Intramolecular metathesis of a vinyl group with vinylidene C=C double bond in Ru complexes

Article abstract of DOI:10.1021/ja054994a

The cationic complex {[Ru]=C=CHCPh₂CH₂CH=CH ₂}BF₄ (3a, [Ru] = (η⁵-C₅H ₅)(PPh₃)₂Ru) in solution transforms to {[Ru]=C=CHCH₂CPh₂CH=CH₂}BF₄ (4a) via a new metathesis process of the terminal vinyl group with the C=C of the vinylidene group which is confirmed by ¹³C labeling studies. This transformation is irreversible as revealed by deuteration and decomplexation studies. The cationic complex {[Ru]=C=CHCPh₂CH₂CMe=CH ₂}BF₄ (3b) undergoes a cyclization process yielding 6b containing a η²-cyclic allene ligand which is fully characterized by single-crystal X-ray diffraction analysis. Analogous complexes 4a′ and 6b′ ([Ru] = (η⁵-C₅H₅)(dppe)Ru) containing dppe ligands were similarly obtained from protonation of the corresponding acetylide complexes via formation of vinylidene intermediate. Protonation of the acetylide complex containing a terminal alkynyl group [Ru]-C≡CCPh₂CH₂C≡CH (2c) generates the vinylidene complex {[Ru]=C=CHCPh₂CH₂C≡CH}BF ₄ (3c) which again undergoes an irreversible transformation to give {[Ru]=C=CHCH₂CPh₂C=CH}BF₄ (4c) possibly via a π-coordinated alkynyl complex followed by hydrogen and metal migration. No similar transformation is observed for the analogous dppe complex 3c′. With an extra methylene group, complex {[Ru]=C=CHCPh₂CH ₂CH₂CH=CH₂}BF₄ (3d) and complex {[Ru]=C=CHCPh₂CH₂Ph}BF₄ (3e) are stable. The presence of a gem-diphenylmethylene moiety at the vinylidene ligand with the appropriate terminal vinyl or alkynyl group along with the correct steric environment implements such a novel reactivity in the ruthenium vinylidene complexes.

Full text of DOI:10.1021/ja054994a

Published on Web 12/01/2005
Intramolecular Metathesis of a Vinyl Group with Vinylidene
CdC Double Bond in Ru Complexes
Yung-Sheng Yen, Ying-Chih Lin,* Shou-Ling Huang, Yi-Hung Liu,
Hui-Ling Sung, and Yu Wang
Contribution from the Department of Chemistry, National Taiwan UniVersity, Taipei,
Taiwan 106, Republic of China
Received July 25, 2005; E-mail: yclin@ntu.edu.tw
Abstract: The cationic complex {[Ru]dCdCHCPh2CH2CHdCH2}BF4 (3a, [Ru] ) (η5-C5H5)(PPh3)2Ru) in
solution transforms to {[Ru]dCdCHCH2CPh2CHdCH2}BF4 (4a) via a new metathesis process of the terminal
vinyl group with the CdC of the vinylidene group which is confirmed by 13C labeling studies. This
transformation is irreversible as revealed by deuteration and decomplexation studies. The cationic complex
{[Ru]dCdCHCPh2CH2CMedCH2}BF4 (3b) undergoes a cyclization process yielding 6b containing a η2-
cyclic allene ligand which is fully characterized by single-crystal X-ray diffraction analysis. Analogous
complexes 4a′ and 6b′ ([Ru] ) (η5-C5H5)(dppe)Ru) containing dppe ligands were similarly obtained from
protonation of the corresponding acetylide complexes via formation of vinylidene intermediate. Protonation
of the acetylide complex containing a terminal alkynyl group [Ru]-CtCCPh2CH2CtCH (2c) generates the
vinylidene complex {[Ru]dCdCHCPh2CH2CtCH}BF4 (3c) which again undergoes an irreversible trans-
formation to give {[Ru]dCdCHCH2CPh2CtCH}BF4 (4c) possibly via a π-coordinated alkynyl complex
followed by hydrogen and metal migration. No similar transformation is observed for the analogous dppe
complex 3c′. With an extra methylene group, complex {[Ru]dCdCHCPh2CH2CH2CHdCH2}BF4 (3d) and
complex {[Ru]dCdCHCPh2CH2Ph}BF4 (3e) are stable. The presence of a gem-diphenylmethylene moiety
at the vinylidene ligand with the appropriate terminal vinyl or alkynyl group along with the correct steric
environment implements such a novel reactivity in the ruthenium vinylidene complexes.
consideration.1a With one more carbon atom, a metal alle-
nylidene complex6 is also of interest for the building of
Introduction
Free vinylidene is a high-energy tautomer of alkyne and could
be effectively stabilized by coordination to transition metals.1
Novel chemical properties of the resulting metal vinylidene
complexes are valuable for organic transformations. For in-
stance, vinylidene complexes of various metals commonly
function as strategic intermediates for catalytic conversion of
alkynes such as cycloaromatization of conjugated enediynes,2
dimerization of terminal alkynes,3 and addition of oxygen,
nitrogen, and carbon nucleophiles to alkynes.4 Furthermore,
some vinylidene complexes have been exploited as catalyst
precursors for olefin-metathesis reactions.5 Reactivities of metal
vinylidene complexes are rationalized by taking electrophilicity
of vinylidene R-carbon, nucleophilicity of vinylidene â-carbon,
and highly unsaturated structures of the vinylidene ligands into
innovative carbon-rich architectures7 and material science.8
Owing to the invention of a common method of approach
by easy activation of propargylic alcohols,9 the chemistry of
metal allenylidenes has been quickly elaborated. Nowadays
nucleophilic addition to the allenylidene ligand is considered
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P.; Gimeno, J. Eur. J. Inorg. Chem. 2001, 571. (c) Touchard, D.; Dixneuf,
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9
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J. AM. CHEM. SOC. 2005, 127, 18037-18045
18037

A R T I C L E S
Yen et al.
as an alternative synthesis of a metal vinylidene complex making
various kinds of vinylidene complexes available for exploitation.
We previously reported10 synthesis of ruthenium cyclopropenyl
complexes by deprotonation reaction of the readily accessible
metal vinylidene complex containing a -CH2R group bound
to Câ of the vinylidene ligand.
substrates which undergo [2 + 2] reactions with transition metals
is rather restricted. Reactions of strained alkenes have received
the most attention, and further studies to expand the scope of
this reaction are needed.26,27 Herein we report a novel trans-
formation of the vinylidene ligand involving metathesis of the
CdC double bond of the vinylidene ligand and a terminal vinyl
group tethered on the ligand.
