Addition of alkynes to coordinated allyl ether in ruthenium(II) chelate complexes

Article abstract of DOI:10.1021/om990473i

Reactions of the ruthenium chelate complex [Ru(η⁵-η²-C₅Me₄CH ₂OCH₂CH=CH₂)(CO)Cl] (1) with acetylenes R¹C=CR² in the presence of AgBF₄ give the ca

Full text of DOI:10.1021/om990473i

5276
Organometallics 1999, 18, 5276-5284
Ad d ition of Alk yn es to Coor d in a ted Allyl Eth er in
Ru th en iu m (II) Ch ela te Com p lexes
Oleg V. Gusev,*,† Alexander M. Kal’sin,† Larisa N. Morozova,†
Pavel V. Petrovskii,† Konstantin A. Lyssenko,† Oleg L. Tok,† Alfred F. Noels,‡
Shane R. O’Leary,§ and Peter M. Maitlis§
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
Vavilov Street 28, 117813 Moscow, Russia, Universite de Liege, Liege, Belgium, and
Department of Chemistry, The University of Sheffield, Sheffield S3 7HF, U.K.
Received J une 18, 1999
Reactions of the ruthenium chelate complex [Ru(η5:η2-C5Me4CH2OCH2CHdCH2)(CO)Cl]
(1) with acetylenes R1CtCR2 in the presence of AgBF4 give the cationic diene chelates [Ru-
(η5:η4-C5Me4CH2OCH2CHdCHCR1dCHR2)(CO)]+BF4- (2a , R1 ) R2 ) Ph; 3a , R1 ) R2 ) Me;
4a , R1 ) Me, R2 ) Ph; 4b, R1 ) Ph, R2 ) Me; 5a , R1 ) H, R2 ) CO2Me; 5b, R1 ) CO2Me, R2
) H; 6a , R1 ) H, R2 ) CH2OMe) and {Ru[η5:η4-C5Me4CH2OCH2C(dCH2)CHdCHPh](CO)}+-
-
-
-
BF4 (7). The crystal structures of [2a ′′]+PF6 and [7]+PF6 have been determined. The
formation of complexes 2-6 is the result of regiospecific addition of acetylenes PhCtCMe,
MeCtCMe, PhCtCMe, HCtCCO2Me, and HCtCCH2OMe to the terminal carbon of the
allylic ether, while phenylacetylene adds to the internal carbon of the olefin. The unsymmetric
acetylenes (PhCtCMe, HCtCCO2Me) give predominantly the isomers 4a and 5a , where
the allylic C-H has added to the acetylenic carbon bearing the less bulky substituent. The
complex [Ru(η5:η2-Me4C5CH2OCH2CHdCH2)(η1-CtCPh)(CO)] (8) was synthesized by the
reaction of 1 with PhCtCLi in THF; the protonation of 8 with Et2O‚HBF4 gave 7.
In tr od u ction
of our study of cross-addition of acetylenes to the
coordinated olefin in the chelate ruthenium complex
[Ru(η5:η2-C5Me4CH2OCH2CHdCH2)(CO)Cl] (1).
The ruthenium-catalyzed cross-additions of acetylenes
to olefins, leading to the formation of dienes or unsatur-
ated aldehydes and ketones, have recently attracted the
attention of several research groups.1-3 The reason for
this strong interest is the high chemoselectivity, which
affords organic compounds difficult to make by other
methods.1-4 Monosubstituted olefins and both terminal
and internal acetylenes are commonly used as the
reagents, and a ruthenacyclopentene mechanism was
suggested for the majority of these reactions.1,2c,3 Par-
ticipation of vinylidene ruthenium complexes as inter-
mediates has also been discussed in some cases.4b,5
Ruthenium chelate η5-tetramethylcyclopentadienyl-
η2-olefin complexes have recently been synthesized in
our laboratories, and their crystal structures and some
reactions were published.6,7 We report here the results
Resu lts a n d Discu ssion
The reaction of 1 with AgBF4 in the presence of
acetonitrile leads to substitution of the chloride ligand
and formation of the cationic chelate [Ru(η5:η2-C5Me4-
-
6
CH2OCH2CHdCH2)(CO)(NCMe)]+BF4
. When the re-
action of 1 with AgBF4 in CH2Cl2 at -30 °C was carried
out in the presence of various acetylenes, the cationic
η5-tetramethylcyclopentadienyl-η4-diene chelates 2-7
were afforded in satisfactory yields (Scheme 1).
The new chelate complexes 2-7 have been character-
ized by microanalysis and spectroscopically (Tables
1-3), and the structures of [2a ′′]+PF6 and [7]+PF6
-
-
have been confirmed by single-crystal X-ray diffracto-
metry. All six cations 2-7 exhibit one ν(CO) band in
the region 2008-2039 cm-1, which is at higher fre-
quency than for the neutral chelate 1 [ν(CO) 1973 cm-1],
due to the positive charge. An additional band [ν(CO2-
Me) 1725 cm-1] is observed for 5a , 5b. The NMR
resonances arising from the carbonyl groups are ob-
served in the region δ 197-207 in the 13C spectra of
2-7. All the methyl and all the ring carbons of the C5-
Me4 ligands are inequivalent in both the 1H and 13C
NMR spectra of 2-7 due to the absence of a plane of
* Corresponding author. Tel: (+7) 095 1359337. Fax: (+7) 095
1355085. E-mail: gusev@ineos.ac.ru.
† Russian Academy of Sciences.
‡ Universite de Liege.
§ The University of Sheffield.
