Unprecedented formation of azulenylidene ligands by reaction of the vinylidene ligand in arylvinylidene pentacarbonyl complexes of chromium and tungsten with alkoxyacetylenes

Article abstract of DOI:10.1021/om700274u

Arylvinylidene(pentacarbonyl)chromium and -tungsten complexes [(CO) ₅M=C=C(C₆H₄R¹-p)R²] (M = Cr, W; R¹ = H; R² = Me, C₆H₄R ³-p [R³ = H, Me, OMe, Cl, ^tBu]; R¹ = Me; R² = C₆H₄Cl-p) react with alkoxyacetylenes, HC≡COR′ (R′ = Et, ^tBu, adamantyl), by 1,3-addition of the CC triple bond to the vinylidene ligand and ring expansion to give azulenylidene complexes [(CO)₅M=C-CH= C(OR′)-C(CR)=CHCH=C(R)CH=CH]. When monosubstituted and unsymmetrically bis-substituted bis(aryl)-vinylidene complexes are employed, mixtures of two isomers are obtained. In the two isomers the substituent either is attached to the seven-membered ring or resides in the para position of the phenyl group. In general, the selectivity of the reactions is low; the isomeric ratio varies between 0.5 and 2 depending on the metal and the substituent. DFT calculations on the reaction mechanism indicate that the reactions are initiated by a nucleophilic addition of the terminal carbon atom of the alkoxyacetylene to the metal-bound C_α atom of the vinylidene ligand. The low selectivity of the reactions is in accord with the results of the calculations. The structure of several azulenylidene complexes was established by X-ray structure analyses.

Full text of DOI:10.1021/om700274u

Organometallics 2007, 26, 3791-3801
3791
Unprecedented Formation of Azulenylidene Ligands by Reaction of
the Vinylidene Ligand in Arylvinylidene Pentacarbonyl Complexes
of Chromium and Tungsten with Alkoxyacetylenes
Sylvia Hagmayer, Angelika Fru¨h, Thomas Haas, Matthias Drexler, and Helmut Fischer*
Fachbereich Chemie, UniVersita¨t Konstanz, Fach M727, 78457 Konstanz, Germany
ReceiVed March 22, 2007
Arylvinylidene(pentacarbonyl)chromium and -tungsten complexes [(CO)5MdCdC(C6H4R1-p)R2] (M
t
) Cr, W; R1 ) H; R2 ) Me, C6H4R3-p [R3 ) H, Me, OMe, Cl, Bu]; R1 ) Me; R2 ) C6H4Cl-p) react
t
with alkoxyacetylenes, HCtCOR′ (R′ ) Et, Bu, adamantyl), by 1,3-addition of the CC triple bond to
the vinylidene ligand and ring expansion to give azulenylidene complexes [(CO)5MdC-CHdC(OR′)-
C(CR)dCHCHdC(R)CHdCH]. When monosubstituted and unsymmetrically bis-substituted bis(aryl)-
vinylidene complexes are employed, mixtures of two isomers are obtained. In the two isomers the
substituent either is attached to the seven-membered ring or resides in the para position of the phenyl
group. In general, the selectivity of the reactions is low; the isomeric ratio varies between 0.5 and 2
depending on the metal and the substituent. DFT calculations on the reaction mechanism indicate that
the reactions are initiated by a nucleophilic addition of the terminal carbon atom of the alkoxyacetylene
to the metal-bound CR atom of the vinylidene ligand. The low selectivity of the reactions is in accord
with the results of the calculations. The structure of several azulenylidene complexes was established by
X-ray structure analyses.
The reactions of [(CO)5MdCdC(R1)R2] have turned out to
be remarkably versatile. They react with imines to give either
iminocarbene complexes,6 zwitterionic adducts from addition
of the imine to the CR atom,6 or azetidinylidene complexes7 by
subsequent cyclization. The type of product depends on the
substitution pattern of the imine. Cycloaddition of the CtC bond
in π-donor-substituted alkynes R-CtC-XR′ (R ) alkyl, aryl;
XR′ ) OR; SR; NR2) to the CRdCâ bond of the vinylidene
ligand affords cyclobutenylidene complexes.8 The cycloaddition
methodology can be extended to the synthesis of di-, tri-, and
tetranuclear cyclobutenylidene complexes by using alkynyl
complexes as the CtC component.9 In contrast, dimethylcy-
anamide leads to demetalation of the vinylidene ligand and
formation of its dimer, butatriene.8a The coupling of a carbonyl
and the vinylidene ligand and the regio- and stereoselective
formation of cyclobutane-1,3-diones is observed on photolysis
of vinylidene complexes.10 Carbonyl-vinylidene complexes of
tungsten were for instance also proposed to be involved in the
photoassisted polymerization of terminal alkynes,11 in the
Introduction
Vinylidene complexes1 such as [(CO)5MdCdC(R1)R2] (M
) Cr, W) may be regarded as the first member of a series of
unsaturated carbene complexes [LnMd(C)xdC(R1)R2]. As in
Fischer-type carbene complexes (x ) 0) the CR atom in
vinylidene complexes is an electrophilic center and the LUMO
is predominantly localized on the CR atom;2 the HOMO is
mainly concentrated on the metal and on the Câ atom.
Consequently, strong electrophiles add to the metal or to the
Câ atom. Examples include (a) the protonation of trans-[Cl-
(PiPr3)2IrdCdCHR] (R ) H, Me, Ph) with HBF4 to afford an
equilibrium mixture of [Cl(PiPr3)2(H)IrdCdCHR]+ and [Cl-
(PiPr3)2IrtC-CH2R]+,3 (b) the formation of the carbyne
complexes trans-[I(CO)4WtC-CtBu(H)R] in the reaction of
[(CO)5WdCdC(R)tBu] (R ) Me, Et) with CF3SO3H/[NMe4]I,4
and (c) the formation of [Tp′(CO)2WtCEt] in the reaction of
the vinylidene anion [Tp′(CO)2WdCdCH2]- with MeI.5 In
contrast, nucleophiles add to the CR atom of vinylidene
complexes.
(6) Fischer, H.; Kirchbauer, F.; Fru¨h, A.; Abd-Elzaher, M. M.; Roth,
G.; Karl, C. C.; Dede, M. J. Organomet. Chem. 2001, 620, 165.
(7) (a) Abd-Elzaher, M. M.; Fischer, H. J. Organomet. Chem. 1999, 588,
235. (b) Abd-Elzaher, M. M.; Froneck, T.; Roth, G.; Gvozdev, V.; Fischer,
H. J. Organomet. Chem. 2000, 599, 288.
(8) (a) Fischer, H.; Podschadly, O.; Fru¨h, A.; Troll, C.; Stumpf, R.;
Schlageter, A. Chem. Ber. 1992, 125, 2667. (b) Fischer, H.; Volkland, H.-
P.; Fru¨h, A.; Stumpf, R. J. Organomet. Chem. 1995, 491, 267. (c) Fischer,
H.; Karl, C. C.; Roth, G. Chem. Ber. 1996, 129, 615. (d) Fischer, H.;
Podschadly, O.; Roth, G.; Herminghaus, S.; Klewitz, S.; Heck, J.;
Houbrechts, S.; Meyer, T. J. Organomet. Chem. 1997, 541, 321.
(9) (a) Fischer, H.; Leroux, F.; Roth, G.; Stumpf, R. Organometallics
1996, 15, 3723. (b) Leroux, F.; Stumpf, R.; Fischer, H. Eur. J. Inorg. Chem.
1998, 1225.
(1) For reviews on the chemistry of vinylidene complexes see: (a) Bruce,
M. I.; Swincer, A. G. AdV. Organomet. Chem. 1983, 22, 59. (b) Bruce, M.
I. Chem. ReV. 1991, 91, 197. (c) Bruneau, C.; Dixneuf, P. H. Acc. Chem.
Res. 1999, 32, 311. (d) Puerta, M. C.; Valerga, P. Coord. Chem. ReV. 1999,
977, 193-195. (e) Cadierno, V.; Gamasa, M. P.; Gimeno, J. Coord. Chem.
ReV. 2004, 248, 1627. (f) Werner, H. Coord. Chem. ReV. 2004, 248, 1693.
(g) Katayama, H.; Ozawa, F. Coord. Chem. ReV. 2004, 248, 1703. (h)
Bruneau, C.; Dixneuf, P. H. Angew. Chem. 2006, 118, 2232; Angew. Chem.,
Int. Ed. 2006, 45, 2176.
(2) See: (a) Re, N.; Sgamellotti, A.; Floriani, C. Organometallics 2000,
19, 1115. (b) Marrone, A.; Re, N. Organometallics 2002, 21, 3562.
(3) Ho¨hn, A.; Werner, H. Angew. Chem. 1986, 98, 745; Angew. Chem.,
Int. Ed. Engl. 1986, 25, 737.
(4) Mayr, A.; Schaefer, K. C.; Huang, E. Y. J. Am. Chem. Soc. 1984,
106, 1517.
(5) Woodworth, B. E.; Frohnapfel, D. S.; White, P. S.; Templeton, J. L.
Organometallics 1998, 17, 1655.
(10) Abd-Elzaher, M. M.; Weibert, B.; Fischer, H. Organometallics 2005,
24, 1050.
(11) Landon, S. J.; Shulman, P. M.; Geoffroy, G. L. J. Am. Chem. Soc.
1985, 107, 6739.
10.1021/om700274u CCC: $37.00 © 2007 American Chemical Society
Publication on Web 06/14/2007

3792 Organometallics, Vol. 26, No. 15, 2007
Hagmayer et al.
Scheme 1
Scheme 2
Scheme 3
tungsten-triggered valence isomerization of cis-1-acetyl-2-
ethynylcyclopropanes,12 and in the (CO)5W-promoted cycliza-
tion of 1-iodo-1-alkynes.13
We now report on a new and unprecedented cyclization of
(CO)5M-coordinated arylvinylidene ligands (M ) Cr, W) with
alkoxyalkynes to yield azulenylidene ligands.
anhydride at -30 °C (M ) W) or -80 °C (M ) Cr) yielded
the vinylidene complexes 6a,b, 7a,b, and 10a,b-12a,b (Scheme
2).
2. Results
These vinylidene complexes were thermally labile and readily
decomposed at room temperature. Therefore only a few
complexes were isolated in a pure form and fully characterized.
All others were characterized by their IR and NMR spectra and
immediately used for the subsequent reactions with alkoxy-
acetylenes.
The pentacarbonyl vinylidene complexes were prepared either
by MdC/NdC metathesis14 or by sequential reaction of the
corresponding metal hexacarbonyl with lithiated methane
derivatives and trifluoroacetic acid anhydride. The addition of
triaryl ketenimine to solutions of the benzylidene tungsten
complex 1a15 initially gave, via insertion of the NdC bond of
the ketenimine into the WdC(carbene) bond, the benzyliden-
imine adducts 2a-4a of the green vinylidene complexes 6a-
8a (Scheme 1). Elimination of the benzylidenimine was achieved
by addition of boron trifluoride diethyl etherate. The analogous
reaction of 1a with N-phenyl phenyl(methyl)ketenimine and
subsequently with BF3‚Et2O afforded pentacarbonyl methyl-
(phenyl)vinylidene tungsten (9a) (Scheme 1).
An alternative procedure involved reaction of [M(CO)6] with
diarylmethanides followed by trifluoroacetic acid anhydride-
induced elimination of OH-. Addition at room temperature of
[M(CO)6] to solutions of diarylmethanides, obtained by depro-
tonation of the sp3-C atom of suitable diarylmethanes, generated
acyl metalates. The reaction was accompanied by a color change
of the solution from red to yellow or violet. The formation of
the acyl metalate could also be followed easily by IR spectros-
copy. Treatment of these acyl metalates with trifluoroacetic acid
When green solutions of the vinylidene complex 6a in CH2-
Cl2 were treated with 3 equiv of ethoxyacetylene, the color of
the solutions slowly (within about 2 h) turned dark violet and
the CO stretching vibrations strongly shifted toward smaller
wavenumbers. Column chromatographic separation of the
reaction mixture yielded violet crystals in ca. 36% yield. From
the NMR spectra it followed that, surprisingly, the 3-ethoxy-
cyclobutenylidene complex 13a (Scheme 3) had not been formed
as expected on the basis of previous results with ynamines and
ethoxypropyne.8a The ν(CO) absorptions of the new complex
(14a) are at lower wavenumbers than those of the 3-ethoxy-2-
methylcyclobutenylidene complex 15a (Scheme 4) obtained by
addition of ethoxypropyne to the CRdCâ bond of 6a. The ν(CO)
absorptions of 13a, formed by addition of ethoxyacetylene to
the CRdCâ bond of 6a, are expected at higher wavenumbers.