Results and Discussion
Preparation of Ruthenium Allenylidene Complexes. The
reported preparation of a ruthenium diphenylallenylidene com-
+
plex in the literature28 is modified to obtain [Ru]dCdCdCPh2
,
(1, [Ru] ) Cp(PPh3)2Ru) in high yield. Many other ruthenium
diphenylallenylidene complexes are known in the literatures.9,29
The reaction of 1 with Grignard reagents RsCH2MgBr yield
the acetylide complexes [Ru]sCtCsC(Ph)2CH2R (2a, R )
CHdCH2; 2b, R ) CMedCH2; 2c, R ) CtCH; 2d, R ) CH2-
CHdCH2; 2e, R ) Ph; Scheme 1) all in high yield. Charac-
teristic spectroscopic data of 2a, 2b, 2c, 2d, and 2e are
comparable with that of analogous indenyl complexes in the
literature.11a Complexes 2a-2e are characterized by IR, 31P,
1H, and 13C NMR spectroscopy. The IR spectra of these
acetylide complexes show typical ν(CtC) absorption bands
within 2077-2084 cm-1. In the 13C NMR spectra 13C reso-
nances of the acetylide ligand fall in the ranges of δ 97.1-98.6
Our attempts to prepare a four-membered ring ligand have
prompted us to synthesize vinylidene complexes containing a
-CPh2CH2R group bound to Câ of the vinylidene ligand. A
number of such complexes are successfully prepared via
alkylation of metal allenylidene by using Grignard reagents.11
Surprisingly, with the presence of a terminal vinyl group, the
+
metal vinylidene complex [Ru]dCdCHCPh2CH2CHdCH2
displays novel intramolecular metathesis reactivity between the
two CdC double bonds. Unlike electrophilic and nucleophilic
additions to the vinylidene ligand, the cycloaddition of the Cd
C double bond of a vinylidene ligand is much less studied. It is
well-known that the [2 + 2] cycloaddition of alkenes and/or
alkynes represents an important approach for the synthesis of
cyclobutane derivatives.12 A thermally forbidden process by the
Woodward-Hoffmann rules,13 this cycloaddition has been
achieved photochemically,14 by thermal reactions via biradical
intermediates,15 by the use of Lewis acid catalysts,16 and by
the use of transition metal catalysts.17 To date, the range of
1
for CR and 114.4-115.2 for Câ. In the H NMR spectrum of
2a, the doublet resonance at δ 3.27 with JH-H ) 6.0 Hz is
assigned to the internal methylene group. Corresponding me-
thylene resonances for complexes 2b, 2c, 2d, and 2e appear at
δ 3.29, 3.31, 2.58, and 3.79, respectively.
Novel Metathesis Reactions. Protonation of complexes 2a-
2e by HBF4 in diethyl ether at 0 °C gave the corresponding
vinylidene complexes [Ru]dCdCHC(Ph)2CH2R+ (3a, R )
CHdCH2; 3b, R ) CMedCH2; 3c, R ) CtCH; 3d, R ) CH2-
CHdCH2; 3e, R ) Ph) as a solid precipitate all with over 90%
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9
18038 J. AM. CHEM. SOC. VOL. 127, NO. 51, 2005

Metathesis of a Vinyl Group with Vinylidene C
dC
A R T I C L E S
Scheme 1
isolated. Thermolysis of 4a in CH3CN yields only 8a quanti-
tatively indicating that the transformation of 3a to 4a is
irreversible (see Scheme 2). Formation of alkyne from metal
vinylidene in acetonitrile has been reported in thermolysis of
the analogous indenyl vinylidene complex. However the reaction
of the indenyl compound yielded only 1,5-enyne 7a.
Characterization of 3a and 4a is achieved by a spectroscopic
method as well as elemental analysis. Significant differences
in the spectroscopic data of 3a and 4a leading to disclosure of
the structural feature can be undoubtedly discerned. Mainly the
1
coupling patterns of H resonances of vinylidene and vinyl
protons of the 1H COSY NMR spectra reveal important
structural information. In the 1H NMR spectrum of 3a, the broad
triplet resonance of the vinylidene proton at δ 4.45 with JH-P
) 3.0 Hz shows coupling only with the phosphine ligands. For
4a, the corresponding 1H resonance of the vinylidene proton at
δ 4.40, in addition to being coupled with two phosphine ligands,
is found to be coupled with the methylene protons at δ 3.09
with JH-H ) 7.8 Hz indicating direct connectivity of the
methylene group to Câ of the vinylidene ligand. For 3a, the
multiplet resonance at δ 5.02 assignable to the methyne proton
of the vinyl group is coupled to the resonance at δ 3.06 with
JH-H ) 6.0 Hz assignable to the saturated internal methylene
group. But in 4a, the corresponding vinyl proton at δ 3.09 only
couples with the resonances of the terminal olefinic dCH2 group
indicating no neighboring CH2 group thus signifying direct
bonding of the vinyl ligand to the CPh2 group. In addition, the
relevant spectroscopic feature of 4a is the characteristic CR
resonance as a triplet at δ 345.6 with JP-C ) 15.1 Hz in the
13C NMR spectrum. All these spectroscopic data support the
proposed formula for 4a. Spectroscopic data of 7a and 8a,
particularly the 1H NMR spectra, are consistent with their
formulas.
Scheme 2
Such a transformation could be interpreted by a novel
metathesis process between the terminal vinyl group and the
CdC of the vinylidene ligand of 3a first giving the possible
cyclobutylidene intermediate 5a shown in the Scheme 2.
Namely, a regiospecific [2+2] cycloaddition of two double
bonds leads to formation of the four-membered ring. This is
followed by a retro-cycloaddition to give 4a. A somewhat
similar cycloaddition, namely, the first half of our metathesis
reaction, has been reported by Gimeno’s group for a ruthenium
vinylidene complex containing an allylphosphine ligand.30
However, in 3a, a further step causes complete metathesis of
two double bonds.
When a stoichiometric amount of CF3COOD is used in
treating 2a leading to 4a in CDCl3, a mixture of deuterated
products was observed (Scheme 3). The vinylidene proton and
the methyne proton of the terminal vinyl group are partly
deuterated. No deuterium incorporation takes place at the
terminal CH2 of the vinyl group or at the saturated methylene
group. In the proton NMR spectrum, the intensity ratio of
vinylidene proton to methyne proton is 3:2. If an excess amount
of CF3COOD is used in the protonation of 2a, both hydrogen
atoms are replaced by deuterium giving 4a-D2. However,
addition of D+ to 4a results in formation of only 4a-Da, but no
4a-Db is observed. The deuterium incorporation is observed to
yield. Complexes 3d and 3e are stable vinylidene compounds
even at 75 °C. Interestingly, vinylidene complexes 3a, 3b, and
3c all display interesting reactivity possibly due to the presence
of the gem-diphenyl group and the unsaturated functional group
at a proper location of the vinylidene ligand.
Treatment of complex 2a with HBF4 affords the cationic
complex [Ru]dCdCHC(Ph)2CH2CHdCH2+ (3a) as a light pink
powder. When complex 3a is dissolved in CDCl3 or CH2Cl2 at
room temperature, a novel transformation takes place and [Ru]d
CdCHCH2CPh2CHdCH2+ (4a) is isolated in 90% yield in ca.
12 h (see Scheme 2). With a chelating diphenylphosphinoethane
(dppe) ligand replacing the two PPh3 ligands, complex [Ru′]d
CdCHC(Ph)2CH2CHdCH2+ ([Ru′] ) (η5-C5H5)(dppe)Ru, 3a′)
undergoes the same metathesis transformation giving 4a′ with
a much faster rate of reaction.
If the CH3CN solution of complex 3a is heated to reflux,
three products, cationic metal acetonitrile [Ru]NCCH3+, 4,4-
diphenyl-hex-1,5-enyne (7a), and 3,3-diphenyl-hex-1,5-enyne
(8a), in a 3:2:1 ratio are isolated in high yield. Complex 4a can
be observed at the initial stage of the reaction at room
(30) (a) Alvarez, P.; Lastra, E.; Gimeno, J.; Bassetti, M.; Falvello, L. R. J. Am.
Chem. Soc. 2003, 125, 2386. (b) Diez, J.; Gamasa, M. P.; Gimeno, J.; Lastra,
E.; Villar, A. Organometallics 2005, 24, 1410. (c) Do¨tz, K. H.; Pfeiffer, J.
Transition Met. Org. Synth. 1998, 1, 335.
