Unexpected Reaction Pathways in the Reaction of Alkoxyalkynyl-chromium(0) Carbenes with Aromatic Dinucleophiles

Article abstract of DOI:10.1002/chem.200305138

Thermal- or SiO₂-induced reactions of the Michael adducts of 1,2-aromatic dinucleophiles and alkynyl-chromium(0) carbene complexes, compounds 7-10, form different products in good yields depending on the nature of the aromatic dinucleophile used. Thus, 1,2-diaminobenzene derivatives 7 and 8 rearrange to pentacarbonylchromium(0) isocyanide complexes 11, 12, 14, and 15 in a process that occurs through bicyclic intermediates 24. Adducts 9 derived from o-aminophenol give 2,3-dihydro-1,5-benzoxazepine derivatives 17 by intramolecular 1,2-addition, followed by protonation at the chromium center and reductive elimination. In contrast, base-promoted addition of the phenolic hydroxy group in compound 9a affords 3-ethoxy-5-phenyl-5,6-dihydro-2H-1,6-benzoxazocin-2-one (18), together with the expected adduct 17a. Compound 18 is formed by a nucleophilic addition to a CO ligand in a preformed carbene complex. This is a new example of the rare attack of a nucleophile on a CO ligand in a Fischer carbene complex. Adducts 10 form seven-membered-ring carbene complexes 19 and 20 by intramolecular aminolysis. In contrast, reaction of alkynyl carbene complexes with 1,8-diaminonaphthalene under very mild conditions leads to 2-substituted perimidines 33 together with the corresponding ethoxymethylmetal carbene complex 32 through an unprecedented fragmentation process in a formal retro-Aumann reaction.

Full text of DOI:10.1002/chem.200305138

FULL PAPER
Unexpected Reaction Pathways in the Reaction of Alkoxyalkynyl-
chromium(0) Carbenes with Aromatic Dinucleophiles**
Miguel A. Sierra,*MarÌa J. Manchen o, Juan C. del Amo, Israel Ferna¬ndez, and
ƒ
Mar Go¬mez-Gallego[a]
Abstract: Thermal- or SiO2-induced re-
actions of the Michael adducts of 1,2-
aromatic dinucleophiles and alkynyl-
chromium(0) carbene complexes, com-
pounds 7 10, form different products in
good yields depending on the nature of
the aromatic dinucleophile used. Thus,
1,2-diaminobenzene derivatives 7 and 8
rearrange to pentacarbonylchromium(0)
isocyanide complexes 11, 12, 14, and 15
in a process that occurs through bicyclic
intermediates 24. Adducts 9 derived
from o-aminophenol give 2,3-dihydro-
1,5-benzoxazepine derivatives 17 by in-
tramolecular 1,2-addition, followed by
protonation at the chromium center and
reductive elimination. In contrast, base-
promoted addition of the phenolic hy-
droxy group in compound 9a affords
3-ethoxy-5-phenyl-5,6-dihydro-2H-1,6-
benzoxazocin-2-one (18), together with
the expected adduct 17a. Compound 18
is formed by a nucleophilic addition to a
CO ligand in a preformed carbene com-
plex. This is a new example of the rare
attack of a nucleophile on a CO ligand in
a Fischer carbene complex. Adducts 10
form seven-membered-ring carbene
complexes 19 and 20 by intramolecular
aminolysis. In contrast, reaction of al-
kynyl carbene complexes with 1,8-dia-
minonaphthalene under very mild con-
ditions leads to 2-substituted perimi-
dines
33
together
with
the
corresponding ethoxymethylmetal car-
bene complex 32 through an unprece-
dented fragmentation process in a for-
mal retro-Aumann reaction.
Keywords: addition reactions ¥ car-
bene complexes ¥ dinucleophiles ¥
isocyanide complexes ¥ perimidines
¥ rearrangements
yields by the reaction of complex 1a and 1,2-diaminopropane
(Reaction (1) of Scheme 1).[6] Additionally, the reaction of
catechol with tungsten complex 1b formed the bicyclic ketal 3
in a process claimed to be a double 1,4-addition process
(Reaction (2) of Scheme 1).[7]
Introduction
Many reactions of a,b-unsaturated Group 6 Fischer carbene
complexes and nucleophiles are analogous to those experi-
enced by organic esters and amides.[2] However, in many cases,
the presence of the metal fragment resulted in the formation
of more sophisticated products than those expected from the
standard 1,4- or 1,2-addition of the nucleophile.[3] The
chemistry developed therefrom has resulted in an impressive
array of synthetically useful processes.[4] Recently, we and
others have demonstrated that the metal fragment of a,b-
unsaturated chromium(0) carbene complexes also participates
in the addition reactions of simple nucleophiles.[5] Simple
amines may also produce other processes than the expected
Michael additions in their reactions with a,b-unsaturated
Group 6 (Fischer) carbenes. For example, Ricart recently
reported the formation of cyclic diaminocarbene 2 in low
Scheme 1.
In spite of the number of reactions reported for a,b-
unsaturated Fischer carbene complexes,[8] reactions in which a
fragmentation of the carbon skeleton is involved are rare. At
the beginning of this work, only one example of this kind of
process had been described.[9a] Thus, Dˆtz and co-workers
reported the spontaneous retro-Fischer fragmentation of
complex 4 to form enyne 5 (Scheme 2). While this work was
ƒ
[a] Prof. Dr. M. A. Sierra, Dr. M. J. Mancheno, J. C. del Amo,
¬
¬
I. Fernandez, Prof. Dr. M. Gomez-Gallego
¬
Departamento de QuÌmica Organica
Facultad de QuÌmica
Universidad Complutense, 28040-Madrid (Spain)
Fax : (‡34)913944103
E-mail: sierraor@quim.ucm.es
[**] A communication on part of this work has been published see ref. [1].
Chem. Eur. J. 2003, 9, 4943 4953
DOI: 10.1002/chem.200305138
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M. A. Sierra et al.
FULL PAPER
These precedents make it probable that even the well-
known addition of amines and phenols to a,b-unsaturated
chromium(0) carbenes may, under some conditions, occur with
the participation of the metal center to afford products other
than the Michael or 1,2-adducts.[10] In our ongoing project
directed towards the synthesis of polymetallic structures,[11] as
well as in the development of methods for the addition of
radicals to a,b-unsaturated complexes,[12] we obtained some
anomalous results for the addition of aromatic 1,2-dinucleo-
philes to alkynylchromium(0) carbene complexes. Different
addition processes were observed as a function of the
dinucleophile employed and led to 2,3-dihydro-1,5-benzox-
azepine derivatives, unprecedented rearrangement of alk-
oxychromium(0) carbene complexes to pentacarbonylisocya-
nide chromium complexes, as well as novel fragmentation
processes. Reported herein is a detailed account of these
processes.
Scheme 2.
in progress, Aumann and co-workers described one more
example of this type of fragmentation in the reaction of
tungsten complexes 6 with 2-chloro-1,4-azadiene (Sche-
me 3).[9b]
Results and Discussion
The substrates used in our study (complexes 7 10) were
prepared by 1,4-addition of 1,2-diaminobenzene (compounds
7 and 8), o-aminophenol (compounds 9 and 10c), catechol
(compound 10a), and o-aminothiophenol (compound 10b) to
the corresponding alkynylchromium(0) carbene complexes,
following the standard reported method.[6, 13]
Scheme 3.
¬
Abstract in Spanish: Las reacciones, inducidas termicamente o
por tratamiento con SiO2, de los aductos de tipo Michael
¬
¬
¬
derivados de la adicion de 1,2-dinucleofilos aromaticos a
alquinilcromo carbenos dan lugar a distintos productos con
¬
buenos rendimientos en funcion de la naturaleza del dinu-
¬
¬
cleofilo aromatico empleado. AsÌ, los derivados de 1,2-
diaminobenceno, 7 y 8, sufren un reordenamiento del esqueleto
para formar los complejos de isonitrilo coordinados a cromo
¬
11, 12, 14 y 15 en un proceso que ocurre a traves de los
intermedios bicÌclicos 24. Los aductos 9 provenientes de
o-aminofenol forman los derivados 2,3-dihidro-1,5-benzoxa-
¬
cepina 17 mediante adicion 1,2-intramolecular, seguida de
¬
¬
¬
protonacion en el centro metalico y eliminacion reductora. En
¬
¬
cambio, la adicion promovida por base del grupo fenolico en el
compuesto 9a proporciona 3-etoxi-5-fenil-5,6-dihidro-2H-1,6-
benzoxazocin-2-ona, 18, junto con el aducto esperado 17a. El
Complexes 7a c, which contain a 1,2-diaminobenzene
moiety, smoothly react to give new chromium complexes on
gentle heating in THF (Scheme 4). These new products lack
the carbene ligand and their outstanding NMR characteristics
were the presence of a signal attributable to a methyl group
(d ˆ 1.76 2.27 and 16.1 20.4 ppm for 1H and 13C NMR,
respectively), as well as a signal assignable to a quaternary
carbon between d ˆ 214.2 214.5 ppm in their 13C NMR
spectra. Additionally, when complex 7b was heated in THF
containing CD3OD, the signal attributable to the CH3 group
disappeared, indicating the complete incorporation of deute-
rium in this group. A single monocrystal of the product
derived from complex 7b was analyzed by X-ray diffraction.[1]
The structure of isocyanide complex 11b was thus established
for this compound (Scheme 4), and hence for compounds 11a
¬
¬
compuesto 18 se forma mediante adicion nucleofila a un
¬
ligando CO en un complejo carbenico preformado. Este
proceso constituye un nuevo ejemplo de la poco estudiada
reactividad derivada del ataque de un nucleofilo a un ligando
CO en un complejo de Fischer. Por otro lado, los aductos 10
forman los complejos cÌclicos de siete eslabones 17 y 20
mediante aminolisis intramolecular. Esto contrasta con la
reactividad de los complejos alquinilcarbenoides 1 con 1,8-
diaminonaftaleno que conducen en condiciones de reaccion
muy suaves a las perimidinas 2-sustituidas 33 junto con el
¬
¬
¬
correspondiente etoximetilmetalcarbeno 34, a traves de un
proceso de fragmentacion sin precedentes que puede conside-
rarse como una reaccion de tipo ™retro-Aumann∫.
