz), 163.5 (d, J = 265 Hz)
ppm. C14H12NF (213.25): calcd. C 78.85, H 5.67, N 6.57; found C
78.74, H 5.55, N 6.42.
3h: Yield 59% (106 mg). Yellow oil. 1H NMR δ = 2.23 (s, 3 H),
2.30 (d, J = 2.4 Hz, 1 H), 4.47 (dd, J = 9.9 and 2.4 Hz, 1 H), 5.88
(d, J = 3.0 Hz, 1 H), 6.09 (d, J = 3.0 Hz, 1 H), 6.15 (d, J = 9.9 Hz,
1 H), 7.25–7.40 (m, 10 H) ppm. 13C NMR δ = 13.6, 31.7, 70.6,
82.4, 106.2, 106.6, 124.9, 127.6, 128.1, 128.4, 129.8, 138.7, 150.5,
151.9 ppm. C22H18O (298.38): calcd. C 88.56, H 6.08; found C
88.40, H 5.85.
3r: Yield 90% (132 mg). Yellow oil. 1H NMR δ = 2.49 (d, J =
3.0 Hz, 1 H), 3.45 (s, 3 H), 5.22 (d, J = 3.0 Hz, 1 H), 6.08 (m, 2
H), 6.58 (t, J = 2.4 Hz, 1 H), 7.42 (m, 3 H), 7.83 (m, 4 H) ppm.
13C NMR δ = 34.2, 35.6, 72.6, 82.9, 106.7, 108.7, 123.1, 125.9,
125.9, 126.1, 126.2, 127.6, 127.9, 128.4, 130.3, 132.6, 133.3,
136.4 ppm. C18H15N (245.32): calcd. C 88.13, H 6.16, N 5.71;
found C 88.01, H 5.99, N 5.68.
1
3i: Yield 61% (74 mg). Pale yellow oil. H NMR δ = 1.10–1.90 (m,
10 H), 2.18 (d, J = 2.7 Hz, 1 H), 2.27 (s, 3 H), 3.55 (m, 1 H), 5.48
(dd, J = 11 and 2.7 Hz, 1 H), 5.88 (d, J = 3.0 Hz, 1 H), 6.06 (d, J
= 3.0 Hz, 1 H) ppm. 13C NMR δ = 13.6, 26.1, 26.2, 27.5, 29.2,
31.0, 70.9, 82.4, 105.9, 107.0, 150.9, 151.1 ppm. C14H18O (202.29):
calcd. C 83.12, H 8.97; found C 83.05, H 8.83.
3s: Yield 91% (115 mg). Yellow oil. 1H NMR δ = 1.87 (s, 3 H),
2.14 (s, 3 H), 2.40 (d, J = 3.0 Hz, 1 H), 4.96 (d, J = 3.0 Hz, 1 H),
5.94 (s, 1 H), 7.23–7.43 (m, 5 H) ppm. 13C NMR δ = 9.81, 11.3,
37.0, 71.7, 82.4, 109.9, 114.6, 127.3, 127.8, 128.6, 138.5, 147.2,
150.0 ppm. C15H14O (210.27): calcd. C 85.68, H 6.71; found C
85.52, H 6.47.
1
3j: Yield 68% (74 mg). Pale yellow oil. H NMR δ = 2.42 (d, J =
3.0 Hz, 1 H), 5.04 (d, J = 3.0 Hz, 1 H), 6.21 (d, J = 3.0 Hz, 1 H),
6.30 (m, 1 H), 7.25–7.43 (m, 6 H) ppm. 13C NMR δ = 37.0, 72.0,
81.9, 106.7, 110.3, 127.5, 127.7, 128.6, 138.2, 142.3, 153.1 ppm.
C13H10O (182.22): calcd. C 85.69, H 5.53; found C 85.56, H 5.35.
3t: Yield 79% (117 mg). Pale yellow oil. 1H NMR δ = 2.24 (s, 3
H), 2.45 (d, J = 2.4 Hz, 1 H), 5.70 (d, J = 2.0 Hz, 1 H), 5.87 (d, J
= 2.4 Hz, 1 H), 6.03 (d, J = 3.6 Hz, 1 H), 7.44–7.53 (m, 3 H), 7.62
(d, J = 6.8 Hz, 1 H), 7.80 (d, J = 8.4 Hz, 1 H), 7.86 (d, J = 8.0 Hz,
1 H), 8.12 (d, J = 8.4 Hz, 1 H) ppm. 13C NMR δ = 13.6, 34.2, 72.0,
82.4, 106.3, 108.2, 123.5, 125.5, 125.7, 126.0, 126.2, 128.4, 128.8,
130.9, 134.0, 150.8, 151.9 ppm. C18H14O (246.30): calcd. C 87.78,
H 5.73; found C 87.60, H 5.64.