+
temperature, and eventually 7a, 8a, and [Ru]NCCH3 are
9
J. AM. CHEM. SOC. VOL. 127, NO. 51, 2005 18039

A R T I C L E S
Scheme 3
Yen et al.
Scheme 4
tathesis leading to separation of two carbon atoms is noticeably
observed by the disappearance of such a C-C coupling between
resonances of two enriched carbon atoms for 4a.
take place only at the vinylidene hydrogen indicating that
transformation of 3a to 4a is irreversible. The H-D exchange
is proposed to proceed via the pathway shown in Scheme 3.
Metathesis of 3a-D before H-D exchange should result in
formation of 4a-Db. Fast transformation of both vinylidene
complexes to acetylide complexes and proton and/or deuterium
should then create an opportunity for exchange of proton and
deuterium leading to the formation of 4a-D0 and 4a-D2. It is
less likely to obtain 4a-Da from 3a-D with only one deuteration
at the vinylidene group. In the 1H NMR spectrum of the product
isolated from 3a-D, we actually observed a vinylidene proton
and internal vinyl proton of a mixture of 4a-D0, 4a-Db, and
4a-D2. For a much faster transformation of vinylidene to
acetylide relative to that of metathesis, a statistical distribution
of 4a (no 4a-Da) should be obtained and the ratio of the
vinylidene proton to the internal vinyl proton is 2:1. Considering
the rate of metathesis is also fast, the observed ratio (3:2) is in
reasonable agreement with the theoretical value.
Definite evidence for the metathesis is obtained from a 13C
labeling study of the reaction. The 13C labeling at both CR and
Câ for 1 is readily achieved by using TMS13Ct13CH to prepare
the propargyl alcohol H13Ct13CC(Ph)2OH for the synthesis of
13CR,13Câ-allenylidene complex 1 from which the isolated
product 4a via 2a and 3a sequentially is found to have 13C
labeling at CR (triplet at δ 345.6 with JC-P ) 15.5 Hz) and an
internal vinyl CH unit (singlet at δ 143.8) with no CsC coupling
between the two carbon atoms. Portions of 13C spectra of
complexes 3a (the second trace from the top) and 4a (the middle
trace) obtained from 2a (the top trace) with 25% 13C enrichment
at CR and Câ are shown in Figure 1. The JC-C of 60.2 Hz
between two enriched carbon atoms is clearly seen in 3a,
indicating direct connectivity. Evidence of intramolecular me-
The indenyl analogue of 3a has been reported11a by Gimeno
and co-workers; however, no such transformation has been
observed. Instead, with the presence of a vinylphosphine bound
to the ruthenium metal center, the [2+2] cycloaddition of the
CdC bond of the vinylidene ligand and the vinyl group of the
phosphine ligand readily occurred.30a It seems that intricate steric
or electronic demand is required for an intramolecular metathesis
to take place.
Formation of Cyclic Allene from 3b. The vinylidene
complex 3b undergoes a different transformation process to give
the cyclic allene complex 6b in high yield; see Scheme 4. The
reaction takes place as soon as 3b is dissolved in solution, and
the reaction is completed in 10 min at room temperature. In
the 31P NMR spectrum of 6b two resonances at δ 41.3 and 40.9
with an AB pattern are observed indicating the presence of a
stereogenic carbon center in the six-membered ring ligand. The
1H NMR spectrum of 6b displays resonances attributed to one
methyl, one diastereotopic methylene, and three methyne groups.
Resonances of two allenic hydrogens appear at δ 5.39 and 2.70
with the latter showing JP-H ) 9.5 Hz thus assignable to the
coordinated portion of the allene ligand. Resonances of two
methyne and a methyl group are overlapped in the region of δ
1.55 and 1.66. The 1H-COSY 2D NMR spectrum reveals
couplings of all relevant resonances. In addition, the very
pertinent spectroscopic feature of 6b is the characteristic doublet
of the doublet 13C resonance at δ 144.7 with JP-C ) 22.6, 2.5
Hz assignable to the central carbon of the allene ligand in the
13C NMR spectrum. Protonation of complex 2b′ containing a
dppe ligand gave 6b′ directly in 97% yield. The vinylidene
complex was not observed. Both 6b and 6b′ in their solid state
9
18040 J. AM. CHEM. SOC. VOL. 127, NO. 51, 2005

Metathesis of a Vinyl Group with Vinylidene C
dC
A R T I C L E S
+
Figure 1. Part of 13C NMR spectra of Ru complexes 2a, 3a, 4a, 2b, and a mixture of 3b and 6b prepared from 25% 13C enriched [Ru]d13Cd13CdC(Ph)2
complex. For atom labeling, see inserted structure.
Table 1. Selected Bond Lengths [Å] and Angles [deg] for
Complex 6b
Ru(1)-P(1)
2.3724(11)
2.225(4)
1.396(6)
1.526(6)
1.549(6)
111.8(4)
119.8(4)
115.8(4)
Ru(1)-P(2)
2.3930(12)
2.088(4)
1.326(6)
1.518(6)
1.558(6)
126.9(4)
110.2(4)
101.4(3)
Ru(1)-C(1)
Ru(1)-C(2)
C(1)-C(2)
C(2)-C(3)
C(1)-C(6)
C(3)-C(4)
C(5)-C(6)
C(4)-C(5)
C(2)-C(1)-C(6)
C(2)-C(3)-C(4)
C(4)-C(5)-C(6)
C(1)-C(2)-C(3)
C(3)-C(4)-C(5)
C(1)-C(6)-C(5)
of a regular Ru-C bond for a ruthenium-allene coordination in
other crystallographically characterized ruthenium allene
complexes.3a The C(1)-C(2) bond length of 1.396(6) Å is in
the range of that of a regularly coordinated double bond. The
uncoordinated double bond of the allene ligand is slightly shorter
(1.326(6) Å). The bond angles C(6)-C(1)-C(2) and C(1)-
C(2)-C(3) of 111.8(4)° and 126.9(4)°, respectively, reveal the
effect of metal coordination of one double bond.
Figure 2. An ORTEP plot of complex 6b drawn at the 30% probability
level. Phenyl groups except the C(ipso) atoms on the phosphine ligand have
been omitted for clarity.
are stable, but 6b decomposed in solution in 4 h at room
temperature and 6b′ is stable.
Transformation of 3b to 6b could proceed via pathway A or
B depicted in Scheme 4. With a methyl group at the vinyl group,
complex 3b undergoes a C-C bond formation between the
terminal vinyl carbon atom and CR giving a six-membered ring
ligand with a stereogenic carbon center. This is followed by
metal and proton migration to give the product (pathway A).
However, the transformation could alternatively proceed via the
same [2+2] cycloaddition pathway B as that in 3a followed by
the same C-C bond formation mentioned above with a 1,3
Single crystals of 6b suitable for X-ray diffraction analysis
are obtained by recrystallization from acetone/diethyl ether. The
solid-state structure is determined. An ORTEP drawing is shown
in Figure 2, and representative bond lengths and angles are listed
in Table 1. The coordination around the Ru atom can be
described as a three-legged piano stool. The Ru-C(1) and Ru-
C(2) bond lengths of 2.225(4) and 2.088(4) Å are in the range
9
J. AM. CHEM. SOC. VOL. 127, NO. 51, 2005 18041

A R T I C L E S
Scheme 5
Yen et al.
between the gem-diphenyl group and the metal fraction.
Surprisingly, the analogous complex 3c′ containing the dppe
ligand would not undergo a similar transformation even under
thermolytic conditions. This may indicate that, in addition to
the steric effect, a proper orientation of two alkynyl groups is
required such that the metal moiety could migrate between two
CtC triple bonds. A slight difference in steric or electronic
environment deters such a transformation.
