Indenyl-ruthenium(II) allenylidene complexes containing terpenic substituents as precursors of optically active terminal alkynes: Scope and limitations

Article abstract of DOI:10.1039/b305608b

The optically active allenylidene complex Ru{=C=C=C(C₉H ₁₆)}(η⁵-C₉H₇)(PPh ₃)₂][PF₆] C(C₉H₁₆) = (1R,4S)-1,3,3-trimethyl-bicyclo[2.2.1]hept-2-ylide

Full text of DOI:10.1039/b305608b

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Indenyl–ruthenium(II) allenylidene complexes containing terpenic
substituents as precursors of optically active terminal alkynes:
scope and limitations†
Victorio Cadierno, Salvador Conejero, M. Pilar Gamasa and José Gimeno*
Departamento de Química Orgánica e Inorgánica,
Instituto Universitario de Química Organometálica “Enrique Moles”
(Unidad Asociada al CSIC), Facultad de Química, Universidad de Oviedo, E-33071 Oviedo,
Spain. E-mail: jgh@sauron.quimica.uniovi.es
Received 19th May 2003, Accepted 17th June 2003
First published as an Advance Article on the web 3rd July 2003
The optically active allenylidene complex [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ][PF ] (C(C H ) = (1R,4S)-1,3,3-
᎐ ᎐ ᎐
9
16
9
7
3
2
6
9
16
trimethyl-bicyclo[2.2.1]hept-2-ylidene) 1 regio- and stereoselectively reacts with unhindered anionic nucleophiles to
5
᎐
᎐
᎐
yield the neutral σ-alkynyl derivatives [Ru{C᎐CC(C H )R}(η -C H )(PPh ) ] (R = H 2a, C᎐N 2b, Me 2c, C᎐CPh 2d).
᎐
᎐
᎐
9
16
9
7
3 2
Protonation of 2a–d with HBF ؒEt O affords the cationic vinylidene complexes [Ru{᎐C᎐C(H)C(C H )R}(η5-C H )-
᎐ ᎐
4
2
9
16
9
7
(PPh3)2][BF4] 3a–d, which can be easily demetalated, by treatment with acetonitrile, yielding the corresponding
᎐
chiral acetylenic compounds HC᎐C(C H )R 4a–d. The novel optically active indenyl–ruthenium() allenylidene
᎐
9
16
complexes [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ][PF ] (C(C H ) = (1R,4R)-1,7,7-trimethyl-bicyclo[2.2.1]hept-2-
᎐ ᎐ ᎐
9
16
9
7
3
2
6
9
16
ylidene) 9 and [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ][PF ] (C(C H ) = (1S,5S)-4,6,6-trimethyl-bicyclo[3.1.1]hept-3-
᎐ ᎐ ᎐
9
14
9
7
3
2
6
9
14
en-2-ylidene) 10 have been prepared by activation of propargylic alcohols derived from the natural ketones (ϩ)-
camphor and (Ϫ)-verbenone, respectively, with [RuCl(η5-C9H7)(PPh3)2] 6. Treatment of 9 with anionic nucleophiles
5
᎐
generates the neutral σ-enynyl complex [Ru{C᎐CC(C H )}(η -C H )(PPh ) ] 11 (C(C H ) = (1R,4R)-1,7,7-trimethyl-
᎐
9
15
9
7
3
2
9
15
bicyclo[2.2.1]hept-2-en-2-yl).
Introduction
Since the discovery of the first allenylidene complex in 1976,1
the chemistry of these unsaturated species has been the topic
in several research groups due to their great potential in
stoichiometric2 and catalytic processes.3–6 In fact, cationic tran-
sition-metal allenylidene derivatives [M]ϩ᎐C᎐C᎐CR1R2, readily
᎐ ᎐ ᎐
available by dehydration of propargylic alcohols upon co-
ordination to an unsaturated metal center,7 can be regarded as
stabilized propargyl cations because of the extensive contri-
᎐
bution of the metal–alkynyl resonance form [M]–C᎐C–
᎐
CϩR1R2.8 Although the reactivity of cationic allenylidenes is
governed by the electron-deficiency of both the Cα and Cγ
atoms of the unsaturated chain,9 it is now well-established that
nucleophilic additions at Cγ regioselectively occur when elec-
tron-rich and/or bulky metallic fragments are used, leading to a
Chart 1 [Ru(η5-C9H7)(PPh3)2]ϩ-mediated propargylic substitutions.
Nicholas reaction in which the metal auxiliary can not be
recovered after the oxidative decomplexation step.
1
2 2
᎐
The efficient access to acetylenes D, prompted us to study the
asymmetric version of our synthetic protocol in order to obtain
novel optically active terminal alkynes. To achieve this, two
different strategies have been developed: (i) the use of chiral
nucleophiles,11d,f and (ii) the use of allenylidene derivatives
bearing chiral auxiliaries.11c,d,e,14 In particular, concerning
the latter strategy, we have recently synthesized the indenyl–
large variety of σ-alkynyl complexes [M]–C᎐C–C(Nu)R R .
᎐
In the context of our studies in the chemistry of indenyl–
ruthenium() complexes,10 and based on these regioselective
nucleophilic attacks, we have developed an efficient synthetic
procedure for the propargylic substitution of 2-propyn-1-ols
mediated by the metallic fragment [Ru(η5-C9H7)(PPh3)2]ϩ
(Chart 1).11 Thus, in a first step allenylidene complexes A are
formed and subsequently transformed into the corresponding
σ-alkynyl derivatives B which undergo a selective Cβ proton-
ation to afford the vinylidene complexes C.12 Finally, demetal-
ation of C with acetonitrile leads to the functionalized terminal
alkynes D in excellent yields.
ruthenium() allenylidene complex [Ru{᎐C᎐C᎐C(C H )}-
᎐ ᎐ ᎐
9
16
(η5-C9H7)(PPh3)2][PF6] (C(C9H16) = (1R,4S)-1,3,3-trimethyl-
bicyclo[2.2.1]hept-2-ylidene) 1, which incorporates a chiral
bicyclic substituent derived from the natural source (Ϫ)-fen-
chone (Chart 2).11c
This system has demonstrated to be a useful chiral inductor,
since the nucleophilic addition of lithium enolates and allyl-
magnesium bromide was found to take place diastereo-
selectively on the less sterically congested exo face of the
allenylidene chain, giving rise to the high-yield synthesis of
optically active γ-keto acetylenes E and the 1,5-enyne F,
respectively (see Chart 2).11c,d,e
This synthetic methodology constitutes an alternative to the
well-known Nicholas reaction in which propargylic alcohols
are easily functionalized via [Co2(CO)6]-stabilized propargyl
cations.13 Although both synthetic procedures require the same
number of steps, the quantitative recovery of the metal frag-
5
ϩ
᎐
ment as the solvato complex [Ru(N᎐CMe)(η -C H )(PPh ) ]
᎐
9
7
3 2
represents a major advantage compared to the classical
In order to evaluate the scope of this stereoselective synthetic
approach to the preparation of novel optically pure terminal
† Part of this work was presented at the 20th International Conference
on Organometallic Chemistry held in Corfu, Greece on 7–12 July 2002:
see ref. 22.