In addition, the 13C NMR spectrum of the new complex showed
11 resonances in the aromatic and olefin region between δ )
115 and 185 ppm instead of 6 as expected. On the basis of the
spectroscopic results the new complex was assigned the structure
14a, containing a bicyclic azulenylidene ligand (Scheme 3)
instead of an unsaturated four-membered carbocyclic carbene
ligand.
(12) Ohe, K.; Yokoi, T.; Miki, K.; Nishino, F.; Uemura, S. J. Am. Chem.
Soc. 2002, 124, 526.
(13) Miura, T.; Murata, H.; Kiyota, K.; Kusama, H.; Iwasawa, N. J. Mol.
Catal. A 2004, 213, 59.
(14) Fischer, H.; Schlageter, A.; Bidell, W.; Fru¨h, A. Organometallics
1991, 10, 389.
(15) (a) Casey, C. P.; Polichnowski, S. W. J. Am. Chem. Soc. 1977, 99,
6097. (b) Casey, C. P.; Polichnowski, S. W.; Shusterman, A. J.; Jones, C.
R. J. Am. Chem. Soc. 1979, 101, 7282. (c) Fischer, H.; Zeuner, S.;
Ackermann, K. J. Chem. Soc., Chem. Commun. 1984, 684.
The formation of azulenylidene complexes is not confined
to the reaction of 6a with ethoxyacetylene. The corresponding
products were obtained when instead of ethoxyacetylene the
bulkier alkyne tert-butyloxyacetylene was employed in the

Unprecedented Formation of Azulenylidene Ligands
Organometallics, Vol. 26, No. 15, 2007 3793
Scheme 4
Scheme 6
Scheme 7
Scheme 5
6. Similar thermal olefin elimination reactions proceeding via
six-membered intermediates have been proposed by Ficini16 and
Arens17 to account for the facile decomposition of alkoxy-
alkynes.
reactions with the vinylidene tungsten complexes 6a-8a and
10a and the vinylidene chromium complex 6b. The new
azulenylidene complexes (Scheme 4) were isolated in moderate
yields. These complexes were formed independently of whether
pure vinylidene complexes or those solutions were employed
that were obtained by the acyl route (Scheme 2). However, when
these solutions were used, they first had to be filtered over silica
or aluminum oxide. After addition of tert-butyloxyacetylene,
the volume of the solutions was reduced at low temperatures
to a few milliliters, thus reducing the amount of decomposition
of the starting complex and increasing the yields. Again,
complexes containing the four-membered cyclobutenylidene
ligand were not detected.
The reaction of the monosubstituted diarylvinylidene tungsten
complexes 7a and 10a with tert-butyloxyacetylene yielded
mixtures of two isomeric azulenylidene complexes. It was not
possible to separate these isomers by column chromatography.
However, on the basis of 2D NMR spectroscopy (HMBC and
HSQC spectra) it was possible to assign the resonances of both
isomers and to determine the isomeric ratio after chromato-
graphic purification of the complexes. The isomeric ratio was
close to 1:1 in both cases (5:4 for 17a/17a′ and 3:4 18a/18a′).
There obviously is no pronounced preference for the formation
of either one of the isomers. In contrast, only one isomer (19a)
was detected in the product mixture of the reaction of 8a with
tert-butyloxyacetylene.
To prevent the decomposition of the azulenylidene complexes
by such a â-elimination pathway, tert-butyloxyacetylene was
replaced by adamantyloxyacetylene. The reaction rates were
similar and the adamantyloxy-substituted azulenylidene tungsten
complexes 21a-25a (Scheme 7) were obtained in modest yields.
In accord with expectation, the adamantyloxy-substituted
complexes 21-25 proved to be somewhat more stable than the
corresponding tert-butyloxy derivatives. But despite their en-
hanced stability, they were unstable at room temperature. Due
to the increased stability, the chromium complexes 21b-25b
could likewise be isolated. However, the reactions of the
chromium vinylidene complexes proceeded much slower than
those of the tungsten complexes and the temperature had to be
raised from -30 °C to 0 °C.
The azulenylidene complexes, derived from monosubstituted
diarylvinylidene complexes, were again obtained as mixtures
of isomers nonseparable by column chromatography. The
determination of exact isomeric ratios was hampered by
insufficient separation of the relevant resonances. Nevertheless,
the isomeric ratios were found to be again close to 1:1 and were
similar to those listed in Scheme 5. In general replacing the
p-methyl substituent by the electron-withdrawing p-chloro group
in monosubstituted vinylidene complexes shifted the ratio toward
those azulenylidene complexes (22′a,b and 23′a,b) having the
substituent attached to the seven-membered ring. A pronounced
change in the isomeric ratio was not observed when the
influences of both substituents were combined (see 24′a,b).
Surprisingly, only one isomer was obtained from the reaction
of the phenyl(4-tert-butylphenyl)vinylidene complex 12 with
In the reaction of the methyl(phenyl)vinylidene complex 9a
with tert-butyloxyacetylene the 8a-methyl azulenylidene com-
plex 20a was formed in 39% isolated yield (Scheme 5).
Most of the new complexes turned out to be quite labile and
readily decomposed at room temperature. A potential decom-
position pathway involving â-elimination is shown in Scheme
(16) Ficini, J. Bull. Soc. Chim. Fr. 1954, 1367.
(17) Nieuwenhuis, J.; Arens, J. F. Rec. TraV. Chim. 1958, 77, 1153.

3794 Organometallics, Vol. 26, No. 15, 2007
Hagmayer et al.
Figure 1. Structure of complex 24b in the crystal (ellipsoids drawn
at 50% level, hydrogen atoms omitted for clarity). Important angles
(deg): C1-Cr1-C6 87.97(12), C2-Cr1-C6 88.98(12), C3-Cr1-
C6 88.59(12), C4-Cr1-C6 95.50(12), C5-Cr1-C6 176.84(12),
C6-C10-C9 104.1(2), C6-C10-C16 109.1(2), C6-C7-C8
112.2(2), C8-C9-C10 106.9(2), C7-C8-O6 133.2(3), C9-C11-
C12 125.6(3), C12-C13-C14 128.2(3), C14-C15-C10 125.0-
(3); for distances see Table 1.
Figure 2. Structure of complex 25a in the crystal (ellipsoids drawn
at 50% level, hydrogen atoms omitted for clarity). Important angles
(deg): W1-C6-C7 128.1(3); W1-C6-C10 126.1(3), C6-C10-
C9 104.6(4), C6-C10-C16 108.1(4), C6-C7-C8 112.8(4), C8-
C9-C10 106.7(4), C7-C8-O6 133.7(4), C9-C11-C12 125.0(4),
C12-C13-C14 125.8(5), C14-C15-C10 123.3(5); for distances
see Table 1.
Table 1. Selected Bond Distances (Å) and Bond Angles (deg)
for Complexes 24b and 25a
24b
25a
M-C5a
1.893(3)
1.908
2.022(5)
2.039
M-COcis (av)a
quently, the C8-C9 bond is short and corresponds to a
conjugated C(sp2)-C(sp2) single bond.l8 The C-C distances
within the five-membered ring and the C9-C11 distance
compare well with those found in the only cyclopentenylidene
complex (26) characterized until now by an X-ray structure
analysis.19 The distances within the bicyclic ring system are also
similar to those in 3-hydroxy-9-phenyl-1,9-dihydroazulen-1-one
(27).20 However, due to the strong acceptor properties of the
pentacarbonylmetal fragment, the C-C single bonds C6-C7
and C8-C9 are somewhat shorter and the C7dC8 double bond
is longer than in 27. The remaining ring distances agree well.
M-C6a
C6-C7
C6-C10
C7-C8
C8-C9
C9-C10
C9-C11
C11-C12
C12-C13
C13-C14
C14-C15
C10-C15
2.048(3)
1.402(4)
1.555(4)
1.393(4)
1.444(4)
1.517(4)
1.346(4)
1.434(4)
1.355(4)
1.445(4)
1.332(4)
1.511(4)
2.169(5)
1.409(6)
1.558(6)
1.386(7)
1.453(6)
1.513(6)
1.337(7)
1.433(7)
1.361(7)
1.444(8)
1.336(7)
1.511(7)
a M ) Cr (24b), W (25a).
adamantyloxyacetylene. On the basis of the NMR spectroscopic
results the product complex was assigned the structure contain-
ing the tert-butyl substituent in position 4 of the phenyl ring
(Scheme 7, 25a,b, R1 ) tert-butyl, R2 ) H).
All new azulenylidene complexes were characterized by their
IR, NMR, and mass spectra and, whenever possible, also by
elemental analyses. The structures of 24b and 25a (Table 1,
Figure 1 and 2) were additionally established by X-ray structure
analyses. In both cases, a few crystals suitable for diffraction
studies were obtained at -30 °C by slow diffusion of petroleum
ether into solution of 24b/24′b and 25a in CH2Cl2, respectively.
The five-membered ring in both complexes only slightly
deviates from planarity (torsion angle C6-C10-C9-C8: -2.5-
(5)° in 25a and 4.1(3)° in 24b) and is almost staggered with
respect to the cis-CO ligands (torsion angle C2-Cr1-C6-C7:
-7.0(3)° in 24b, C3-W1-C6-C7: 13.6(4)° in 25a). In
contrast, the seven-membered ring is strongly puckered and
adopts a boat conformation, C9, C11, C14, and C15 forming
the bottom part of the “boat”. The angle between the planes
formed by C9/C10/C15 and C9/C11/C14/C15 is 45.3° in 24b
and 47.5° in 25a. The olefin planes C6/C7/C8 and C8/C9/C11
are coplanar, thus allowing for optimal conjugation. Conse-
3. Calculations and Discussion
The reactions of arylvinylidene(pentacarbonyl)chromium and
-tungsten with π-donor-substituted alkynes are highly chemose-
lective. The product formation strongly depends on the sub-
stituent at the Câ atom of the alkyne. Ynamines and ethoxypro-
pyne add to the CR-Câ bond of the diphenylvinylidene ligand
to form cyclobutenylidene ligands; the formation of an azule-
nylidene ligand is not observed.8a Conversely, the reactions of
(18) Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen, A.
G.; Taylor, R. J. Chem. Soc., Perkin Trans. 2 1987, S1.
(19) Fischer, H.; Meisner, T.; Hofmann, J. Chem. Ber. 1990, 123, 1799.
(20) van de Grample, J. C.; Cuperus, A. J.; Vos, A. Rec. TraV. Chim.
Pays-Bas 1971, 90, 587.

Unprecedented Formation of Azulenylidene Ligands
Organometallics, Vol. 26, No. 15, 2007 3795
Scheme 8
Scheme 9
alkoxyacetylene with arylvinylidene complexes afford azule-
nylidene complexes, and the formation of cyclobutenylidene
complexes is not observed.
The reactions leading to azulenylidene complexes are remi-
niscent of those of arylketenes with ethoxyacetylene.21 Already
earlier it was reported that diphenylketenes react with ethoxy-
acetylene to give two cyclic ketones, 3-ethoxy-4,4-diphenylcy-
clobut-2-enone and 3-ethoxy-8a-phenyl-8aH-azulen-1-one.21
Both ketones, the cyclobutenones and the azulenones, are formed
in nearly equal amounts.21c Both types of reactions, those of
vinylidene complexes and of ketenes, are obviously closely
related, and pentacarbonyl(vinylidene) complexes may be
regarded as organometallic analogues of ketenes. However, the
reactions of vinylidene complexes with alkoxyalkynes proceed
considerably more chemoselectively, yielding exclusiVely either
cyclobutenylidene or azulenylidene complexes.
A similar mechanism seems plausible to account for the
formation of the azulenylidene complexes and is supported by
the results of DFT calculations.
Based on these calculations the energetically most feasible
sequence for the reaction of pentacarbonyl(diphenylvinylidene)-
chromium (6b) with methoxyacetylene is shown in Scheme 9.