Treatment of 2d with acid affords the vinylidene complex
3d in almost quantitative yield. However even with a terminal
vinyl group tethered on the vinylidene ligand for 3d, no
metathesis of the two double bonds is observed. Thermolysis
in toluene causes extensive decomposition of 3d. Both
5-methylenebicyclo[2,1,1]hexane and 6-methylenebicyclo[3,1,1]-
heptane are known.31 And a simple calculation seems to indicate
that the latter has less ring strain. However, we do not see
formation of a metathesis product. As expected, complex 3e is
also a stable compound. The fact that complex 3d is stable with
respect to the metathesis process could reflect that, even with
the presence of a gem-diphenyl substituted group imposing the
steric effect, proper conditions do not exist in this complex like
the situation for the allyl terminus in 3a and 3b. The fact that
the vinylidene complex 3d failed to react may exemplify that
the reactivity of a given vinylidene is highly sensitive to the
structural changes at a site remote from the reacting double bond.
hydrogen shift to yield 6b. Deuteration should cause scrambling
of deuterium for the reaction proceeding via the pathway B
which is not experimentally observed. Considering the much
faster rate of the reaction and the presence of a more stable
tertiary carbocation, we believe this transformation could
preferably proceed via pathway A.
A labeling study using H13Ct13CC(Ph)2OH for the prepara-
tion of 3b reveals that the reaction proceeds via pathway A
giving the product 6b with labeling at two neighboring allenyl
carbon atoms (δ 144.3, 131.4 with JC-C ) 81.4 Hz); see the
bottom trace of Figure 1 which is the 13C NMR spectrum of a
mixture containing equal amounts of 3b and 6b. The 13C NMR
spectrum of 2b with 25% enriched 13C at CR and Câ is also
shown in Figure 1 for comparison.
Protonation of 2c. Vinylidene complex 3c with a terminal
alkynyl group on the chain bound at the vinylidene ligand is
obtained in almost quantitative yield from the protonation
reaction of 2c. Complex 3c is stable at room temperature.
However, when heated to 56 °C, complex 3c in solution is
converted to 4c in 4 h; see Scheme 5. If the thermolysis is carried
out in CH3CN, organic 1,5-diyne 9c is obtained in high yield.
Again 1H NMR spectra of 3c and 4c are informative illuminating
their structural features. The coupling pattern on the terminal
alkynyl proton and vinylidene proton noticeably discloses the
structural information. For 3c, the resonance at δ 4.81 assignable
to the vinylidene proton only couples with two phosphine
ligands. But the corresponding resonance at δ 4.67 for 4c is
observed to have additional coupling to the methylene protons
at δ 3.09 with JH-H ) 7.8 Hz indicating direct connectivity of
the methylene group with the vinylidene ligand. Transformation
of 3c to 4c could proceed via formation of a π-coordinated
alkyne complex from 3c followed by metal migration to the
terminal alkynyl group (see Scheme 5). Therefore it is not
surprising to observe formation of Rω-bisalkynyl compound 9c
when the reaction is carried out in CH3CN. The driving force
of such a transformation could be attributed to the steric effect
Concluding Remark
In summary, ruthenium complexes {[Ru]dCdCHCPh2-
CH2R}BF4 3a-3e containing vinylidene ligands tethering with
a terminal vinyl or alkynyl group were synthesized. For 3d (R
) CH2CHdCH2) and 3e (R ) Ph), normal behavior of a
vinylidene complex was observed. However, a novel intramo-
lecular metathesis process causes irreversible transformation of
3a (R ) CHdCH2) to 4a. Transformation of 3b (R ) CMed
CH2) to the cyclic allene complex 6b involved a CsC bond
formation giving a six-membered ring and a change of
coordination to a η2-allene mode. For 3c (R ) CtCH), a metal
moiety could also irreversibly migrate to the terminal alkynyl
group to give 4c possibly with less steric demand between the
metal center and the ligand. In vinylidene complexes 3a, 3b,
and 3c, a gem-diphenyl moiety along with an unsaturated
functional group properly aligned with the vinylidene ligand in
a particular orientation could be the reason for such a novel
reactivity to take place. In contrast, the vinylidene complexes
3d and 3e failed to react, illustrating that the reactivity of a
given vinylidene is highly sensitive to the structural changes at
a site remote from the reacting double bond.
Experimental Section
General Procedures. The manipulations were performed under an
atmosphere of dry nitrogen using vacuum-line and standard Schlenk
techniques. Solvents were dried by standard methods and distilled under
nitrogen before use. All reagents were obtained from commercial
suppliers (TMS13Ct13CH from Isotec) and used without further
purification. Compounds [Cp(PPh3)2Ru(dCdCdCPh2)][PF6] (1) and
its dppe analogues [Cp(dppe)Ru(dCdCdCPh2)][PF6] (1′) were pre-
pared by following the methods28 reported in the literature. Infrared
(31) (a) Roth, W. R.; Enderer, K. Justus Liebigs Ann. Chem. 1970, 733, 44. (b)
Wiberg, K. B.; Chen, W. J. Org. Chem. 1972, 37, 3235. (c) Inoue, Y.;
Mukai, T.; Hakushi, T. Chem. Lett. 1982, 1045. (d) Binmore, G. T.; Della,
E. W.; Janowski, W. K.; Mallon, P.; Walton, J. C. Aust. J. Chem. 1994,
47, 1285.
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Metathesis of a Vinyl Group with Vinylidene C
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A R T I C L E S
spectra were recorded on a Nicolet-MAGNA-550 spectrometer. The
C, H, and N analyses were carried out with a Perkin-Elmer 2400
microanalyzer. Mass spectra (FAB) were recorded using a JEOL SX-
102A spectrometer; 3-nitrobenzyl alcohol (NBA) was used as the
matrix. NMR spectra were recorded on a Bruker AC-300 instrument
at 300 MHz (1H), 121.5 MHz (31P), or 75.4 MHz (13C) using SiMe4 or
85% H3PO4 as a standard or an Avance 500 FT-NMR spectrometers.
755.2 (M+ - PF6); 565.1 (M+ - PF6, -C3(Ph)2). Anal. Calcd for
C46H39P3F6Ru: C, 61.40; H, 4.36. Found: C, 61.48; H, 4.42.
Spectroscopic data for [Ru]sCtCsC(Ph)2CH2CHdCH2 (2a′, [Ru]
) Cp(dppe)Ru, 89% yield): 1H NMR (C6D6): δ 8.03-7.06 (m, 30H,
Ph); 5.95 (m, 1H, CHdCH2); 4.96 (dd, 2H, CHdCH2, JH-H ) 10.5,
14.3 Hz); 4.92 (s, 5H, Cp); 2.83 (d, 2H, C(Ph)2CH2, JH-H ) 6.55 Hz);
2.49, 2.13 (m, 4H, CH2 of dppe). 31P NMR (C6D6): δ 87.2. 13C NMR
(C6D6): δ 149.2-125.2 (Ph); 115.1 (CHdCH2); 112.2 (Câ); 98.2 (CR);
82.6 (Cp); 51.5 (Cγ); 47.2 (C(Ph)2CH2); 27.9 (CH2 of dppe). MS(FAB)
m/z: 796.1 (M+); 565.1 (M+ - C3(Ph)2, CH2CHdCH2). Anal. Calcd
for C49H44P2Ru: C, 73.94; H, 5.57. Found: C, 74.02; H, 5.63.