alkynes, in this paper we report on the reactivity of [Ru{᎐C᎐
᎐ ᎐
C᎐C(C H )}(η5-C H )(PPh ) ][PF ] 1 towards a series of
᎐
9
16
9
7
3
2
6
D a l t o n T r a n s . , 2 0 0 3 , 3 0 6 0 – 3 0 6 6
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
3060

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᎐
4b, Me 4c, C᎐CPh 4d) using our two-step method proceeds
᎐
cleanly and efficiently (see Scheme 1). Thus, the cationic vinyl-
idene derivatives [Ru{᎐C᎐C(H)C(C H )R}(η5-C H )(PPh ) ]-
᎐ ᎐
9
16
9
7
3 2
᎐
᎐
[BF ] (R = H 3a, C᎐N 3b, Me 3c, C᎐CPh 3d) were initially
᎐
᎐
4
prepared (78–92% yield) by selective protonation of 2a–d with
HBF4 in diethyl ether at Ϫ20 ЊC.12 Analytical and spectroscopic
data are in agreement with the proposed formulations (see the
Experimental section for details). Relevant spectroscopic
features are: (i) (1H NMR) the doublet (3a; 3J(HH) = 10.5 Hz)
or singlet (3b–d) signal for the acidic Ru᎐C᎐CH proton
᎐ ᎐
(δH 3.88–4.08), and (ii) (13C-{1H} NMR) the typical low-field
resonance of the carbenic Ru᎐C carbon, which appears as a
᎐
α
doublet of doublets (2J(CP) = 15.3–17.7 Hz) at δC 342.03–
347.75, as well as the Cβ singlet signal (δC 108.34–116.84). In a
second step vinylidenes 3a–d were treated with acetonitrile at
Chart 2 Structure of the optically active compounds 1, E and F.
unhindered anionic nucleophiles. In addition, the synthesis and
reactivity of two new chiral indenyl–ruthenium() allenylidene
complexes derived from the commercially available ketones
(ϩ)-camphor and (Ϫ)-verbenone is also reported.
room temperature, affording the novel optically active terminal
᎐
alkynes 4a–d and the cationic nitrile complex [Ru(N᎐CMe)-
᎐
(η5-C9H7)(PPh3)2][BF4] 5 (see Scheme 1). Alkynes 4b–d have
been easily isolated from the reaction mixture by filtering off
the unsoluble solvate 5 (77–89% yield). In contrast, due to its
low boiling point, alkyne 4a could not be isolated being instead
characterized in situ by NMR spectroscopy. Characteristic
spectroscopic data for 4a–d are: (i) (1H NMR) the doublet (4a;
4J(HH) = 2.4 Hz) or singlet (4b–d) resonance for the acetylenic
Results and discussion
Synthesis and characterization of the optically active terminal
᎐
᎐
᎐
alkynes HC᎐CC(C H )R (R ؍ H 4a, C᎐N 4b, Me 4c, C᎐CPh
᎐
᎐
᎐
9
16
4d)
᎐CH proton at δ 1.91–2.35, (ii) (13C-{1H} NMR) the typical
᎐
᎐
H
As expected from our previous studies,11c,d,e the allenylidene
᎐
signals for the HC᎐C carbons which appear in the ranges
᎐
complex [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ][PF ] 1 reacts
71.95–75.47 and 78.55–89.35 ppm, respectively, and (iii) (IR)
᎐ ᎐ ᎐
9
16
9
7
3
2
6
᎐
᎐
᎐
the stretching ν(᎐C–H) and ν(C᎐C) absorption bands at 3251–
with a slight excess (ca. 1.1 equiv.) of LiHBEt , NaC᎐N, LiMe
or LiC᎐CPh, in tetrahydrofuran at Ϫ20 ЊC, to afford the neutral
᎐
᎐
᎐
3
3324 and 2070–2111 cmϪ1, respectively.
᎐
᎐
5
᎐
σ-alkynyl derivatives [Ru{C᎐CC(C H )R}(η -C H )(PPh ) ]
᎐
9
16
9
7
3 2
᎐
᎐
Synthesis and reactivity of novel optically active indenyl–
ruthenium(II) allenylidene complexes
(R = H 2a, C᎐N 2b, Me 2c, C᎐CPh 2d), resulting from the
᎐
᎐
regioselective addition of the nucleophile at the Cγ atom of
the cumulenic chain (75–91% yield; Scheme 1).
The high diastereoselectivity observed in the nucleophilic addi-
tions on complex 1 prompted us to prepare novel indenyl–
ruthenium() allenylidene derivatives containing optically
active substituents. To this regard the chemical behaviour of the
chloride complex [RuCl(η5-C9H7)(PPh3)2] 615 towards propar-
gylic alcohols derived from the commercially available and
optically pure ketones (ϩ)-camphor and (Ϫ)-verbenone, i.e.
(1R,2S,4R)-2-ethynyl-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-ol
7 and (1S,2R,5S)-2-ethynyl-4,6,6-trimethyl-bicyclo[3.1.1]hept-
3-en-2-ol 8 (see Scheme 2),16,17 has been explored. Thus, follow-
ing the standard Selegue synthetic procedure,7 the chiral allenyl-
idene derivatives [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ][PF ]
᎐ ᎐ ᎐
9
16
9
7
3
2
6
(C(C9H16)
idene)
=
(1R,4R)-1,7,7-trimethyl-bicyclo[2.2.1]hept-2-yl-
9
and [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ][PF ]
᎐ ᎐ ᎐
9
14
9
7
3
2
6
(C(C9H14) = (1S,5S)-4,6,6-trimethyl-bicyclo[3.1.1]hept-3-en-2-
ylidene) 10 have been prepared by reaction of 6 with propar-
gylic alcohols 7 and 8, respectively, in refluxing methanol and in
the presence of NaPF6 (Scheme 2).
Scheme 1 Synthetic procedure used in the preparation of the optically
active terminal alkynes 4a–d.
Allenylidene complexes 9 and 10 have been isolated as
air-stable red solids in 80 and 75% yields, respectively. Their
Complexes 2a–d have been analytically and spectroscopically
characterized (IR and 31P-{1H}, 1H and 13C-{1H} NMR; see the
Experimental section for details). In particular, the formation
of an alkynyl chain was identified on the basis of: (i) (IR) the
᎐
presence of a typical ν(C᎐C) absorption band at 2069–
᎐
2089 cmϪ1, and (ii) (13C-{1H} NMR) characteristic resonances
᎐
for the Ru–C ᎐C –C carbon nuclei (δC 90.64–102.45 (dd,
᎐
α
β
γ
ca. 2J(CP) = 23 Hz, Cα), 107.14–116.40 (s, Cβ) and 53.46–
56.09 (s, Cγ)). Remarkably, these nucleophilic attacks proceed
also in a diastereoselective manner since only one diastereo-
isomer was detected by NMR spectroscopy. By analogy with
our previous reports,11c,d,e an exo addition of the incom-
ing nucleophiles to the allenylidene chain in 1 is proposed.
These results confirm that the bicyclic (1R,4S)-1,3,3-trimethyl-
bicyclo[2.2.1]hept-2-ylidene unit is an excellent chiral inductor,
even when small nucleophiles are employed.
Transformation of σ-alkynyl complexes 2a–d into the corre-
Scheme 2 Synthesis of the optically active indenyl–ruthenium()
allenylidene complexes 9 and 10.