The LUMO in vinylidene complexes is an in-plane orbital
predominantly localized on the metal-bound CR atom. In
alkoxyacetylenes the nucleophilic center is the Câ atom. Thus,
the reaction is initiated by an in-plane nucleophilic approach
of the Câ atom of the alkyne to the CR atom of the vinylidene
complex (A f B). Interaction of the Câ atom with the CR atom
leads to lengthening of the CrdCR bond, the CdC bond of the
vinylidene complex, and the CtC bond of the alkyne as well
as to a bending of the Cr-C-C angle away from the
approaching alkyne. In the transition state (B) the CR(vinylidene)-
Câ(alkyne) distance has been reduced to 2.37 Å and the axis of
the alkyne is almost perpendicularly oriented with respect to
the vinylidene plane. The overall Gibbs free energy for the
process A f B is 41 kJ/mol. Further lengthening of the Cr-C
and the C-C bonds, reduction of the Cr-CR-Câ angle, and
interaction of the Câ atom of the alkyne with the metal give C.
Formation of this complex (A f C) stabilizes the system (6b
+ methoxyacetylene) by 78 kJ/mol. The barrier for the
rearrangement of the ligand in C into the norcaradienylidene
ligand in E (∆G ) -91 kJ/mol) via D is slightly lower (∆Gq
) 39 kJ/mol) than that for the addition step A f C. In contrast,
the barrier for alkyne dissociation from C to re-form the starting
compounds (C f B f A) is much higher (119 kJ/mol). The
final transformation of the norcaradienylidene ligand in E into
the azulenylidene ligand in the product complex G (∆G ) -15
kJ/mol) via F proceeds almost barrierless (∆Gq ) 6 kJ/mol)
(Scheme 9 and Figure 3).
DFT calculations indicate that the cyclobutenylidene complex
28 is more stable than the azulenylidene complex 29 by 54 kJ/
mol.
This is in accord with the exclusive formation of a cyclobute-
nylidene complex in the reaction of pentacarbonyl(diphenylvi-
nylidene)tungsten with ethoxypropyne.8a The calculated energy
difference in favor of the cyclobutenylidene complex decreases
by about 47 kJ/mol when R ) Me is replaced by R ) H.
For the formation of 3-ethoxy-8a-phenyl-8aH-azulen-1-one
a mechanism involving initial addition (I) of ethoxyacetylene
to the carbonyl group of diphenylketene was proposed followed
by a ring closure to give the spirocarbonium ion II (Scheme
8). Subsequent formation of the norcaradiene derivative III and
ring enlargement afford the azulen-1-one.21c
The overall reaction is characterized by an early transition
state, and the reaction rate is determined by the approach of
the alkyne and formation of the adduct C.
Since the initial reaction step is an in-plane attack of the
alkyne at the CR atom of the vinylidene ligand, two different
directions for an alkyne approach are possible when monoaryl-
(21) (a) Jenny, E. F.; Schenker, K.; Woodward, R. B. Angew. Chem.
1961, 73, 756. (b) Barton, D. H. R.; Gardner, J. N.; Petterson, R. C.; Stamm
O. A. J. Chem. Soc. 1962, 2708. (c) Druey, J.; Jenny, E. F.; Schenker, K.;
Woodward, R. B. HelV. Chim. Acta 1962, 71, 600. (d) Teufel, H.; Jenny,
E. F. Tetrahedron Lett. 1971, 21, 1769.

3796 Organometallics, Vol. 26, No. 15, 2007
Hagmayer et al.
The reactions of alkoxyacetylenes with vinylidene complexes
and with ketenes differ not only in their chemoselectivity but
also in the syn/anti selectivity of the alkyne approach. In general,
those reactions of alkoxyacetylenes that tend to be syn selective
with vinylidene complexes are anti selective with ketenes and
vice versa. The extreme case is observed in the reactions with
the methoxyphenyl-substituted compounds. Whereas the reaction
of ethoxyacetylene with OdCdC(Ph)C6H4OMe-p is highly syn
selective [syn/anti ratio ) 50 ((30) in nitromethane and 16 ((
5) in pentane], in the corresponding reaction of tert-butyloxy-
acetylene with [(CO)5WdCdC(Ph)C6H4OMe-p] the formation
of only the anti isomer 19 (Scheme 4) was detected.
Experimental Section
Figure 3. Gibbs free energy profile for the reaction of [(CO)5Crd
CdCPh2] with HCtCOMe at 298 K (see also Scheme 9).
All operations were performed in an inert gas atmosphere (argon
or nitrogen) using standard Schlenk techniques. Solvents were dried
by distillation from CaH2 (CH2Cl2), LiAlH4 (petroleum ether), and
sodium/benzophenone ketyl (THF, Et2O). The silica gel used for
chromatography (Baker, silica gel for flash chromatography) was
nitrogen-saturated. The yields refer to analytically pure compounds
and are not optimized. Instrumentation: 1H NMR and 13C NMR
spectra were recorded on a Bruker AC 250 spectrometer or on a
Varian Inova 400 spectrometer at -50 °C. Chemical shifts are
reported relative to the residual solvent peaks. IR spectra were
recorded on a Biorad FTS 60. MS measurements were carried out
on a Finnigan MAT 312 instrument. The UV/vis spectra were
recorded on a Hewlett-Packard 8453 diode array spectrophotometer.
The photochemical reactions were performed in a Duran glass
apparatus using a Hg high-pressure lamp (Heraeus TQ 250). The
following compounds were prepared according to literature pro-
cedures: the complexes 1a,15 6a,14 and 6b,8c adamantyloxyacety-
lene,22 tert-butyloxyacetylene,22 and ethoxyacetylene.23 The keten-
imines were synthesized from the corresponding amides.24 Phenyl(4-
tolyl)methane, phenyl(4-chlorophenyl)methane, phenyl(4-tert-
butylphenyl)methane, and 4-chlorophenyl(4′-methylphenyl)methane
were prepared from the corresponding alcohols according to
published methods.25 The ylide complexes 2a-5a were likewise
synthesized following a published procedure.14 The alcohols of
phenyl(4-tert-butylphenyl)methane and 4-chlorophenyl(4′-meth-
ylphenyl)methane were obtained by the method of Blackwell et
al.26 All other chemicals were used as obtained from commercial
suppliers.
General Procedure for the Preparation of Vinylidene Com-
plexes. Method A. An equimolar amount of the corresponding
ketenimine was added at -70 °C to a solution of 1a in dichlo-
romethane. The dark red solution turned light red. On addition of
pentane, a red precipitate was formed. Filtration over sodium sulfate
at -70 °C and washing with cold (-70 °C) pentane afforded the
red ylide complexes 2a-5a in ca. 80% yield. These were im-
mediately dissolved at -70 °C in a large volume of dichlo-
romethane. An equimolar amount of BF3‚Et2O in 5 mL of CH2Cl2
was added. When the red reaction mixture was slowly warmed to
room temperature, the red color turned to a dirty brownish-green.
The solvent was removed in vacuo at -30 °C. The residue was
dissolved in 30 mL of pentane, and the solution was chromato-
graphed at -30 °C on silica gel with pentane/CH2Cl2. The green
band was collected. Removal of the solvent in vacuo at -30 °C
gave the vinylidene complexes 6a-9a in 11-90% yield (based on
the ylide complex 2a-5a).
Table 2. Gibbs Free Energies (in kJ/mol) for the Steps “A”
f ”B” and “B” f ”C” (see also Figure 4) of the Reactions
of Methoxyacetylene with [(CO)5CrdCdC(C6H4R-p)Ph] (R
t
) H, Cl, Me, Bu) at 298 K as Calculated at the LACPV*/
BP86 Level of Theory
R
H
Cl
Me
tBu
∆G(“A”f“B”), syn approach
∆G(“A”f“B”), anti approach
∆G(“B”f“C”), syn approach
∆G(“B” f“C”), anti approach
40.5
40.6
-78.2
-78.2
43.0
45.7
-72.3
-72.8
43.7
39.0
-75.0
-73.5
39.7
40.4
-78.1
-79.1
substituted diarylvinylidene complexes are used. The alkyne can
add to CR of the vinylidene ligand either adjacent to the
substituted phenyl group (syn approach) or from the opposite
side (anti approach). The syn approach then leads via interaction
of the alkyne-Câ atom with the ipso carbon atom of the
substituted phenyl group to azulenylidene complexes carrying
the substituent X at the seven-membered ring (X′a,b). Con-
versely, an anti approach gives azulenylidene complexes having
the group X in the phenyl substituent (Xa,b). Thus, the isomer
preferentially formed is determined by the direction of the
approaching alkyne, and the energy differences of the initial
intermediates B/B′ and C/C′ will determine the isomeric ratio.
On the basis of the experimentally found isomeric ratios (see
Schemes 4 and 7) the energies of B and B′ (and C and C′) are
expected to be similar. The calculated energies for the transition
states B for syn and anti approach of methoxyacetylene to the
methyl-substituted vinylidene chromium complex 7b, the chloro-
substituted vinylidene complex 10b, and the tert-butyl-
substituted complex 12b are very similar. The same applies to
the various syn and anti intermediates C and C′ (Table 2). For
instance, the transition state “B” for the syn addition of
methoxyacetylene to the chloro-substituted vinylidene chromium
complex 10b is only 2.7 kJ/mol lower in energy than that for
the anti addition. Conversely, for the reaction of methoxyacety-
lene with 7b ∆Ganti is 4.7 kJ/mol less than ∆Gsyn. Therefore, in
the reactions of methoxyacetylene (a) with the chloro-substituted
complex 10b formation of the syn isomer and (b) with the
methyl-substituted complex 7b formation of the anti isomer
should be slightly favored. Note that the experimentally
determined syn/anti ratios of the azulenylidene complexes
formed in the reactions of adamantyloxyacetylene with 10b (4:
3) and with 7b (1:2) are in accord with these expectations.
However, the agreement should be regarded with care consider-
ing error limits and the difficulties in measuring exact isomeric
ratios. The corresponding energy difference ∆Gsyn - ∆Ganti for
the reaction of 12b with methoxyacetylene is -0.7 kJ/mol.
Method B. At room temperature, a solution of 3.1 mL of BuLi
(5 mmol, 1.6 M in hexane) was added dropwise to a solution of 5
(22) Perica`s, M. A.; Serratosa, F.; Valent´ı, E. Tetrahedron 1987, 43, 2311.
(23) Brandsma, L. PreparatiVe Acetylenic Chemistry; Elsevier: Am-
sterdam, 1988; p 171.
(24) Stevens, C. L.; Singhal, G. H. J. Org. Chem. 1964, 29, 34.
(25) Krug, C.; Hartwig, J. F. J. Am. Chem. Soc. 2002, 124, 1674.
(26) Blackwell, J.; Hickinbottom, W. J. J. Chem. Soc. 1961, 1405-1407.

Unprecedented Formation of Azulenylidene Ligands
Organometallics, Vol. 26, No. 15, 2007 3797
mmol of the appropriate diarylmethane in 50 mL of THF. The
orange solution was stirred for 1 h at room temperature. Then 5
mmol of M(CO)6 (M ) W: 1.76 g; M ) Cr: 1.10 g) was added.
The solution turned yellow (violet for 10a,b and 11a,b). After 30
min, the solvent was removed in vacuo. The remaining oily residue
was dissolved in 50 mL of CH2Cl2 and treated at -30 °C (M )
W) or -80 °C (M ) Cr) with 0.7 mL (5 mmol) of (F3CCO)2O.
The solution was stirred for 5 min and subsequently filtered over
neutral Al2O3 (M ) W) or silica gel (M ) Cr). Rapid elution with
50 mL of cold petroleum ether gave green solutions of 6a,b-12a,b.
These solutions were immediately used for the subsequent re-
actions.
2CO)+], 356 (11) [(M - 3CO)+], 300 (40) [(M - 5CO)+]. Anal.
Calcd for C14H8O5W (440.1): C, 38.21; H, 1.83. Found: C, 38.51;
H, 2.00.
Pentacarbonyl[p-chlorophenyl(phenyl)vinylidene]tungsten
(10a). Method B. Acyl tungstate: IR (THF): ν(CO) 2048 m, 1908
s, 1893 s, 1862 w cm-1. 10a: IR (petroleum ether): ν(CO) 2094
m, 2004 sh, 1983 s, 1976 sh cm-1. 1H NMR (400 MHz, CD2Cl2):
δ 7.24-7.45 (m, 9H, C6H5, C6H4). 13C NMR (100.6 MHz, CD2-
Cl2): δ 126.2, 128.5, 128.6, 128.8, 130.3, 131.5, 140.0, 140.8 (C6H5,
C6H4, Câ), 192.8 (cis-CO, JWC ) 126.1 Hz), 208.6 (trans-CO), 373.4
(WdC).