Spectroscopic data for 2b′ (90% yield): 1H NMR (C6D6): δ 7.96-
7.06 (m, 30H, Ph); 4.94 (s, 5H, Cp); 4.87 (s, 1H, -CH2); 4.61 (s, 1H,
-CH2); 2.84 (s, 2H, CH2); 2.28, 1.97 (m, 4H, CH2 of dppe); 1.67 (s,
3H, CH3). 31P NMR (C6D6): δ 86.8. 13C NMR (C6D6): δ 149.7-112.3
(Ph); 114.1 (-CH2); 112.3 (Câ); 98.5 (CR); 82.3 (Cp); 51.1 (Cγ); 49.6
Synthesis of Complex [Ru]sCtCsC(Ph)2CH2R (2a, R ) CHd
CH2). To a 30 mL THF solution of 1 (0.2 g, 0.19 mmol) was added
CH2CHdCH2MgBr (1.0 M in Et2O; 0.19 mL, 0.19 mmol). The mixture
is stirred at -20 °C for 30 min. Then the solution was warmed to room
temperature, and the solvent was removed under vacuum. The solid
residue was first dissolved in CH2Cl2 (5 mL), and then MeOH (15
mL) was added. While the volume of the solvent of the resulting yellow-
orange solution was reduced to 5 mL, yellow precipitate formed which
was filtered and washed with cold MeOH (2 × 5 mL) and dried under
vacuum to give 2a (yield 85%). Spectroscopic data for 2a: 1H NMR
(C6D6): δ 7.75-6.86 (m, 40H, Ph), 6.34 (m, 1H, dCH), 5.01 (dd, 2H,
JHH ) 21.0 Hz, JHH ) 12.0 Hz, dCH2), 4.46 (s, 5H, Cp), 3.27 (d, 2H,
JHH ) 6.0 Hz, CH2). 31P NMR (C6D6): δ 51.0. 13C NMR (C6D6): δ
149.8-125.4 (m, Ph), 138.2 (s, dCH), 115.7 (s, dCH2), 115.1 (s, Câ),
97.4 (t, JCP ) 23.9 Hz, CR), 85.7 (s, Cp), 51.9 (s, Cγ), 48.0 (s, CH2).
Mass m/z 922.3 (M+), 881.2 (M+ - CH2CHdCH2), 619.2 (M+ - CH2-
CHdCH2 - PPh3). IR (KBr, cm-1) ν 2083 (CtC). Anal. Calcd for
C59H50P2Ru: C, 76.85; H, 5.47. Found: C, 76.80; H, 5.57.
(CH2); 27.5 (CH2 of dppe); 24.7 (CH3). MS(FAB) m/z: 811.2 (M+
+
1); 755.1 (M+ - CH2C(CH3)CH2); 565.1 (M+ - C3(Ph)2CH2C(CH3)-
CH2). Anal. Calcd for C49H46P2Ru: C, 73.75; H, 5.81. Found: C, 73.81;
H, 5.88.
Spectroscopic data for 2c′ (88% yield): 1H NMR (C6D6): δ 8.06-
7.06 (m, 30H, Ph); 4.92 (s, 5H, Cp); 2.85 (d, 2H, CH2, JH-H ) 2.45
Hz); 2.57, 2.15 (m, 4H, CH2 of dppe); 1.67 (t, 1H, tCH, JH-H ) 2.45
Hz). 31P NMR (C6D6): δ 87.4. 13C NMR (C6D6): δ 148.1-125.5 (Ph);
112.2 (Câ); 99.4 (CR); 83.4 (tC); 82.6 (Cp); 70.3 (tC); 51.1 (Cγ);
33.9 (CH2); 28.1 (CH2 of dppe). MS(FAB) m/z: 794.2 (M+); 755.2
(M+ - CH2CtCH); 565.1 (M+ - C3(Ph)2, CH2CtCH). Anal. Calcd
for C49H42P2Ru: C, 74.13; H, 5.33. Found: C, 74.19; H, 5.39.
Spectroscopic data for 2d′ (91% yield): 1H NMR (C6D6): δ 8.05-
7.02 (m, 30H, Ph); 5.96 (m, 1H, dCH); 5.11 (dd, 2H, dCH2); 4.91 (s,
5H, Cp); 2.46, 2.18, 2.10 (m, 4H, 2H, 2H, CH2 of dppe, 2CH2). 31P
NMR (C6D6): δ 87.2. 13C NMR (C6D6): δ 149.5-125.1 (Ph); 113.4
(dCH2); 112.3 (Câ); 97.8 (CR); 82.5 (Cp); 51.7 (Cγ); 41.7 (CH2); 30.7
Complexes 2b-2e (2b, R ) CMedCH2; 2c, R ) CtCH; 2d, R )
CH2CHdCH2; 2e, R ) Ph) were similarly prepared. Spectroscopic data
for 2b (in 85% yield): 1H NMR (C6D6): δ 7.64-6.86 (m, 40H, Ph),
5.10 (s, 1H, dCH2), 4.97 (s, 1H, dCH2), 4.48 (s, 5H, Cp), 3.29 (s, 2H,
CH2), 1.90 (s, 3H, CH3). 31P NMR (C6D6): δ 50.3. 13C NMR (C6D6):
δ 150.0-125.2 (m, Ph), 143.4 (s, dCCH3), 115.2 (s, Câ), 114.6 (s,
dCH2), 96.7 (t, JCP ) 24.1 Hz, CR), 51.3 (s, Cγ), 50.8 (s, CH2), 24.9
(s, CH3). Mass m/z 936.0 (M+), 881.0 (M+ - CH2CMedCH2), 691.1
(M+ - C2CPh2CH2CMedCH2). IR (KBr, cm-1) ν 2082 (CtC). Anal.
Calcd for C60H52P2Ru: C, 76.99; H, 5.60. Found: C, 76.95; H, 5.74.
Spectroscopic data for 2c (yield 87%): 1H NMR (C6D6): δ 7.76-
6.87 (m, 40H, Ph), 4.50 (s, 5H, Cp), 3.31 (d, JHH ) 2.1 Hz, CH2), 1.74
(t, JHH ) 2.1 Hz, CtCH). 31P NMR (C6D6): δ 51.2. 13C NMR (C6D6):
δ 148.5-125.7 (m, Ph), 114.4 (s, Câ), 98.6 (t, JCP ) 24.1 Hz, CR),
85.6 (s, Cp), 83.5 (s, CtC), 71.0 (s, tCH), 51.4 (s, Cγ), 34.9 (s, CH2).
Mass m/z 920.0 (M+), 881.0 (M+ - CH2CtCH), 691.2 (M+ - C2-
CPh2CH2CtCH). IR (KBr, cm-1) ν 2084 (CtC). Anal. Calcd for
C59H48P2Ru: C, 77.02; H, 5.26. Found: C, 77.15; H, 5.31.
(CH2); 27.8 (CH2 of dppe). MS(FAB) m/z: 810.2 (M+); 755.2 (M+
-
CH2CH2CHdCH2); 565.1 (M+ - C3(Ph)2, CH2CH2CHdCH2). Anal.
Calcd for C50H46P2Ru: C, 74.14; H, 5.72. Found: C, 74.21; H, 5.80.