᎐
᎐
sponding terminal alkynes HC᎐CC(C H )R (R = H 4a, C᎐N
᎐
᎐
9
16
D a l t o n T r a n s . , 2 0 0 3 , 3 0 6 0 – 3 0 6 6
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spectroscopic data are in agreement with the presence of an
allenylidene chain and can be compared to those previously
reported for other indenyl–ruthenium() allenylidene com-
plexes [Ru(᎐C᎐C᎐CR1R2)(η5-C H )(PPh ) ][PF ].9c,18 Thus, the
᎐ ᎐ ᎐
9
7
3
2
6
IR spectra (KBr) exhibit a broad and strong ν(C᎐C᎐C) absorp-
᎐ ᎐
tion band (asymmetric stretching vibration) at ca. 1960 cmϪ1
and the 13C-{1H} NMR spectra display the characteristic low-
Scheme 3 Synthesis of the optically active σ–enynyl complex 11.
field resonance for the carbenic Ru᎐C atom (δ 305.06 (9) and
᎐
α
C
280.16 (10); dd signal, 2J(CP) = 18.9–20.2 Hz). The spectra also
show two singlet signals in the range 174.75–202.21 ppm corre-
sponding to the β- and γ-carbon nuclei of the cumulenic chain.
The selective synthesis of allenylidenes 9 and 10 from prop-
argylic alcohols 7 and 8 is noteworthy since the competitive
formation of their vinylvinylidene tautomers is not observed.
As it is well-known,2 dehydration of coordinated 2-propyn-1-ol
derivatives containing hydrogen atoms adjacent to the hydroxy
group can also occur giving rise to vinylvinylidene derivatives G
(see Chart 3). Indeed, this is the main drawback of the Selegue
protocol for the synthesis of transition-metal allenylidenes.
Thus, we have reported that activation of such type of propar-
gylic alcohols by [RuCl(η5-C9H7)(PPh3)2] 6 leads preferentially
to the corresponding vinylvinylidene isomers.19 Ab initio theor-
etical calculations are consistent with this behaviour, disclosing
that the vinylvinylidene model [Ru{᎐C᎐C(H)CH᎐CH }(η5-C -
the Experimental section). In particular, the presence of a
σ-enynyl moiety was identified on the basis of: (i) (IR) the
Ϫ1
1
᎐
expected ν(C᎐C) absorption band at 2060 cm , (ii) ( H NMR)
᎐
the appearance of a doublet signal (3J(HH) = 3.3 Hz) at δH 5.94
assignable to the endocyclic olefinic proton, and (iii) (13C-{1H}
NMR) typical resonances for the Ru–Cα and Cβ carbon atoms,
which appear at δC 113.14 (dd, 2J(CP) = 25.1 Hz) and 110.21 (s),
respectively.
The formation of σ-enynyl complex 11 most probably
involves an initial isomerization of 9 into its vinylvinylidene
tautomer H (Fig. 1), followed by the classical deprotonation of
the acidic [Ru]᎐C᎐CH proton in the presence of base.12,19b
᎐ ᎐
However, the direct deprotonation of one of the methylenic
protons in the δ position of allenylidene 9 cannot be totally
discarded.2 Remarkably, treatment of 11 with HBF4 regenerates
quantitatively the allenylidene derivative 9, confirming the
higher thermodynamic stability of 9 vs. H. Assuming that vinyl-
idene H is the first product formed in this protonation process,21
the final isolation of 9 clearly confirms that vinylvinylidene–
allenylidene tautomerizations can easily occur in solution.19b
᎐ ᎐
᎐
2
5
H5)(PH3)2]ϩ is ca. 2.1 kcal molϪ1 more stable than its allenyl-
idene tautomer [Ru{᎐C᎐C᎐C(H)CH }(η5-C H )(PH ) ]ϩ.19b
᎐ ᎐ ᎐
3
5
5
3 2
The experimental formation of the allenylidenes 9 and 10 vs.
the expected vinylvinylidene isomers (according the calcu-
lations) stems from the higher strain energy shown by the endo-
cyclic cycloalkene units of the latter. The relief of this energy by
the adoption of the less strained exocyclic counterparts is likely
the driving force which leads to the selective formation of the
allenylidenes.
Fig. 1 Structure of the vinylvinylidene complex H.
Conclusions
In this work we report further applications of the synthetic
protocol developed in our group (Chart 1),11 which allows the
preparation of the novel functionalized terminal alkynes 4a–d
in optically pure form. They have been obtained via regio- and
diastereoselective nucleophilic additions at Cγ of the chiral
Chart 3 Competitive allenylidene vs. vinylvinylidene formation.
allenylidene complex [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ]-
᎐ ᎐ ᎐
9
16
9
7
3 2
In order to asses the capacity of the chiral bicyclic units in
complexes 9 and 10 to induce stereoselective nucleophilic addi-
tions at Cγ, their reactivity towards anionic nucleophiles has
been studied. Thus, we have found that the treatment of allenyl-
[PF6] (C(C9H16) = (1R,4S)-1,3,3-trimethyl-bicyclo[2.2.1]hept-2-
ylidene) 1 (Scheme 1). These results show the excellent chiral
induction of the bicyclic C(C9H16) moiety even when small
nucleophiles are used. In contrast, the treatment of the analo-
gous allenylidene complex [Ru{᎐C᎐C᎐C(C H )}(η5-C H )-
᎐
idene 9 with ca. 1.1 equiv. of LiHBEt , NaC᎐N, LiMe or
᎐
᎐ ᎐ ᎐
3
9
16
9
7
᎐
LiC᎐CPh, in THF at Ϫ20 ЊC, generates the σ-enynyl derivative
(PPh3)2][PF6](C(C9H16)=(1R,4R)-1,7,7-trimethyl-bicyclo[2.2.1]-
hept-2-ylidene) 9, bearing methylenic hydrogen atoms at Cδ,
with anionic nucleophiles leads to a deprotonation process
᎐
5
᎐
[Ru{C᎐CC(C H )}(η -C H )(PPh ) ] 11 (C(C H ) = (1R,4R)-
᎐
9
15
9
7
3
2
9
15
1,7,7-trimethyl-bicyclo[2.2.1]hept-2-en-2-yl), resulting from
the formal deprotonation of the methylenic Cδ atom of
the (1R,4R)-1,7,7-trimethyl-bicyclo[2.2.1]hept-2-ylidene unit.
5
᎐
affording the σ-enynyl derivative [Ru{C᎐CC(C H )}(η -C H )-
᎐
9
15
9
7
(PPh3)2] 11 (Scheme 3). This behaviour is in accord with the
NMR spectra of the crude reaction mixtures show no reson-
competitive tautomerization of allenylidene–vinylvinylidene
᎐
ances of the expected σ-alkynyl species [Ru{C᎐CC(C H )-
that enables the deprotonation of the [Ru]᎐C᎐CH moiety in the
᎐
᎐ ᎐
9
16
R}(η5-C9H7)(PPh3)2]. Complex 11 can be also prepared (87%
yield) by reaction of 9 with typical bases such as KOtBu
(Scheme 3).
latter tautomer due to the basic properties of the nucleophiles.
Moreover, we have found that the presence of an endocyclic
C᎐C bond on the chiral unit of the allenylidene chain, i.e. com-
᎐
Although addition products have been observed after the
treatment of allenylidene 10 with anionic nucleophiles, the reac-
tions lead to unseparable mixtures of complexes. Two competi-
tive processes, i.e. nucleophilic addition at Cγ vs. nucleophilic
addition at the endocyclic carbon–carbon double bond,20 may
be operative.
plex [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ][PF ] (C(C H ) =
᎐ ᎐ ᎐
9
14
9
7
3
2
6
9
14
(1S,5S)-4,6,6-trimethyl-bicyclo[3.1.1]hept-3-en-2-ylidene) 10,
leads to competitive nucleophilic addition at Cγ vs. endocyclic
olefin. These facts limit the scope of our synthetic methodology
of optically active terminal alkynes. In summary, the results
reported here provide an extension of our previous studies
directed to the application of ruthenium()–allenylidene
complexes in stereoselective organic synthesis.