¬
¬
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Reaction of Alkoxyalkynylchromium Carbenes with Aromatic Dinucleophiles
4943 4953
Scheme 5.
Scheme 4.
and 11c obtained from complexes 7a and 7c, respectively.[14]
The rearrangement alkoxychromium(0) carbene ! pentacar-
bonylchromium(0) isocyanide also occurred in the presence of
silica gel, and compounds 11 could be obtained from
compounds 7 either by column chromatography or by stirring
a solution of complexes 7 in THF in the presence of SiO2.
Under these conditions compound 7c produced complex 12 as
a result of the hydrolysis of the imine group of the initially
formed isocyanide complex 11c. This is an expected result
because aliphatic imines are considerably more prone to
hydrolysis than aromatic imines.
groups is essential for the reaction to take place. Because
adduct 16, derived from the addition of the more basic
aliphatic amino group of o-aminobenzylamine to complex 1d,
remained unaltered under the usual reaction conditions and
only decomposed after prolonged heating. This behavior
differs dramatically compared to that experienced by adducts
7 derived from 1,2-diaminobenzene (Scheme 6).
A different reaction outcome was obtained when complex
1c was reacted with 1,2-diaminobenzene in THF from À788C
to room temperature. Under these conditions, instead of the
expected isocyanide complex 11d or its hydrolysis product 12,
a new chromium complex was obtained. As representative
features, this compound retained the [(CO)5Cr] moiety (d ˆ
223.0 ppm (COtrans) and (d ˆ 217.4 ppm (COcis)), a carbene
carbon (d ˆ 285.1 ppm), and two diastereotopic methylene
groups, one of which corresponded to the OCH2 group (d ˆ
3.45 and 3.30 ppm). Additionally, the carbene signal at d ˆ
285.1 ppm clearly correlated with the signals corresponding to
the additional CH2 group d ˆ 4.21 and 2.52 ppm) in an HMBC
experiment. These and the additional data collected (see the
Experimental Section) allowed us to assign structure 13 to this
compound. Furthermore, while complex 13 remained un-
changed after prolonged heating in THF, it rapidly gave a
mixture of the isocyanide complexes 11d and 12 upon silica-
gel chromatography. Therefore, we can conclude that complex
13 is a product derived from the quenching of an intermediate
in the rearrangement of the nonisolated primary addition
product, 7d, to the isocyanide complex 11d (Scheme 5).
A double carbene ! isocyanide rearrangement can also be
performed in one step with the bisadduct 8. Treatment of
compound 8 with SiO2 resulted in a mixture of complex 14,
that contained one rearranged carbene moiety and an
unaltered metal carbene fragment, together with the doubly
rearranged complex 15, and unreacted starting material. The
doubly rearranged product 15 was isolated in an acceptable
yield of 60% by heating complex 8 in THF. Thus, two
simultaneous rearrangements can be effected in a single
operation (Scheme 6). The 1,2-disposition of the diamino
Scheme 6.
Complexes 9 derived from o-aminophenol were studied
next. These compounds were stable on silica gel but also
reacted to give a new class of compounds upon heating in
THF. These new products did not retain the metallic moiety
and their spectroscopic data were fully compatible with the
2,3-dihydro-1,5-benzoxazepine structure 17 (Scheme 7). In
addition, the trideuterated compound [D3]-17b was obtained
when complex 9b was heated in THF containing CD3OD. In
Chem. Eur. J. 2003, 9, 4943 4953
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M. A. Sierra et al.
FULL PAPER
Scheme 7.
an attempt to induce the cyclization at a low temperature by
increasing the nucleophilicity of the phenol group, adduct 9a
was treated with NaH/THF at 08C. Upon warming to room
temperature, a mixture of 2,3-dihydro-1,5-benzoxazepine
(17a) and a new compound 18 were obtained in 38% and
36% yields, respectively. This new compound incorporated
one additional carbon in its structure which suggested the
incorporation of one CO ligand. Based on extensive 1D and
2D NMR studies and analytical data, the structure of
3-ethoxy-5-phenyl-5,6-dihydro-2H-1,6-benzoxazocin-2-one
(18) was assigned to this compound (Scheme 7).
To reverse the regiochemistry of the addition of o-amino-
phenol to the carbene triple bond, the phenol group was
deprotonated with tBuONa and the resulting phenolate
reacted with chromium complex 1a. Under these conditions,
1,4-addition takes place and the cyclic complex 19 arising from
the intramolecular aminolysis was obtained. No 1,4-adduct
10c was observed. The trend observed in the addition of the
phenoxide anion derived from o-aminophenol was main-
tained for adduct 10b derived from o-aminothiophenol and
complex 1a. In this case, carbene complex 20 together with its
oxidation product 21 were obtained in 11% and 51% yields,
respectively, by heating compound 10b in THF. Finally, 1,2-
dihydroxybenzene reacted with complexes 1a and 1c to form
the bicyclic dioxolane complexes 22. These results are
analogous to those reported for the tungsten derivative 1b
(R ˆ Ph) (Scheme 8).[7]
Scheme 8.
pounds 9 also form the corresponding 1,2-adducts 27. In these
cases, the electron-donor ability of the heteroatom (O) joined
to the carbene is less than that observed for a nitrogen
derivative and a-bond breakage does not occur. Thus, the
intermediates 27 primarily formed by intramolecular 1,2-
addition are protonated at the metal center followed by
reductive elimination in 28 to yield benzoxazepines 17 after
imine enamine tautomerism of 29. In these cases, the
incorporation of the label occurs at the former carbene
carbon and at the methylene group. No label incorporation
was observed when compound 17b (R ˆ Fc) was heated in the
presence of CD3OD. Therefore, the deuterium should be
incorporated in the enamine 29 to imine 17 tautomerism,
which explains the appearance of two additional labels in
compound [D3]-17b. In contrast, compound 18 is formed
through the competitive addition of o-aminophenolate to one
CO ligand to form intermediate 30 that gives the isolated
compound 18 by reductive elimination. This is one of the rare
examples of nucleophilic attack on a CO ligand in a
preformed Group 6 metal carbene complex.[15] Finally, the
reaction of deprotonated o-aminophenol leads to the initial
conjugated addition of phenolate, followed by base-catalyzed
1,2-addition of the amino group and ethoxide elimination to
form the cyclic carbene complexes 19. However, reaction of o-
aminothiophenol with carbene complex 1a allows the iso-
lation of adduct 10b that gives carbene complex 20 (11%) and
its oxidation product 21 (51%) on refluxing in THF.
The nature of the reaction products, in the processes
discussed above, depends on the additional nucleophile group
once an amino group has been added to the triple bond, and
on the structure of the 1,2-adducts formed by evolution of the
intermediates 23. Thus, the results obtained may be ration-
alized through two divergent reaction pathways (Scheme 9).
Compounds 7 and 8 would form intermediates 24 by intra-
molecular 1,2-addition and afford 26 through breakage of the
bond a to chromium center in their imine tautomers 25.
Finally, protonation of enolate 26 would give compounds 11.
Support for this proposal can be found in the isolation of
hemiaminal complex 13, which should be formed by EtOH
addition to intermediate 25 (R ˆ tBu) and which produces
isonitrile complexes 11d and 12 by acid hydrolysis. Com-
From the above results it is clear that if the 1,2-addition
process can be inhibited, maybe, new processes could be
discovered. Therefore, the peri-interaction present in 1,8-
diaminonaphtalene 31 should inhibit the 1,2-addition. Reac-
tion of carbene complexes 1 with 31 in CH2Cl2 at room
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Reaction of Alkoxyalkynylchromium Carbenes with Aromatic Dinucleophiles
4943 4953
Scheme 9.
temperature produced a new complex identified as pentacar-
bonyl[(ethoxy)methylcarbene]metal(0) 32, together with a
new nonmetallic compound (Scheme 10). The spectroscopic
and analytical data for this compound were consistent with
the perimidine structure 33. The reaction is independent of
the nature of the substituent attached to the triple bond. Thus,
aryl, ferrocenyl, and alkyl substituents produce the hetero-
cyclic compounds 33 in excellent yields. The reaction is
general for cyclic systems having diamino groups in a relative
peri-position, as proved by the reaction of carbene complexes
1a and 1b with 5,6-diaminoacenaphthene 34[16] that forms
compounds 35. These products can be converted into the
heterocyclic compound 36 in 88% and 89% yields, respec-
tively, together with the corresponding metal carbene com-
plex 32 (55% and 67% yield) by silica-gel treatment
(Scheme 10).