Synthesis of Vinylidene Complex {[Ru]dCdCHC(Ph)2CH2R}-
BF4 (3a, R ) CHdCH2). To a Schlenk flask charged with 2a (0.1 g,
0.11 mmol) in diethyl ether (15 mL), HBF4 (54% in Et2O) was added
dropwise at 0 °C under nitrogen. Immediately, a pink precipitate formed,
but addition of HBF4 was continued until no further solid formed. The
precipitate was filtered and washed with diethyl ether (2 × 10 mL)
and dried under vacuum to give 3a (yield 95%). Spectroscopic data
for 3a: 1H NMR (CDCl3): δ 7.40-6.92 (m, 40H, Ph), 5.02 (m, 1H,
dCH), 5.00 (s, 5H, Cp), 4.87 (m, 2H, dCH2), 4.45 (t, 1H, 4JPH ) 3.0
Hz, CdCH), 3.06 (s, 2H, JHH ) 6.0 Hz, CH2). 31P NMR (CDCl3): δ
42.1. Mass m/z 923.3 (M+ - BF4), 691.2 (M+ - BF4 - C2HCPh2-
CH2CHdCH2). Anal. Calcd for C59H51BF4P2Ru: C, 70.17; H, 5.09.
Found: C, 70.14; H, 5.12.
Spectroscopic data for 2d (in 85% yield): 1H NMR (C6D6): δ 7.76-
6.86 (m, 40H, Ph), 5.90 (m, 1H, dCH), 4.96 (m, 2H, dCH2), 4.46 (s,
5H, Cp), 2.58-2.46 (m, 4H, CH2CH2). 31P NMR (C6D6): δ 50.9. 13C
NMR (C6D6): δ 150.2-125.5 (m, Ph), 140.4 (s, dCH), 115.0 (s, Câ),
113.8 (s, dCH2), 97.1 (t, JCP ) 23.9 Hz, CR), 52.3 (s, Cγ), 42.6 (s,
CH2), 31.0 (s, CH2). Mass m/z 936.1 (M+), 881.0 (M+ - CH2CH2-
Complexes 3b-3e (3b, R ) CMedCH2; 3c, R ) CtCH; 3d, R )
CH2CHdCH2; 3e, R ) Ph) were similarly prepared. Spectroscopic data
for 3b (yield 91%): 1H NMR (CDCl3): δ 7.56-6.76 (m, 40H, Ph),
4.99 (s, 5H, Cp), 4.62 (s, 1H, dCH2), 4.56 (t, 1H, 4JPH ) 3.0 Hz, Cd
CH), 4.53 (s, 1H, dCH2), 3.10 (s, 2H, CH2), 0.86 (s, CH3). 31P NMR
(CDCl3): δ 42.1.
CHdCH2), 691.1 (M+ - C2CPh2CH2CH2CHdCH2). IR (KBr, cm-1
)
ν 2083 (CtC). Anal. Calcd for C60H52P2Ru: C, 76.99; H, 5.60.
Found: C, 76.95; H, 5.78.
Spectroscopic data for 2e (in 83% yield): 1H NMR (C6D6): δ 7.55-
6.84 (m, 45H, Ph), 4.46 (s, 5H, Cp), 3.79 (s, 2H, CH2). 31P NMR
(C6D6): δ 50.2. 13C NMR (C6D6): δ 149.6-125.3 (m, Ph), 114.9 (s,
Câ), 97.8 (t, JCP ) 24.1 Hz, CR), 52.9 (s, Cγ), 49.1 (s, CH2). Mass m/z
972.4 (M+), 881.3 (M+ - CH2Ph), 691.2 (M+ - C2CPh2CH2Ph). IR
(KBr, cm-1) ν 2077 (CtC). Anal. Calcd for C63H52P2Ru: C, 77.84;
H, 5.39. Found: C, 77.98; H, 5.49.
Spectroscopic data for 3c (yield 94%): 1H NMR (CDCl3): δ 7.41-
4
6.84 (m, 40H, Ph), 5.05 (s, 5H, Cp), 4.81 (t, JPH ) 3.0 Hz, CdCH),
4
4
3.00 (d, JHH ) 2.1 Hz, CH2), 1.96 (t, JHH ) 2.1 Hz, CtCH). 31P
NMR (CDCl3): δ 41.5. 13C NMR (CDCl3): δ 346.7 (t, JP-C ) 15.1
Hz, CR), 145.7-127.1 (m, Ph), 120.1 (Câ), 94.5 (Cp), 81.1 (CtCH),
72.6 (≡CH), 50.5 (Cγ), 33.4 (CH2). Mass m/z 920.0 (M+ - 1 - BF4),
691.0 (M+ - BF4 - C2HCPh2CH2CtCH). Anal. Calcd. for C59H49-
BF4P2Ru: C, 70.31; H, 4.90. Found: C, 70.38; H, 5.08.
Dppe analogues 2a′-2d′ ([Ru] ) Cp(dppe)Ru) were also prepared
from 1′ and corresponding Grignard reagents using similar methods.
Spectroscopic data for 1′: 1H NMR (CDCl3): δ 7.56-7.00 (m, 30H,
Ph); 5.34 (s, 5H, Cp); 2.80 (m, 4H, CH2 of dppe). 31P NMR (CDCl3):
δ 82.2. 13C NMR (CDCl3): δ 290.8 (CR); 204.9 (Câ); 157.7 (Cγ);
142.7-128.1 (Ph); 91.2 (Cp); 28.5 (CH2 of dppe). MS (FAB) m/z:
Spectroscopic data for 3d (yield 96%): 1H NMR (CDCl3): δ 7.41-
6.81 (m, 40H, Ph), 5.69 (m, 1H, dCH), 5.00 (s, 5H, Cp), 4.90 (s, 2H,
4
dCH2), 4.59 (t, 1H, JPH ) 3.0 Hz, CdCH), 2.36 (m, 2H, CH2), 1.54
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A R T I C L E S
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(m, 2H, CH2). 31P NMR (CDCl3): δ 41.8. 13C NMR (CDCl3): δ 347.5
(t, JP-C ) 15.1 Hz, CR), 146.7-126.7 (Ph), 137.7 (dCH), 120.2 (d
CH2), 115.0 (Câ), 94.2 (Cp), 50.9 (Cγ), 41.0, (CH2), 29.2 (CH2). Mass
m/z 936.1 (M+ - 1 - BF4), 691.1 (M+ - BF4 - C2HCPh2CH2CH2-
CHdCH2). Anal. Calcd for C60H53BF4P2Ru: C, 70.38; H, 5.22.
Found: C, 70.43; H, 5.20.
8a as a colorless oil (yield 87%). Spectroscopic data of 7a are consistent
with that of literature data.
Preparation of 8a. A Schlenk flask was charged with 4a (0.1 g,
0.11 mmol) and CH3CN (15 mL). The solution was heated to reflux
under nitrogen for 1 h and then cooled to room temperature. The solvent
was reduced to 5 mL under vacuum, and then the residual mixture
was added to 30 mL of diethyl ether. The pale-orange precipitate thus
formed was filtered and washed with diethyl ether (2 × 10 mL) and
dried under vacuum to give {[Ru]NCCH3}BF4. The filtrate was
evaporated to dryness, and crude product was purified by column
chromatography on silica gel with hexanes as eluent. Evaporation of
the solvent gave terminal enyne 8a as a colorless oil (yield 77%).
Spectroscopic data for 8a: 1H NMR (CDCl3): δ 7.31-7.19 (m, 10H,
Ph), 6.52 (dd, 1H, JHH ) 17.7 Hz, JHH ) 10.8 Hz, dCH), 5.28 (d, 1H,
JHH ) 10.8 Hz, dCH2), 4.86 (d, 1H, JHH ) 17.7 Hz, dCH2), 3.12 (d,
2H, JHH ) 2.4 Hz, CH2), 1.90 (t, 1H, JHH ) 2.4 Hz, tCH). 13C NMR
(CDCl3): δ 145.1 (s, Ph), 143.8 (s, dCH), 128.5 (s, Ph), 128.2 (s,
Ph), 126.5 (s, Ph), 115.3 (s, dCH2), 81.6 (s, tC), 71.5 (s, tCH), 53.5
(s, CPh2), 30.1 (s, CH2).