(1) Mitsudo, T.; Zhang, S.-W.; Nagao, M.; Watanabe, Y. J . Chem.
Soc., Chem. Commun. 1991, 598.
(2) (a) Trost, B. M.; Indolese, A. F. J . Am. Chem. Soc. 1993, 115,
4361. (b) Trost, B. M.; Muller, T. J . J . J . Am. Chem. Soc. 1994, 116,
4985. (c) Trost, B. M.; Indolese, A. F.; Muller, T. J . J .; Treptow, B. J .
Am. Chem. Soc. 1995, 117, 615.
(3) Derien, S.; Dixneuf, P. H. J . Chem. Soc., Chem. Commun. 1994,
2551.
(4) (a) Trost, B. M.; Flygare, J . A. J . Org. Chem. 1994, 59, 1078. (b)
Trost, B. M.; Martinez, J . A.; Kulawiec, R. J .; Indolese, A. F. J . Am.
Chem. Soc. 1993, 115, 10402. (c) Trost, B. M.; Imi, K.; Indolese, A. F.
J . Am. Chem. Soc. 1993, 115, 8831.
1
symmetry in these complexes. In the H NMR spectra
of 2-7 the protons of the CH2-O-CH2 fragments are
(5) Merlic, C. A.; Pauly, M. E. J . Am. Chem. Soc. 1996, 118, 11319.
(6) Gusev, O. V.; Morozova, L. N.; O’Leary, S. R.; Adams, H.; Bailey,
N. A.; Maitlis, P. M. J . Chem. Soc., Dalton Trans. 1996, 2571.
(7) Gusev, O. V.; Morozova, L. N.; O’Leary, S. R.; Adams, H.; Bailey,
N. A.; Maitlis, P. M. J . Organomet. Chem. 1997, 536-537, 191.
10.1021/om990473i CCC: $18.00 © 1999 American Chemical Society
Publication on Web 11/13/1999

Addition of Alkynes to Coordinated Allyl Ether
Organometallics, Vol. 18, No. 25, 1999 5277
Sch em e 1
Ta ble 1. Yield s, ν(CO), a n d Elem en ta l An a lysis for
th e Com p lexes 2-8
resonance due to a quarternary carbon at δ 88-118
(Table 3) are observed in accordance with the suggested
1
structure of 3. The H and 13C NMR spectra of 3a ′ also
elemental analysis (%):
found (calc)
IR, ν(CO) cm-1
show an additional set of Me group signals that pre-
sumably belong to the second isomer 3a ′′, present to the
extent of e10%.
complex
(CH2Cl2)
yield (%)
C
H
2+(BF4-
3+(BF4-
4+(BF4-
)
2012
2008
2004
2039, 1725a
87
80
89
15
30
91
69
56.54 (57.45) 4.72 (4.99)
46.49 (46.87) 5.03 (5.46)
52.92 (52.79) 5.98 (5.21)
38.84 (39.35) 4.16 (4.22)
39.76 (40.38) 4.57 (4.71)
52.44 (51.88) 5.39 (4.96)
62.36 (62.31) 5.85 (5.75)
-
)
)
Com p lexes fr om P h en ylp r op yn e. Reaction of the
unsymmetric phenylpropyne with 1 gives a mixture of
three isomeric chelates [Ru(η5:η4-C5Me4CH2OCH2CHd
CHCMedCHPh)(CO)]+BF4- (4a ′, 4a ′′) and [Ru(η5:η4-C5-
Me4CH2OCH2CHdCHCPhdCHMe)(CO)]+BF4- (4b) in
the ratio 4a ′:4a ′′:4b ) 1.8:1.0:1.5. The NMR spectra
show that here again the addition of the acetylene
occurs exclusively to the terminal carbon of the olefin
for all three complexes 4a ′, 4a ′′, and 4b. Thus three
pairs of doublets at δ 3.19 and 5.11, 2.94 and 4.48, and
3.31 and 4.59, arising from -CHdCH- moieties, are
5+(PF6-
)
6+(PF6-
) 2028
7+(BF4
8
)
2024
2069, 2098b
a
b
ν(COOMe). ν(CtC).
observed as AX patterns with the expected chemical
shifts and coupling constants.6,7 In the 13C NMR spectra
the -O-CH2 shows two resonances for each chelate in
the region δ 60-65.
1
observed in the H NMR spectrum of 4a ′, 4a ′′, and 4b.
Com p lexes fr om Dip h en yla cet ylen e. The X-ray
structure of chelate 2 shows that it arises from addition
of diphenylacetylene to the terminal carbon of the
In the 13C NMR spectrum the signals of three tertiary
carbons and one quarternary carbon are found for each
of three isomers 4a ′, 4a ′′, and 4b , due to the -CHd
CH-CMe{Ph}dCHPh{Me} moiety. In the 1H NMR
spectrum the dCHPh groups of isomers 4a ′, 4a ′′ show
two singlets at δ 4.50 and 3.31, while 4b shows a doublet
at δ 2.24 (J ) 7.0 Hz) and a quartet at δ 4.00 (J ) 7.0
Hz), corresponding to the dCHMe group. This is evi-
dence that the terminal carbon of the olefin can attack
at the carbon of the acetylene bearing either the methyl
or the phenyl substituents to afford 4a ′ + 4a ′′ or 4b,
respectively. Addition to the carbon carrying the less
bulky substituent is more preferred, and the overall
ratio of (4a ′ + 4a ′′):4b is 1.9:1.0.