3k: Yield 67% (73 mg). Brown oil. 1H NMR δ = 2.45 (d, J =
2.4 Hz, 1 H), 5.06 (d, J = 2.4 Hz, 1 H), 6.00 (s, 1 H), 6.13 (q, J =
2.8 Hz, 1 H), 6.68 (q, J = 2.3 Hz, 1 H), 7.21–7.39 (m, 5 H), 8.11
(s, 1 H) ppm. 13C NMR δ = 36.3, 72.2, 83.1, 106.5, 108.6, 117.4,
127.3, 127.6, 128.7, 129.9, 139.5 ppm. IR (neat): ν = 2118 (CϵC),
˜
3289 (ϵC–H), 3430 (N–H) cm–1. C13H11N (181.23): calcd. C 86.15,
H 6.12, N 7.73; found C 85.88, H 5.93, N 7.50.
N-(1-Phenyl-2-propenyl)indole: Yield 74% (103 mg). Pale yellow oil.
1H NMR δ = 5.01 (d, J = 16.9 Hz, 1 H), 5.36 (d, J = 10.3 Hz, 1
H), 6.09 (d, J = 5.7 Hz, 1 H), 6.30–6.39 (m, 1 H), 6.52 (d, J =
3.3 Hz, 1 H), 7.07–7.29 (m, 9 H), 7.62 (d, J = 7.7 Hz, 1 H) ppm.
13C NMR δ = 61.9, 101.5, 110.1, 118.5, 119.6, 120.9, 121.5, 126.2,
127.5, 127.9, 128.7, 128.8, 136.0, 139.0 ppm.
3l: Yield 94% (110 mg). Yellow oil. 1H NMR δ = 2.43 (d, J =
2.4 Hz, 1 H), 3.43 (s, 3 H), 5.06 (d, J = 2.4 Hz, 1 H), 6.02 (s, 1 H),
6.07 (s, 1 H), 6.55 (s, 1 H), 7.22–7.44 (m, 5 H) ppm. 13C NMR δ
= 34.2, 35.4, 72.2, 83.0, 106.7, 108.5, 122.9, 127.1, 127.7, 128.6,
130.4, 139.0 ppm. C14H13N (195.26): calcd. C 86.12, H 6.72, N
7.17; found C 85.85, H 6.55, N 6.99.
1
6a: Yield 50% (71 mg). White crystals. H NMR δ = 2.44 (d, J =
1
3m: Yield 86% (110 mg). Pale yellow oil. H NMR δ = 2.40 (s, 3
2.7 Hz, 1 H), 2.89 (s, 6 H), 4.93 (s, 1 H), 6.67 (d, J = 8.6 Hz, 2 H),
7.19–7.38 (m, 7 H) ppm. 13C NMR δ = 40.6, 41.9, 72.2, 85.3, 112.8,
126.7, 127.7, 128.4, 128.5, 129.1, 141.7, 149.5 ppm. C17H17N
(235.32): calcd. C 86.77, H 7.28, N 5.95; found C 86.47, H 7.19, N
5.82.
H), 2.48 (s, 1 H), 5.13 (s, 1 H), 6.55 (s, 1 H), 6.74 (s, 1 H), 7.25–
7.54 (m, 5 H) ppm. 13C NMR δ = 15.3, 38.7, 72.3, 83.9, 124.6,
124.9, 128.6, 128.8, 130.9, 139.5, 140.6, 142.3 ppm. C14H12S
(212.31): calcd. C 79.20, H 5.70; found C 79.11, H 5.64.
1
1
3n: Yield 52% (72 mg). White crystals. H NMR δ = 2.41 (d, J =
6b: Yield 58% (106 mg). Brown solid. H NMR δ = 2.49 (d, J =
2.6 Hz, 1 H), 5.23 (s, 1 H), 7.02–7.52 (m, 10 H), 7.87 (br., 1 H)
ppm. 13C NMR δ = 34.6, 71.3, 84.8, 111.2, 116.2, 119.4, 119.6,
122.2, 122.6, 125.8, 126.9, 127.8, 128.5, 136.6, 140.6 ppm. C17H13N
(231.29): calcd. C 88.28, H 5.67, N 6.06; found C 88.12, H 5.51, N
5.95.