Pentacarbonyl(p-chlorophenyl(phenyl)vinylidene]-
chromium (10b). Method B. Acyl chromate: IR (THF): ν(CO)
2036 m, 1908 s, 1892 s, 1864 w cm-1. 10b: IR (petroleum ether):
Pentacarbonyl[phenyl(p-tolyl)vinylidene]tungsten (7a). Method
A. The reaction of 600 mg (0.86 mmol) of complex 3a in 250 mL
of CH2Cl2 with BF3‚Et2O (reaction time: about 3 h) and chroma-
tography with pentane/CH2Cl2 (20:3) gives green 7a in yields
varying between 22 and 33% (based on 3a).
1
ν(CO) 2089 m, 2007 sh, 1983 s cm-1. H NMR (400 MHz, CD2-
Cl2): δ 7.26-7.49 (m, 9H, C6H5, C6H4). 13C NMR (100.6 MHz,
CD2Cl2): δ 126.3, 128.5, 128.6, 128.8, 130.3, 131.5, 140.0, 140.9
(C6H5, C6H4, Câ), 212.2 (cis-CO), 222.6 (trans-CO), 404.6
(CrdC).
Method B. Acyl tungstate: IR (THF): ν(CO) 2047 m, 1907
vs, 1890 sh cm-1
.
Pentacarbonyl[p-chlorophenyl(p-tolyl)vinylidene]tungsten (11a).
Method B. Acyl tungstate: IR (THF): ν(CO) 2049 m, 1911 s,
1894 sh, 1866 w cm-1. 11a: IR (petroleum ether): ν(CO) 2095
Complex 7a. Mp: 53 °C (dec). IR (petroleum ether): ν(CO)
2093 m, 2003 sh, 1982 s, 1974 sh cm-1. 1H NMR (400 MHz, CD2-
Cl2): δ 2.20 (s, 3H, CH3), 7.03-7.24 (m, 9H, C6H5, C6H4); (250
MHz, d6-acetone): δ 2.33 (s, 3H, CH3), 7.1-7.5 (m, 9H, C6H5,
C6H4). 13C NMR (100.6 MHz, CD2Cl2): δ 20.1 (CH3), 125.2, 127.7,
127.86, 127.9, 128.3, 134.7, 137.5, 140.9 (C6H5, C6H4), 192.2 (cis-
CO, JWC ) 127.5 Hz), 208.6 (trans-CO), 376.1 (WdC); (62.5 MHz,
d6-acetone): δ 21.0 (CH3), 125.6, 127.9, 128.7, 129.0, 129.4, 129.8,
130.5, 132.3, 137.7 (C6H5, C6H4), 193.8 (cis-CO, JWC ) 124.7 Hz),
209.0 (trans-CO), 373.7 (WdC). EI-MS (70 eV): m/z (%) 516 (8)
[M+], 488 (36) [(M+ - CO)+], 460 (21) [(M - 2CO)+], 432 (54)
[(M - 3CO)+], 404 (33) [(M - 4CO)+], 376 (100) [(M - 5CO)+],
192 (54) [(CdC(C6H5)C6H4CH3)+]. Anal. Calcd for C20H12O5W
(516.16): C, 46.54; H, 2.34. Found: C, 46.57; H, 4.41.
1
m, 2003 sh, 1979 s cm-1. H NMR (400 MHz, CD2Cl2): δ 2.41
(CH3), 7.16-7.63 (m, 8H, C6H4). 13C NMR (100.6 MHz, CD2-
Cl2): δ 20.9 (CH3), 128.4, 128.6, 129.1, 129.2, 129.5, 130.2, 135.8,
136.9, 137.7, 140.3 (C6H4, Câ), 192.8 (cis-CO, JWC ) 126.1 Hz),
209.0 (trans-CO), 375.1 (WdC).
Pentacarbonyl[p-chlorophenyl(p-tolyl)vinylidene]chromium
(11b). Method B. Acyl chromate: IR (THF): ν(CO) 2037 w, 1907
s, 1891 sh, 1866 w cm-1. 11b: IR (petroleum ether): ν(CO) 2089
1
s, 2001 sh, 1979 vs cm-1. H NMR (400 MHz, CD2Cl2): δ 2.49
(CH3), 7.26-7.71 (m, 8H, C6H4). 13C NMR (100.6 MHz, CD2-
Cl2): δ 21.0 (CH3), 126.7, 128.5, 128.7, 129.3, 129.6, 130.3, 131.5,
135.9, 136.9, 137.8, 140.4 (C6H4, Câ), 212.3 (cis-CO), 223.0 (trans-
CO), 406.0 (CrdC).
Pentacarbonyl[phenyl(p-tolyl)vinylidene]chromium (7b). Me-
thod B. Acyl chromate: IR (THF): ν(CO) 2036 s, 1908 vs, 1890
sh cm-1. 7b: IR (petroleum ether): ν(CO) 2087 m, 2026 vw, 2005
Pentacarbonyl[p-tert-butylphenyl(phenyl)vinylidene]-
tungsten (12a). Method B. Acyl tungstate: IR (THF): ν(CO) 2047
m, 1909 vs, 1888 sh cm-1. 12a: IR (petroleum ether): ν(CO) 2092
1
s, 1987 s, 1982 sh cm-1. H NMR (400 MHz, CD2Cl2): δ 2.0 (s,
3H, CH3), 7.03-7.38 (m, 9H, C6H5, C6H4). 13C NMR (100.6 MHz,
CD2Cl2): δ 21.1 (CH3), 123.4, 124.7, 125.4, 125.9, 126.1, 127.3,
127.4, 127.7, 128.2, 128.8 (C6H5, C6H4, Câ), 212.4 (cis-CO), 224.2
(trans-CO), 413.3 (CrdC).
1
m, 2002 m, 1983 s, 1973 m cm-1. H NMR (400 MHz, CD2Cl2):
δ 1.15 (s, 9H, CH3), 7.00 - 7.19 (m, 9H, C6H5, C6H4). 13C NMR
(100.6 MHz, CD2Cl2): δ 31.3 (CH3), 34.4 (C(CH3)3), 125.5, 126.1,
128.4, 128.6, 128.8, 138.6, 141.8, 148.7 (C6H5, C6H4, Câ), 193.1
(cis-CO, JWC ) 126.1 Hz), 209.6 (trans-CO), 377.2 (WdC)
Pentacarbonyl[p-methoxyphenyl(phenyl)vinylidene]-
tungsten (8a). Method A. The reaction of 500 mg (0.75 mmol) of
complex 4a in 250 mL of CH2Cl2 with BF3‚Et2O (reaction time:
about 3 h) and the chromatography with pentane/CH2Cl2 (10:4)
afforded green crystals in yields varying from 26 to 31% (based
on 4a). Mp: 52 °C. IR (pentane): ν(CO) 2094 m, 2004 s, 1988
vs, 1975 s cm-1. 1H NMR (250 MHz, d6-acetone): δ 3.79 (s, 3H,
CH3), 7.0-7.5 (m, 9H, C6H5, C6H4). 13C NMR (62.5 MHz, d6-
acetone): δ 55.2 (CH3), 115.2, 119.6, 127.8, 128.5, 129.7, 129.8,
130.5, 132.0, 159.6 (C6H5, C6H4, Câ), 193.8 (cis-CO), 209.3 (trans-
CO), 375.1 (WdC). EI-MS (70 eV): m/z (%) 532 (3) [M+], 504
(8) [(M - CO)+], 476 (6) [(M - 2CO) +], 448 (4) [(M - 3CO)+],
420 (7) [(M - 4CO)+], 392 (15) [(M - 5CO)+]. C20H12O6W
(532.16).
Pentacarbonyl[p-tert-butylphenyl(phenyl)vinylidene]-
chromium (12b). Method B. Acyl chromate: IR (THF): ν(CO)
2036 m, 1908 vs, 1891 sh cm-1. 12b: IR (petroleum ether): ν-
1
(CO) 2086 m, 2004 s, 1986 s, 1981 s cm-1. H NMR (400 MHz,
CD2Cl2): δ 1.15 (s, 9H, CH3), 7.35 - 7.67 (m, 9H, C6H5, C6H4,
Câ). 13C NMR (100.6 MHz, CD2Cl2): δ 30.1 (CH3), 34.6 (C(CH3)3),
126.2-150.8 (C6H5, C6H4, Câ), 213.1 (cis-CO), 224.5 (trans-CO),
409.3 (CrdC)
General Procedure for the Reaction of Vinylidene Complexes
with Alkoxyacetylenes. Method C. Solutions of vinylidene
complexes (1 mmol dissolved in 5 mL of CH2Cl2) were treated at
temperatures between -10 and -30 °C with 3 equiv of alkoxy-
acetylene dissolved in 5 mL of CH2Cl2. The progress of the reaction
was controlled by IR spectroscopy. The reactions of the tungsten
complexes required between 3 and 6 h, and those of the chromium
complexes up to 5 days. In the course of the reactions the green
color turned dark violet. The solvent was removed in vacuo at -30
°C. The residue was dissolved at -30 °C in pentane/CH2Cl2 and
chromatographed on silica gel at -50 °C. With pentane/CH2Cl2 a
violet to blue band (color depending on the type of complex) was
eluted. Evaporation of the solvent in vacuo at -50 °C gave the
azulenylidene complexes in yields ranging from 20 to 40% (based
on vinylidene complex).
Pentacarbonyl[methyl(phenyl)vinylidene]tungsten (9a). Method
A. The reaction of 1.2 g (1.93 mmol) of 5a in 450 mL of CH2Cl2
at -80 °C with BF3‚Et2O (reaction time: about 3.5 h) and the
chromatography with pentane/CH2Cl2 (10:1) gave green 9a in yields
between 12 and 28% (based on 5a). Mp: 35 °C (dec). IR
1
(pentane): ν(CO) 2095 m, 1997 sh, 1989 vs, 1979 sh cm-1. H
NMR (250 MHz, d6-acetone): δ 2.11 (s, 3H, CH3), 7.1-7.4 (m,
5H, C6H5). 13C NMR (62.5 MHz, d6-acetone): δ 25.7 (CH3), 122.7,
125.9, 127.1, 129.5, 130.3 (C6H5, Câ), 193.8 (cis-CO, JWC ) 124.37
Hz), 210.1 (trans-CO), 380.4 (WdC). FAB-MS (NBOH/CH2Cl2):
m/z (%) 440 (37) [M+], 412 (100) [(M - CO) +], 384 (22) [(M -

3798 Organometallics, Vol. 26, No. 15, 2007
Hagmayer et al.
Method D. Alkoxyacetylene (2 mmol; 0.23 mL of tert-
butyloxyacetylene or 0.36 g of adamantyloxyacetylene) was added
at -30 °C to a freshly prepared solution of the vinylidene complexes
obtained by method B. The volume of the solution was reduced at
-30 °C to 10 mL. The progress of the reactions was controlled by
IR spectroscopy. The color of the solution changed from green to
dark violet (M ) W) or blue (M ) Cr). The conversion of the
vinylidene complex was complete after 24 h (M ) W, -30 °C) or
6 h (M ) Cr: adamantyloxyacetylene, 0 °C). The solvent was
removed in vacuo at -30 °C, and the residue was twice chromato-
graphed on silica at -50 °C first with petrolether/CH2Cl2 (5:1) and
then with petroleum ether/Et2O (5:1) to give pure azulenylidene
complexes.
butyloxyacetylene). Mp: 115 °C (dec). IR (petroleum ether): ν-
(CO) 2045 m, 1956 s, 1946 m, 1925 s cm-1. 1H NMR (400 MHz,
3
CD2Cl2): δ 1.67 (s, 9H, CH3), 6.28 (dd, JHH ) 6.7 and 10.9 Hz,
3
1H, 5-H), 6.40 (d, JHH ) 6.4 Hz, 1H, 4-H), 6.60 (ddoverlapped and
3
d
overlapped, 2H, 7-H, 8-H), 6.67 (dd, JHH ) 6.8 and 10.9 Hz, 1H,
6-H), 7.11 (m, 5H, C6H5), 7.72 (s, 1H, 2-H). 13C NMR (100.6 MHz,
CD2Cl2): δ 27.8 (C(CH3)3), 70.6 (C-8a), 86.7 (OC(CH3)3), 116.8
(C-4), 126.4 (C-12), 127.0 (C-7), 127.2 (C-10, -11, -13, -14), 127.8
(C-5), 136.3 (C-8), 137.0 (C-6), 137.8 (C-9), 138.9 (C-2), 139.9
(C-3a), 172.7 (C-3), 217.3 (cis-CO), 228.8 (trans-CO), 338.2 (Crd
C). FAB-MS (NBOH): m/z (%) 468 (7) [(M+)], 440 (4) [(M -
CO)+], 412 (11) [(M - 2CO)+], 384 (46) [(M - 3CO)+], 356 (66)
[(M - 4CO)+], 328 (100) [(M - 5CO)+], 300 (8) [(M - 4CO -
C4H8)+], 272 (57) [(M - 5CO - C4H8)+]. UV/vis: λmax (log ꢀ)
606 (4.160), 338 (3.910) [pentane]. Anal. Calcd for C25H20O6Cr
(468.43): C, 64.09; H, 4.31. Found: C, 64.16; H, 4.47.