1
coordinated olefin. In the H and 13C NMR spectra of 2
two sets of resonances are observed in the ratio 2.6:1.0;
we assign these to the conformers 2a ′ and 2a ′′ 8a,b,9 (see
1
below). In the H NMR spectrum for both isomers the
coordinated diene fragment is characterized by two pairs
of doublets at δ 4.77, 3.56 and 3.33, 4.89, and also by
singlets at δ 4.98 and 3.58, respectively, while in the
13C NMR the isomers have three tertiary carbon reso-
nances at δ 60-86 and one signal (due to a quarternary
carbon) in the region δ 90-118 (Table 3). Thus, the
NMR data confirm the presence of the CHdCH-CPhd
CHPh moiety in both isomers. It should be noted that
similar isomers are observed for all the other cations
3a -6a .
Com p lexes fr om 2-Bu tyn e. 2-Butyne also adds to
the terminal carbon of the olefin to give the diene
chelate [Ru(η5:η4-C5Me4CH2OCH2CHdCHCMedCHMe)-
(CO)]+BF4- (3a ′). The incorporation of 2-butyne results
in the appearance of two more methyl resonances in the
1H and 13C NMR spectra of 3a ′ than are found in 1. Two
doublets at δ 3.11 and 5.02 confirm the presence of a
-CHdCH- moiety, while the doublet at δ 1.83 (J ) 6.3
Hz) and the quartet at δ 3.90 (J ) 6.3 Hz) arise from a
dCHMe group. In the 13C NMR spectrum three reso-
nances due to tertiary carbons at δ 71-85 and one
Com p lexes fr om Meth yl P r op iola te. Methyl pro-
piolate, a monosubstituted acetylene, reacts with 1
similarly to phenylpropyne, with the terminal carbon
of the coordinated olefin adding to both the substituted
carbon and the unsubstituted carbon of the acetylene
to give a mixture of the three isomers [Ru(η5:η4-C5Me4-
CH2OCH2CHdCHCHdCHCO2Me)(CO)]+BF4- (5a′, 5a′′)
and {Ru[η5:η4-C5Me4CH2OCH2CHdCH-C(CO2Me)d
CH2](CO)}+BF4- (5b) in the ratio 5a ′:5a ′′:5b ) 1.0:4.7:
2.1. The ester CO2Me groups of the isomers 5a ′, 5a ′′,
and 5b show three singlets at δ 3.79, 3.78, and 4.01 in
1
the H NMR spectrum and at δ 168.0, 53.4; 168.4, 57.0;
and 164.7, 55.7 in the 13C NMR spectrum, respectively.
The presence of the diene fragments -CHdCH-CHd
CHCO2Me of isomers 5a ′, 5a ′′ is indicated by four pairs
of multiplets at δ 3.1-6.3 in the 1H NMR spectrum
and by four pairs of tertiary carbons at δ 62-95 in
the 13C NMR spectrum. The diene moiety -CHdCH-
(8) (a) Ernst, R. D.; Melendez, E.; Stahl, L.; Ziegler, M. L.; Orga-
nometallics 1991, 10, 3635. (b) Melendez, E.; Illaraza, R.; Yap, G. P.
A.; Reingold, A. L. J . Organomet. Chem. 1996, 522, 1.
(9) Mashima, K.; Fukumoto, H.; Tani, K.; Haga, M.; Nakamura, A.
Organometallics 1998, 17, 410.

5278 Organometallics, Vol. 18, No. 25, 1999
Gusev et al.
Ta ble 2. 1H NMR Da ta for Ru th en iu m Ch ela tes [Ru (η5:η4-C5Me4CH2OCH2CHdCHCR1dCHR2)(CO)]+ (δ)a
a
b
c
All spectra obtained in CDCl3 at 300K, J in Hz. One singlet arising from R1 ) Me. 6H, 2Me. dIn (CD3)2CO.
Ta ble 3. 13C NMR Da ta for Ru th en iu m Ch ela tes [Ru (η5:η4-C5Me4CH2OCH2CHdCHCR1dCHR2)(CO)]+ (δ)a
a
b
All spectra obtained in CDCl3 at 300K, J in Hz. Five quanternary carbons arise from Cp* ring, and one arises from diene moiety.
c Three resonances arise from tertiary carbons of diene moiety. Four resonances arise from Cp* methyls, and two arise from acetylenic
d
methyls; two resonances are overlapped. e Four resonances arise from Cp* methyls, and one arises from acetylenic methyl. f In (CD3)2CO.
C(CO2Me)dCH2 of isomer 5b shows four proton signals
at δ 2.48, 3.42, 4.65, and 5.29 in the H NMR spectrum,
and signals due to one secondary carbon at δ 52.4, two
tertiary carbons at δ 85.2, 91.5, and one quarternary
carbon at δ 95-105 in the 13C NMR spectrum. The
protons of one of the methylene groups of the CH2OCH2
moiety in 5b at δ 3.20 and 4.36 show vicinal coupling
constants J ) 2.9 Hz and J ) 1.4 Hz along with J AB )
1
15.7 Hz due to their interaction with the vinyl proton
of the diene moiety (-O-CH2-CHd), which is typical
for all complexes 2-6 and confirms the proposed
structure. The alternative diene structure, -C(d
CH2)CHdCHCO2Me, formed as a result of addition of
methyl propiolate to the internal carbon of the olefin,

Addition of Alkynes to Coordinated Allyl Ether
Organometallics, Vol. 18, No. 25, 1999 5279
Sch em e 2
by the resonances of three tertiary carbons at δ 124.8,
128.2, 131.7 and one quaternary carbon at δ 130.2 in
the 13C NMR spectrum. The signals of two acetylenic
carbons appear in the region δ 90-110 together with
five quarternary carbons of the C5Me4 ring.