More sophisticated structures can be obtained by this
procedure in a single step. A double rearrangement was
performed on biscarbene complex 37 with 1,8-diaminonaph-
thalene 31 (1:2 stoichiometric ratio) to give quantitative yields
of compound 38, which contains two 1,3-diazaphenalenyl
moieties. The metallic fragment was recovered again as
complex 32a (Scheme 11).
To establish the mechanism of this novel rearrangement,
the reaction of complex 1a (M ˆ Cr, R ˆ Ph) and diamine 31
was carried out in CD3OD. The deuterated perimidine [D1]-33
(R ˆ Ph) was obtained together with the monodeuterated
carbene complex [D1]-32a. This result suggests the participa-
tion of a chromium carbene enolate as an intermediate in the
Scheme 10.
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M. A. Sierra et al.
FULL PAPER
dihydro-1,5-benzoxazepine derivatives 17 by intramolecular
1,2-addition, followed by protonation at the chromium center
and reductive elimination. When the intramolecular addition
was promoted by base-deprotonation of the phenol, 3-ethoxy-
5-phenyl-5,6-dihydro-2H-1,6-benzoxazocin-2-one (18) was
isolated together with the expected adduct 17a. Finally,
adducts 10b and 10c form seven-membered-ring carbene
complexes 20 and 19 by intramolecular aminolysis. In
contrast, the use of 1,8-diaminonaphthalene promotes a new
reaction pathway through a fragmentation process that might
be considered to be an unprecedented ™retro-Aumann∫
reaction. This novel cleavage allows the synthesis of perimi-
dines in good yields under mild reaction conditions.[18]
Scheme 11.
formation of complex 32a. Deuterium could be incorporated
by deuteration of this enolate to yield the labeled compound
[D1]-32a. The isolation of compounds 35 in the reaction
implies that the observed rearrangement is initiated by the
Michael addition of diamine 31 to the alkynyl carbene
complex to form the intermediate complex 39. This inter-
mediate should afford complex 40 by conjugated addition.
Intermediate 40 should have a strong peri-interaction released
by cleavage to form perimidine 33 together with enolate 41,
that protonates to yield chromium carbene complex 32. This
transformation, which leads to the ethoxymethyl carbene
complex by the cleavage of the a-carbon bond of the carbene,
might be considered to be an unprecedented ™retro-Aumann
reaction∫ (Scheme 12).[17]
Experimental Section
General procedures: 1H NMR and 13C NMR spectra were recorded at 258C
as specified on a Varian XL-300S (300.1 and 75.4 MHz), Bruker Avance300
(300.1 and 75.4 MHz) and Bruker 200-AC (200.1 and 50 MHz) spectrom-
eters. Chemical shifts are given relative to TMS (d(1H) ˆ 0.0 ppm) or
CDCl3 (d(13C) ˆ 77.0 ppm). IR spectra were taken on a Perkin Elmer781
spectrometer. Mass spectra were carried out on a GC-MS HP-5989 (60 eV)
mass spectrometer with methanol as the solvent. Melting points were
determined on a Gallenkamp apparatus and are uncorrected. All solvents
used in this work were purified by distillation and were freshly distilled
immediately before use. Tetrahydrofuran (THF) and diethyl ether (Et2O)
were distilled from sodium benzophenone, CH2Cl2 and Et3N from CaH2.
Flame-dried glassware and standard Schlenk techniques were used for
moisture-sensitive reactions. Merck silica gel (230 400 mesh) was used as
the stationary phase for the purification of crude reaction mixtures by flash
column chromatography. Products were identified by TLC (kiesegel 60F-
254), UV light (l ˆ 254 nm); 5% phosphomolybdic acid solution in 95%
EtOH was used to develop the plates. All commercially available
compounds were used without further purification. The following products
were prepared according to literature methods:
Conclusion
The thermal- or SiO2-induced reactions of the Michael
adducts of 1,2-aromatic dinucleophiles and alkynylchro-
mium(0)carbene complexes form different products in ex-
cellent yields, depending on the nature of the dinucleophile.
Thus, 1,2-diaminobenzene derivatives 7 and 8 rearranged to
pentacarbonylchromium(0) isocyanide complexes 11 and 15,
respectively, through bicyclic intermediates 25. The evidence
for intermediates 25 was obtained by the isolation of
compound 13 in the reaction of complex 1c and 1,2-
diaminobenzene. o-Aminophenol-derived adducts give 2,3-
Ethynylferrocene,[19] pentacarbonyl[(ethoxy)(2-phenylethynyl)carbene]-
chromium(0),[20] decacarbonyl-[m-1,3-phenylenediethynyl)bis(ethoxycarbe-
ne)]dichromium(0),[11a] pentacarbonyl[(ethoxy)(2-propyl-ethynyl)carbe-
ne]chromium(0),[21] pentacarbonyl[(ethoxy)(2-tert-butylethynyl)carbene]-
chromium(0).[21]
Pentacarbonyl[(ethoxy)(2-ferrocenylethynyl)carbene]chromium(0) (1d):
To a solution of ethynylferrocene (1.6 g, 7.62 mmol) in dry Et2O (30 mL)
at À788C was added dropwise n-butyllithium (5.3 mL, 8.38 mmol, 1.6m in
hexanes). The mixture was stirred at À788C for 45 min and then the
solution was transferred via cannula at 08C to a suspension of chromium
hexacarbonyl (1.75 g, 7.62 mmol) in
dry Et2O (40 mL) at 08C. The mixture
was allowed to reach room temper-
ature and was stirred for 15 min.
Anhydrous THF (40 mL) was added
and the mixture was stirred at room
temperature overnight. Et3OBF4
(2.89 g, 15.24 mmol) was added in
one portion at À788C. The solution
was stirred at this temperature for
15 min and then allowed to reach
room temperature for an additional
hour. Solvents were removed under
reduced pressure and the residue was
dissolved in Et2O and filtered on silica
gel. The solvent was evaporated and
the residue was subjected to flash
column chromatography under argon
pressure (SiO2, hexanes) to give com-
plex 1d (2.29 g, 66%) as a deep purple
solid. 1H NMR (200 MHz, CDCl3):
Scheme 12.
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Reaction of Alkoxyalkynylchromium Carbenes with Aromatic Dinucleophiles
4943 4953
d ˆ 4.58 (q, J ˆ 7.1 Hz, 2H; OCH2), 4.55 (m, 4H; CH), 4.22 (s, 5H; Cp),
1.48 ppm (t, J ˆ 7.1 Hz, 3 H ; CH3); 13C NMR (50 MHz, CDCl3): d ˆ 309.0
purification was required. 1H NMR (200 MHz, CDCl3): d ˆ 9.84 (brs, 2H;
NH), 7.27 7.07 (m, 4H; ArH), 6.83 (t, J ˆ 7.4 Hz, 2H; ArH), 6.67 (d, J ˆ
7.6 Hz, 2H; ArH), 6.43 (s, 2H; CH), 6.40 (d, J ˆ 7.3 Hz, 2H; ArH), 6.08 (m,
ˆ
(Cr C), 225.6 (COtrans), 216.7 (COcis), 145.4 (Cq), 92.6 (Cq), 75.4 (OCH2),
73.4 (CH), 72.7 (CH), 71.0 (Cp), 60.4 (Cq), 14.9 ppm (CH3); IR (CCl4): nÄ ˆ
2131, 2056, 1988, 1952, 1292, 1198 cmÀ1; elemental analysis calcd (%) for
C20H14CrFeO6: C 52.43, H 3.08; found: C 52.71, H 3.33.
2H; ArH), 4.90 (q, J ˆ 7.0 Hz, 4H; OCH2), 3.77 (brs, 4H; NH2), 1.57 ppm
13
ˆ
(t, J ˆ 7.0 Hz, 6H; CH3); C NMR (50 MHz, CDCl3): d ˆ 302.9 (Cr C),
224.0 (COtrans), 218.1 (COcis), 147.5, 140.6, 135.6, 130.3, 128.7, 128.4, 127.3,
126.3, 124.9, 121.5, 118.6, 116.5 (aromatic C and CH), 74.9 (OCH2),
15.7 ppm (CH3); IR (CCl4): nÄ ˆ 2050, 1931, 1541, 1184 cmÀ1; elemental
analysis calcd (%) for C38H30Cr2N4O12: C 54.42, H 3.61, N 6.68; found: C
54.70, H 3.85, N 6.83.