Conversion of 3a′ to 4a′. Complex 3a′ (90 mg, 0.113 mmol) was
dissolved in 10 mL of CH2Cl2 and stirred for 1 h at room temperature.
Then diethyl ether was added, and 5a was precipitated as an orange
solid which was filtered and washed with ether and dried under vacuum
to give 4a′ (85 mg, 0.106 mmol) in 93% yield. Spectroscopic data for
4a′: 1H NMR (CDCl3): δ 7.67-6.70 (m, 30H, Ph); 6.00 (m, 1H, d
CH, JH-H ) 10.8, 16.8 Hz); 5.22 (s, 5H, Cp); 5.03 (d, 1H, dCH2,
JH-H ) 10.7 Hz); 4.43 (d, 1H, dCH2, JH-H ) 17.5 Hz); 3.20 (t, 1H,
CdCH, JH-H ) 7.25 Hz); 2.76 (m, 4H, CH2 of dppe); 2.21 (d, 2H,
CH2, JH-H ) 7.25 Hz). 31P NMR (CDCl3): δ 87.2. 13C NMR (CDCl3):
δ 341.7 (t, CR, JP-C ) 16.3 Hz); 145.2-126.2 (Ph); 114.5 (Câ); 108.5
(dCH2); 91.4 (Cp); 53.2 (Cγ); 28.7 (CH2); 27.3 (CH2 of dppe). MS
(FAB) m/z: 796.1 (M+ - 1); 565.1 (M+ - 1, sC3(Ph)2, CH2CHCH2).
Anal. Calcd for C49H45P2BRuF4: C, 66.59; H, 5.13. Found: C, 66.62;
H, 5.18.
Preparation of 6b. A Schlenk flask was charged with 3b (0.10 g,
0.10 mmol) and CH2Cl2 (15 mL) under nitrogen. The solution was
stirred at room temperature for 1 min. The solvent was reduced to 5
mL under vacuum, and then 30 mL of diethyl ether were added to
give an orange precipitate which was filtered and washed with diethyl
ether (2 × 10 mL) and dried under vacuum to give 6b (yield 83%).
Spectroscopic data for 6b: 1H NMR (CD2Cl2): δ 7.58-6.30 (m, 40H,
Ph), 5.39 (br, 1H, dCH), 4.96 (s, 5H, Cp), 2.76 (d, JHH ) 14.0 Hz, 1H
of CH2), 2.70 (t, JP-H ) 10.0 Hz, br, 1H, dCH), 1.66 (m, 1H, CH),
1.56 (d, JHH ) 5.5 Hz, CH3 + 1H of CH2). 31P NMR (CDCl3): δ 41.3,
40.9 (d, JP-P ) 36.4 Hz, 2 PPh3). 13C NMR (CD2Cl2, 258K): δ 151.1-
125.5 (Ph), 144.7 (dd, JP-C ) 22.6, 2.5 Hz, dCd), 131.6 (dCH); 90.4
(Cp), 57.7 (CPh2), 51.2 (CH2), 43.4 (dCH), 35.2 (dCH), 20.3 (CH3).
Mass m/z 937.1 (M+ - BF4), 675.1 (M+ - BF4 - PPh3). Anal. Calcd
for C60H53BF4P2Ru: C, 70.38; H, 5.22. Found: C, 70.29; H, 5.17.
Spectroscopic data for 6b′: 1H NMR (CDCl3): δ 7.68-6.65 (m,
30H, Ph); 5.04 (s, 5H, Cp); 4.96 (s, 1H, CH); 3.25, 2.70, 2.62, 2.25
(m, 4H, CH2 of dppe); 2.40, 1.42 (m, 2H, C(Ph)2CH2); 1.17 (m, 1H,
CH); 1.14 (m, 1H, CH); 0.82 (d, JH-H ) 7.9 Hz, 3H, CH3). 31P NMR
(CDCl3): δ 78.1, 74.2 (AX, JP-P ) 25.1 Hz). 13C NMR (CDCl3): δ
151.1-126.4 (Ph); 143.5 (d, JP-C ) 24.8 Hz, dCd); 132.7 (dCH);
90.6 (Cp); 58.1 (CPh2); 51.2 (CH2); 43.2 (C(CH3)); 32.9 (dCH); 27.5,
24.8 (CH2 of dppe); 19.2 (CH3). MS (FAB) m/z: 811.2 (M+ - BF4);
565.1 (M+ - BF4, C3(Ph)2CH2C(CH3)CH2). Anal. Calcd for C49H47P2-
BF4Ru: C, 66.44; H, 5.34. Found: C, 66.49; H, 5.41.
Spectroscopic data for 3e (yield 93%): 1H NMR (CDCl3): δ 7.39-
4
6.39 (m, 45H, Ph), 4.96 (s, 5H, Cp), 4.10 (t, 1H, JPH ) 3.0 Hz, Cd
CH), 3.65 (s, 2H, CH2). 31P NMR (CDCl3): δ 42.0. 13C NMR
(CDCl3): δ 346.8 (t, JP-C ) 15.1 Hz, CR), 147.0-126.8 (Ph), 118.7
(Câ), 94.7 (Cp), 53.0 (Cγ), 49.2, (CH2). Mass m/z 973.1 (M+ - BF4),
881.1 (M+ - BF4 - CH2Ph), 691.0 (M+ - BF4 - C2HCPh2CH2Ph).
Anal. Calcd for C63H53BF4P2Ru: C, 71.39; H, 5.04. Found: C, 71.43;
H, 5.11.
Complexes 3a′, 3c′, and 3d′ were also prepared using similar
procedures. Spectroscopic data for 3a′ (96% yield): 1H NMR
(CDCl3): δ 7.47-6.67 (m, 30H, Ph); 5.84 (m, 1H, dCH); 5.23 (s,
5H, Cp); 4.83 (m, 1H, dCH2); 3.45 (s, 1H, CdCH); 2.73 (m, 4H, CH2
of dppe); 2.27 (d, 2H, CH2C(Ph)2). 31P NMR (CDCl3): δ 77.6. Complex
3b′ was not obtained. Upon protonation of 2b′ complex 6b′ was directly
obtained in 97% yield.
Spectroscopic data for 3c′ (95% yield): 1H NMR (CDCl3): δ 7.50-
6.69 (m, 30H, Ph); 5.39 (s, 5H, Cp); 4.96 (s, 1H, CH); 3.75 (s, 1H,
CHC(Ph)2); 2.80 (m, 4H, CH2 of dppe); 2.15 (d, 2H, CH2; JH-H ) 2.4
Hz); 1.94 (t, 1H, tCH, JH-H ) 2.4 Hz). 31P NMR (CDCl3): δ 77.5.
13C NMR (CDCl3): δ 343.2 (t, CR, JP-C ) 15.5 Hz); 145.9-126.7
(Ph); 120.9 (Câ); 91.8 (Cp); 81.3 (tC); 72.4 (tCH); 49.7 (Cγ); 31.8
(CH2); 26.9 (CH2 of dppe). MS(FAB) m/z: 795.2 (M+); 755.2 (M+
-
1, sCH2CtCH); 565.1 (M+ - C3H(Ph)2, CH2CtCH). Anal. Calcd
for C49H43P2BF4Ru: C, 66.75; H, 4.91. Found: C, 66.82; H, 4.98.