The signals of the -CHdCH2 moiety are observed at
1
δ 2.04, 2.84, 4.06 and at δ 39.5, 68.0 in the H and 13C
NMR spectra, respectively. The spectral data show that
the complex 8 is only one isomer in solution. The reasons
that only one diastereomer of 8 has been obtained in
more than 50% yield from two equally populated dia-
stereomers of 16 are not clear. It should be noted that
the reaction of 1 with KX (X ) Br, I) led to formation of
a mixture of diastereomers [Ru(η5:η2-Me4C5CH2OCH2-
CHdCH2)(CO)X].6
σ-Acetylide ruthenium complexes usually undergo
protonation to vinylidene compounds.10a,b However,
protonation of 8 by Et2O‚HBF4 does not stop at vi-
nylidene complex formation, but addition of the vi-
nylidene to the coordinated olefin occurs, yielding the
previously described diene chelate 7 as the final product
(Scheme 3).
can be ruled out since there the bridged methylene
group is linked to the quarternary carbon of the diene
moiety and only one constant J AB ) ∼16 Hz should be
observed.
Com p lexes fr om Meth yl P r op a r gyl Eth er . Addi-
tion of methyl propargyl ether to 1 occurs regiospecifi-
cally so that the terminal carbon of the olefin links only
to the unsubstituted carbon of the acetylene, unlike the
situation for phenylpropyne and methyl propiolate. This
gives a mixture of isomers indentified as [Ru(η5:η4-C5-
Me4CH2OCH2CHdCHCHdCHCH2OMe)(CO)]+BF4- (6a′,
6a ′′), in the ratio 6a ′:6a ′′ ) 1.0:1.7, from their NMR
Cr ystal Str u ctu r es of th e [Ru {η2:η5-C5Me4CH2OC-
H2CHdCH-CP h dCHP h }CO]+ (2a ′′+) a n d [Ru {η2:
η5-C5Me4CH2OCH2(CH2d)C-CHdCHP h }CO]+ (7+).
X-ray structure determinations have been carried out
on [Ru{η5:η4-C5Me4CH2OCH2CHdCH-CPhdCHPh}-
CO]+PF6- and on [Ru{η2:η5-C5Me4CH2OCH2(CH2d)C-
1
spectra. In the H and 13C NMR spectra of 6a ′, 6a ′′ the
signals of the MeO groups are observed at δ 3.38, 3.41
and 58.8, 58.9, respectively. Resonances arising from the
methylene group of CH2OMe moiety are found in the
region δ 3.8-4.1 and at 69.7 (6a ′) and 71.0 (6a ′′). In the
13C NMR spectrum the diene fragment -CHdCH-CHd
CHCH2OMe shows two sets of tertiary carbons at δ 71.2,
77.4, 90.3, 92.2 (6a ′) and 59.5, 77.7, 84.5, 91.3 (6a ′′).
Com p lexes fr om P h en yla cetylen e. The reaction of
1 with phenylacetylene unexpectedly gave the diene
chelate {Ru[η5:η4-C5Me4CH2OCH2C(dCH2)CHdCHPh]-
(CO)}+BF4- (7), wherein the unsubstituted carbon of the
acetylene is linked to the internal carbon of the coordi-
nated olefin. The structure of 7 was determined by
single-crystal X-ray diffractometry. Complex 7 exists in
CHdCHPh}CO]+PF6 (Figures 1, 2), prepared by ad-
-
dition ofNH4PF6 toaqueoussolutionsofthetetrafluoroborate
salts of [2a ′′]+ and [7]+, respectively. Representations
of the structures found for the cations of 2a ′′ and 7 with
the atomic numbering schemes are presented in Figures
1 and 2, and the selected bond lengths and bond angles
are given in Table 4.
In both structures the ruthenium atom is coordinated
by the tetramethylcyclopentadienyl ligand, the carbonyl
group, and the terminal diene moiety of the pendant
chain of the substituted cyclopentadienyl ring. It should
be noted that in complex 7 the diene moiety is linked
to the pendant chain by the internal diene atom (C(13)),
while in complex 2a ′′ it is linked to the terminal atom
(C(12)).
The main differences in the geometry of these two
complexes are found in the diene fragment. In complex
7 the CH2dC(CH2)-CHdCHPh diene moiety has an
s-cis-conformation (Figure 1, 3a), while in 2a ′′ the (CH2)-
CHdCH-CPhdCHPh fragment is characterized by an
s-trans-conformation (Figures 2, 3b). The torsion angles
C(12)C(13)C(14)C(15) are 125.5° and -2.5° in 2a ′′ and
7, respectively. Analogous torsion angles in the un-
chelated diene complexes are about 122°. 8a,b,9 Our data
suggest that the double bonds are more localized in the
s-cis-diene in 7 than in the s-trans-diene in complex 2a ′′.