Synthesis of a,b-unsaturated alkoxychromium(0) carbenes 7, 8, 16, 9, 10, 35,
and 13: These compounds were synthesized following the method
described by Ricart et al.[6]
Pentacarbonyl[(ethoxy)(2-phenyl-2-(o-phenylenediamine)ethenyl)carbe-
ne]chromium(0) (7a): To a solution of pentacarbonyl[(ethoxy)(2-phenyl-
ethynyl)carbene]chromium(0) (1a, 350 mg, 1 mmol) in anhydrous THF
(50 mL) at À788C was added o-phenylenediamine (108 mg, 1 mmol). The
mixture was allowed to reach room temperature and was then stirred until
the starting material had disappeared (2 h, checked by TLC). The solvent
was removed in vacuo, and the residue was subjected to flash column
chromatography under argon pressure (SiO2, hexanes) to give carbene
complex 7a (388 mg, 85%) as a red solid. 1H NMR (300 MHz, CDCl3): d ˆ
Pentacarbonyl[(ethoxy)(2-ferrocenyl-2-(o-aminobenzylamino)ethenyl)-
carbene]chromium(0) (16): To a solution of pentacarbonyl[(ethoxy)(2-
ferrocenylethynyl)carbene]chromium(0) (1d, 100 mg, 0.22 mmol) in anhy-
drous CH2Cl2 (5 mL) at room temperature was added o-aminobenzylamine
(27 mg, 0.22 mmol). The mixture was stirred until the starting material had
disappeared (3 h, checked by TLC). The solvent was removed in vacuo to
afford carbene complex 16 (120 mg, 95%) as a dark orange solid. No
further purification was required. 1H NMR (300 MHz, CDCl3): d ˆ 9.29
(brs, 1H; NH), 7.11 (t, J ˆ 7.2 Hz, 1H; ArH), 7.05 (d, J ˆ 7.5 Hz, 1H; ArH),
6.76 (s, 1H; CH), 6.73 (t, J ˆ 7.5 Hz, 1H; ArH), 6.66 (d, J ˆ 7.8 Hz, 1H;
ArH), 4.60 (s, 2H; CH), 4.50 (q, J ˆ 7.2 Hz, 2H; OCH2), 4.45 (s, 2H; CH),
1
10.02 (brs, 1H; NH), 7.24 (m, 5H; ArH), 6.86 (t, J (H, H) ˆ 6.7 Hz, 1H;
ArH), 6.66 (d, J ˆ 8.0 Hz, 1H; ArH), 6.59 (s, 1H; CH), 6.44 6.30 (m, 2H;
ArH), 4.88 (q, J ˆ 7.0 Hz, 2H; OCH2), 3.76 (brs, 2H; NH2), 1.57 ppm (t, J ˆ
4.34 (d, J ˆ 5.1 Hz, 2H; CH2), 4.25 (s, 5H; Cp), 3.51 (s, 2H; NH2), 0.98 ppm
13
ˆ
7.0 Hz, 3H; CH3); C NMR (50 MHz, CDCl3): d ˆ 300.5 (Cr C), 224.0
13
ˆ
(t, J ˆ 7.2 Hz, 3H; CH3); C NMR (75 MHz, CDCl3): d ˆ 280.2 (Cr C),
(COtrans), 218.3 (COcis), 149.3, 140.2, 134.8, 130.2, 128.6, 128.5, 127.1, 126.3,
125.3, 121.7, 118.9, 116.3 (aromatic C and CH), 74.7 (OCH2), 15.8 ppm
(CH3); IR (CCl4): nÄ ˆ 2050, 1921, 1539, 1188 cmÀ1; elemental analysis calcd
(%) for C22H18CrN2O6: C 57.64, H 3.96, N 6.11; found: C 57.79, H 4.23, N
6.27.
224.2 (COtrans), 219.3 (COcis), 156.4, 144.3, 129.8, 129.5, 120.6, 119.6, 119.1,
116.4 (aromatic C and CH), 81.3 (Cq), 73.2 (CH), 71.4 (CH), 71.1 (OCH2),
70.8 (Cp), 47.2 (CH2), 14.7 ppm (CH3); IR (CCl4): nÄ ˆ 2046, 1923,
1545 cmÀ1; elemental analysis calcd (%) for C27H24CrFeN2O6: C 55.88, H
4.17, N 4.83; found: C 55.61, H 4.03, N 5.01.
Pentacarbonyl[(ethoxy)(2-ferrocenyl-2-(o-phenylenediamine)ethenyl)car-
bene]chromium(0) (7b): To a solution of pentacarbonyl[(ethoxy)(2-ferro-
cenylethynyl) carbene]chromium(0) (1d, 458 mg, 1 mmol) in anhydrous
THF (50 mL) at À308C was added o-phenylenediamine (108 mg, 1 mmol).
The mixture was allowed to reach room temperature and was then stirred
until the starting material had disappeared (5 h, checked by TLC). The
solvent was removed in vacuo, and the crude residue was crystallized at low
temperature in pentane/Et2O (1:1) to afford carbene complex 7b (419 mg,
74%) as a dark red solid. 1H NMR (300 MHz, CDCl3): d ˆ 10.22 (brs, 1H;
NH), 6.98 (m, 1H; ArH), 6.96 (s, 1H; CH), 6.68 (d, 1J ˆ 7.8 Hz, 1H; ArH),
6.61 6.52 (m, 2H; ArH), 4.75 (q, J ˆ 6.9 Hz, 2H; OCH2), 4.28 (d, J ˆ
2.1 Hz, 2H; CH), 4.26 (d, J ˆ 2.1 Hz, 2H; CH), 4.16 (s, 5H; Cp), 3.71(brs,
2H; NH2), 1.48 ppm (t, J ˆ 6.9 Hz, 3H; CH3); 13C NMR (75 MHz, CDCl3):
Pentacarbonyl[(ethoxy)(2-phenyl-2-(o-hydroxyphenylamino)ethenyl)car-
bene]chromium(0) (9a): To a solution of pentacarbonyl[(ethoxy)(2-phenyl-
ethynyl)carbene]chromium(0) (1a, 700 mg, 2 mmol) in anhydrous THF
(80 mL) at À788C was added o-aminophenol (218 mg, 2 mmol). The
mixture was allowed to reach room temperature and was then stirred until
the starting material had disappeared (2 h, checked by TLC). The solvent
was removed in vacuo to afford carbene complex 9a (900 mg, 98%) as a
red solid. No further purification was required. 1H NMR (200 MHz,
CDCl3): d ˆ 10.38 (brs, 1H; NH), 7.29 (m, 5H; ArH), 6.81 (brs, 2H; ArH),
6.54 (s, 1H; CH), 6.46 (t, J ˆ 7.5 Hz, 1H; ArH), 6.19 (d, J ˆ 7.8 Hz, 1H;
ArH), 4.91 (q, J ˆ 7.0 Hz, 2H; OCH2), 1.60 ppm (t, J ˆ 7.0 Hz, 3H; CH3);
13
ˆ
C NMR (50 MHz, CDCl3): d ˆ 300.7 (Cr C), 224.2 (COtrans), 218.3
(COcis), 147.4, 146.7, 135.2, 130.2, 128.7, 126.4, 125.7, 123.9, 122.5, 120.4, 115.7
(aromatic C and CH), 74.9 (OCH2), 15.7 ppm (CH3); IR (CCl4): nÄ ˆ 2048,
1969, 1929, 1547, 1221, 1197 cmÀ1; elemental analysis calcd (%) for
C22H17CrNO7: C 57.52, H 3.73, N 3.05; found: C 57.74, H 3.91, N 2.92.
ˆ
d ˆ 286.1 (Cr C), 224.1 (COtrans), 219.0 (COcis), 153.7, 140.9, 128.0, 126.7,
124.9, 121.2, 118.7, 116.3 (aromatic C and CH), 81.3 (Cq), 76.8 (OCH2), 73.7
(CH), 71.2 (CH), 70.8 (Cp), 15.8 ppm (CH3); IR (CCl4): nÄ ˆ 2046, 1925,
1545, 1508, 1194 cmÀ1; elemental analysis calcd (%) for C26H22CrFeN2O6: C
55.14, H 3.92, N 4.95; found: C 55.29, H 4.18, N 5.13.
Pentacarbonyl[(ethoxy)(2-ferrocenyl-2-(o-hydroxyphenylamino)ethenyl)-
carbene]chromium(0) (9b): To a solution of pentacarbonyl[(ethoxy)(2-
ferrocenylethynyl)carbene]chromium(0) (1d, 150 mg, 0.33 mmol) in anhy-
drous THF (15 mL) at À788C was added o-aminophenol (36 mg,
0.33 mmol). The mixture was allowed to reach room temperature and
was then stirred until the starting material had disappeared (4 h, checked
by TLC). The solvent was removed in vacuo to afford carbene complex 9b
(185 mg, 100%) as a dark red solid. No further purification was required.
1H NMR (300 MHz, CDCl3): d ˆ 10.32 (brs, 1H; NH), 7.04 (s, 1H; CH),
6.95 (brs, 1H; ArH), 6.80 (brs, 1H; ArH), 6.64 (t, J ˆ 7.5 Hz, 1H; ArH),
6.55 (d, J ˆ 7.5 Hz, 1H; ArH), 5.34 (brs, 1H; OH), 4.76 (q, J ˆ 7.0 Hz, 2H;
OCH2), 4.29 (m, 4H; CH), 4.18 (s, 5H; Cp), 1.49 ppm (t, J ˆ 7.0 Hz, 3H;
Pentacarbonyl[(2-propyl-2-(o-phenylenediamine)ethenyl)carbene](ethoxy)-
chromium(0) (7c): To a solution of pentacarbonyl[(ethoxy)(2-propylethy-
nyl)carbene]chromium(0) (1e, 150 mg, 0.47 mmol) in anhydrous THF
(25 mL) at À788C was added o-phenylenediamine (51 mg, 0.47 mmol).