Analytical and spectroscopic data (IR and 31P-{1H}, 1H and
13C-{1H} NMR) of 11 support the proposed formulation (see
D a l t o n T r a n s . , 2 0 0 3 , 3 0 6 0 – 3 0 6 6
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30.28 (s, CH3), 26.18, 29.47 and 42.00 (s, CH2), 43.63 (s, C),
48.70 (s, CH), 55.04 (s, C and Cγ), 73.88 (s, C-1 and C-3), 93.90
Experimental
General comments
(s, C-2), 102.45 (br, Ru–Cα), 108.92 and 109.38 (s, C-3a, C-7a
᎐
and C ), 121.61 (s, C᎐N), 122.26, 122.95, 125.26 and 126.02 (s,
᎐
β
The manipulations were performed under an atmosphere of
dry nitrogen using vacuum-line and standard Schlenk tech-
niques. All reagents were obtained from commercial suppliers
and used without further purification. Solvents were dried
by standard methods and distilled under nitrogen before
C-4, C-5, C-6 and C-7), 127.01–138.12 (m, Ph); MS (FAB) m/z
927 [M ϩ 1], 741 [M Ϫ C13H16N ϩ 1], 478 [M Ϫ C13H16N Ϫ
PPh3 ϩ 1], 363 [M Ϫ C13H16N Ϫ PPh3 Ϫ C9H7 ϩ 1]. This
complex was too sensitive to moisture and oxygen to give satis-
factory elemental analyses. 2c: Yield: 0.77 g, 84% (Found: C,
76.04; H, 6.16. RuC58H56P2 requires C, 75.88; H, 6.04%.);
use. Compounds [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ][PF ]
᎐ ᎐ ᎐
9
16
9
7
3
2
6
1,11c [RuCl(η5-C9H7)(PPh3)2] 6,15 (1R,2S,4R)-2-ethynyl-1,7,7-
νmax/cmϪ1 (C᎐C) 2072m (KBr); δ (C D ) 54.12 and 54.95 (d,
᎐
16
᎐
P
6
6
trimethyl-bicyclo[2.2.1]heptan-2-ol
ethynyl-4,6,6-trimethyl-bicyclo[3.1.1]hept-3-en-2-ol 8
7
and (1S,2R,5S)-2-
2J(PP) = 34.0 Hz); δH (C6D6) 1.21 (s, 6H, CH3), 1.30 and 1.85
(m, 2H each, CH2), 1.40 and 1.58 (s, 3H each, CH3), 1.66 and
2.14 (m, 1H each, CH2), 2.91 (m, 1H, CH), 4.67 and 4.70 (d, 1H
17
were
prepared following the methods reported in literature. Infrared
spectra were recorded on a Perkin-Elmer 1720-XFT spectro-
meter. Conductivities were measured at room temperature, in
ca. 10Ϫ3 mol dmϪ3 acetone solutions, with a Jenway PCM3 con-
ductimeter. The C, H and N analyses were carried out with
a Perkin-Elmer 2400 microanalyzer. High-resolution mass spec-
tra were recorded using a MAT-95 spectrometer. FAB mass
spectra were recorded using a VG-Autospec spectrometer
operating in positive mode; 3-nitrobenzyl alcohol (NBA) was
used as the matrix. NMR spectra were recorded on a Bruker
DPX300 instrument at 300 MHz (1H), 121.5 MHz (31P), or 75.4
MHz (13C) using SiMe4 or 85% H3PO4 as standards. DEPT
experiments have been carried out for all compounds reported
in this paper. Abbreviations used: s, singlet; br, broad singlet; d,
doublet; dd, doublet of doublets; m, multiplet. The numbering
for the indenyl skeleton is as follows:
3
3
each, J(HH) = 2.6 Hz, H-1 and H-3), 5.47 (dd, 1H, J(HH) =
2.6 and 2.6 Hz, H-2), 6.48–7.77 (m, 34H, Ph, H-4, H-5, H-6 and
H-7); δC (C6D6) 18.98, 24.90, 27.81 and 28.85 (s, CH3), 27.13,
34.36 and 41.30 (s, CH2), 43.55 and 51.10 (s, C), 50.72 (s, CH),
2
53.46 (s, Cγ), 74.61 (br, C-1 and C-3), 86.30 (dd, J(CP) = 23.2
and 23.2 Hz, Ru–Cα), 95.06 (s, C-2), 109.77, 110.19 and 116.40
(s, C-3a, C-7a and Cβ), 123.34, 123.74, 125.72 and 126.02 (s,
C-4, C-5, C-6 and C-7), 127.16–139.32 (m, Ph). 2d: Yield: 0.75
g, 75% (Found: C, 77.84; H, 5.95. RuC58H56P2 requires C, 77.90;
H, 5.83%.); νmax/cmϪ1 (C᎐C) 2069m, (C᎐C) 2210w (KBr); δ
᎐
᎐
᎐
᎐
P
2
(C6D6) 53.76 and 55.11 (d, J(PP) = 32.1 Hz); δH (C6D6) 1.32,
1.61 and 1.73 (s, 3H each, CH3), 1.36 and 1.93 (m, 2H each,
CH2), 1.57 and 2.36 (m, 1H each, CH2), 2.63 (m, 1 H, CH), 4.61
(br, 2H, H-1 and H-3), 5.54 (br, 1H, H-2), 6.49–7.59 (m, 39H,
Ph, H-4, H-5, H-6 and H-7); δC (C6D6) 20.47, 27.38 and 31.00
(s, CH3), 27.21, 31.21 and 42.54 (s, CH2), 45.05 and 54.70 (s, C),
2
49.86 (s, CH), 56.06 (s, Cγ), 74.22 (d, J(CP) = 2.8 Hz, C-1 or
2
᎐
C-3), 74.49 (d, J(CP) = 4.6 Hz, C-1 or C-3), 83.43 (s, C᎐CPh),
᎐
2
94.00 (dd, J(CP) = 23.6 and 23.6 Hz, Ru–Cα), 95.07 (s, C-2),
95.89 (s, C᎐CPh), 107.14, 109.80 and 110.05 (s, C-3a, C-7a
᎐
᎐
and Cβ), 123.21, 123.78, 126.06 and 126.22 (s, C-4, C-5, C-6 and
C-7), 127.10–139.00 (m, Ph).