2.6 Hz, 1 H), 2.91 (s, 6 H), 4.96 (s, 1 H), 6.67 (d, J = 8.8 Hz, 2 H),
7.19 (d, J = 8.8 Hz, 2 H), 7.47–7.56 (m, 4 H) ppm. 13C NMR δ =
40.7, 41.9, 73.0, 84.3, 112.6, 125.3, 125.4, 127.8, 127.9, 128.3, 128.9,
145.7, 149.6 ppm. C18H16NF3 (303.32): calcd. C 71.28, H 5.32, N
4.62; found C 71.55, H 5.28, N 4.42.
3o: Yield 95% (115 mg). Pale yellow oil. 1H NMR δ = 0.90–1.25
(m, 5 H), 1.58–1.74 (m, 5 H), 2.18 (d, J = 2.7 Hz, 1 H), 3.47 (dd,
J = 2.7 and 7.0 Hz, 1 H), 3.60 (s, 3 H), 6.04 (m, 2 H), 6.52 (t, J =
2.4 Hz, 1 H) ppm. 13C NMR δ = 26.1, 26.2, 30.0, 31.5, 34.1, 36.2,
42.0, 70.7, 83.8, 106.6, 107.5, 122.0, 130.5 ppm. C14H19N (201.31):
calcd. C 83.53, H 9.51, N 6.96; found C 83.45, H 9.34, N 6.83.
6c: Yield 53% (86 mg). Yellow oil. 1H NMR δ = 2.45 (s, 1 H), 2.90
(s, 6 H), 4.88 (s, 1 H), 6.6 (d, J = 8.4 Hz, 2 H), 7.16–7.2 (m, 6 H)
ppm. 13C NMR δ = 40.5, 41.3, 72.6, 84.8, 112.7, 128.3, 128.6,
129.1, 132.5, 140.4, 149.7 ppm. C17H16NCl (269.77): calcd. C
75.69, H 5.98, N 5.19; found C 75.91, H 5.93, N 4.89.
6d: Yield 23% (34 mg). Yellow crystals. 1H NMR δ = 2.30 (s, 3 H),
2.43 (d, J = 2.6 Hz, 1 H), 2.89 (s, 6 H), 4.89 (s, 1 H), 6.66 (d, J =
6.6 Hz, 2 H), 7.07–7.26 (m, 6 H) ppm. 13C NMR δ = 21.1, 40.7,
3p: Yield 92% (116 mg). Pale yellow oil. 1H NMR δ = 2.33 (s, 3
H), 2.41 (d, J = 3.0 Hz, 1 H), 3.43 (s, 3 H), 5.02 (d, J = 3.0 Hz, 1
H), 6.05 (m, 2 H), 6.55 (t, J = 2.4 Hz, 1 H), 7.12 (d, J = 8.1 Hz, 2 41.6, 72.1, 85.5, 112.6, 127.5, 128.2, 129.1, 129.1, 136.1, 138.8,
H), 7.23 (d, J = 8.1 Hz, 2 H) ppm. 13C NMR δ = 21.0, 34.1, 35.1,
149.4 ppm. C18H19N (249.35): calcd. C 86.70, H 7.68, N 5.62;
71.9, 83.2, 106.6, 108.4, 122.8, 127.4, 129.2, 130.6, 136.0, found C 86.43, H 7.58, N 5.44.
Eur. J. Org. Chem. 2006, 881–890
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
887

Y. Inada, M. Yoshikawa, M. D. Milton, Y. Nishibayashi, S. Uemura
FULL PAPER
6f: Yield 30% (51 mg). Yellow crystals. H NMR δ = 2.52 (s, 1 H),
1
9.7 Hz, 1 H), 7.86 (d, J = 3.9 Hz, 1 H), 8.31 (dd, J = 5.3 and
2.88 (s, 6 H), 5.09 (s, 1 H), 6.66 (d, J = 8.8 Hz, 2 H), 7.25 (d, J = 9.7 Hz, 2 H) ppm. 13C NMR δ = 35.2, 72.1, 84.7, 117.0, 122.6,
8.8 Hz, 2 H), 7.41–7.88 (m, 7 H) ppm. 13C NMR δ = 40.6, 42.1,
72.7, 85.1, 112.6, 125.6, 125.8, 125.9, 126.1, 127.5, 127.8, 128.2,
128.4, 128.6, 132.3, 133.3, 139.0, 149.5 ppm. HRMS: m/z calcd. for
C21H19N [M] 285.1517; found 285.1516.