The mixture was allowed to reach room temperature and was then stirred
until the starting material had disappeared (45 min, checked by TLC). The
solvent was removed in vacuo to give carbene complex 7c (200 mg, 99%)
as a dark yellow oil. No further purification was required. 1H NMR
(300 MHz, CDCl3): d ˆ 9.95 (brs, 1H; NH), 7.10 (t, J ˆ 7.5 Hz, 1H; ArH),
6.92 (d, J ˆ 7.5 Hz, 1H; ArH), 6.74 6.69 (m, 2H; ArH), 6.35 (s, 1H; CH),
4.79 (q, J ˆ 6.9 Hz, 2H; OCH2), 3.73 (brs, 2H; NH2), 2.08 (t, J ˆ 7.5 Hz, 2 H ;
CH3); 13C NMR (50 MHz, CDCl3): d ˆ 288.6 (Cr C), 224.2 (COtrans), 219.0
ˆ
CH2), 1.47 (t, J ˆ 6.9 Hz, 3H; CH3), 1.45 (m, 2H; CH2), 0.81 ppm (t, J ˆ
(COcis), 151.0, 148.2, 126.9, 126.2, 125.3, 122.4, 120.6, 116.0 (aromatic C and
CH), 77.9 (Cq), 74.0 (OCH2), 71.2 (CH), 71.0 (Cp), 70.5 (CH), 15.7 ppm
(CH3); IR (CCl4): nÄ 2046, 1985, 1919, 1549, 1439 cmÀ1; elemental analysis
calcd (%) for C26H21CrFeNO7: C 55.05, H 3.73, N 2.47; found: C 55.19, H
3.96, N 2.62.
13
ˆ
7.2 Hz, 3H; CH3); C NMR (75 MHz, CDCl3): d ˆ 293.2 (Cr C), 223.9
(COtrans), 218.6 (COcis), 157.1, 142.2, 129.3, 127.5, 122.3, 119.0, 118.6, 116.2
(aromatic C and CH), 74.0 (OCH2), 34.2 (CH2), 21.8 (CH2), 15.8 (CH3),
13.8 ppm (CH3); IR (CCl4): nÄ ˆ 2050, 1927, 1547, 1190 cmÀ1; elemental
analysis calcd (%) for C19H20CrN2O6: C 53.77, H 4.75, N 6.60; found: C
53.94, H 4.89, N 6.77.
Pentacarbonyl[(ethoxy)(2-phenyl-2-(o-aminobenzenethiol)ethenyl)carbe-
ne]chromium(0) (10b): To a solution of pentacarbonyl[(ethoxy)(2-phenyl-
ethynyl)carbene]chromium(0) (1a, 350 mg, 1 mmol) in anhydrous THF
(50 mL) at À788C was added o-aminobenzenethiol (125 mg, 1 mmol). The
mixture was allowed to reach room temperature and was then stirred until
the starting material had disappeared (1.5 h, checked by TLC). The solvent
was removed in vacuo and the crude reaction was submitted to flash
column chromatography to yield carbene complex 10b (226 mg, 48%) as a
Synthesis of bis-carbene complex (8): To a solution of decacarbonyl[(m-1,3-
phenylenediethynyl)bis(ethoxycarbene)]dichromium(0)[11a] (37, 200 mg,
0.32 mmol) in anhydrous THF (15 mL) at À788C was added o-phenyl-
enediamine (70 mg, 0.64 mmol). The mixture was allowed to reach room
temperature and was then stirred until the starting material had disap-
peared (30 min, checked by TLC). The solvent was removed in vacuo to
yield biscarbene complex 8 (270 mg, 100%) as a deep red solid. No further
1
dark red solid. H NMR (200 MHz, CDCl3): d ˆ 7.38 7.19 (m, 7H; ArH),
Chem. Eur. J. 2003, 9, 4943 4953
www.chemeurj.org
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4949

M. A. Sierra et al.
FULL PAPER
6.82 6.73 (m, 3H; ArH and CH), 4.47 (q, J ˆ 7.0 Hz, 2H; OCH2), 4.33 (brs,
2H; NH2), 0.75 ppm (t, J ˆ 7.0 Hz, 3H; CH3); 13C NMR (50 MHz, CDCl3):
(CH3); IR (CCl4): nÄ ˆ 2137 (CN), 2054, 1998, 1958, 1639 cmÀ1; elemental
analysis calcd (%) for C20H12CrN2O5 : C 58.26, H 2.93, N 6.79; found: C
58.51, H 3.17, N 6.65.
ˆ
d ˆ 326.0 (Cr C), 224.0 (COtrans), 216.5 (COcis), 149.0, 144.5, 138.2, 137.1,
135.1, 132.6, 128.6, 128.2, 119.3, 115.9, 111.6 (aromatic C and CH), 75.8
(OCH2), 13.8 ppm (CH3); IR (CCl4): nÄ ˆ 2054, 1979, 1940, 1610, 1541,
1230 cmÀ1; elemental analysis calcd (%) for C22H17CrNO6S: C 55.58, H
3.60, N 2.95, S 6.74; found: C 55.79, H 3.83, N 2.82, S 6.58.
Isocyanide complex 11b: Complex 7b (1.13 g, 2 mmol) was subjected to
flash column chromatography on silica gel under argon pressure to yield
complex 11b (935 mg, 90%) as an orange solid. M.p. 1358C (decomp);
1H NMR (300 MHz, CDCl3): d ˆ 7.32 7.24 (m, 2H; ArH), 7.01 (t, J ˆ
7.3 Hz, 1H; ArH), 6.79 (d, J ˆ 7.8 Hz, 1H; ArH), 4.77 (s, 2H; CH), 4.40
(s, 2H; CH), 4.16 (s, 5H; Cp), 2.08 ppm (s, 3H; CH3); 13C NMR (75 MHz,
[(2Z)(3-(6-aminoacenaphthen-5-ylamino)-3-phenyl-2-propenyliden]pen-
tacarbonylchromium(0) (35a): Complex 1a (150 mg, 0.43 mmol) and 5,6-
diaminoacenaphthene (34, 79 mg, 0.43 mmol) in CH2Cl2 (15 mL) were
stirred for 6.5 h at room temperature to give complex 35a (229 mg, 100%)
as a dark red solid. 1H NMR (300 MHz, CDCl3): d ˆ 10.96 (brs, 1H; NH),
7.31 7.15 (m, 5H; ArH), 7.04 (d, J ˆ 7.4 Hz, 1H; ArH), 6.74 6.70 (m, 2H;
ArH), 6.65 (s, 1H; CH), 6.35 (d, J ˆ 7.4 Hz, 1H; ArH), 4.91 (q, J ˆ 7.0 Hz,
ˆ
CDCl3): d ˆ 216.7 (COtrans), 214.5 (Cr-CN), 214.3 (COcis), 171.2 (C N),
148.8, 129.5, 126.2, 123.4, 120.7 (aromatic C and CH), 82.0 (Cq), 71.2 (CH),
69.5 (Cp), 68.8 (CH), 18.6 ppm (CH3); IR (CCl4): nÄ ˆ 2141 (CN), 2056,
‡
1998, 1954, 1626, 1464, 1215 cmÀ1; MS (ESI): 521.1 [M‡H] ; elemental
analysis calcd (%) for C24H16CrFeN2O5 : C 55.41, H 3.10, N 5.38; found: C
55.64, H 3.27, N 5.55.
2H; OCH2), 4.30 (s, 2H; NH2), 3.18 (m, 4H; 2CH2), 1.57 ppm (t, J ˆ 7.0 Hz,
13
ˆ
3H; CH3); C NMR (50 MHz, CDCl3): d ˆ 300.7 (Cr C), 224.1 (COtrans),
Deuteration experiments: A solution of carbene 7b (100 mg, 0.18 mmol) in
anhydrous THF (2.5 mL) and CD3OD (0.5 mL) was heated at 508C under
an argon atmosphere until the starting material had disappeared (10 h,
checked by TLC). The solvent was removed under reduced pressure and
the crude reaction mixture was dissolved in hexanes/Et2O (2:1) and filtered
through a double pad of Celite and SiO2 to yield, after removing the
solvent, compound [D3]-11b (80 mg, 87%).
218.3 (COcis), 147.9, 144.8, 141.5, 139.2, 137.0, 135.3, 131.2, 129.8, 129.3,
128.7, 128.5, 126.0, 125.5, 122.6, 118.7, 114.4 (aromatic C and CH), 75.0
(OCH2), 30.3 (CH2), 29.7 (CH2), 15.7 ppm (CH3); IR (CCl4): nÄ ˆ 2050, 1983,
1927, 1535, 1219 cmÀ1; elemental analysis calcd (%) for C28H22CrN2O6:
C 62.92, H 4.15, N 5.24; found: C 63.15, H 4.32, N 5.41.