Preparations
5
᎐
᎐
᎐
[Ru{C᎐CC(C H )R}(ꢀ -C H )(PPh ) ] (R ؍ H 2a, C᎐N 2b,
᎐
9
16
9
7
3 2
᎐
Me 2c, C᎐CPh 2d). General procedure. A solution of the allenyl-
[Ru{᎐C᎐C(H)C(C H )R}(ꢀ5-C H )(PPh ) ][BF ] (R ؍ H 3a,
᎐
᎐ ᎐
9
16
9
7
3
2
4
idene complex [Ru{᎐C᎐C᎐C(C H )}(η5-C H )(PPh ) ][PF ]
C᎐N 3b, Me 3c, C᎐CPh 3d). General procedure. A diluted solu-
᎐
᎐
᎐ ᎐ ᎐
᎐
᎐
9
16
9
7
3
2
6
(1.05 g, 1 mmol) in 50 cm3 of THF was treated at Ϫ20 ЊC with a
tion of HBF4ؒEt2O in diethyl ether was added dropwise at
Ϫ20 ЊC to a stirred solution of the corresponding σ-alkynyl
slight excess (1.1 mmol) of LiHBEt3 (1 M solution in THF),
5
᎐
᎐
᎐
NaC᎐N, LiMe (1.6 M solution in diethyl ether) or LiC᎐CPh
complex [Ru{C᎐CC(C H )R}(η -C H )(PPh ) ] 2a–d (1 mmol)
᎐
᎐
᎐
9
16
9
7
3 2
(prepared in situ by addition of LinBu 1.6 M to a solution of
in 100 cm3 of diethyl ether. Immediately, an insoluble brown
solid precipitated but the addition was continued until no
further solid was formed. The solution was then decanted, and
the solid residue washed with diethyl ether (3 × 20 cm3) and
vacuum-dried. 3a: Yield: 0.77 g, 78% (Found: C, 69.16; H, 5.60.
RuC57H55F4P2B requires C, 68.83; H, 5.53%.); conductivity
᎐
PhC᎐CH in THF at Ϫ20 ЊC). The reaction mixture was slowly
᎐
warmed to room temperature and then evaporated to dry-
ness. The resulting solid residue was dissolved in diethyl ether
(ca. 20 cm3) and filtered through Al2O3 (neutral; activity grade
I). Removal of the solvent gave the σ-alkynyl complexes 2a–d as
orange solids. 2a: Yield: 0.80 g, 89% (Found: C, 75.43; H, 6.08.
(acetone, 20 ЊC) 118 ΩϪ1 cm2 molϪ1; νmax/cmϪ1 (BF4 ) 1057s
Ϫ
RuC57H54P2 requires C, 75.89; H, 6.03%.); νmax/cmϪ1 (C᎐C)
(KBr); δP (CD2Cl2) 40.52 and 40.65 (d, 2J(PP) = 22.3 Hz);
δH (CD2Cl2) 0.62, 0.65 and 1.08 (s, 3H each, CH3), 1.17, 1.31
and 1.45 (m, 2H each, CH2), 1.63 (m, 1H, CH), 2.27 (d, 1H,
3J(HH) = 10.5 Hz, C H), 4.08 (d, 1H, 3J(HH) = 10.5 Hz, Ru᎐C᎐
᎐
᎐
2089m (KBr); δP (C6D6) 53.40 and 53.69 (d, 2J(PP) = 31.5 Hz);
δH (C6D6) 1.25, 1.27 and 1.41 (s, 3H each, CH3), 1.31 (m, 2H,
CH2), 1.55 (br, 1H, CH), 1.64, 1.90, 2.08 and 2.42 (m, 1H each,
CH2), 2.67 (m, 1H, CH), 4.64 and 4.69 (d, 1H each, J(HH) =
2.7 Hz, H-1 and H-3), 5.51 (dd, 1H, J(HH) = 2.7 and 2.7 Hz,
H-2), 6.42 and 6.68 (m, 2H each, H-4, H-5, H-6 and H-7), 6.92–
7.49 (m, 30H, Ph); δC (C6D6) 21.72, 25.73 and 32.49 (s, CH3),
27.14, 29.32 and 43.99 (s, CH2), 40.11 and 50.72 (s, C), 49.17 (s,
᎐ ᎐
γ
3
CH), 5.38 (br, 2H, H-1 and H-3), 5.76 (m, 2H, H-4, H-5, H-6 or
H-7), 5.91 (br, 1H, H-2), 6.78–7.48 (m, 32H, Ph and H-4, H-5,
H-6 or H-7); δC (CD2Cl2) 21.62, 23.45 and 31.66 (s, CH3), 26.26,
27.95 and 44.37 (s, CH2), 41.06 and 50.19 (s, C), 48.69 (s, CH),
51.76 (s, CγH), 81.54 and 82.57 (br, C-1 and C-3), 99.12 (s, C-2),
110.80 (s, Cβ), 116.64 and 117.03 (s, C-3a and C-7a), 123.49,
123.66, 130.78 and 130.65 (s, C-4, C-5, C-6 and C-7), 128.66–
134.45 (m, Ph), 342.03 (dd, 2J(CP) = 16.3 and 16.3 Hz, Ru᎐C ).
3
2
CH), 56.09 (s, CγH), 74.33 (d, J(CP) = 4.9 Hz, C-1 or C-3),
74.54 (d, 2J(CP) = 3.7 Hz, C-1 or C-3), 90.64 (dd, 2J(CP) = 23.8
and 23.8 Hz, Ru–Cα), 94.78 (s, C-2), 108.82, 109.54 and 110.24
(s, C-3a, C-7a and Cβ), 122.95, 123.37, 125.60 and 125.99 (s,
C-4, C-5, C-6 and C-7), 127.21–139.02 (m, Ph). 2b: Yield: 0.84
᎐
α
3b: Yield: 0.77 g, 78%; conductivity (acetone, 20 ЊC) 115 ΩϪ1
Ϫ
cm2 molϪ1; νmax/cmϪ1 (BF ) 1057s, (C᎐N) 2230w (KBr);
᎐
᎐
4
2
g, 91%; νmax/cmϪ1 (C᎐C) 2070m, (C᎐N) 2218w (KBr); δ
δP (CDCl3) 36.22 and 38.16 (d, J(PP) = 21.5 Hz); δH (CDCl3)
᎐
᎐
᎐
᎐
P
(CDCl3) 54.04 and 54.58 (d, 2J(PP) = 32.5 Hz); δH (CDCl3) 1.13,
1.23 and 1.30 (s, 3H each, CH3), 0.86, 1.38, 1.57, 1.67, 1.77 and
1.86 (m, 1H each, CH2), 2.18 (m, 1H, CH), 4.42 and 4.48 (d, 1H
0.61, 1.08 and 1.17 (s, 3H each, CH3), 1.12 (m, 2H, CH2), 1.20–
1.41 (m, 3H, CH2), 1.76 (m, 1H, CH), 1.95 (m, 1H, CH2), 3.88
(s, 1H, Ru᎐C᎐CH), 5.57 (br, 2H, H-1 and H-3), 5.62 (d, 1H,
᎐ ᎐
3
3
each, J(HH) = 2.4 Hz, H-1 and H-3), 5.09 (dd, 1H, J(HH) =
2.4 and 2.4 Hz, H-2), 6.45 and 6.74 (m, 2H each, H-4, H-5, H-6
and H-7), 7.03–7.30 (m, 30H, Ph); δC (CDCl3) 19.35, 26.01 and
3J(HH) = 7.8 Hz, H-4, H-5, H-6 or H-7), 5.79 (d, 1H, 3J(HH) =
8.3 Hz, H-4, H-5, H-6 or H-7), 6.05 (br, 1H, H-2), 6.70–7.60 (m,
32H, Ph and H-4, H-5, H-6 or H-7); δC (CDCl3) 18.72, 23.92
D a l t o n T r a n s . , 2 0 0 3 , 3 0 6 0 – 3 0 6 6
3063

View Article Online
᎐
and 30.00 (s, CH3), 25.25, 28.54 and 42.18 (s, CH2), 44.86 and
51.13 (s, C), 48.21 (s, CH), 54.87 (s, Cγ), 79.82 (d, 2J(CP) = 7.5
Hz, C-1 or C-3), 81.39 (d, 2J(CP) = 6.5 Hz, C-1 or C-3), 99.47 (s,
and 52.15 (s, C), 48.83 (s, CH), 54.82 (s, CC᎐CH), 75.47 (s,
᎐
᎐
᎐
᎐
C᎐CH), 78.55 (s, C᎐CH), 118.69 (s, C᎐N). 4c: Yield: 0.14 g
᎐
᎐
᎐
(colourless oil), 82 %; νmax/cmϪ1 (C᎐C) 2104w, (H–C᎐) 3314s
᎐
᎐
᎐
᎐