For 7 we find two equal bonds C(14)-C(15) and C(12)-
C(13) of length 1.38(1) Å and one bond C(13)-C(14) of
length 1.47(1) Å, while in complex 2a ′′ the corresponding
bond lengths seem more similar (1.40(1), 1.43(1), and
1.47(1) Å, respectively). The Ru-Cdiene bond lengths
vary from 2.150(8) to 2.311(8) Å in 2a ′′ and 2.202(7) to
2.359(7) Å in cation 7, with the longer distance in both
structures to the terminal carbon C(15). In structure 7,
1
solution as a single isomer. In the H NMR spectrum
the diene fragment -C(dCH2)-CHdCHPh shows two
pairs of doublets at δ 3.83 (J ) 11.2 Hz), 5.68 (J ) 11.2
Hz) and 2.06 (J ) 2.9 Hz), 3.07 (J ) 2.9 Hz). The signals
of the methylene group protons of the -CH2OCH2-
moiety, which are bound to the quaternary carbon of
the diene, appear as two doublets (J AB ) 14.7 Hz), with
no other coupling observed; this is in contrast to the
analogous signals for complexes 2-6. The 13C NMR
spectrum of 7 shows signals at δ 47.8 (CH2), 75.9 (CH),
82.5 (CH) and the quarternary carbon in the region 94-
106 arising from the diene fragment.
Syn th esis a n d P r oton a tion of [Ru (η5:η2-Me4C5-
CH 2OCH 2CH dCH 2)(η1-CtCP h )(CO)] (8). Nucleo-
philic substitution occurred at the ruthenium center
when complex 1 was reacted with LiCtCPh in THF at
-78 °C; this led to the σ-acetylide complex 8 in 69%
yield (Scheme 2).
Complex 8 was characterized spectroscopically. In the
IR spectrum ν(CO) at 2069 cm-1 and ν(CtC) at 2098
1
cm-1 are observed. In the H and 13C NMR spectra the
four methyl signals of the C5Me4 ring are found. The
1H NMR spectrum shows two doublets at δ 3.33, 4.06
(J ) 13.0 Hz) and two doublets of doublets at δ 3.05,
4.22 (J ) 15.0 Hz, J ) 2.0 Hz) arising from the CH2-
OCH2 moiety. The presence of the phenyl is shown by
(10) (a) Bruce, M. I. Chem. Rev. 1991, 91, 197. (b) Davies, S. G.;
McNally, J . P.; Smallridge, A. J . Adv. Organomet. Chem. 1990, 30, 1.
1
a multiplet at δ 7.1-7.8 in the H NMR spectrum and

5280 Organometallics, Vol. 18, No. 25, 1999
Gusev et al.
Sch em e 3
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) in th e Str u ctu r es 2a ′′ a n d 7
C28H29O2RuPF6 (2a ′′)
C22H25O2RuPF6 (7)
Bond Lengths
Ru-C(1)
2.199(8) Ru-C(1)
2.252(7) Ru-C(2)
2.277(8) Ru-C(3)
2.211(9) Ru-C(4)
2.187(8) Ru-C(5)
2.288(9) Ru-C(12)
2.150(9) Ru-C(13)
2.253(8) Ru-C(14)
2.311(8) Ru-C(15)
1.886(7) Ru-C(22)
2.181(7)
2.227(7)
2.207(6)
2.211(6)
2.202(7)
2.236(9)
2.169(7)
2.202(7)
2.359(7)
1.914(8)
1.44(2)
1.44(1)
1.13(1)
1.51(1)
1.50(1)
1.38(1)
1.47(1)
1.38(1)
Ru-C(2)
Ru-C(3)
Ru-C(4)
Ru-C(5)
Ru-C(12)
Ru-C(13)
Ru-C(14)
Ru-C(15)
Ru-C(28)
O(1)-C(6)
O(1)-C(11)
O(2)-C(28)
C(1)-C(6)
C(11)-C(12)
C(12)-C(13)
C(13)-C(14)
C(14)-C(15)
1.42(1)
1.45(1)
O(1)-C(11)
O(1)-C(6)
1.155(9) O(2)-C(22)
1.50(1)
1.51(1)
1.40(1)
1.47(1)
1.43(1)
C(1)-C(6)
C(11)-C(13)
C(12)-C(13)
C(13)-C(14)
C(14)-C(15)
F igu r e 1. General view of complex 7 and atomic number-
Bond Angles
ing. Thermal ellipsoids are drawn at the 50% probability
C(12)-Ru-C(15)
C(13)-Ru-C(14)
C(13)-Ru-C(12)
C(13)-Ru-C(15)
C(14)-Ru-C(12)
C(14)-Ru-C(15)
C(6)-O(1)-C(11)
O(1)-C(6)-C(1)
O(1)-C(11)-C(12)
99.5(3)
38.9(3)
36.7(3)
65.3(3)
65.5(3)
36.5(3)
C(12)-Ru-C(15)
C(13)-Ru-C(14)
C(13)-Ru-C(12)
C(13)-Ru-C(15)
C(14)-Ru-C(12)
C(14)-Ru-C(15)
76.8(3)
39.2(3)
36.4(4)
66.3(3)
67.2(4)
35.1(3)
111.5(9)
114.0(8)
114.1(9)
-
level. The PF6 anion is omitted for clarity.
113.6(7) C(6)-O(1)-C(11)
113.8(7) O(1)-C(6)-C(1)
113.5(7) O(1)-C(11)-C(13)
C(13)-C(12)-C(11) 121.7(8) C(12)-C(13)-C(14) 119.4(9)
C(12)-C(13)-C(14) 117.6(8) C(12)-C(13)-C(11) 122.2(9)
C(13)-C(14)-C(16) 120.7(7) C(14)-C(13)-C(11) 118.1(10)
C(15)-C(14)-C(13) 112.6(7) C(15)-C(14)-C(13) 121.1(10)
C(15)-C(14)-C(16) 126.6(7) C(14)-C(15)-C(16) 123.7(8)
C(14)-C(15)-C(22) 124.9(7) O(2)-C(22)-Ru
O(2)-C(28)-Ru 172.8(7)
175.4(8)
(1)C(11)C(12)) and 7 (RuC(13)C(11)O(1)C(6)C(1)) are
characterized by the sofa conformation with the O(1)
atom deviating by 0.72 Å. In both structures the oxygen
atom of the pendant chain is oriented away from the
CO group (Figure 3a,b).