[(2Z)(3-(6-aminoacenaphthen-5-ylamino)-3-phenyl-2-propenyliden]pen-
tacarbonyltungsten(0) (35b): Analogously to complex 35a, complex 1b
(150 mg, 0.31 mmol) and 5,6-diaminoacenaphthene (34, 57 mg, 0.31 mmol)
in CH2Cl2 (15 mL) were stirred at room temperature for 6 h to give
complex 35b (206 mg, 100%) as a dark red solid. 1H NMR (300 MHz,
CDCl3): d ˆ 11.10 (brs, 1H; NH), 7.31 7.17 (m, 5H; ArH), 7.04 (d, J ˆ
7.4 Hz, 1H; ArH), 6.74 6.70 (m, 3H; ArH and CH), 6.37 (d, J ˆ 7.4 Hz,
1H; ArH), 4.76 (q, J ˆ 7.1 Hz, 2H; OCH2), 4.29 (brs, 2H; NH2), 3.18 (m,
4H; 2CH2), 1.54 ppm (t, J ˆ 7.1 Hz, 3H; CH3); 13C NMR (75 MHz, CDCl3):
Isocyanide complex 11c: A solution of complex 7c (100 mg, 0.24 mmol) in
anhydrous THF was heated at 508C under an argon atmosphere until the
starting material had disappeared (29 h, checked by TLC). The solvent was
removed under reduced pressure and the crude reaction mixture was
dissolved in hexanes/Et2O (1:1) and filtered through a short pad of Celite.
The solvent was evaporated to yield (37 mg, 43%) complex 11c as a yellow
oil. No further purification was required. 1H NMR (200 MHz, CDCl3): d ˆ
7.28 7.19 (m, 2H; ArH), 6.99 (m, 1H; ArH), 6.71 (d, J ˆ 7.7 Hz, 1H; ArH),
2.43 (t, J ˆ 7.3 Hz, 2H; CH2), 1.77 (s, 3H; CH3), 1.68 (m, 2H; CH2),
0.97 ppm (t, J ˆ 7.3 Hz, 3H; CH3); 13C NMR (75 MHz, CDCl3): d ˆ 216.7
ˆ
d ˆ 277.3 (W C), 203.8 (COtrans), 199.0 (COcis), 151.5, 144.9, 141.5, 139.1,
137.1, 135.2, 131.1, 130.0, 129.1, 128.6, 125.5, 125.4, 120.4, 118.8, 117.6, 114.5
(aromatic C and CH), 77.6 (OCH2) , 30.3 (CH2), 29.7 (CH2), 15.5 ppm
(CH3); IR (CCl4): nÄ ˆ 2058, 1969, 1929, 1537, 1219 cmÀ1; elemental analysis
calcd (%) for C28H22N2O6W: C 50.47; H 3.33; N 4.20; found, C 50.70, H 3.21,
N 4.36.
ˆ
(COtrans), 214.5 (COcis), 175.7 (C N), 148.3, 129.7, 126.5, 123.5, 120.7
(aromatic C and CH), 42.9 (CH2), 20.4 (CH3), 19.3 (CH2), 13.7 ppm (CH3).
The signal attributable to the isonitrile group could not be detected; IR
(CCl4): nÄ ˆ 2139 (CN), 2056, 1996, 1956, 1664, 1477, 1446, 1257 cmÀ1
.
Complex 13: To a solution of pentacarbonyl[(ethoxy)(2-tert-butylethynyl)-
carbene]chromium(0) (1c, 225 mg, 0.68 mmol) in anhydrous THF (22 mL)
at À788C was added o-phenylenediamine (74 mg, 0.68 mmol). The mixture
was allowed to reach room temperature and was then stirred until the
starting material had disappeared (1.5 h, checked by TLC). The solvent was
removed in vacuo to give complex 13 (290 mg, 97%) as a dark yellow solid.
1H NMR (300 MHz, CDCl3): d ˆ 10.32 (brs, 1H; NH), 7.11 7.00 (m, 2H;
ArH), 6.80 (t, J ˆ 7.5 Hz, 1H; ArH), 6.72 (d, J ˆ 8.1 Hz, 1H; ArH), 4.63 (s,
1H; NH), 4.21 (d, J ˆ 12.9 Hz, 1H; CH2), 3.45 (m, 1H; OCH2), 3.30 (m,
Isocyanide complex 12: To a solution of complex 7c (100 mg, 0.24 mmol) in
hexanes/AcOEt 10:1 at room temperature was added SiO2 (1.0 g). The
mixture was stirred under an argon atmosphere until the starting material
had disappeared (46 h, checked by TLC). The solvent was removed under
reduced pressure and the crude reaction mixture was dissolved in AcOEt
and filtered through a short pad of Celite. Flash column chromatography
yielded compound 12 (43 mg, 58%) as a white solid. M.p. 1958C; 1H NMR
(300 MHz, CDCl3): d ˆ 7.15 7.08 (m, 2H; ArH), 6.75 6.65 (m, 2H; ArH),
3.99 ppm (brs, 2H; NH2); 13C NMR (75 MHz, CDCl3): d ˆ 216.6 (COtrans),
214.5 (COcis), 142.8, 130.1, 126.4, 118.5, 115.8 ppm (aromatic C and CH).
The signal attributable to the isonitrile group could not be detected; IR
(CCl4): nÄ ˆ 2143 (CN), 2058, 1940, 1495 cmÀ1; elemental analysis calcd (%)
for C12H6CrN2O5 : C 46.47, H 1.95, N 9.03; found: C 46.72, H 2.17, N 9.18.
1H; OCH2), 2.52 (d, J ˆ 12.9 Hz, 1H; CH2), 1.05 (t, J ˆ 7.0 Hz, 3H; CH3),
13
ˆ
1.03 ppm (s, 9H; CH3); C NMR (50 MHz, CDCl3): d ˆ 285.1 (Cr C),
223.0 (COtrans), 217.4 (COcis), 139.0, 128.6, 126.8, 123.6, 119.5, 119.2
(aromatic C and CH), 99.0 (Cq), 60.2 (OCH2), 53.4 (CH2), 42.9 (Cq),
25.4 (CH3), 15.3 ppm (CH3); IR (CCl4): nÄ ˆ 2056, 1944, 1913, 1473 cmÀ1
.
Isocyanide complexes 11d and 12: To a solution of complex 1c (102 mg,
0.76 mmol) in 25 mL of anhydrous THF at À788C was added 1,2-
diaminobenzene (82 mg, 0.76 mmol). The mixture was allowed to reach
room temperature and stirred under an argon atmosphere until the starting
material had disappeared (1 h, checked by TLC). The solvent was removed
under reduced pressure and the crude reaction mixture was purified by
flash column chromatography to yield compound 11d (63 mg, 21%) as an
oil and complex 12 (93 mg, 40%).
Synthesis of isocyanidechromium(0) complexes:
Isocyanide complex 11a
Method A: SiO2 (500 mg) was added to a solution of carbene complex 7a
(50 mg, 0.11 mmol) in hexanes/AcOEt 10:1 at room temperature. The
heterogeneous mixture was stirred under argon pressure until the starting
material disappeared (48 h, checked by TLC). The crude reaction mixture
was dissolved in AcOEt and filtered through a short pad of Celite. Flash
column chromatography yielded compound 11a (27 mg, 60%) as a pale
yellow solid.
11d: 1H NMR (300 MHz, CDCl3): d ˆ 7.30 7.20 (m, 2H; ArH), 6.98 (t, J ˆ
7.4 Hz, 1H; ArH), 6.63 (d, J ˆ 7.9 Hz, 1H; ArH), 1.76 (s, 3H; CH3),
1.22 ppm (s, 9H; CH3); 13C NMR (75 MHz, CDCl3): d ˆ 216.7 (COtrans),
Method B: A solution of complex 7a (100 mg, 0.22 mmol) in anhydrous
THF (5 mL) was heated at 508C under an argon atmosphere until the
starting material had disappeared (8 h, checked by TLC). The crude
reaction mixture was dissolved into a mixture of hexanes/Et2O (2:1) and
filtered through a double pad of Celite and SiO2 to yield, after removing the
solvent, compound 11a (66 mg, 73%). M.p. 94 96 8C; 1H NMR (300 MHz,
CDCl3): d ˆ 7.97 (d, J ˆ 7.5, 2H; ArH), 7.44 7.32 (m, 3H; ArH), 7.29 (t, J ˆ
7.2 Hz, 2H; ArH), 7.03 (t, J ˆ 7.2 Hz, 1H; ArH), 6.82 (d, J ˆ 7.8 Hz, 1H;
ArH), 2.23 ppm (s, 3H; CH3); 13C NMR (75 MHz, CDCl3): d ˆ 216.6
ˆ
214.5 (COcis), 181.8 (C N), 148.0, 129.7, 127.4, 123.4, 120.4 (aromatic C and
CH), 40.8 (Cq), 27.8 (CH3), 16.1 ppm (CH3). The signal corresponding to
the isonitrile group could not be detected; IR (CCl4): nÄ ˆ 2139 (CN), 2056,
1996, 1958, 1655, 1475 cmÀ1
; elemental analysis calcd (%) for
C18H16CrN2O5: C 55.11, H 4.11, N 7.14; found: C 55.35, H 4.29, N 7.33.