C-2), 108.34 (s, Cβ), 116.48 and 117.87 (s, C-3a and C-7a),
(Nujol); δH (C6D6) 0.83, 1.05, 1.11 and 1.20 (s, 3H each, CH3),
᎐
121.90 (s, C᎐N), 123.37 and 123.76 (s, C-4, C-5, C-6 or C-7),
0.94, 1.15, 1.32 and 1.74 (m, 1H each, CH2), 1.52 (m, 2H, CH2),
᎐
᎐
128.28–133.89 (m, Ph and C-4, C-5, C-6 or C-7), 345.26 (dd,
1.98 (s, 1H, ᎐CH), 2.25 (m, 1H, CH); δ (C D ) 17.82, 22.88,
᎐
C
6
6
2J(CP) = 17.4 and 17.4 Hz, Ru᎐C ); MS (FAB) m/z 927 [Mϩ],
26.55 and 26.79 (s, CH3), 25.96, 33.85 and 40.63 (s, CH2), 42.57
᎐
α
741 [Mϩ Ϫ C13H16N], 478 [Mϩ Ϫ C13H16N Ϫ PPh3], 363 [Mϩ Ϫ
C13H16N Ϫ PPh3 Ϫ C9H7]. This complex was too sensitive to
moisture and oxygen to give satisfactory elemental analyses. 3c:
Yield: 0.77 g, 87% (Found: C, 69.67; H, 5.42. RuC58H57F4P2B
and 47.63 (s, C), 50.09 (s, CH), 52.11 (s, CC᎐CH), 71.95 (s,
᎐
᎐
᎐
᎐
C᎐CH), 89.35 (s, C᎐CH); HRMS m/z calcd. for C H20 (found)
᎐
᎐
13
176.156545 (176.157256). 4d: Yield: 0.23 g (colourless oil), 89%;
νmax/cmϪ1 (C᎐C) 2111w, (C᎐C) 2164w, (H–C᎐) 3324s (Nujol);
᎐
᎐
᎐
᎐
᎐
᎐
requires C, 69.39; H, 5.72%.); conductivity (acetone, 20 ЊC) 112
δH (C6D6) 1.22 (m, 1H, CH2), 1.36, 1.44, 1.62 (s, 3H each, CH3),
1.24–1.42 and 1.75–1.83 (m, 2H each, CH2), 2.16 (m, 1H, CH2),
Ϫ
Ω
Ϫ1 cm2 molϪ1; νmax/cmϪ1 (BF4 ) 1057s (KBr); δP (CDCl3) 34.18
and 39.07 (d, 2J(PP) = 22.5 Hz); δH (CDCl3) 0.62, 0.71, 0.86 and
2.17 (s, 1H, ᎐CH), 2.26 (m, 1H, CH), 7.05–7.41 (m, 5H, Ph);
᎐
᎐
1.05 (s, 3H each, CH3), 1.15, 1.22 and 1.44 (m, 2H each, CH2),
δC (C6D6) 19.45, 26.12 and 30.04 (s, CH3), 26.38, 31.17 and
1.59 (m, 1H, CH), 4.04 (s, 1H, Ru᎐C᎐CH), 5.39 and 5.57 (br, 1
42.35 (s, CH2), 44.50 and 51.45 (s, C), 49.64 (s, CH), 55.31 (s,
᎐ ᎐
H each, H-1 and H-3), 5.45 and 5.60 (d, 1H each, 3J(HH) = 8.3
Hz, H-4, H-5, H-6 or H-7), 5.99 (br, 1H, H-2), 6.53–7.50 (m,
32H, Ph and H-4, H-5, H-6 or H-7); δC (CDCl3) 18.04, 22.48,
25.42 and 26.53 (s, CH3), 25.08, 32.99 and 39.97 (s, CH2), 44.24
and 51.23 (s, C), 49.29 (s, CH), 53.51 (s, Cγ), 78.85 and 81.00 (d,
2J(CP) = 8.5 Hz, C-1 and C-3), 99.04 (s, C-2), 113.71 (d, 2J(CP)
= 2.4 Hz, C-3a or C-7a), 116.84 (s, Cβ), 120.24 (s, C-3a or C-7a),
122.03 and 124.58 (s, C-4, C-5, C-6 or C-7), 128.24–134.23 (m,
CC᎐CH), 73.03 (s, C᎐CH), 83.82 and 85.33 (s, C᎐CH and
᎐
᎐
᎐
᎐
᎐
᎐
᎐
᎐
C᎐CPh), 91.15 (s, C᎐CPh), 128.05, 128.50 and 132.02 (s, CH of
᎐
᎐
Ph), 138.81 (C of Ph); HRMS m/z calcd. for C20H22 (found)
262.172241 (262.172151).
[Ru{᎐C᎐C᎐C(C H )}(ꢀ5-C H )(PPh ) ][PF ] 9. To a solution
᎐ ᎐ ᎐
9
16
9
7
3
2
6
of [RuCl(η5-C9H7)(PPh3)2] 6 (0.776 g, 1 mmol) in 50 cm3 of
MeOH were added NaPF6 (0.336 g, 2 mmol) and (1R,2S,4R)-2-
ethynyl-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-ol 7 (0.356 g,
2 mmol). The reaction mixture was heated under reflux for 30
min. The solvent was then removed under vacuum, the crude
product extracted with CH2Cl2, and the extract filtered. Con-
centration of the resulting solution to ca. 5 cm3 followed by the
addition of 50 cm3 of diethyl ether precipitated a red solid,
which was washed with diethyl ether (2 × 20 cm3) and dried in
vacuo. Yield: 0.84 g, 80% (Found: C, 64.93; H 5.09. RuC57-
H53F6P3 requires C, 64.45; H, 5.09%.); conductivity (acetone,
2
Ph and C-4, C-5, C-6 or C-7), 342.06 (dd, J(CP) = 17.7 and
15.3 Hz, Ru᎐C ). 3d: Yield: 1.00 g, 92% (Found: C, 71.57; H
᎐
α
5.36. RuC65H59F4P2B requires C, 71.62; H, 5.45%.); conductiv-
Ϫ
ity (acetone, 20 ЊC) 115 ΩϪ1 cm2 molϪ1; νmax/cmϪ1 (BF4 ) 1057s,
2
᎐
(C᎐C) 2205w (KBr); δ (CD Cl ) 36.68 and 39.10 (d, J(PP) =
᎐
P
2
2
21.7 Hz); δH (CD2Cl2) 0.77 (s, 3H, CH3), 1.35 (s, 6H, CH3),
1.18–1.25 (m, 3H, CH2), 1.42 (m, 2H, CH2), 1.77 (m, 1H, CH2),
2.17 (m, 1H, CH), 4.05 (s, 1H, Ru᎐C᎐CH), 5.36 and 5.44 (br,
᎐ ᎐
3
1H each, H-1 and H-3), 5.69 and 5.79 (d, 1H each, J(HH) =
Ϫ
7.9 Hz, H-4, H-5, H-6 or H-7), 6.20 (br, 1H, H-2), 6.84–7.50 (m,
37H, Ph and H-4, H-5, H-6 or H-7); δC (CD2Cl2) 19.72, 25.29
and 30.51 (s, CH3), 25.86, 30.51 and 42.12 (s, CH2), 46.50 and
52.26 (s, C), 49.23 (s, CH), 56.40 (s, Cγ), 79.31 and 80.40 (d,
20 ЊC) 138 ΩϪ1 cm2 molϪ1; νmax/cmϪ1 (᎐C᎐C᎐C) 1963s, (PF )
᎐ ᎐ ᎐
6
2
838s (KBr); δP (CDCl3) 47.09 and 47.21 (d, J(PP) = 23.2 Hz);
δH (CDCl3) 1.04, 1.05 and 1.14 (s, 3H each, CH3), 1.30, 1.53,
1.62 and 1.86 (m, 1H each, CH2), 1.77 (m, 2H, CH2), 2.27 (m,
1H, CH), 5.19 (br, 2H, H-1 and H-3), 5.35 (br, 1H, H-2), 6.28
and 6.36 (d, 1H each, 3J(HH) = 7.7 Hz, H-4, H-5, H-6 or H-7),
6.91–7.67 (m, 32H, Ph and H-4, H-5, H-6 or H-7); δC (CDCl3)
18.87, 25.19 and 26.51 (s, CH3), 25.24, 34.38 and 44.95 (s, CH2),
47.72 (s, CH), 57.57 and 64.34 (s, C), 83.52 and 84.60 (br, C-1
and C-3), 98.10 (s, C-2), 112.55 and 114.07 (s, C-3a and C-7a),
123.21, 124.09, 129.17 and 131.39 (s, C-4, C-5, C-6 and C-7),
123.31–135.27 (m, Ph), 183.24 (s, Cβ), 202.21 (s, Cγ), 305.06 (dd,
2J(CP) = 18.9 and 18.9 Hz, Ru᎐C ).