The following numbering scheme has been applied for assigning
the NMR resonances of the azulenylidene complexes:
Pentacarbonyl(3-tert-butoxy-8a-p-tolylbicyclo[5.3.0]deca-2,-
3a,5,7-tetraenylidene)tungsten (17a) and Pentacarbonyl(3-tert-
butoxy-6-methyl-8a-phenylbicyclo[5.3.0]deca-2,3a,5,7-tetrae-
nylidene)tungsten (17′a). Method C. The reaction employing 8
equiv of tert-butyloxyacetylene was complete after about 5.5 h.
The reaction mixture was chromatographed at -50 °C on silica
with pentane/CH2Cl2 (5:1). Violet powder. Yield: 33% (based on
7a). Method D. Yield: 0.29 g (24% based on tert-butyloxyacety-
lene).
Pentacarbonyl(3-ethoxy-8a-phenylbicyclo[5.3.0]deca-2,3a,5,7-
tetraenylidene)tungsten (14a). Method C. The reaction was
complete after about 2 h. The reaction mixture was chromato-
graphed at -40 °C on silica with pentane/CH2Cl2 (20:3). Violet
crystal. Yield: 36% (based on 6a). Mp: 118 °C (dec). IR
Mp: 80-83 °C. IR (petroleum ether): ν(CO) 2055 m, 1953 s,
1936 m, 1920 s cm-1. Isomer 17a: 1H NMR (400 MHz, CD2Cl2):
3
δ 1.66 (s, 9H, C(CH3)3), 2.19 (s, 3H, CH3), 6.24 (dd, JHH ) 6.6
and 11.0 Hz, 1H, 5-H), 6.57 (dd br, 1H, 7-H), 6.59 (d, 3JHH ) 6.6
(pentane): ν(CO) 2058 m, 1986 vw, 1958 vs, 1941 m, 1924 s cm-1
.
Hz, 1H, 4-H), 6.65 (d, 3JHH ) 10.1 Hz, 1H, 8-H), 6.73 (dd, 3JHH
)
1H NMR (250 MHz, d6-acetone): δ 1.53 (t, JHH ) 7.0 Hz, 3H,
CH2CH3), 4.80 (m, 2H, OCH2CH3), 6.3-6.9 (m, 5H, 4-H, 5-H,
6-H, 7-H, 8-H), 7.0-7.2 (m, 5H, C6H5), 7.79 (s, 1H, 2-H). 13C
NMR (62.5 MHz, d6-acetone): δ 14.4 (OCH2CH3), 71.4 (C-8a),
73.15 (OCH2), 119.8, 127.3, 128.2, 128.4, 129.7, 137.9, 138.4,
139.1, 140.8, 140.9 (C-2, C-3a, C-4, C-5, C-6, C-7, C-8, C6H5),
180.5 (C-3), 198.5 (cis-CO, JWC ) 126.7 Hz), 207.3 (trans-CO),
309.2 (WdC). FAB-MS (NBOH): m/z (%) 572 (8) [M+], 544 (3)
[(M - CO)+], 516 (18) [(M - 2CO)+], 488 (19) [(M - 3CO)+],
460 (30) [(M - 4CO)+], 432 (11) [(M+ - 5CO)+], 249 (46) [(M+
- W(CO)5)+]. UV/vis: λmax (log ꢀ) 234 (4.8), 336 (4.04), 574 (4.3)
[pentane]. Anal. Calcd for C23H16O6W (572.2): C, 48.27; H, 2.81.
Found: C, 48.00; H, 2.81.
3
6.3 and 11.0 Hz, 1H, 6-H) , 6.94-7.18 (m br, 9H, C6H4, C6H5,
both isomers), 7.60 (s, 1H, 2-H). 13C NMR (100.6 MHz, CD2Cl2):
δ 20.6 (CH3), 27.8 (C(CH3)3), 70.7 (C-8a), 87.0 (OC(CH3)3), 118.1
(C-4), 126.3, 127.4, 127.9, 136.0, 134.4, 140.6 (aryl of 17a and
17′a), 126.9 (C7), 128.1 (C-5), 136.9 (C-6), 137.3 (C-8), 139.8 (C-
3a), 140.9 (C-2), 176.2 (C-3), 198.2 (cis-CO, JWC ) 127.3 Hz),
208.0 (trans-CO), 309.3 (WdC). Isomer 17′a: 1H NMR (400 MHz,
CD2Cl2): δ 1.66 (s, 9H, (C(CH3)3), 1.95 (s, 3H, CH3), 6.03 (d,
3JHH ) 6.8 Hz, 1H, 5-H), 6.43 (d , 3JHH ) 10.3 Hz, 1H, 7-H), 6.52
3
3
(d, JHH ) 6.8 Hz, 1H, 4-H), 6.54 (d, JHH ) 4.5 Hz, 1H, 8-H),
6.94-7.18 (m br, 9H, C6H4, C6H5, both isomers), 7.60 (s, 1H, 2-H).
13C NMR (100.6 MHz, CD2Cl2): δ 25.3 (CH3), 27.8 (C(CH3)3),
70.5 (C-8a), 86.9 (OC(CH3)3), 118.9 (C-4), 125.5 (C-5), 126.3,
127.4, 127.9, 136.0, 134.4, 140.6 (aryl of 17a and 17′a), 130.2 (C-
7), 136.1 (C-8), 139.6 (C-3a), 140.8 (C-2), 148.8 (C-6), 176.9 (C-
3), 198.3 (cis-CO, JWC ) 126.8 Hz), 207.8 (trans-CO), 306.1 (Wd
C). FAB-MS (NBOH): m/z (%): 558 (15) [(M - 2CO)+], 530
(38) [(M - 3CO)+], 502 (90) [(M - 4CO)+], 474 (27) [(M -
5CO)+], 446 (89) [(M - 4CO - C4H8)+], 418 (100) [(M - 5CO
- C4H8)+]. Anal. Calcd for C26H22O6W (614.31): C, 50.83; H,
3.61. Found: C, 46.82; H, 4.39.
Pentacarbonyl(3-tert-butoxy-8a-phenylbicyclo[5.3.0]deca-2,-
3a,5,7-tetraenylidene)tungsten (16a). Method C. The reaction was
complete after about 2 h. The reaction mixture was chromato-
graphed at -40 °C on silica with pentane/CH2Cl2 (20:3). Violet
crystal. Yield: 36% (based on 6a). Method D. Yield: 0.22 g (19%
based on tert-butyloxyacetylene).
Mp: 64-66 °C. IR (petroleum ether): ν(CO) 2055 m, 1954 s,
1
1938 m, 1920 s cm-1. H NMR (400 MHz, CD2Cl2): δ 1.67 (s,
9H, CH3), 6.25 (dd, 3J ) 6.7 Hz and 3J ) 10.4 Hz, 1H, 5-H), 6.58
3
3
Pentacarbonyl(3-tert-butoxy-8a-p-chlorophenylbicyclo[5.3.0]-
deca-2,3a,5,7-tetraenylidene)tungsten (18a) and Pentacarbonyl-
(3-tert-butoxy-6-chloro-8a-phenylbicyclo[5.3.0]deca-2,3a,5,7-
tetraenylidene)tungsten (18′a). Method D. Yield: 0.10 g (8%
based on tert-butyloxyacetylene). IR (petroleum ether): ν(CO) 2055
m, 1957 m, 1941 m, 1922 s cm-1. Isomer 18a: 1H NMR (400
(dd, J ) 6.7 and 10.5 Hz, 1H, 7-H), 6.61 (d, J ) 6.5 Hz, 1H,
4-H), 6.67 (d, 3J ) 10.0 Hz, 1H, 8-H), 6.74 (dd, 3J ) 6.8 and 10.2
Hz, 1H, 6-H), 7.12 (m, 5H, C6H5), 7.62 (s, 1H, 2-H). 13C NMR
(100.6 MHz, CD2Cl2): δ 27.8 (C(CH3)3), 70.9 (C-8a), 87.1
(OC(CH3)3), 118.2 (C-4), 126.4 (C-12), 127.0 (C-7), 127.3 (C-10,
-11, -13, -14), 128.2 (C-5), 136.9 (C-6), 137.3 (C-8), 139.6 (C-
3
MHz, CD2Cl2): δ 1.66 (s, 9H, CH3), 6.26 (dd, JHH ) 6.7 and
3a), 140.5 (C-9), 141.0 (C-2), 176.2 (C-3), 198.1 (cis-CO, JWC
)
11.2 Hz, 1H, 5-H), 6.58 (ddoverlapped, 1H, 7-H), 6.63 (doverlapped, 1H,
127.2 Hz), 208.0 (trans-CO, JWC ) 122.9 Hz), 309.0 (WdC). FAB-
MS (NBOH): m/z (%) 600 (8) [M+], 544 (13) [(Μ - 2CO)+],
516 (47) [(Μ - 3CÃ)+], 488 (92) [(Μ - 4CO)+], 460 (30) [(Μ -
5CÃ)+], 432 (76) [(Μ - 4CO - C4Η8)+], 404 (100) [(Μ - 5CO
- C4Η8)+]. Anal. Calcd for C25H20O6W (600.28): C, 50.02; H,
3.36. Found: C, 49.79; H, 3.31.
4-H), 6.67 (doverlapped, 3JHH ) 10.6 Hz, 1H, 8-H), 6.75 (dd, 3JHH
)
6.0 and 11.0 Hz, 1H, 6-H), 7.12-7.17 (m, 9H, C6H4, C6H5, both
isomers), 7.63 (s, 1H, 2-H). 13C NMR (100.6 MHz, CD2Cl2): δ
27.8 (CH3), 70.3 (C-8a), 87.3 (OC(CH3)3), 118.3 (C-4), 126.8 (C-
7), 127.3, 127.4, 127.6, 131.5, 138.4, 140.3 (aryl of 18a and 18′a),
128.5 (C-5), 136.9 (C-6), 137.1 (C-8), 139.1 (C-3a), 141.2 (C-2),
176.1 (C-3), 198.1 (cis-CO), 207.8 (trans-CO), 308.2 (WdC).
Isomer 18′a: 1H NMR (400 MHz, CD2Cl2): δ 1.66 (s, 9H, CH3),
Pentacarbonyl(3-tert-butoxy-8a-phenylbicyclo[5.3.0]deca-2,-
3a,5,7-tetraenylidene)chromium (16b). Method C. Yield: 21%
(based on 6b). Method D. Yield: 0.13 g (14% based on tert-

Unprecedented Formation of Azulenylidene Ligands
Organometallics, Vol. 26, No. 15, 2007 3799
3
3
6.39 (d, JHH ) 7.2 Hz, 1H, 5-H), 6.54 (d, JHH ) 7.3 Hz, 1H,
2CO)+], 584 (48) [(M - 3CO)+], 584 (100) [(M - 4CO)+], 538
(33) [(M - 5CO)+]. C31H26O6W (678.39).