123.3, 127.7, 128.6, 128.9, 132.5, 133.4, 134.5, 137.0, 137.2, 137.8,
140.0, 141.4 ppm. C19H13Cl (276.76): calcd. C 82.46, H 4.73; found
C 82.20, H 4.72.
Preparation of [Cp*RuCl(µ2-SMe)2RuCp*(C=C=CHPh)]BF4 (4a):
A typical experimental procedure for the preparation of the title
compound is described below. In a 200-mL flask were placed 1a
(510 mg, 0.80 mmol), NH4BF4 (109 mg, 1.04 mmol) and MgSO4
(1 g) under nitrogen. Anhydrous tetrahydrofuran (THF) (100 mL)
was added, and then the mixture was magnetically stirred at room
temperature. After the addition of 2a (219 mg, 1.66 mmol), the re-
action flask was kept at room temperature for 30 min. Then, the
solvent was removed under reduced pressure, and the residue was
recrystallized from CH2Cl2/diethyl ether to give black crystals of
4a (378 mg, 0.467 mmol; 58%).
1
6g: Yield 23% (36 mg). Reddish brown oil. H NMR δ = 1.13 (t,
J = 7.0 Hz, 6 H), 2.45 (s, 1 H), 3.31 (q, J = 7.0 Hz, 4 H), 4.91 (s,
1 H), 6.61 (d, J = 7.9 Hz, 2 H), 7.16–7.40 (m, 7 H) ppm. 13C NMR
δ = 12.5, 41.9, 44.3, 72.1, 85.4, 111.7, 126.6, 127.7, 128.5, 129.2,
141.8, 146.7 ppm. C19H21N (263.38): calcd. C 86.65, H 8.04, N
5.32; found C 86.62, H 8.24, N 5.14.
1
6h: Yield 49% (87 mg). Pale brown oil. H NMR δ = 2.46 (d, J =
2.6 Hz, 1 H), 3.26 (s, 3 H), 4.95 (s, 1 H), 6.91–7.40 (m, 14 H) ppm.
13C NMR δ = 40.2, 42.2, 72.5, 84.9, 120.1, 120.7, 121.4, 126.9,
127.7, 128.5, 128.6, 129.1, 133.6, 141.3, 147.8, 148.8 ppm. C22H19N
(297.36): calcd. C 88.85, H 6.44, N 4.71; found C 88.75, H 6.56, N
4.59.
4a: Black crystals. 1H NMR δ = 1.66 (s, 15 H), 1.85 (s, 15 H), 2.73
(s, 6 H), 7.39 (t, J = 7.5 Hz, 2 H), 7.66 (t, J = 7.5 Hz, 1 H), 7.72
(d, J = 7.5 Hz, 2 H), 8.89 (s, 1 H) ppm. 13C NMR δ = 10.4, 10.6,
20.1, 99.4, 105.6, 130.2, 132.4, 134.0, 142.6, 151.2, 198.0,
319.7 ppm. IR (KBr): ν = 1945 (C=C=C) cm–1. C H BClF Ru S
1
6i: Yield 63% (107 mg). Red solid; m.p. 57.0–57.8 °C. H NMR δ
= 2.46 (d, J = 2.0 Hz, 1 H), 4.95 (d, J = 2.0 Hz, 1 H), 5.64 (br. s,
1 H), 6.87 (t, J = 7.6 Hz, 2 H), 7.00 (m, 4 H), 7.02–7.26 (m, 5 H),
7.30 (m, 2 H), 7.38 (d, J = 7.6 Hz, 1 H) ppm. 13C NMR δ = 42.1,
72.6, 84.9, 117.7, 117.8, 120.9, 126.9, 127.7, 128.6, 128.6, 129.3,
˜
31 42
4
2 2
(803.19): calcd. C 46.36, H 5.27; found C 46.00, H 5.15.
Reaction of 2a with [D5]Pyrrole in the Presence of 1a and NH4BF4:
In a 20-mL flask were placed 1a (0.03 mmol) and NH4BF4
(0.06 mmol) under nitrogen. Anhydrous ClCH2CH2Cl (18 mL) was
added, and then the mixture was magnetically stirred at room tem-
perature. After the addition of 1a (0.60 mmol) and [D5]pyrrole
(3.00 mmol), the reaction flask was kept at 60 °C for 1 h. The sol-
vent was concentrated under reduced pressure maintained by an
aspirator, and then the residue was purified by TLC (SiO2) with
EtOAc/n-hexane (3:7) to give 2-(1-phenyl-2-propynyl)pyrrole (3lЈ)
as a brown oil (83 mg, 0.46 mmol; 77% yield).