2
᎐
J(CP) = 8.0 Hz, C-1 and C-3), 86.44 (s, C᎐CPh), 94.52 (s,
᎐
᎐
C᎐CPh), 99.50 (s, C-2), 112.23 (s, C ), 116.68 and 118.76 (s,
᎐
β
C-3a and C-7a), 123.46–134.29 (m, Ph, C-4, C-5, C-6 and C-7),
347.75 (dd, 2J(CP) = 17.1 and 17.1 Hz, Ru᎐C ).
᎐
α
᎐
Spectroscopic characterization of HC᎐CC(C H )H 4a. In an
᎐
9
16
NMR-tube, the vinylidene complex 3a (0.099 g, 0.1 mmol) was
dissolved in acetonitrile-d3 (ca. 0.7 cm3). After 5 h at room tem-
5
᎐
perature, the terminal alkyne 4a and [Ru(N᎐CCD )(η -C H )-
᎐
᎐
3
9
7
α
(PPh3)2][BF4] were formed in almost quantitative yield. δH
(CD3CN) 0.99, 1.00 and 1.11 (s, 3H each, CH3), 1.21, 1.40, 1.54
and 1.74 (m, 1H each, CH2), 1.65 (m, 2H, CH2), 2.12 (dd, 1H,
4J(HH) = 2.4 and 2.4 Hz, CH), 2.25 (m, 1H, CH), 2.35 (d, 1H,
[Ru{᎐C᎐C᎐C(C H )}(ꢀ5-C H )(PPh ) ][PF ] 10. This com-
᎐ ᎐ ᎐
9
14
9
7
3
2
6
plex, isolated as a red solid, was prepared as described for 9
starting from [RuCl(η5-C9H7)(PPh3)2] 6 (0.776 g, 1 mmol),
NaPF6 (0.336 g, 2 mmol) and (1S,2R,5S)-2-ethynyl-4,6,6-tri-
methyl-bicyclo[3.1.1]hept-3-en-2-ol 8 (0.352 g, 2 mmol). Yield:
0.783 g, 75% (Found: C, 62.33; H 4.56. RuC57H51F6P3ؒ
3/4CH2Cl2 requires C, 62.61; H, 4.77%.); conductivity (acetone,
4
᎐
J(HH) = 2.4 Hz, ᎐CH); δ (CD CN) 20.58, 24.46 and 31.78 (s,
᎐
C
3
CH3), 26.61, 29.28 and 44.15 (s, CH2), 39.71 and 50.07 (s, C),
᎐
᎐
49.26 and 51.33 (s, CH), 73.57 (s, C᎐CH), 84.60 (s, C᎐CH).
᎐
᎐
Ϫ
HC᎐CC(C H )R (R ؍ C᎐N 4b, Me 4c, C᎐CPh 4d). General
20 ЊC) 123 ΩϪ1 cm2 molϪ1; νmax/cmϪ1 (᎐C᎐C᎐C) 1959s, (PF )
᎐
᎐
᎐
᎐
᎐
᎐
᎐ ᎐ ᎐
9
16
6
procedure. A solution of the corresponding vinylidene com-
840s (KBr); δP (CDCl3) 47.99 (br); δH (CDCl3) 0.79, 1.27 and
1.85 (s, 3H each, CH3), 2.14 and 2.86 (br, 1H each, CH), 2.58
and 2.65 (br, 1H each, CH2), 5.13 (br, 2H, H-1 and H-3), 5.45
plex [Ru{᎐C᎐C(H)C(C H )R}(η5-C H )(PPh ) ][BF ] 3b–d (1
᎐ ᎐
9
16
9
7
3
2
4
mmol) in 40 cm3 of acetonitrile was stirred at room temperature
for 5 h. The solvent was then removed under vacuum and the
solid residue extracted with diethyl ether (ca. 60 cm3) and fil-
tered through silica-gel. A yellow solid containing mainly the
(br, 1H, H-2), 5.83 (br, ᎐CH), 6.14 (m, 2H, H-4, H-5, H-6 or
᎐
H-7), 6.92–7.35 (m, 32H, Ph and H-4, H-5, H-6 or H-7);
δC (CDCl3) 21.69, 25.33 and 27.21 (s, CH3), 42.34 (s, CH2),
51.78 and 60.19 (s, CH), 57.59 (s, C), 82.89 and 83.15 (s, C-1
and C-3), 96.72 (s, C-2), 111.02 and 111.68 (s, C-3a and C-7a),
122.70, 123.06, 128.87 and 129.77 (s, C-4, C-5, C-6 and C-7),
5
᎐
nitrile complex [Ru(N᎐CMe)(η -C H )(PPh ) ][BF ] 5 remained
᎐
9
7
3
2
4
insoluble. The extract was evaporated to dryness yielding
terminal alkynes 4b–d. 4b: Yield: 0.14 g (yellow solid), 77%
(Found: C, 83.47; H, 9.08; N, 7.34. C13H17N requires C, 83.37;
128.03–135.16 (m, Ph), 128.45 (s, ᎐CH), 169.05 (s, ᎐C), 174.75
᎐
᎐
H, 9.15; N, 7.48%.); νmax/cmϪ1 (C᎐C) 2070w, (C᎐N) 2236w,
(s, Cβ), 184.47 (s, Cγ), 280.16 (dd, J(CP) = 20.2 and 20.2 Hz,
2
᎐
᎐
᎐
᎐
᎐
H–C᎐) 3251s (KBr); δ (C D ) 0.91, 1.14 and 1.30 (s, 3H each,
Ru᎐C ).