Analysis of the molecular packing reveals that the
crystal structures 2 and 7 consist of the discrete cations
and anions with no abnormally close intermolecular
contacts.
F igu r e 2. General view of complex 2a ′′ and atomic
numbering. Thermal ellipsoids are drawn at the 50%
-
Th e Isom er ism of Com p lexes 2a -6a . According to
the 1H NMR data the complexes 2a -6a exist in solution
as pairs of isomers 2a ′-6a ′ and 2a ′′, 4a ′′-6a ′′, which
are not the regioisomers. It has previously been shown
that acetylacetonate ruthenium(II) complexes [Ru(η4-
diene)(acac)2] tend to complex dienes s-trans,8a,b while
pentamethylcyclopentadienylruthenium(II) complexes
tend to complex them s-cis.9 The X-ray structure for 2a
probability level. The PF6 anion is omitted for clarity.
the phenyl ring is approximately coplanar with the
diene fragment (C(14)C(15)C(16)C(17) torsion angle is
172.5°). In complex 2a ′′ two Ph rings have different
orientations with respect to the diene fragment, with
torsion angles C(13)C(14)C(16)C(17) and C(14)C(15)C-
(22)C(23) equal to -31.1° and -92.2°, respectively.
The six-membered metallacycles in 2a ′′ (RuC(1)C(6)O-

Addition of Alkynes to Coordinated Allyl Ether
Organometallics, Vol. 18, No. 25, 1999 5281
of 2a ′′. The approximate energy of activation ∆Gq value
for the interconversion 2a ′ f 2a ′′ is about 18 kcal/mol.
Thus, the isomerism of 2a ′ and 2a ′′ is not caused by
the different configuration of the substituents in the
olefin fragments. Both complexes are the products of cis-
addition of an allylic C-H bond to acetylene. Acetylene
adds to the coordinated olefin trans to the chelate
bridge.
Another possible reason for isomerism in complexes
2a -6a could be because the oxygen of the CH2-O-CH2
fragment can be directed toward the carbonyl group or
away from it (Scheme 5).
However it is doubtful that such conformers could be
seen in solution. The oxygen in this fragment would not
be coordinated, and as a consequence, the activation
energy of such an interconversion should be comparable
with that in organic cyclic oxygen containing compounds
with a similar ring size. The ∆Gq is usually low (≈9-
12 kcal/mol), and the average signals are observed at
room temperature in NMR spectra of such compounds.
Therefore, the most probable isomerism type of com-
plexes 2a -6a is conformerism of the diene moiety. The
diene fragment can have either s-cis- or s-trans-
conformation, and there are two states of s-trans-
conformation: when the Ha proton is oriented to a metal
atom (s-trans-isomer II) and away from it (s-trans-
isomer I), as shown in Scheme 6.
Mech a n istic Con sid er a tion s. The following regu-
larities have been revealed for the cross-addition reac-
tions of acetylenes to the coordinated olefin in the
chelate complex 1: (1) the formation of coordinated 1,3-
dienes takes place in all cases; (2) the addition to the
coordinated olefin occurs regiospecifically either to
terminal carbon (complexes 2-6) or to the internal
carbon (complex 7); (3) in unsymmetric acetylenes the
carbon bearing the less bulky substituent is favored to
add to the olefin.
Previous studies of the catalytic cross-addition of
acetylenes to olefins have been shown to proceed via a
ruthenacyclopentene1,2c,3 or through a vinylidene mechan-
ism.4b,5 The regularities found for the formation of 2-6
can be satisfactorily explained by a metallacyclopentene
mechanism, as outlined in Scheme 7.
The catalytic reactions with nonchelate ruthenium
complexes usually lead to the formation of 1,4-dienes.1,2c,3
In the stoichiometric reactions discussed here formation
of a 1,4-diene in the chelate complex would lead to a
highly strained structure, which would have only two
bridging atoms, -CH2-O-. The formation of a 1,4-diene
would also be prohibited because of the impossibility of
â-elimination from the methylene group bound to the
oxygen, which is in a rigid chelate cycle and distant from
the ruthenium center.
The reaction of 1 with phenylacetylene in the presence
of AgBF4 leads to addition of the unsubstituted acetyl-
ene carbon to the internal olefin carbon. The result is
rather unexpected because it was shown earlier that the
addition of acetylenes to internal olefins was several
times slower than addition of acetylenes to terminal
olefins.2c The regioselectivity of this reaction indicated
that the mechanisms of formation of 7 and 2-6 are
different. A possible intermediate here could be the
phenylvinylidene complex [Ru(η5:η2-Me4C5CH2OCH2-
F igu r e 3. Projections of the cations 7 (a) and 2a ′′ (b) to
the plane of the cyclopentadienyl ring. The Ph groups are
omitted for clarity.
shows an s-trans diene conformation in the solid.
Complexes 2a -6a are thus proposed to exist in solution
either as mixtures of s-trans and s-cis isomers or two
different s-trans isomers, analogous to those found in
the acetylacetonate ruthenium complexes.8a,b The isom-
erism of complexes 2a -6a can be explained not only in
terms of isomerism of the diene but also because of the
other reasons. For instance the presence of the isomers
could be stipulated by Z/E-isomerism of substituents at
the double bonds or by CH2-O-CH2 moiety conform-
erism (Scheme 4). Z/E-isomerism of the substituents
could not be realized because of the specificity of diene
chelate formation (see below).