3
4-H), 6.59 (doverlapped, 1H, 7-H), 6.66 (doverlapped, JHH ) 10.5 Hz,
1H, 8-H), 7.12 - 7.17 (m, 9H, C6H4,C6H5, both isomers), 7.61 (s,
1H, 2-H). 13C NMR (100.6 MHz, CD2Cl2): δ 27.8 (CH3), 70.6
(C-8a), 87.3 (OC(CH3)3), 116.4 (C-4), 127.2 (C-5), 127.3, 127.4,
127.6, 131.5, 138.4, 140.3 (aryl of 18a and 18′a), 128.5 (C-7), 136.7
(C-8), 140.5 (C-3a), 141.1 (C-2), 141.4 (C-6), 175.4 (C-3), 197.9
(cis-CO), 208.0 (trans-CO), 309.3 (WdC). FAB-MS: m/z (%) 578
(19) [(M - 2CO)+], 550 (34) [(M - 3 CO)+], 522 (100) [(M -
4CO)+], 494 (40) [(M - 5CO)+], 466 (97) [(M - 4CO - C4H8)+],
438 (78) [(M - 5CO - C4H8)+]. C25H19ClO6W (634.73).
Pentacarbonyl(3-adamantyloxy-8a-phenylbicyclo[5.3.0]deca-
2,3a,5,7-tetraenylidene)chromium (21b). Method D. Yield: 0.26
g (24% based on adamantyloxyacetylene). IR (petroleum ether):
ν(CO) 2045 s, 1956 m, 1944 m, 1923 m cm-1. 1H NMR (400 MHz,
CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2), 2.23 (s, 6H, 2-, 6-,
and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH), 6.28 (dd br, 1H, 5-H),
3
6.42 (d, JHH ) 5.7 Hz, 1H, 4-H), 6.60 (ddoverlapped, 2H, 7-H and
8-H), 6.67 (dd br, 1H, 6-H), 7.11-7.54 (m, 5H, C6H5), 7.80 (s,
1H, 2-H). 13C NMR (100.6 MHz, CD2Cl2): δ 30.8 (3-, 5-, and
8-CH), 35.2 (4-, 9-, and 10-CH2), 41.0 (2-, 6-, and 7-CH2), 70.4
(C-8a), 86.5 (OAd), 116.8 (C-4), 126.4 (C-12), 127.0 (C-7), 127.2
(C-10, -11, -13, -14), 127.8 (C-5), 136.3 (C-8), 137.0 (C-6), 138.4
(C-9), 138.9 (C-2), 140.1 (C-3a), 172.6 (C-3), 217.3 (cis-CO), 228.8
(trans-CO), 337.0 (CrdC). FAB-MS: m/z (%) 546 (3) [(M)+], 518
(1) [(M - CO)+], 490 (3) [(M - 2CO)+], 462 (40) [(M - 3CO)+],
434 (38) [(M - 4CO)+], 406 (100) [(M - 5CO)+]. C31H26O6Cr
(546.54).
Pentacarbonyl(3-tert-butoxy-3a-p-methoxyphenylbicyclo[5.3.0]-
deca-2,3a,5,7-tetraenylidene)tungsten(0) (19a). Method C. The
reaction employing 10 equiv of tert-butyloxyacetylene was complete
after about 6 h. The reaction mixture was chromatographed at -50
°C on silica with pentane/CH2Cl2 (5:2). Violet powder. Yield: 27%
(based on 8a). Yield: 27% (based on 8a). Mp: 43-48 °C (dec).
IR (pentane): ν(CO) 2057 m, 1984 w, 1955 vs, 1937 s, 1920 s
1
cm-1. H NMR (250 MHz, d6-acetone): δ 1.75 (s, 9H, C(CH3)3),
3.66 (s, 3H, OCH3), 6.3-7.1 (m, 9H, 4-H-8-H, C6H4), 7.86 (s,
1H, 2-H). 13C NMR (62.5 MHz, d6-acetone): δ 27.8 (C(CH3)3),
55.0 (OCH3), 70.9 (C-8a), 88.8 (OC(CH3)3), 119.9-141.5 (C-2,
C-4-C-11, C-13, C-14), 158.7 (C-12), 178.2 (C-3), 198.8 (cis-
CO, JWC ) 125.13), 208.1 (trans-CO), 308.6 (WdC). UV/vis: λmax
(log ꢀ) 230 (4.8), 244 (4.8), 336 (4.31), 578 (4.38) [pentane]. FAB-
MS (NBOH/CH2Cl2): m/z (%) 630 (5) [M+], 574 (15) [(M -
2CO)+], 546 (35) [(M - 3CO)+], 518 (77) [(M - 4CO)+], 490
(21) [(M - 5CO)+], 462 (58) [(M - 4CO - C4H8)+], 434 (49)
[(M - 5CO - C4H8)+], 251 (100) [(M - C4H8 - W(CO)5)+].
Anal. Calcd for C26H22O7W (630.30): C, 49.54; H, 3.52. Found:
C, 49.80; H, 3.26.
Pentacarbonyl(3-adamantyloxy-8a-p-tolylbicyclo[5.3.0]deca-
2,3a,5,7-tetraenylidene)tungsten (22a) and Pentacarbonyl(3-
adamantyloxy-6-methyl-8a-phenylbicyclo[5.3.0]deca-2,3a,5,7-
tetraenylidene)tungsten (22′a). Method D. Yield: 0.35 g (25%
based on adamantyloxyacetylene). IR (petroleum ether): ν(CO)
2054 s, 1952 s, 1935 m, 1917 s cm-1. Isomer 22a: 1H NMR (400
MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2), 2.20 (s, 3H,
CH3), 2.23 (s, 6H, 2-, 6-, and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH),
6.24 (dd, 3JHH ) 7.0 and 10.2 Hz, 1H, 5-H), 6.56 (dd br, 1H, 7-H),
3
3
6.62 (d, JHH ) 6.4 Hz, 1H, 4-H), 6.67 (d, JHH ) 10.1 Hz, 1H,
3
3
8-H), 6.74 (dd, JHH ) 6.5 Hz and JHH ) 10.7 Hz, 1H, 6-H) ,
6.96-7.16 (m br, 9H, C6H4 and C6H5, both isomers), 7.71 (s, 1H,
2-H). 13C NMR (100.6 MHz, CD2Cl2): δ 20.7 (CH3), 31.0 (3-, 5-,
and 8-CH), 35.2 (4-, 9-, and 10-CH2), 40.8 (2-, 6-, and 7-CH2),
70.5 (C-8a), 86.72 (OAd), 118.1 (C-4), 126.4, 127.4, 128.0, 136.2,
136.5, 140.8 (aryl of 22a and 22′a), 127.0 (C-7), 128.2 (C-5), 136.9
(C-6), 137.4 (C-8), 139.9 (C-3a), 141.5 (C-2), 176.0 (C-3), 198.3
Pentacarbonyl(3-tert-butoxy-8a-methylbicyclo[5.3.0]deca-2,-
3a,5,7-tetraenylidene)tungsten(0) (20a). Method C. The reaction
employing 5 equiv of tert-butyloxyacetylene was complete after
about 5 h. The reaction mixture was chromatographed at -50 °C
on silica with pentane/CH2Cl2 (20:3). Violet powder. Yield: 39%
(based on 9a). Mp: 64-66 °C (dec). IR (pentane): ν(CO) 2057
m, 1977 vw, 1954 vs, 1940 m, 1923 s cm-1. 1H NMR (250 MHz,
d6-acetone): δ 1.15 (s, 3H, CH3), 1.68 (s, 9H, C(CH3)3), 6.3-7.1
(m, 5H, 4-H, 5-H, 6-H, 7-H, 8-H), 7.79 (s, 1H, 2-H). 13C NMR
(62.5 MHz, d6-acetone): δ 23.0 (CH3), 27.8 (C(CH3)3), 65.5 (C-
8a), 88.4 (OC(CH3)3), 120.5, 126.0, 129.3, 138.2 (C-4-C-8), 141.5
(C-3a), 141.9 (C-2), 175.7 (C-3), 199.5 (cis-CO), 206.6 (trans-CO),
310.4 (WdC). UV/vis: λmax (log ꢀ) 244 nm (4.73), 336 (3.92),
568 (4.22) [pentane]. FAB-MS (NBOH): m/z (%) 538 (5) [M+],
482 (15) [(M - 2CO)+], 454 (12) [(M - 3CO)+], 426 (25) [(M -
4CO)+], 398 (7) [(M - 5CO)+], 370 (27) [(M - 4CO - C4H8)+],
1
1
(cis-CO, JWC ) 127.1 Hz), 207.8 (trans-CO, JWC ) 118.7 Hz),
308.6 (WdC). Isomer 22′a: 1H NMR (400 MHz, CD2Cl2): δ 1.71
(s, 6H, 4-, 9-, and 10-CH2), 1.97 (s, 3H, CH3), 2.23 (s, 6H, 2-, 6-,
3
and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH), 6.04 (d, JHH ) 6.1
Hz, 1H, 5-H), 6.44 (d , 3JHH ) 10.3 Hz, 1H, 7-H), 6.54 (d br, 1H,
4-H), 6.58 (d, br, 1H, 8-H), 6.96-7.16 (m br, 9H, C6H4 and C6H5,
both isomers), 7.71 (s, 1H, 2-H). 13C NMR (100.6 MHz, CD2Cl2):
δ 25.4 (CH3), 31.0 (3-, 5-, and 8-CH), 35.2 (4-, 9-, and 10-CH2),
40.8 (2-, 6-, and 7-CH2), 70.3 (C-8a), 86.67 (OAd), 118.9 (C-4),
125.6 (C-5), 126.4, 127.4, 128.0, 136.2, 136.5, 140.8 (aryl of 22a
and 22′a), 130.3 (C-7), 136.2 (C-8), 139.8 (C-3a), 141.5 (C-2), 148.8
(C-6), 176.7 (C-3), 198.3 (cis-CO, JWC ) 127.0 Hz), 208.0 (trans-
CO, JWC ) 118.8 Hz), 305.4 (WdC). FAB-MS: m/z (%) 692 (3)
[(M)+], 636 (61) [(M - 2CO)+], 608 (35) [(M - 3CO)+], 580
(100) [(M - 4CO)+], 552 (28) [(M - 5CO)+]. C32H28O6W
(692.42).
342 (10) [(M - 5CO - C4H8)+], 159 (35) [(M - C4H8
-
W(CO)5)+]. C20H18O6W (538.21). The crystals contain 1 equiv of
pentane. Anal. Calcd for C20H18O6W‚C5H12 (610.36): C, 49.20;
H, 4.95. Found: C, 49.19; H, 4.99.
Pentacarbonyl(3-adamantyloxy-8a-phenylbicyclo[5.3.0]deca-
2,3a,5,7-tetraenylidene)tungsten (21a). Method D. Yield: 0.27
g (20% based on adamantyloxyacetylene). IR (petroleum ether):
Pentacarbonyl(3-adamantyloxy-8a-p-tolylbicyclo[5.3.0]deca-
2,3a,5,7-tetraenylidene)chromium (22b) and Pentacarbonyl(3-
adamantyloxy-6-methyl-8a-phenylbicyclo[5.3.0]deca-2,3a,5,7-
tetraenylidene)chromium (22′b). Method D. Yield: 0.23 g (21%
based on adamantyloxyacetylene). IR (petroleum ether): ν(CO)
2045 s, 1955 s, 1942 m, 1922 s cm-1. Isomer 22b: 1H NMR (400
MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2), 2.20 (s, 3H,
CH3), 2.23 (s, 6H, 2-, 6-, and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH),
1
ν(CO) 2055 m, 1953 s, 1942 sh, 1953 s, 1919 s cm-1. H NMR
(400 MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2), 2.23 (s,
6H, 2-, 6-, and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH), 6.24 (dd,
3
3JHH ) 6.6 and 10.8 Hz, 1H, 5-H), 6.57 (dd, JHH ) 6.3 and 10.0
3
3
Hz, 1H, 7-H), 6.63 (d, JHH ) 6.4 Hz, 1H, 4-H), 6.67 (d, JHH
)
3
10.1 Hz, 1H, 8-H), 6.74 (dd, JHH ) 6.3 and 11.0 Hz, 1H, 6-H),
7.12 (m, 5H, C6H5), 7.70 (s, 1H, 2-H). 13C NMR (100.6 MHz, CD2-
Cl2): δ 30.8 (3-, 5-, and 8-CH), 35.2 (4-, 9-, and 10-CH2), 41.0
(2-, 6-, and 7-CH2), 70.7 (C-8a), 86.8 (OAd), 118.2 (C-4), 126.4
(C-12), 127.0 (C-7), 127.3 (C-10, -11, -13, -14), 128.3 (C-5), 136.9
(C-6), 137.3 (C-8), 139.6 (C-3a), 140.7 (C-9), 141.7 (C-2), 176.1
3
3
6.28 (dd, JHH ) 6.6 and 10.8 Hz, 1H, 5-H), 6.40 (d, JHH ) 6.2
3
Hz, 1H, 4-H), 6.60 (ddoverlapped, 2H, 7-H and 8-H), 6.67 (dd, JHH
) 5.2 and 10.9 Hz, 1H, 6-H), 6.94-7.31 (m, 9H, C6H5,C6H5, both
isomers), 7.79 (s, 1H, 2-H). 13C NMR (100.6 MHz, CD2Cl2): δ
20.7 (CH3), 31.0 (3-, 5-, 8-CH), 35.2 (4-, 9-, 10-CH2), 40.8 (2-, 6-,
7-CH2), 70.1 (C-8a), 86.42 (OAd), 116.7 (C-4), 126.3-128.9 and
136.1 (C6H5, C6H4, both isomers), 126.9 (C-7), 127.7 (C-5), 136.4
1
(C-3), 198.2 (cis-CO, JWC ) 127.0 Hz), 208.0 (trans-CO), 308.1
(WdC). FAB-MS: m/z (%) 678 (5) [(M)+], 622 (34) [(M -

3800 Organometallics, Vol. 26, No. 15, 2007
Hagmayer et al.