Decacarbonyl[bisisocyanide]dichromium(0)] complex (15): A solution of
complex 8 (100 mg, 0.12 mmol) in anhydrous THF (5 mL) was heated at
508C under an argon atmosphere until the starting material had disap-
peared (17 h, checked by TLC). The mixture was subjected to flash
chromatography under argon pressure (SiO2, hexanes) to yield complex 15
ˆ
(COtrans), 214.5 (Cr-CN), 214.3 (COcis), 168.6 (C N), 148.5, 137.9, 131.4,
129.7, 128.4, 128.4, 127.5, 126.2, 123.7, 120.5 (aromatic C and CH), 18.0 ppm
4950
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2003, 9, 4943 4953

Reaction of Alkoxyalkynylchromium Carbenes with Aromatic Dinucleophiles
4943 4953
(54 mg, 60%) as an oil. 1H NMR (300 MHz, CDCl3): d ˆ 8.64 (s, 1H; ArH),
8.13 (m, 2H; ArH), 7.32 7.25 (m, 5H; ArH), 7.05 (t, J ˆ 7.3 Hz, 2H; ArH),
6.82 (d, J ˆ 7.5 Hz, 2H; ArH), 2.27 ppm (s, 6H; CH3); 13C NMR (75 MHz,
compound [D3]-17b (46 mg, 70%) with 33% of deuteration grade in the
CH group, and 58% and 72% of deuteration grade in the methylene group.
3-Ethoxy-5-phenyl-5,6-dihydro-2H-1,6-benzoxazocin-2-one (18): To a sol-
ution of complex 9a (100 mg, 0.22 mmol) in anhydrous THF (2 mL) at 08C
was added 10.5 mg of NaH (0.26 mmol, 60% in mineral oil). The reaction
was stirred at 08C during 1 h, left to reach room temperature, then stirred
until the starting material had disappeared (4 h, checked by TLC). The
mixture was quenched with H2O, dried over MgSO4, and filtered through a
short pad of Celite. Flash column chromatography on silica gel yielded
compound 17a (23 mg, 39%), and compound 18 (23 mg, 36%) as a pale
yellow solid.
ˆ
CDCl3): d ˆ 216.6 (COtrans), 214.3 (Cr-CN), 214.3 (COcis), 168.0 (C N),
148.4, 138.0, 130.4 129.7, 128.6, 128.4, 126.2, 123.8, 120.5, 118.1 (aromatic C
and CH), 18.0 ppm (CH3); IR (CCl4): nÄ ˆ 2137 (CN), 2054, 1998, 1959, 1637,
1223 cmÀ1; elemental analysis calcd (%) for C34H18Cr2N4O10: C 54.70, H
2.43, N 7.51; found: C 54.94, H 2.27, N 7.68.
Synthesis of decacarbonyl[isocyanide-carbene]dichromium(0) complex
(14) and bisisocyanide complex (15): To a solution of decacarbonyl[(m-
1,3-phenylenediethynyl)bis(ethoxycarbene)]dichromium(0) (37, 250 mg,
0.4 mmol) in anhydrous THF (20 mL) at À788C was added o-phenyl-
enediamine (86 mg, 0.8 mmol). The mixture was stirred until the starting
material had disappeared (30 min, checked by TLC). The solvent was
removed in vacuo, and the crude reaction mixture was submitted to flash
column chromatography to yield the bisisocyanide complex 15 (86 mg,
29%), complex 14 (80 mg, 25%), as a deep red solid, and the starting
biscarbene complex (40 mg, 12%).
18: M.p. 165 167 8C; 1H NMR (300 MHz, CDCl3): d ˆ 8.09 (s, 1H; NH),
7.20 7.13 (m, 3H; ArH), 7.07 6.91 (m, 5H; ArH), 6.73 (t, J ˆ 8.0 Hz, 1H;
ArH), 5.88 (d, J ˆ 2.3 Hz, 1H; CH), 5.68 (d, J ˆ 2.3 Hz, 1H; CH), 3.94 (q,
J ˆ 7.0 Hz, 2H; OCH2), 1.39 ppm (t, J ˆ 7.0 Hz, 3H; CH3); 13C NMR
(50 MHz, CDCl3): d ˆ 166.4 (Cq), 150.9 (Cq), 148.2 (Cq), 135.2 (Cq), 129.1,
128.5, 128.0, 126.5, 125.6 (Cq), 123.0, 121.0, 120.9 (aromatic CH), 113.2
(CH), 66.3 (OCH2), 63.1 (CH), 14.2 ppm (CH3); IR (CCl4): nÄ ˆ 1684, 1647,
‡
1497, 1321, 1138 cmÀ1; MS (EI), m/z (%): 295 (100) [M] , 266 (44), 238 (38),
14: 1H NMR (300 MHz, CDCl3): d ˆ 9.95 (brs, 1H; NH), 8.10 (s, 1H;
ArH), 7.97 (s, 1H; ArH), 7.28 (m, 4H; ArH), 7.05 (m, 1H; ArH), 6.89 6.78
(m, 2H; ArH), 6.68 6.64 (m, 2H; CH and ArH), 6.43 6.40 (m, 2H; ArH),
4.92 (q, J ˆ 6.9 Hz, 2H; OCH2), 3.79 (brs, 2H; NH2), 2.14 (s, 3H; CH3),
1.59 ppm (t, J ˆ 6.9 Hz, 3H; CH3); 13C NMR (75 MHz, CDCl3): d ˆ 301.8
220 (36), 196 (48), 131 (70), 103 (96), 77 (66); elemental analysis calcd (%)
for C18H17NO3: C 73.20, H 5.80, N 4.74; found: C 73.42, H 5.99, N 4.58.
Pentacarbonylchromium(0) carbene complex (19): To
a solution of
2-aminophenol (55 mg, 0.5 mmol) in anhydrous THF (2 mL) at room
temperature was added tBuONa (49 mg, 0.5 mmol) in one portion. The
mixture was stirred for 30 min and then a solution of complex 1a (175 mg,
0.5 mmol) in anhydrous THF (4 mL) was added. The starting material had
disappeared after 15 min. The solvent was removed under reduced
pressure, and the crude reaction mixture was subjected to flash chroma-
tography under argon pressure on silica gel (hexanes) to give carbene
complex 19 (80 mg, 40%) as a dark red solid. 1H NMR (300 MHz, CDCl3):
d ˆ 10.00 (brs, 1H; NH), 7.81 7.77 (m, 2H; ArH), 7.42 7.40 (m, 3H;
ArH), 7.23 (s, 1H; CH), 7.18 (m, 2H; ArH), 7.09 ppm (t, J ˆ 7.8 Hz, 2H;
ˆ
(Cr C), 224.1 (COtrans), 218.2 (COcis), 216.5 (COtrans), 214.2 (COcis), 173.5,
167.3, 148.2, 140.4, 138.2, 135.1, 131.4, 129.7, 129.2, 128.6, 128.1, 127.4, 126.5,
126.1, 125.0, 123.9, 121.9, 120.3, 119.1, 118.0, 116.4 (aromatic C and CH),
74.8 (OCH2), 17.6 (CH3), 15.8 ppm (CH3). The signal corresponding to the
isonitrile group could not be detected.; IR (CCl4): nÄ ˆ 2137 (CN), 2052,
1998, 1959, 1932, 1541, 1373, 1188 cmÀ1; elemental analysis calcd (%) for
C36H24Cr2N4O11: C 54.55, H 3.05, N 7.07; found: C 54.74, H 3.21, N 7.26.
2-Ethoxy-4-phenyl-2,3-dihydro-1,5-benzoxazepine (17a):
A solution of
complex 9a (100 mg, 0.22 mmol) in anhydrous THF (5 mL) was refluxed
under argon atmosphere until the starting material had disappeared (5 h,
checked by TLC). The solvent was removed in vacuo, the crude reaction
mixture was dissolved in hexanes/Et2O (2:1) and filtered through a double
pad of SiO2 and Celite. The solvent was removed under reduced pressure to
give compound 17a (27 mg, 47%) as a brown solid. M.p. 64 66 8C;
1H NMR (300 MHz, CDCl3): d ˆ 7.95 7.92 (m, 2H; ArH), 7.42 7.40 (m,
3H; ArH), 7.26 7.23 (m, 1H; ArH), 7.15 (m, 1H; ArH), 7.08 (m, 1H;
ArH), 7.02 7.00 (m, 1H; ArH), 5.54 (dd, 1J ˆ 9.7 Hz, 2J ˆ 3.8 Hz, 1H; CH),
4.01 (m, 1H; OCH2), 3.64 (m, 1H; OCH2), 3.26 (dd, 1J ˆ 13.8 Hz, 2J ˆ
ArH); 13C NMR (75 MHz, CDCl3): d ˆ 274.7 (Cr C), 223.1 (COtrans), 217.3
ˆ
(COcis), 153.7, 150.4, 132.9, 132.8, 131.2, 129.1, 129.0, 127.5, 127.5, 126.1,
121.8, 119.0 ppm (aromatic
C
and CH); IR (CCl4): nÄ ˆ 2052, 1938,
1560 cmÀ1; elemental analysis calcd (%) for C22H11CrNO6: C 58.12, H
2.68, N 3.39; found: C 58.38, H 2.89, N 3.21.