Interconversion of 2a ′-6a ′ and 2a ′′, 4a ′′-6a ′′ isomers
could be an argument for denying Z/E-isomerism for
these complexes. Attempts to carry out NMR experi-
ments at temperatures high enough to coalesce any
resonances that were exchanging failed due to decom-
position under these conditions. Therefore a 2D 1H
EXSY NMR experiment was carried out on 2a at 300 K
in acetone-d6 (Figure 4), and this revealed the exchange
of complex 2a ′ protons with the corresponding protons
(11) Gatti, G.; Serge, A. L.; Morandi, C. J . Chem. Soc. B 1966, 1203.

5282 Organometallics, Vol. 18, No. 25, 1999
Gusev et al.
Sch em e 4
Sch em e 6
ence to TMS. IR spectra were obtained with Specord
M-82. Microanalyses were performed by Laboratory of
Microanalysis of the Institute of Organoelement Com-
pounds. The chelate complex 1 was prepared according
to literature methods.6
F igu r e 4. 2D EXSY 1H NMR spectrum (region of the
olefinic protons) of the mixture of isomers 2a ′ and 2a ′′ (400
MHz, acetone-d6, 300 K, τm ) 1 s, initial delay 2 s, number
of scans 256, a matrix 1024 × 256 was acquired by the
TPPI technique and zero-filled to the size 1024 × 1024).
In ter a ction of 1 w ith Acetylen es in th e P r esen ce
of AgBF 4 (Gen er a l P r oced u r e). Silver tetrafluorobo-
rate (80 mg; 0.4 mmol) was added to a solution of 1 (140
mg; 0.4 mmol) and PhCtCH (100 µL; 1 mmol) in CH2-
Cl2 (20 cm3) at -78 °C, stirred for 0.5 h, and then was
allowed to warm to room temperature. The solution was
filtered and concentrated to 2 cm3. Addition of ether
precipitated a pale yellow solid, which was collected on
Sch em e 5
1
a frit and dried in vacuo. Yield of 7: 210 mg (91%). H
NMR (CD2Cl2): 1.30 (s, 3H, Me); 1.74 (s, 3H, Me); 1.79
(s, 3H, Me); 2.06 (d, 1H, dCHH, J ) 2.9 Hz); 2.31 (s,
3H, Me); 3.07 (d, 1H, dCHH, J ) 2.9 Hz); 3.15 (d, 1H,
OCHH, J ) 14.7 Hz); 3.57 (d, 1H, Cp*CHHO, J ) 14.0
Hz); 3.83 (d, 1H, dCHPh, J ) 11.2 Hz); 4.51 (d, 1H,
Cp*CHHO, J ) 14.0 Hz); 5.06 (d, 1H, OCHH, J ) 14.7
Hz); 5.68 (d, dCH-, J ) 11.2 Hz); 7.39 (s, 5H, C6H5).
13C NMR (CD2Cl2): 6.5 (Me); 7.9 (Me); 8.2 (Me); 9.4
(Me); 47.8 (CH2); 58.3 (CH2); 66.1 (CH2); 75.9 (CH); 82.5
(CH); 94.3 (C); 94.5 (C); 97.2 (C); 98.8 (C); 104.3 (C);
106.1 (C); 125.4 (CH); 127.4 (CH); 128.4 (CH); 131.7 (C);
204.0 (CO).
CHdCH2)(η1-CdCHPh)(CO)]+ by analogy with the reac-
tion that was found recently.5 The fact that protonation
of [Ru(η5:η2-Me4C5CH2OCH2CHdCH2)(η1-CtCPh)(CO)]
(8) also gives 7 as a sole product is indirect support for
this suggestion (Scheme 8).
Exp er im en ta l Deta ils
Gen er a l P r oced u r es. All experiments were per-
The diene complexes 2-6 were prepared by an
1
formed under argon in solvents purified by standard
analogous method. Their IR, H NMR, and 13C NMR
1
methods. H and 13C NMR spectra were obtained with
spectra are given in Tables 1, 2 and 3, correspondingly.
Syn th esis of [Ru (η1-CtCP h )(η2:η5-Me4C5CH2OC-
H 2CH dCH 2)(CO)] (8). Solid PhCtCLi (32 mg, 0.30
Bruker AMX 400 and Varian VXR 400 spectrometers.