133.5, 141.3, 141.9, 142.9 ppm. IR (neat): ν = 2114 (CϵC), 3289
˜
(ϵC–H), 3399 (N–H) cm–1. C21H17N (283.37): calcd. C 89.01, H
6.05, N 4.94; found C 88.79, H 6.10, N 5.27.
6j and 6k: Yield 60% (93 mg) (a mixture of 6j and 6k was obtained
in a ratio of 1 to 5). Yellow oil. 6k. 1H NMR δ = 2.35 (d, J =
3.0 Hz, 1 H), 4.94 (d, J = 3.0 Hz, 1 H), 6.24 (t, J = 3.0 Hz, 1 H),
6.30 (m, 1 H), 6.73 (t, J = 3.0 Hz, 1 H), 7.11–7.38 (m, 10 H) ppm.
13C NMR δ = 35.3, 71.6, 84.0, 108.1, 108.9, 120.1, 122.8, 126.7,
1
127.4, 128.2, 128.9, 132.1, 139.5, 139.9 ppm. 6j. H NMR δ = 2.41
(d, J = 3.0 Hz, 1 H), 6.22 (m, 1 H), 7.00 (m, 2 H) ppm. C19H15N
(257.33): calcd. C 88.68, H 5.88, N 5.44; found C 88.88, H 5.84, N
5.37.
6l: Yield 48% (71 mg). Green oil. 1H NMR δ = 2.44 (d, J = 2.6 Hz,
1 H), 2.69 (s, 3 H), 2.86 (t, J = 8.1 Hz, 2 H), 3.23 (t, J = 8.1 Hz, 2
H), 4.89 (s, 1 H), 6.38 (d, J = 7.7 Hz, 1 H), 7.04–7.39 (m, 7 H)
ppm. 13C NMR δ = 28.6, 36.2, 42.3, 56.2, 72.2, 85.4, 106.8, 123.7,
126.6, 126.7, 127.6, 128.4, 130.4, 130.9, 141.8, 152.4 ppm. C18H17N
(247.33): calcd. C 87.41, H 6.93, N 5.66; found C 87.31, H 6.98, N
5.65.
6m: Yield 52% (97 mg). Pale yellow oil. 1H NMR δ = 1.85 (s, 3
H), 2.04 (s, 1 H), 3.79 (s, 3 H), 3.85 (s, 3 H), 5.90 (s, 1 H), 6.36 (s,
1 H), 7.24–7.39 (m, 6 H), 7.55 (br. s, 1 H) ppm. 13C NMR δ =
24.2, 30.2, 55.4, 56.0, 72.7, 83.1, 95.4, 100.6, 111.3, 126.4, 126.8,
128.5, 137.6, 138.5, 156.9, 159.8, 167.8 ppm. C19H19NO3 (309.36):
calcd. C 73.77, H 6.19, N 4.53; found C 73.55, H 6.27, N 4.46.
2-(1-Phenyl-2-propynyl)pyrrole (3lЈ): Brown oil. 1H NMR (CDCl3):
δ = 2.45 (d, J = 2.4 Hz, 0.20 H), 5.06 (d, J = 2.4 Hz, 1 H), 7.21–
7.39 (m, 5 H), 8.11 (s, 1 H) ppm. IR (neat): ν = 2585 (ϵC–D), 3428
˜
(N–H) cm–1. This result indicates the 80% deuterium content at
the C-3 position.
Ruthenium-Catalyzed Intramolecular Cyclization Reactions of Pro-
pargylic Alcohols: A typical experimental procedure for the intra-
molecular cyclization reaction of 7a catalyzed by [Cp*RuCl(µ2-
SMe)2RuCp*Cl] (1a) is described below. In a 50-mL flask were
placed 1a (19 mg, 0.03 mmol) and NH4BF4 (6 mg, 0.06 mmol) un-
der nitrogen. Anhydrous ClCH2CH2Cl (30 mL) was added, and
then the mixture was magnetically stirred at room temperature. Af-
ter the addition of 7a (136.8 mg, 0.6 mmol), the reaction flask was
kept at 60 °C for 24 h. The solvent was concentrated under reduced
pressure maintained by an aspirator, and then the residue was puri-
fied by TLC (SiO2) with EtOAc/n-hexane (1:9) to give 4-ethynyl-
4,10-dihydro-3,9-dioxabenzo[f]azulene (8a) as a pale yellow oil
(102.9 mg, 0.49 mmol; 82% yield).