᎐
᎐
H
6
6
α
CH3), 0.99, 1.05, 1.61 (m, 1H each, CH2), 1.36 (m, 2H, CH2),
5
t
᎐
᎐
᎐
1.75 (m, 2H, CH and CH), 1.91 (s, 1H, ᎐CH); δ (C D ) 18.75,
[Ru{C᎐CC(C H )}(ꢀ -C H )(PPh ) ] 11. KO Bu (0.146 g, 1.3
᎐
2
C
6
6
9 15 9 7 3 2
24.89 and 29.73 (s, CH3), 25.60, 29.78 and 42.08 (s, CH2), 43.74
mmol) was added, at Ϫ20 ЊC, to a solution of [Ru{᎐C᎐C᎐
᎐ ᎐ ᎐
D a l t o n T r a n s . , 2 0 0 3 , 3 0 6 0 – 3 0 6 6
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C(C9H16)}(η5-C9H7)(PPh3)2][PF6] 9 in 60 cm3 of THF. The mix-
ture was slowly warmed to room temperature, and the solvent
was then removed in vacuo. The resulting solid residue was dis-
solved in diethyl ether (ca. 20 cm3) and filtered through Al2O3
(neutral; activity grade I). Removal of the solvent gave the
σ-enynyl complex 11 as an orange solid. Yield: 0.87 g, 87%
(Found: C, 75.81; H 5.82. RuC55H45P2 requires C, 76.07; H,
2002, 3816; (x) S. Csihony, C. Fischmeister, C. Bruneau,
I. T. Horvath and P. H. Dixneuf, New J. Chem., 2002, 26, 1667.
4 Dehydrogenative dimerization of tin hydrides: S. M. Maddock and
M. G. Finn, Angew. Chem., Int. Ed., 2001, 40, 2138.
5 Propargylic substitutions: (a) Y. Nishibayashi, I. Wakiji and
M. Hidai, J. Am. Chem. Soc., 2000, 122, 11019; (b) Y. Nishibayashi,
I. Wakiji, Y. Ishii, S. Uemura and M. Hidai, J. Am. Chem. Soc.,
2001, 123, 3393; (c) Y. Nishibayashi, M. Yoshikawa, Y. Inada,
M. Hidai and S. Uemura, J. Am. Chem. Soc., 2002, 124, 11846;
(d ) Y. Inada, Y. Nishibayashi, M. Hidai and S. Uemura, J. Am.
Chem. Soc., 2002, 124, 15172; (e) Y. Nishibayashi, G. Onodera,
Y. Inada, M. Hidai and S. Uemura, Organometallics, 2003, 22,
873; ( f ) M. Hidai, in Perspectives in Organometallic Chemistry,
ed. C. G. Screttas and B. R. Steele, RSC, Cambridge, 2003, p. 62;
(g) Y. Nishibayashi, Y. Inada, M. Hidai and S. Uemura, J. Am.
Chem. Soc., 2003, 125, 6060.
5.82%.); νmax/cmϪ1 (C᎐C) 2060w (KBr); δ (C D ) 51.47 and
᎐
᎐
P
6
6
52.26 (d, 2J(PP) = 29.5 Hz); δH (C6D6) 0.92 and 1.39 (s, 3H each,
CH3), 1.20 (br, 4H, CH3 and CH2), 1.36, 1.66 and 2.05 (m, 1H,
each, CH2), 2.42 (dd, 1 H, 3J(HH) = 3.3 and 3.3 Hz, CH), 4.65
and 4.70 (d, 1H each, 3J(HH) = 2.6 Hz, H-1 and H-3), 5.57 (dd,
3
3
1H, J(HH) = 2.6 and 2.6 Hz, H-2), 5.94 (d, 1H, J(HH) =
3.3 Hz, =CH), 6.33 and 6.66 (m, 2H each, H-4, H-5, H-6 and
H-7), 6.87–7.70 (m, 30H, Ph); δC (C6D6) 13.51, 20.52 and 20.62
(s, CH3), 27.12 and 32.10 (s, CH2), 51.87 (s, CH), 55.71 and
6 Cycloaddition reactions: Y. Nishibayashi, Y. Inada, M. Hidai and
S. Uemura, J. Am. Chem. Soc., 2002, 124, 7900.
7 J. P. Selegue, Organometallics, 1982, 1, 217.
2
56.15 (s, C), 74.82 (d, J(CP) = 6.5 Hz, C-1 or C-3), 75.02 (d,
8 For a review on transition-metal-stabilized propargyl cations see:
H. El Amouri and M. Gruselle, Chem. Rev., 1996, 96, 1077.
9 For theoretical calculations on transition-metal allenylidene
complexes see: (a) B. E. R. Schilling, R. Hoffmann and D. L.
Lichtenberger, J. Am. Chem. Soc., 1979, 101, 585; (b) H. Berke,
G. Huttner and J. Von Seyerl, Z. Naturforsch., B, 1981, 36, 1277;
(c) V. Cadierno, M. P. Gamasa, J. Gimeno, M. González-Cueva,
E. Lastra, J. Borge, S. García-Ganda and E. Pérez-Carreño,
Organometallics, 1996, 15, 2137; (d ) E. Pérez-Carreño, PhD Thesis,
University of Oviedo, 1996; (e) A. J. Edwards, M. A. Esteruelas,
F. J. Lahoz, J. Modrego and L. A. Oro, Organometallics, 1996, 15,
3556; ( f ) M. A. Esteruelas, A. V. Gómez, A. M. López, J. Modrego
and E. Oñate, Organometallics, 1997, 16, 5826; (g) N. Re,
A. Sgamellotti and C. Floriani, Organometallics, 2000, 19, 1115;
(h) M. Baya, P. Crochet, M. A. Esteruelas, E. Gutiérrez-Puebla,
A. M. López, J. Modrego, E. Oñate and N. Vela, Organometallics,
2000, 19, 2585; (i) R. F. Winter, K. W. Klinkhammer and S. Zálisˇ,
Organometallics, 2001, 20, 1317; (j) A. Marrone and N. Re,
Organometallics, 2002, 21, 3562.
2J(CP) = 7.6 Hz, C-1 or C-3), 95.55 (s, C-2), 109.04 and 109.72
(s, C-3a and C-7a), 110.21 (s, Cβ), 113.14 (dd, 2J(CP) = 25.1 and
25.1 Hz, Ru–Cα), 122.86, 123.29, 125.73 and 126.12 (s, C-4, C-5,
C-6 and C-7), 127.30–139.01 (m, Ph and C᎐CH).
᎐
Acknowledgements
This work was supported by the Ministerio de Ciencia y
Tecnología (MCyT) of Spain (Project BQU2000-0227) and the
Gobierno del Principado de Asturias (Project PR-01-GE-4).
S.C. thanks the Ministerio de Educación, Cultura y Deporte
(MECD) of Spain for the award of a PhD grant.
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22 The 20th International Conference on Organometallic Chemistry
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M. P. Gamasa and J. Gimeno, in Perspectives in Organometallic
Chemistry, ed. C. G. Screttas and B. R. Steele, RSC, Cambridge,
2003, p. 285.
20 Nucleophilic additions on the C᎐C bond of verbenones are known.
᎐
See for example: (a) R. Krishnamurti and H. G. Kuivila, J. Org.
Chem., 1986, 51, 4947; (b) P. Ballester, A. Costa, A. G. Raso,
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D a l t o n T r a n s . , 2 0 0 3 , 3 0 6 0 – 3 0 6 6
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