All chemical shifts are reported in ppm (δ) with refer-

Addition of Alkynes to Coordinated Allyl Ether
Organometallics, Vol. 18, No. 25, 1999 5283
Sch em e 7
Ta ble 5. Cr ysta l Da ta a n d Deta ils of th e X-r a y
Sch em e 8
Exp er im en ts for 2a ′′ a n d 7
2a ′′
7
formula
mol wt
C
28H29O2RuPF6
C22H25O2RuPF6
567.46
643.55
cryst size, mm
cryst system
space group
cell constants
a, Å
0.10 × 0.20× 0.20 0.15× 0.20× 0.25
orthorhombic
orthorhombic
Pca21
Pbca
30.83(2)
8.103(5)
10.494(6)
2622(3)
4
16.847(4))
14.805(4)
18.318(5)
4569(2)
8
b, Å
c, Å
V, Å3
Z
D
calc, g cm-3
1.631
1.650
diffractometer
temp, K
radiation (Å)
Siemens P3/PC
153
Siemens P3/PC
153
mmol) was added to solution of 1 (107 mg, 0.30 mmol)
in THF (10 cm3) at 0 °C, and the mixture was stirred
for 1 h. The solution was allowed to warm to room
temperature, solvent was removed under vacuum, and
the residue was crystallized from a mixture of petroleum
ether and ether. Yield of 8: 87 mg, 69%. IR spectrum
Mo KR
(λ ) 0.71073)
θ-2θ
56
3220
Mo KR
(λ ) 0.71073)
θ-2θ
55
5120
scan mode
2θmax, deg
tot unique reflns
collcd
1
(CH2Cl2): ν(CtC) 2098 and ν(CO) 2069 cm-1. H NMR
abs coeff, µ(Mo KR),
0.727
0.822
mm-1
(C6D6): 1.44 (s, 3H, Me); 1.74 (s, 3H, Me); 1.88 (s, 3H,
Me); 1.91 (s, 3H, Me); 2.04 (d, 1H, dCHH, J ) 12.0 Hz);
2.84 (d, 1H, dCHH, J ) 8.0 Hz); 3.05 (dd, 1H, OCHH,
J ) 15.0; J ) 2.0 Hz); 3.33 (d, 1H, Cp*CHHO, J ) 13.0
Hz); 4.05 (d, 1H, Cp*CHHO, J ) 13.0 Hz); 4.06 (dddd,
1H, -CHd, J ) 12.0, J ) 8.0, J ) 2.0, J ) 1.0 Hz); 4.22
(dd, 1H, OCHH, J ) 15.0; J ) 1.0 Hz); 6.9-7.2 (m, 5H,
Ph). 13C NMR (C6D6): 9.0 (Me); 10.0 (Me); 10.1 (Me);
10.4 (Me); 39.5 (dCH2); 62.1 (CH2); 66.1 (CH2); 68.0
(CH); 90.4 (C); 90.7 (C); 96.5 (C); 103.7 (C); 107.0 (C);
107.7 (C); 108.9 (C); 124.8 (CH); 128.2 (CH); 130.2 (CH);
131.6 (CH); 205.6 (CO).
P r ot on a t ion of [R u (η5:η2-C5Me4CH 2OCH 2CH d
CH2)(η1-CtCP h )(CO)] (8). A solution of Et2O‚HBF4
(50 mg, 0.3 mmol) in ether (5 cm3) was added dropwise
to a solution of 8 (84 mg, 0.2 mmol) at -78 °C. The
resultant solution was stirred for 0.5 h and then allowed
to warm to room temperature. The solid precipitate was
largest diff peak and
hole, e‚Å-3
0.692; -2.242
4.189; -0.822
R1 (on F for reflns
with I > 2σ(I))
0.0445
(2420 reflns)
0.0722
(3197 reflns)
0.1935
wR2 (on F2 for all reflns) 0.1233
(3147 reflns)
(4399 reflns)
filtered, washed with Et2O, crystallized from CH2Cl2/
Et2O, and dried in vacuo. Yield of 7: 61 mg (60%).
X-r a y Da ta Collection , Str u ctu r e Deter m in a tion ,
a n d Refin em en t for 2a ′′ a n d 7. Single crystals of
complexes [2a ′′]+PF6- and [7]+PF6- were grown at room
temperature (25 °C) by a layering method, with
dimethoxyethane added to the sample dissolved in
methylene chloride. Accurate unit cell parameters and
orientation matrixes were obtained by least-squares
refinement of 24 carefully centered reflections in the 23°
e θ e 27° range. Two standard reflections were moni-
tored every 98 reflections for 2 and 7 and showed no

5284 Organometallics, Vol. 18, No. 25, 1999
Gusev et al.
significant variations in both cases. Data were corrected
for Lorentz and polarization effects. Rather small, well-
formed, and essentially isometric single crystals were
carefully chosen. The quality of the results and the
relatively low absorption coefficient values justified our
not making absorption corrections.
The structures were solved by direct methods and
subsequent difference Fourier maps. The difference
Fourier synthesis for 7 revealed additional peaks which
were interpreted as a disorder of the fluorine atoms of
the PF6- anion. The occupancies of the positions of three
fluorine sets (labeled F, F′ and F′′) were refined to 0.39,
0.35, and 0.26, respectively. The positions for all H
atoms in both molecules were calculated geometrically
and refined in the “ridding” approximation. All struc-
tures were refined by a full-matrix least-squares method
against F2 in the anisotropic-isotropic (H atoms and
fluorines of the disordered PF6- anion) approximation.
The absolute structure in crystal of 2a ′′ was determined
using the Flack parameter, which was equal to 0.08-
(14). All calculations were carried out on an IBM PC
with SHELXTL PLUS 5 (gamma-version) programs.
Crystal data and details of the X-ray experiments are
given in Table 5.
Ack n ow led gm en t. We thank the Russian Founda-
tion for Basic Research (Grants 96-03-32773 and 97-
03-33086) and INTAS (Grant 94-393) for support.
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
parameters, atomic coordinates and equivalent isotropic dis-
placement parameters, bond lengths and angles, anisotropic
displacement parameters, and hydrogen coordinates and
isotropic displacement parameters for the crystal structures
of [2a ′′]PF6 and [7]PF6 and figure of the 2D 1H EXSY NMR
spectrum (high-field region) for the mixture of isomers 2a ′ and
2a ′′. This material is available free of charge via the Internet
at http://pubs.acs.org.
OM990473I