4-Ethynyl-4,10-dihydro-3,9-dioxabenzo[f]azulene (8a): 1H NMR δ =
2.52 (t, J = 1.5 Hz, 1 H), 4.90 (t, J = 15.6 Hz, 2 H), 5.23 (s, 1 H),
6.10 (d, J = 1.5 Hz, 1 H), 7.10–7.21 (m, 2 H), 7.25–7.31 (m, 2 H),
7.47 (d, J = 7.5 Hz, 1 H) ppm. 13C NMR δ = 33.5, 69.2, 73.0,
80.2, 108.8, 117.4, 122.8, 124.8, 127.7, 129.3, 132.9, 141.1, 145.2,
157.3 ppm. HRMS: m/z calcd. for C14H10O2 [M] 210.0681; found
210.0680.
1
6n: Yield 38% (64 mg). Pale yellow oil. H NMR δ = 2.26 (dd, J
= 1.3 and 2.6 Hz, 1 H), 3.73 (s, 6 H), 3.78 (s, 3 H), 5.69 (s, 1 H),
6.13 (s, 2 H), 7.15 (d, J = 7.3 Hz, 1 H), 7.23 (t, J = 7.3 Hz, 2 H),
7.43 (d, J = 7.3 Hz, 2 H) ppm. 13C NMR δ = 30.5, 55.3, 55.9,
68.9, 84.8, 91.5, 110.8, 125.8, 127.1, 127.7, 140.9, 158.5, 160.4 ppm.
C18H18O3 (282.33): calcd. C 76.57, H 6.43; found C 76.48, H 6.44.
6o: Yield 87% (126 mg). Blue solid. 1H NMR δ = 2.45 (s, 1 H),
5.66 (s, 1 H), 7.03–8.33 (m, 12 H) ppm. 13C NMR δ = 35.8, 71.7,
85.2, 116.9, 122.4, 123.0, 126.7, 127.5, 128.5, 133.5, 134.5, 137.1,
137.6, 141.3 ppm. C19H14 (242.31): calcd. C 94.18, H 5.82; found
C 94.31, H 5.74.
4-Ethynyl-6-methyl-4,10-dihydro-3,9-dioxabenzo[f]azulene
Yield 63% (85 mg). Yellow oil. H NMR δ = 2.31(s, 3 H), 2.52 (d,
(8b):
1
6p: Yield 81% (135 mg). Blue oil. 1H NMR δ = 2.48 (d, J = 2.6 Hz, J = 2.7 Hz, 1 H), 4.87 (q, J = 14.7 Hz, 2 H), 5.18 (s, 1 H), 6.10 (d,
1 H), 5.64 (d, J = 2.6 Hz, 1 H), 7.11–7.35 (m, 7 H), 7.59 (t, J =
J = 2.7 Hz, 1 H), 7.06 (s, 2 H), 7.27 (t, J = 2.7 Hz, 2 H) ppm. 13C
888
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2006, 881–890

Ru-Catalyzed Propargylation of Aromatic Compounds with Propargylic Alcohols
NMR δ = 20.8, 33.6, 69.2, 72.9, 80.4, 108.8, 117.5, 122.5, 128.2, 126.2, 128.7, 131.4, 137.4, 155.4, 156.3, 160.1 ppm. C18H15ClO3
FULL PAPER
129.7, 132.4, 134.4, 141.1, 145.4, 155.0 ppm. HRMS: m/z calcd. for
(314.76): calcd. C 68.68, H 4.80; found C 68.50, H 4.83.
C15H12O2 [M] 224.0837; found 224.0836.
13-Ethynyl-10,12-dimethoxy-8,13-dihydrobenzo[e]-naphtho[1,2-b]oxe-
6-Chloro-4-ethynyl-4,10-dihydro-3,9-dioxabenzo[f]azulene
(8c): pine (10d): Yield 34% (67 mg). White solid; m.p. 175.1–176.3 °C.