(C-8), 137.0 (C-6), 138.5 (C-2), 140.2 (C-3a), 172.6 (C-3), 217.4
(cis-CO), 228.2 (trans-CO), 337.2 (CrdC). Isomer 22′b: 1H NMR
(400 MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2), 2.00 (s,
3H, CH3), 2.23 (s, 6H, 2-, 6-, and 7-CH2), 2.31 (s, 3H, 3-, 5-, and
8-CH), 6.06 (d, 3JHH ) 6.4 Hz, 1H, 5-H), 6.43 (d, 3JHH ) 10.3 Hz,
C6H5,C6H5, both isomers), 7.83 (s, 1H, 2-H). 13C NMR (100.6 MHz,
CD2Cl2): δ 31.0 (3-, 5-, and 8-CH), 35.2 (4-, 9-, and 10-CH2),
40.8 (2-, 6-, and 7-CH2), 70.0 (C-8a), 86.70 (OAd), 115.1 (C-4),
126.8 (C-5), 126.8-132.2 (C6H5,C6H5, both isomers), 128.5 (C-
7), 136.2 (C-8), 138.6 (C-2), 140.5 (C-3a), 140.7 (C-6), 171.8 (C-
3), 217.3 (cis-CO), 228.7 (trans-CO), 337.7 (CrdC). FAB-MS: m/z
(%) 581 (4) [(M)+], 525 (4) [(M - 2CO)+], 497 (4) [(M - 3CO)+],
469 (41) [(M - 4CO)+], 441 (100) [(M - 5CO)+]. C31H25O6ClCr
(580.98).
3
1H, 4-H), 6.51 (d, JHH ) 10.2 Hz, 1H, 7-H), 6.54 (doverlapped, 1H,
8-H), 6.94-7.31 (m, 9H, C6H5,C6H5, both isomers), 7.79 (s, 1H,
2-H). 13C NMR (100.6 MHz, CD2Cl2): δ 25.1 (CH3), 31.0 (3-, 5-,
and 8-CH), 35.2 (4-, 9-, and 10-CH2), 40.8 (2-, 6-, and 7-CH2),
70.0 (C-8a), 86.37 (OAd), 117.4 (C-4), 125.1 (C-5), 126.3-128.9
(C6H5, C6H4, both isomers), 130.2 (C-7), 135.3 (C-8), 138.5 (C-2),
139.3 (C-3a), 148.9 (C-6), 173.2 (C-3), 217.5 (cis-CO), 228.6
(trans-CO), 333.6 (CrdC). FAB-MS: m/z (%) 560 (4) [(M)+], 476
(14) [(M - 3CO)+], 448 (27) [(M - 4CO)+], 420 (100) [(M -
5CO)+]. C32H28O6Cr (560.57).
Pentacarbonyl(3-adamantyloxy-6-chloro-8a-p-tolylbicyclo-
[5.3.0]deca-2,3a,5,7-tetraenylidene)tungsten (24a) and Pentac-
arbonyl(3-adamantyloxy-6-methyl-8a-p-chlorphenylbicyclo[5.3.0]-
deca-2,3a,5,7-tetraenylidene)tungsten (24′a). Method D. Yield:
0.07 g (5% based on adamantyloxyacetylene). IR (petroleum
ether): ν(CO) 2054 m, 1954 s, 1938 m, 1919 s cm-1. Isomer 24a:
1H NMR (400 MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2),
2.23 (soverlapped, 3H, CH3), 2.23 (s, 6H, 2-, 6-, and 7-CH2), 2.31 (s,
Pentacarbonyl(3-adamantyloxy-8a-p-chlorophenylbicyclo-
[5.3.0]deca-2,3a,5,7-tetraenylidene)tungsten (23a) and Pentac-
arbonyl(3-adamantyloxy-6-chloro-8a-phenylbicyclo[5.3.0]deca-
2,3a,5,7-tetraenylidene)tungsten (23′a). Method D. Yield: 0.10
g (7% based on adamantyloxyacetylene). IR (petroleum ether): ν-
(CO) 2054 m, 1956 m, 1940 m, 1920 m cm-1. Isomer 23a: 1H
NMR (400 MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2),
2.23 (s, 6H, 2-, 6-, and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH),
6.26 (dd, 3JHH ) 6.7 and 10.8 Hz, 1H, 5-H), 6.57 (dd br, 1H, 7-H),
6.62 (d, 3JHH ) 5.1 Hz, 1H, 4-H), 6.66 (doverlapped, 3JHH ) 10.6 Hz,
1H, 8-H), 6.75 (dd, 3JHH ) 6.0 and 11.0 Hz, 1H, 6-H) , 6.96-7.31
(m, 9H, C6H5,C6H5, both isomers), 7.71 (s, 1H, 2-H). 13C NMR
(100.6 MHz, CD2Cl2): δ 31.0 (3-, 5-, and 8-CH), 35.2 (4-, 9-, and
10-CH2), 40.8 (2-, 6-, and 7-CH2), 70.4 (C-8a), 87.1 (OAd), 118.4
(C-4), 127.2 (C-7), 128.2 (C-5), 126.8 - 131.5 and 140.5 (C6H5,
C6H5, both isomers), 136.9 (C-6), 137.1 (C-8), 139.1 (C-3a), 141.1
(C-2), 175.9 (C-3), 198.9 (cis-CO, JWC ) 127.4 Hz), 208.0 (trans-
CO, JWC ) 118.7 Hz), 308.2 (WdC). Isomer 23′a: 1H NMR (400
MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2), 2.23 (s, 6H,
3
3H, 3-, 5-, and 8-CH), 6.39 (d, JHH ) 7.2 Hz, 1H, 5-H), 6.53
3
(doverlapped, 1H, 4-H), 6.56 (d, JHH ) 8.9 Hz, 1H, 7-H), 6.65 (d,
3JHH ) 10.5 Hz, 1H, 8-H), 6.99 (m, 9H, C6H5,C6H5, both isomers),
7.69 (s, 1H, 2-H). 13C NMR (100.6 MHz, CD2Cl2): δ 20.7 (CH3),
31.0 (3-, 5-, and 8-CH), 35.2 (4-, 9-, and 10-CH2), 40.8 (2-, 6-,
and 7-CH2), 70.1 (C-8a), 87.0 (OAd), 116.0 (C-4), 127.2 (C-5),
127.4, 128.2, 128.5, 131.4, 136.0, 136.6 (C6H5,C6H5, both isomers),
128.4 (C-7), 137.3 (C-8), 140.5 (C-3a), 141.2 (C-6), 141.7 (C-2),
176.3 (C-3), 198.0 (cis-CO, JWC ) 127.0 Hz), 207.8 (trans-CO,
JWC ) 118.7 Hz), 308.5 (WdC). Isomer 24′a: 1H NMR (400 MHz,
CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2), 1.95 (s, 3H, CH3),
2.23 (s, 6H, 2-, 6-, and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH),
3
3
6.04 (d, JHH ) 6.8 Hz, 1H, 5-H), 6.42 (d , JHH ) 10.3 Hz, 1H,
7-H), 6.54 (doverlapped, 1H, 4-H), 6.51 (d, 3JHH ) 8.2 Hz, 1H, 8-H),
7.04-7.20 (m, 9H, C6H5,C6H5, both isomers), 7.68 (s, 1H, 2-H).
13C NMR (100.6 MHz, CD2Cl2): δ 25.3 (CH3), 31.0 (3-, 5-, and
8-CH), 35.2 (4-, 9-, and 10-CH2), 40.8 (2-, 6-, 7-CH2), 69.6 (C-
8a), 86.9 (OAd), 119.0 (C-4), 125.8 (C-5), 127.4, 128.2, 128.5,
131.4, 136.0, 136.6 (C6H5,C6H5, both isomers), 130.4 (C-7), 135.7
(C-8), 139.5 (C-3a), 141.9 (C-2), 148.8 (C-6), 176.9 (C-3), 198.3
(cis-CO, JWC ) 127.3 Hz), 208.0 (trans-CO, JWC ) 118.8 Hz),
304.2 (WdC). FAB-MS: m/z (%) 727 (10) [(M)+], 671 (30) [(M
- 2CO)+], 615 (100) [(M - 4CO)+]. C32H27O6ClW (726.87).
2-, 6-, and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH), 6.39 (d, 3JHH
)
7.2 Hz, 1H, 5-H), 6.54 (dbr , 1H, 4-H), 6.57 (doverlapped, 1H, 7-H),
3
6.66 (doverlapped, JHH ) 10.6 Hz, 1H, 8-H), 6.96-7.31 (m, 9H,
C6H5,C6H5, both isomers), 7.69 (s, 1H, 2-H). 13C NMR (100.6 MHz,
CD2Cl2): δ 31.0 (3-, 5-, and 8-CH), 35.2 (4-, 9-, and 10-CH2),
40.8 (2-, 6-, and 7-CH2), 70.0 (C-8a), 87.0 (OAd), 116.4 (C-4),
127.3 (C-5), 126.8 - 130.5 and 138.4 (C6H5,C6H5, both isomers),
128.5 (C-7), 136.7 (C-8), 140.4 (C-3a), 141.2 (C-6), 141.4 (C-2),
175.3 (C-3), 198.1 (cis-CO, JWC ) 127.6 Hz), 207.8 (trans-CO,
JWC ) 118.8 Hz), 307.1 (WdC). FAB-MS: m/z (%) 713 (2) [(M)+],
657 (12) [(M - 2CO)+], 629 (32) [(M - 3CO)+], 601 (100) [(M
- 4CO)+], 573 (27) [(M - 5CO)+], C31H25O6ClW (712.84).
Pentacarbonyl(3-adamantyloxy-6-chloro-8a-p-tolylbicyclo-
[5.3.0]deca-2,3a,5,7-tetraenylidene)chromium (24b) and Pen-
tacarbonyl(3-adamantyloxy-6-methyl-8a-p-chlorphenylbicyclo-
[5.3.0]deca-2,3a,5,7-tetraenylidene)chromium (24′b). Method D.