Spectroscopic data for 3d′ (93% yield): 1H NMR (CDCl3): δ 7.51-
6.56 (m, 30H, Ph); 5.52 (m, 1H, dCH); 5.32 (s, 5H, Cp); 4.89 (d, 1H,
dCH2, JH-H ) 8.1 Hz); 4.83 (d, 1H, dCH2, JH-H ) 17.2 Hz); 3.68 (s,
1H, CH); 2.83, 2.58 (m, 4H, CH2 of dppe); 1.56 (br, 4H, 2CH2). 31P
NMR (CDCl3): δ 77.8. 13C NMR (CDCl3): δ 341.5 (t, CR); 147.1-
126.0 (Ph); 120.8 (Câ); 114.6 (dCH2); 91.5 (Cp); 51.4 (Cγ); 39.9 (CH2);
29.5 (CH2); 26.7 (CH2 of dppe). MS(FAB) m/z: 811.2 (M+); 755.2
(M+ - CH2CH2CHdCH2); 565.1 (M+ - C3H(Ph)2, CH2CH2CHdCH2).
Anal. Calcd for C50H47P2BF4Ru: C, 66.89; H, 5.27. Found: C, 66.93;
H, 5.31.
Preparation of Complex {[Ru]dCdCHCH2C(Ph)2CHdCH2}-
BF4 (4a). A Schlenk flask was charged with 3a (0.1 g, 0.11 mmol)
and CH2Cl2 (15 mL). The solution was heated to reflux under nitrogen
for 4 h and then cooled to room temperature. The solvent was reduced
to 5 mL under vacuum, and then the residual mixture was added to 30
mL of diethyl ether. The orange precipitate thus formed was filtered
and washed with diethyl ether (2 × 10 mL) and dried under vacuum
to give 4a (yield 90%). Spectroscopic data for 4a: 1H NMR (CDCl3):
δ 7.41-6.78 (m, 40H, Ph), 6.51 (dd, 1H, JHH ) 18.0, 10.8 Hz, dCH),
5.29 (d, 1H, JHH ) 10.8 Hz, dCH2), 4.87 (s, 5H, Cp), 4.71 (d, 2H, JHH
) 18.0 Hz, dCH2), 4.40 (m, 1H, CdCH), 3.09 (d, 2H, JHH ) 7.8 Hz,
CH2). 31P NMR (CDCl3): δ 43.9. 13C NMR (C6D6): δ 345.6 (t, JP-C
) 15.1 Hz, CR), 145.4-126.6 (Ph), 143.7 (dCH), 115.3 (dCH2), 110.5
(s, Câ), 94.4 (s, Cp), 54.0 (s, Cγ), 31.9 (s, CH2). Mass m/z 923.3 (M+
- BF4), 691.2 (M+ - BF4 - C2H CH2CPh2CHdCH2). Anal. Calcd
for C59H51BF4P2Ru: C, 70.17; H, 5.09. Found: C, 70.19; H, 5.15.
Thermolysis of 3a in Acetonitrile. Complex 3a (0.1 g, 0.11 mmol)
was dissolved in 15 mL of CH3CN at room temperature. The solution
was heated to reflux for 1 h under nitrogen. Solvent was then removed
under vacuum. The solvent was reduced to 5 mL under vacuum, and
then the residual mixture was added to 30 mL of diethyl ether. The
pale-orange precipitate thus formed was filtered and washed with diethyl
ether (2 × 10 mL) and dried under vacuum to give {[Ru]NCCH3}BF4.
The filtrate was evaporated to dryness, and the crude product was
purified by column chromatography on silica gel with hexanes as eluent.
Evaporation of the solvent gave a mixture of terminal enyne 7a and
Preparation of 4c. A Schlenk flask was charged with 3c (0.1 g,
0.10 mmol) and CHCl3 (10 mL)/CH2Cl2 (5 mL) under nitrogen. The
resulting solution was heated to reflux for 4 h and then cooled to room
temperature. The solvent was reduced to 5 mL under vacuum, and the
mixture was added to 30 mL of diethyl ether. The gray precipitate thus
formed was filtered and washed with diethyl ether (2 × 10 mL) and
dried under vacuum to give 4c (yield 74%). Spectroscopic data for 4c:
9
18044 J. AM. CHEM. SOC. VOL. 127, NO. 51, 2005

Metathesis of a Vinyl Group with Vinylidene C
dC
A R T I C L E S
1H NMR (CDCl3): δ 7.77-6.79 (m, 40H, Ph), 4.83 (s, 5H, Cp), 4.67
(m, 1H, CdCH), 3.09 (d, JHH ) 7.8 Hz, CH2), 2.78 (s, tCH). 31P
solved and refined by the SHELXTL33 program. The structure was
solved using direct methods and confirmed by Patterson methods
refining on intensities of all data (33 919 reflections) to give R1 )
0.0584 and wR2 ) 0.1370 for 11 445 unique observed reflections (I
> 2σ(I)). Hydrogen atoms were placed geometrically using the riding
model with thermal parameters set to 1.2 times that for the atoms to
which the hydrogen is attached and 1.5 times that for the methyl
hydrogens.
NMR (CDCl3): δ 43.8. Mass m/z 921.1 (M+ - BF4), 691.1 (M+
-
BF4 - C2HCH2CPh2CtCH). Anal. Calcd for C59H49BF4P2Ru: C,
70.31; H, 4.90. Found: C, 70.37; H, 5.03.
The same reaction in CH3CN for 1 h gave [Ru]NCCH3 and
+
HCtCC(Ph)2CH2CtCH, 9c. Two products were separated by the
method used for the separation of 8a and [Ru]NCCH3+. Spectroscopic
data for 9c (yield 83%): 1H NMR (CDCl3): δ 7.49-7.21 (m, 10H,
Ph), 3.16 (d, 1H, JHH ) 2.4 Hz, tCH), 2.66 (s, 1H, tCH), 2.01 (t,
1H, JHH ) 2.4 Hz, CH2). 13C NMR (CDCl3): δ 143.3 (s, Ph), 128.3 (s,
Ph), 127.4 (s, Ph), 127.1 (s, Ph), 87.2 (s, tC), 80.7 (s, tC), 73.9 (s,
tCH), 71.4 (s, tCH), 48.9 (s, CPh2), 32.7 (s, CH2).
Single-Crystal X-ray Diffraction Analysis of 6b. Single crystals
of 6b suitable for an X-ray diffraction study were grown as mentioned
above. A single crystal of dimensions 0.25 × 0.20 × 0.15 mm3 was
glued to a glass fiber and mounted on an SMART CCD diffractometer.
The diffraction data were collected using 3 kW sealed-tube Mo KR
radiation (T ) 295 K). Exposure time was 5 s per frame. SADABS32
(Siemens area detector absorption) absorption correction was applied,
and decay was negligible. Data were processed, and the structure was
Acknowledgment. This research is supported by the National
Science Council of Taiwan, the Republic of China. Valuable
suggestions on the mechanism from Professor Kung Wang of
West Virginia University and Professor Charles P. Casey of
University of Wisconsin at Madison are gratefully acknowl-
edged.
Supporting Information Available: Complete crystallo-
graphic data for 6b (CIF). This material is available free of
charge via the Internet at http://pubs.acs.org.
JA054994A
(32) The SADABS program is based on the method of Blessing; see: Blessing,
(33) SHELXTL: Structure Analysis Program, version 5.04; Siemens Industrial
R. H. Acta Crystallogr., Sect. A 1995, 51, 33-38.
Automation Inc.: Madison, WI, 1995.
9
J. AM. CHEM. SOC. VOL. 127, NO. 51, 2005 18045