1
Yield 40% (59 mg). Yellow solid; m.p. 65.8–66.8 °C. H NMR δ =
2.58 (d, J = 2.4 Hz, 1 H), 4.88 (dq, J = 1.8 and 14.7 Hz, 2 H), 5.26
(s, 1 H), 6.12 (d, J = 1.8 Hz, 1 H), 7.10 (d, J = 8.4 Hz, 1 H), 7.23–
7.31 (m, 2 H), 7.50 (d, J = 2.4 Hz, 1 H) ppm. 13C NMR δ = 33.2,
69.4, 73.9, 79.1, 108.8, 117.2, 124.1, 127.6, 129.2, 129.9, 134.6,
1H NMR δ = 2.32 (d, J = 2.8 Hz, 1 H), 3.82 (d, J = 5.6 Hz, 6 H),
4.85 (d, J = 12.8 Hz, 1 H), 6.24 (d, J = 12.8 Hz, 1 H), 6.31 (d, J =
2.8 Hz, 1 H), 6.47 (d, J = 2.4 Hz, 1 H), 6.52 (d, J = 2.4 Hz, 1 H),
7.02 (d, J = 8.8 Hz, 1 H), 7.36 (t, J = 7.2 Hz, 1 H), 7.58–7.63 (m,
2 H), 7.72 (d, J = 8.4 Hz, 1 H), 8.29 (d, J = 8.4 Hz, 1 H) ppm. 13C
141.4, 144.5, 155.8 ppm. C14H9ClO2 (244.67): calcd. C 68.72, H NMR δ = 24.8, 55.4, 56.0, 70.0, 70.8, 86.1, 98.6, 105.0, 116.1, 119.1,
3.71; found C 68.47, H 4.00.
121.9, 122.6, 123.5, 126.9, 128.4, 129.3, 129.8, 133.3, 138.6, 155.2,
156.6, 160.0 ppm.
4-Ethynyl-8-methyl-4,10-dihydro-3,9-dioxabenzo[f]azulene
Yield 72% (97 mg). Yellow oil. H NMR δ = 2.33 (s, 3 H), 2.50 (d, X-ray Crystallographic Studies of 6n and 10c: Colorless crystals
(8d):
1
J = 2.8 Hz, 1 H), 4.85 (q, J = 14.8 Hz, 2 H), 5.18 (s, 1 H), 6.10 (d,
J = 2.8 Hz, 1 H), 6.99 (t, J = 7.6 Hz, 1 H), 7.14 (d, J = 7.6 Hz, 1
H), 7.27 (d, J = 7.6 Hz, 2 H) ppm. 13C NMR δ = 15.8, 33.6, 67.5,
72.6, 80.5, 108.7, 117.4, 117.5, 124.4, 125.3, 130.7, 131.6, 132.9,
suitable for X-ray analysis were obtained by recrystallization from
CH2Cl2/n-hexane. CCDC-196412 (6n) and CCDC-288345 (10c)
contain the supplementary crystallographic data for these crystals.
These data can be obtained free of charge from The Cambridge
140.9, 145.5, 154.9 ppm. HRMS: m/z calcd. for C15H12O2 [M] Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_requ-
224.0837; found 224.0833.
est/cif.data_request/cif.
4-Ethynyl-8-methoxy-4,10-dihydro-3,9-dioxabenzo[f]azulene
(8e): Supporting Information (see footnote on the first page of this arti-
1
Yield 56% (81 mg). Yellow solid; m.p. 114.8–116.0 °C. H NMR δ
= 2.44 (d, J = 2.7 Hz, 1 H), 3.79 (t, J = 15.4 Hz, 3 H), 4.83 (d, J
= 14.7 Hz, 2 H), 5.21 (s, 1 H), 6.04 (s, 1 H), 6.82 (d, J = 7.2 Hz, 1
H), 6.96 (m, 2 H), 7.20 (s, 1 H) ppm. 13C NMR δ = 33.4, 55.9,
68.2, 73.0, 79.9, 108.8, 112.0, 117.5, 119.1, 124.9, 134.7, 141.0,
145.2, 145.5, 152.8 ppm. HRMS: m/z calcd. for C15H12O3 [M]
240.0786; found 240.0781.
cle): 13C NMR spectra of 8a, 8b, 8d, 8e, 8f, 10a, 10b, and 10d.
Acknowledgments
This work was supported by a Grant-in-Aid for Scientific Research
for Young Scientists (A) (No.15685006) to Y.N. from the Ministry
of Education, Culture, Sports, Science, and Technology, Japan. Y.I.
is a recipient of the JSPS Predoctoral Fellowships for Young Scien-
tists.
7-Ethynyl-7,11-dihydro-8,12-dioxanaphtho[2,1-f]azulene (8f): Yield
68% (106 mg). Orange solid; m.p. 120.0–121.2 °C. 1H NMR δ =
2.51 (d, J = 2.7 Hz, 1 H), 4.96 (q, J = 15.8 Hz, 2 H), 5.25 (s, 1 H),
6.04 (t, J = 15.8 Hz, 1 H), 7.28 (d, J = 1.5 Hz, 1 H), 7.41–7.59 (m,
4 H), 7.77 (d, J = 7.8 Hz, 1 H), 8.22 (d, J = 7.8 Hz, 1 H) ppm. 13C
NMR 33.8, 68.3, 72.7, 80.6, 108.8, 118.0, 121.8, 124.4, 125.4, 126.3,
127.8, 128.2, 128.3, 134.4, 141.1, 145.4, 152.4 ppm. HRMS: m/z
calcd. for C18H12O2 [M] 260.0837; found 260.0841.