Yield: 0.10 g (8% based on adamantyloxyacetylene). IR (petroleum
ether): ν(CO) 2044 m, 1956 s, 1947 s, 1924 cm-1. Isomer 24b:
1H NMR (400 MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2),
2.23 (s, 6H, 2-, 6-, and 7-CH2), 2.24 (s, 3H, CH3), 2.31 (s, 3H, 3-,
Pentacarbonyl{3-adamantyloxy-8a-p-chlorphenylbicyclo[5.3.0]-
deca-2,3a,5,7-tetraenylidene}chromium (23b) and Pentacarbo-
nyl{3-adamantyloxy-6-chloro-8a-phenylbicyclo[5.3.0]deca-2,-
3a,5,7-tetraenylidene}chromium (23′b). Method D. Yield: 0.19
g (17% based on adamantyloxyacetylene). IR (petroleum ether):
ν(CO) 2045 s, 1958 m, 1947 m, 1925 m cm-1. Isomer 23b: 1H
NMR (400 MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2),
2.23 (s, 6H, 2-, 6-, and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH),
3
3
5-, and 8-CH), 6.30 (d, JHH ) 8.5 Hz, 1H, 4-H), 6.42 (d, JHH
)
7.3 Hz, 1H, 5-H), 6.57 (s br, 2H, 7-H, 8-H), 6.88-7.30 (m, 9H,
C6H5,C6H5, both isomers), 7.83 (s, 1H, 2-H). 13C NMR (100.6 MHz,
CD2Cl2): δ 20.7 (CH3), 31.0 (3-, 5-, 8-CH), 35.2 (4-, 9-, 10-CH2),
40.8 (2-, 6-, 7-CH2), 69.7 (C-8a), 86.7 (OAd), 114.9 (C-4), 126.8
(C-5), 128.1 (C-11, C-13), 128.9 (C-10, C-14), 128.4 (C-7), 135.9
(C-9), 136.3 (C-8), 136.6 (C-12), 138.6 (C-2), 140.5 (C-3a), 140.7
(C-6), 171.8 (C-3), 217.1 (cis-CO), 228.9 (trans-CO), 338.1 (Crd
C). Isomer 24′b: 1H NMR (400 MHz, CD2Cl2): δ 1.98 (CH3),
1.71 (s, 6H, 4-, 9-, 10-CH2), 2.23 (s, 6H, 2-, 6-, 7-CH2), 2.31 (s,
3H, 3-, 5-, 8-CH), 6.07 (d br, 1H, 5-H), 6.33 (doverlapped, 1H, 4-H),
6.42 (doverlapped, 1H, 7-H), 6.46 (doverlapped, 1H, 8-H), 6.88-7.30 (m,
4H, C6H5,C6H5, both isomers), 7.81 (s, 1H, 2-H). 13C NMR (100.6
MHz, CD2Cl2): δ 25.0 (CH3), 31.0 (3-, 5-, 8-CH), 35.2 (4-, 9-,
10-CH2), 40.8 (2-, 6-, 7-CH2), 69.4 (C-8a), 86.6 (OAd), 117.7 (C-
4), 125.5 (C-5), 128.1-129.1 (C6H5,C6H5, both isomers), 130.5 (C-
7), 131.6 (C-12), 134.8 (C-8), 138.6 (C-2), 139.1 (C-3a), 148.9
(C-6), 173.1 (C-3), 217.5 (cis-CO), 228.5 (trans-CO), 333.2 (Crd
C). FAB-MS: m/z (%) 595 (2) [(M)+], 539 (5) [(M - 2CO)+],
3
6.29 (dd, JHH ) 6.8 and 10.8 Hz, 1H, 5-H), 6.42 (doverlapped, 1H,
4-H), 6.58 (ddoverlapped and doverlapped, 2H, 7-H, 8-H), 6.70 (dd, 3JHH
) 6.1 and 10.4 Hz, 1H, 6-H) , 6.99-7.32 (m, 4H, C6H5,C6H5, both
isomers), 7.81 (s, 1H, 2-H). 13C NMR (100.6 MHz, CD2Cl2): δ
31.0 (3-, 5-, and 8-CH), 35.2 (4-, 9-, and 10-CH2), 40.8 (2-, 6-,
and 7-CH2), 69.7 (C-8a), 86.74 (OAd), 117.0 (C-4), 126.9 (C-7),
126.8 - 132.2 and 131.5 (C6H5,C6H5, both isomers), 128.0 (C-5),
135.8 (C-8), 137.0 (C-6), 138.6 (C-2), 139.8 (C-3a), 172.4 (C-3),
217.1 (cis-CO), 228.9 (trans-CO), 336.4 (CrdC). Isomer 23′b: 1H
NMR (400 MHz, CD2Cl2): δ 1.71 (s, 6H, 4-, 9-, and 10-CH2),
2.23 (s, 6H, 2-, 6-, and 7-CH2), 2.31 (s, 3H, 3-, 5-, and 8-CH),
1
6.33 (d, JHH ) 7.3 Hz, 1H, 4-H), 6.42 (doverlapped, 1H, 5-H), 6.59
(doverlapped, 1H, 7-H), 6.59 (dbr, 1H, 8-H), 6.99-7.32 (m, 5H,

Unprecedented Formation of Azulenylidene Ligands
Organometallics, Vol. 26, No. 15, 2007 3801
3
3
Table 3. Crystal Data and Refinement Details for
Compounds 24b and 25a
10.3 Hz, 1H, 5-H), 6.42 (dd, JHH ) 6.0 Hz and JHH ) 10.0 Hz,
1H, 4-H), 6.58 (ddoverlapped and doverlapped, 2H, 7-H, 8-H), 6.70 (dd,
3JHH ) 6.0 Hz and JHH ) 10.9 Hz, 1H, 6-H), 7.14 (m, 4H, 10-,
3
24b
25a
11-, 13-H, 14-H), 7.76 (s, 1H, 2-H). 13C NMR (100.6 MHz, CD2-
Cl2): δ 30.7 (CH3), 31.0 (3-, 5-, 8-CH), 34.0 (C(CH3)3), 35.2 (4-,
9-, 10-CH2), 40.8 (2-, 6-, 7-CH2), 70.1 (C-8a), 86.3 (OAd), 116.6
(C-4), 124.2 (C-10, -11, -13, -14), 126.8 (C-7), 127.8 (C-5),
136.1 (C-9), 136.5 (C-7), 136.8 (C-6), 138.0 (C-2), 139.9 (C-3a),
149.2 (C-12), 172.5 (C-3), 217.3 (cis-CO), 229.0 (trans-CO), 337.5
(CrdC). FAB-MS: m/z (%) 603 (1) [(M)+], 575 (1) [(M - CO)+],
547 (3) [(M - 2CO)+], 619 (15) [(M - 3CO)+], 491 (31) [(M -
4CO)+], 463 (100) [(M - 5CO)+]. C35H34O6Cr (602.65)
X-ray Structure Analyses of 24b and 25a. Single crystals
suitable for X-ray structure analyses were obtained from petroleum
ether/CH2Cl2 mixtures at -30 °C. The measurements were per-
formed at 100(2) K with a crystal mounted on a glass fiber on a
STOE IPDS II diffractometer (graphite monochromator, Mo KR
radiation, λ ) 0.71073 Å, scan rate 3-30° min-1 in ω). For crystal
data and refinement details see Table 3. The structures were solved
by direct methods using the SHELX-97 program package.27 The
positions of the hydrogen atoms were calculated by assuming ideal
geometry, and their coordinates were refined together with those
of the attached carbon atoms as “riding model”. All other atoms
were refined anisotropically.
DFT-Calculations. All ab initio calculations were performed
using Jaguar28 (version 5.5.016) running on Linux-2.4.20-28.7smp
on six Athlon MP 2400+ dual-processor workstations (Beowulf-
cluster) parallelized with MPICH 1.2.4. Initial structures were
obtained by MM+ optimization using Hyperchem.29 Geometries
were optimized using the LACVP* basis set (ECP for Cr and W,
N31G6* for all other atoms) and the BP86 density functional. The
second derivatives were calculated to ensure that true minima were
found, by showing no large negative frequencies. All reported
energies are at 298 K. Transition states were approximated by
performing a geometry scan along the corresponding atom-atom
distances, where new bonds were formed. The maximum energy
structures from these geometry scans were used as transition state
guesses for standard (simple quasi-Newton) transition state searches
implemented in Jaguar. Second derivatives were used for transition
state validation.
formula
Mr
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
C32H27ClCrO6
1189.97
triclinic
P1h
10.242(2)
11.681(2)
11.758(2)
88.62(3)
86.38(3)
81.58(3)
1388.6(4)
2
1.423
0.553
616
51.08
-12 e h e 12
-14 e k e 14
-14 e l e 14
16 711
5156
361
C35H34O6W×CH2Cl2
819.40
monoclinic
P21/c
14.096(3)
18.137(4)
13.118(3)
90
93.17(3)
90
3348.6(12)
4
1.625
3.654
1632
51.42
-17 e h e 16
-22 e k e 22
-15 e l e 15
40 986
6297
406
Z
F(calcd) (g/cm3)
µ (mm-1
F(000)
)
max. 2θ (deg)
index range
no. of data
no. of unique data
no. of params
R(F) for I > 2σ(I)
wR2(F2), all data
goodness-of-fit on F2
max., min. ∆F (e/Å3)
0.0481
0.0941
1.038
0.349, -0.370
0.0394
0.0966
1.030
2.030, -1.749
511 (26) [(M - 3CO)+], 483 (54) [(M - 4CO)+], 455 (100) [(M
- 5CO)+]. C32H27O6ClCr (595.01)
Pentacarbonyl(3-adamantyloxy-8a-p-tert-butylphenylbicyclo-
[5.3.0]deca-2,3a,5,7-tetraenylidene)tungsten (25a). Method D.
Yield: 0.41 g (28% based on adamantyloxyacetylene). Only isomer
25a could be detected. IR (petroleum ether): ν(CO) 2053 m, 1953
s, 1935 m, 1918 s cm-1. 1H NMR (400 MHz, CD2Cl2): δ 1.15 (s,
9H, CH3), 1.69 (s, 6H, 4-, 9-, and 10-CH2), 2.21 (s, 6H, 2-, 6-, and
3
7-CH2), 2.30 (s, 3H, 3-, 5-, and 8-CH), 6.28 (dd, JHH ) 6.7 and
3
11.0 Hz, 1H, 5-H), 6.56 (dd, JHH ) 6.4 and 10.0 Hz, 1H, 7-H),
3
3
6.63 (d, JHH ) 6.9 Hz, 1H, 4-H), 6.66 (d, JHH ) 10.4 Hz, 1H,
8-H), 6.75 (dd, 3JHH ) 6.3 and 11.0 Hz, 1H, 6-H), 7.14 (d, 3JHH
)
8.2 Hz, 4H, 10-, 11-,13-, and 14-H), 7.66 (s, 1H, 2-H). 13C NMR
(100.6 MHz, CD2Cl2): δ 30.6 (CH3), 31.0 (3-, 5-, and 8-CH), 34.0
(C(CH3)3), 35.2 (4-, 9-, and 10-CH2), 40.8 (2-, 6-, and 7-CH2), 70.3
(C-8a), 86.7 (OAd), 118.0 (C-4), 124.2 (C-10, -11, -13, -14), 127.8
(C-7), 128.2 (C-5), 136.75 (C-9), 136.8 (C-6), 137.4 (C-8), 140.5
(C-3a), 141.5 (C-2), 149.1 (C-12), 176.0 (C-3), 198.1 (cis-CO, JWC
) 127.1 Hz), 208.1 (trans-CO, JWC ) 117.8 Hz), 308.5 (WdC).
FAB-MS: m/z (%) 734 (3) [(M)+], 678 (26) [(M - 2CO)+], 650
(44) [(M - 3CO)+], 622 (100) [(M - 4CO)+], 594 (59) [(M -
5CO)+]. C35H34O6W (734.50).
Acknowledgment. Support of this work by the Wacker-
Chemie GmbH (gift of chemicals) is gratefully acknowledged.
Supporting Information Available: CIF files of the complexes
24b and 25a, tables giving the bond distances, bond angles, and
torsion angles of 24b and 25a, and tables giving the Cartesian
coordinates and energies (at 298 K) of the calculated structures,
optimized minima, and transistion states. This material is available
free of charge via the Internet at http://pubs.acs.org.
Pentacarbonyl(3-adamantyloxy-8a-p-tert-butylphenylbicyclo-
[5.3.0]deca-2,3a,5,7-tetraenylidene)chromium (25b). Method D.
Yield: 0.31 g (26% based on adamantyloxyacetylene). Only isomer
25b was observed. IR (petroleum ether): ν(CO) 2044 m, 1954 s,
OM700274U
(27) Sheldrick, G. M. SHELXTL-97, Programs for Crystal Structure
Analysis; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(28) Jaguar 5.5; Schro¨dinger, LLC: Portland, OR, 2003.
1942 m, 1922 s cm-1. H NMR (400 MHz, CD2Cl2): δ 1.15 (s,
1
9H, CH3), 1.69 (s, 6H, 4-, 9-, 10-CH2), 2.21 (s, 6H, 2-, 6-, 7-CH2),
2.30 (s, 3H, 3-, 5-, 8-CH), 6.31 (dd, JHH ) 6.4 Hz and JHH
3
3
)
(29) Hyperchem (version 5); Hypercube Inc.: Gainsville, FL, 32601.