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aromatic compounds with propargylic alcohols bearing an in-
ternal alkyne moiety can be promoted by cationic thiolate-
bridged diruthenium complexes, where the reaction mechanism
of the propargylation is considered to be quite different from
that of the present reaction described in this paper[7b] As a
consequence, the details of the result will be reported in due
11-Ethynyl-8,10-dimethoxy-6,11-dihydrodibenzo[b,e]oxepine (10a):
1
Yield 16% (27 mg). Yellow solid; m.p. 135.5–137.0 °C. H NMR δ
= 2.37 (d, J = 2.7 Hz, 1 H), 3.80 (d, J = 14.1 Hz, 6 H), 4.77 (d, J
= 12.9 Hz, 1 H), 5.47 (d, J = 2.7 Hz, 1 H), 6.17 (d, J = 12.9 Hz, 1
H), 6.45 (d, J = 2.7 Hz, 2 H), 6.84 (q, J = 7.8 Hz, 2 H), 7.11 (t, J
= 7.8 Hz, 1 H), 7.23 (m, 1 H) ppm. 13C NMR δ = 30.9, 55.4, 55.9,
70.5, 70.9, 86.2, 98.6, 105.5, 120.5, 121.6, 125.1, 128.9, 132.0, 137.9,
156.5, 156.9, 160.0 ppm. HRMS: m/z calcd. for C18H16O3 [M]
280.1099; found 280.1097.
11-Ethynyl-2,8,10-trimethoxy-6,11-dihydrodibenzo[b,e]oxepine
(10b): Yield 19% (35 mg). White solid; m.p. 140.2–141.6 °C. 1H
NMR δ = 2.27 (d, J = 3.0 Hz, 1 H), 3.68 (d, J = 7.8 Hz, 6 H), 3.77
(s, 3 H), 4.68 (d, J = 13.4 Hz, 1 H), 5.33 (d, J = 3.0 Hz, 1 H), 5.90
(d, J = 13.4 Hz, 1 H), 6.32 (d, J = 3.0 and 13.0 Hz, 2 H), 6.62 (m,
3 H) ppm. 13C NMR δ = 31.2, 55.4, 55.8, 56.1, 70.5, 71.2, 86.0,
98.4, 104.9, 114.8, 116.0, 116.4, 118.8, 121.4, 126.9, 138.2, 151.0,
154.2, 156.6, 159.9 ppm. HRMS: m/z calcd. for C19H18O4 [M]
310.1205; found 310.1205.
2-Chloro-11-ethynyl-8,10-dimethoxy-6,11-dihydrodibenzo[b,e]oxep-
ine (10c): Yield 21% (40 mg). White crystals, m.p. 149.8–150.8 °C.
1H NMR δ = 2.31 (d, J = 2.4 Hz, 1 H), 3.73 (d, J = 16.0 Hz, 6 H),
4.69 (d, J = 13.2 Hz, 1 H), 5.33 (d, J = 2.4 Hz, 1 H), 6.10 (d, J =
13.2 Hz, 1 H), 6.38 (s, 2 H), 6.69 (d, J = 8.4 Hz, 1 H), 6.99 (dd, J
= 2.4 and 8.4 Hz, 1 H), 7.16 (d, J = 2.4 Hz, 1 H) ppm. 13C NMR
δ = 30.6, 55.4, 55.9, 70.5, 71.4, 85.5, 98.7, 105.6, 118.8, 121.9, 125.8,
Eur. J. Org. Chem. 2006, 881–890
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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889

Y. Inada, M. Yoshikawa, M. D. Milton, Y. Nishibayashi, S. Uemura
FULL PAPER
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catalyzed by transition-metal complexes has been reported by
several groups: a) Rhenium-catalyzed propargylation with pro-
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E. Bustelo, P. H. Dixneuf, Adv. Synth. Catal. 2005, 347, 393; c)
Gold-catalyzed propargylation of aromatic compounds such as
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bearing an internal alkyne moiety has been reported: M.
Georgy, V. Boucard, J.-M. Campagne, J. Am. Chem. Soc. 2005,
127, 14180.
Received: November 3, 2005
Published Online: January 5, 2006
890
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2006, 881–890