Pentacarbonylchromium(0) carbene complex (20) and 2-phenyl-1,5-benzo-
thiazepin-4(5H)-one (21): A solution of complex 10b (100 mg, 0.21 mmol)
in anhydrous THF (5 mL) was heated at 508C under argon atmosphere
until the starting material had disappeared (29 h, checked by TLC). The
solvent was removed in vacuo, the crude reaction was subjected to flash
column chromatography to give compound 21 (27 mg, 51%) as a white
solid and carbene complex 20 (10 mg, 11%) as a dark red oil.
1
2
3.8 Hz, 1H; CH2), 2.70 (dd, J ˆ 13.8 Hz, J ˆ 9.7 Hz, 1H; CH2), 1.60 ppm
13
ˆ
(t, J ˆ 7.1 Hz, 3H; CH3); C NMR (50 MHz, CDCl3): d ˆ 165.5 (C N),
145.0 (Cq), 142.4 (Cq), 138.6 (Cq), 130.7, 128.6, 127.3, 126.7, 126.2, 124.7 and
123.4, (aromatic CH), 109.3 (CH), 64.1 (OCH2), 35.8 (CH2), 15.1 ppm
(CH3); IR (CCl4): nÄ ˆ 1608, 1572, 1477, 1221, 1097 cmÀ1; MS (ESI): 268.3
21: M.p. 106 108 8C; 1H NMR (200 MHz, CDCl3): d ˆ 8.06 8.00 (m, 3H;
ArH), 7.84 (d, J ˆ 8.0 Hz, 1H; ArH), 7.47 7.40 (m, 5H; ArH), 7.32 ppm (t,
J ˆ 7.5 Hz, 1H; ArH); 13C NMR (50 MHz, CDCl3): d ˆ 168.0, 154.1, 135.0.
133.6, 130.9, 129.0, 127.5, 126.3, 125.2, 123.2, 121.6 ppm (aromatic C and
CH); IR (CCl4): nÄ ˆ 1635, 1578, 1554, 1514, 1481, 1435, 1225 cmÀ1; MS
‡
[M‡H] .
2-Ethoxy-4-ferrocenyl-2,3-dihydro-1,5-benzoxazepine (17b): A solution of
complex 9b (96 mg, 0.17 mmol) in anhydrous THF (5 mL) was refluxed
under argon atmosphere until the starting material had disappeared (5 h,
checked by TLC). The solvent was removed in vacuo, the crude reaction
mixture was dissolved in hexanes/Et2O (2:1) and filtered through a double
pad of SiO2 and Celite. The solvent was removed under reduced pressure to
give compound 17b (54 mg, 86%) as an orange solid. M.p. 89 91 8C;
1H NMR (200 MHz, CDCl3): d ˆ 7.16 6.95 (m, 4H; ArH), 5.54 (dd, 1J ˆ
9.6 Hz, 2J ˆ 4.1 Hz, 1H; CH), 4.86 (brs, 1H; CH), 4.76 (brs, 1H; CH), 4.44
(brs, 2H; CH), 4.16 (s, 5H; Cp), 4.09 (m, 1H; OCH2), 3.66 (m, 1H; OCH2),
2.88 (dd, 1J ˆ 13.7 Hz, 2J ˆ 4.1 Hz, 1H; CH2), 2.61 (dd, 1J ˆ 13.7 Hz, 2J ˆ
9.6 Hz, 1H; CH2), 1.26 ppm (t, J ˆ 7.1 Hz, 3H; CH3); 13C NMR (50 MHz,
‡
(70 eV): m/z (%): 253 (6) [M] , 236 (16), 212 (10), 211 (100), 108 (21), 82
(14), 69 (33); elemental analysis calcd (%) for C15H12NOS: C 71.12, H 4.38,
N 5.53, S 12.66; found: C 71.37, H 4.54, N 5.72, S 12.83.
20: 1H NMR (200 MHz, CDCl3): d ˆ 10.63 (brs, 1H; NH), 7.75 (m, 2H;
ArH), 7.49 (m, 2H; ArH), 7.34 ppm (m, 6H; ArH and CH); 13C NMR
ˆ
(50 MHz, CDCl3): d ˆ 280.6 (Cr C), 227.9 (COtrans), 217.16 (COcis), 161.8,
141.4, 138.2, 136.7, 136.2, 134.1, 133.4, 129.9, 128.7, 128.6, 128.1, 123.0 ppm
(aromatic C and CH); IR (CCl4): nÄ ˆ 2054, 1940, 1551, 1472, 1254 cmÀ1
.
Complex 22a: To a solution of pentacarbonyl[(ethoxy)(2-phenylethynyl)-
carbene]chromium(0) (1a, 175 mg, 0.5 mmol) and catechol (55 mg,
0.5 mmol) in anhydrous Et2O (5 mL) at room temperature was added
Et3N (101 mg, 1 mmol). The mixture was stirred until the starting material
had disappeared (48 h, checked by TLC). The solvent was removed in
vacuo, and the reaction mixture was subjected to flash column chromatog-
raphy under argon pressure (SiO2, hexanes) to give carbene complex 22a
ˆ
CDCl3): d ˆ 167.9 (C N), 144.9 (Cq), 142.8 (Cq), 126.3, 125.4, 124.8, 123.4
(aromatic CH), 109.3 (CH), 82.6 (Cq), 71.6 (CH), 71.1 (CH), 69.7 (Cp), 68.3
(CH), 68.2 (CH), 63.9 (OCH2), 36.9 (CH2), 15.1 ppm (CH3); IR (CCl4): nÄ ˆ
1605, 1585, 1472, 1097 cmÀ1; elemental analysis calcd (%) for C21H21FeNO2:
C 67.22, H 5.64, N 3.73; found: C 67.05, H 5.81, N 3.89.
1
Deuteration experiment: A solution of complex 9b (100 mg, 0.18 mmol) in
anhydrous THF (5 mL) and CD3OD (0.5 mL) was heated at 508C under an
argon atmosphere until the starting material had disappeared (24 h,
checked by TLC). The solvent was removed under reduced pressure and
the crude reaction mixture was dissolved in hexanes/Et2O (1:1) and filtered
through a double pad of Celite and SiO2 to give, after removing the solvent,
(115 mg, 50%) as an orange solid. H NMR (300 MHz, CDCl3): d ˆ 7.50
7.47 (m, 2H; ArH), 7.35 7.26 (m, 3H; ArH), 6.72 (s, 4H; ArH), 4.80 (q, J ˆ
7.1 Hz, 2H; OCH2), 4.22 (s, 2H; CH2), 1.12 ppm (t, J ˆ 7.1 Hz, 3H; CH3);
13
ˆ
C NMR (50 MHz, CDCl3): d ˆ 353.8 (Cr C), 223.4 (COtrans), 215.9
(COcis), 146.8, 140.6, 129.0, 128.4, 124.9, 121.6, 115.2, 108.5 (aromatic C and
CH), 78.5 (OCH2), 69.3 (CH2), 14.2 ppm (CH3); IR (CCl4): nÄ ˆ 2064, 1989,
Chem. Eur. J. 2003, 9, 4943 4953
www.chemeurj.org
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4951

M. A. Sierra et al.
FULL PAPER
13
1946, 1485, 1238 cmÀ1; elemental analysis calcd (%) for C22H16CrO8: C
57.40, H 3.50; found: C 57.67, H 3.71.
3H; CH3); C NMR (50 MHz, CDCl3): d ˆ 156.9 (C N), 140.5, 135.3,
128.2, 121.7, 119.4, 107.8 (aromatic C and CH), 37.6 (CH2), 20.7 (CH2),
13.6 ppm (CH3); IR (KBr): nÄ ˆ 3393, 2961, 1636, 1607, 1585, 1414,
1373 cmÀ1; elemental analysis calcd (%) for C14H14N2: C 79.97, H 6.71, N
13.32; found: C 80.06, H 6.62, N 13.25.
ˆ
Complex 22c: To
a solution of complex 1c (165 mg, 0.5 mmol) in
anhydrous THF (5 mL) was added a solution of catechol (55 mg, 0.5 mmol)
and tBuONa (99 mg, 1 mmol) in THF (5 mL) at room temperature. The
mixture was stirred for 24 h. The solvent was evaporated in vacuo and the
reaction mixture was subjected to flash column chromatography under
argon pressure (SiO2, hexanes) to give carbene complex 22c (102 mg,
2-Phenyl-6,7-dihydro-1H-cyclopenta[gh]perimidine (36): Following the
general procedure, from carbene complex 35a (229 mg, 0.24 mmol) after
flash column chromatography on silica gel were obtained perimidine 36
(102 mg, 88%) as a yellow solid, and carbene complex 32a (62 mg, 55%).
Analogously, from tungsten complex 1b (206 mg, 0.31 mmol) were
obtained perimidine 36 as an orange solid (75 mg, 89%) and carbene
complex 32b (83 mg, 67%).
1
46%) as an orange solid. H NMR (300 MHz, CDCl3): d ˆ 6.68 6.59 (m,
4H; ArH), 4.60 (q, J ˆ 7.1 Hz, 2H; OCH2), 3.89 (s, 2H; CH2), 1.09 (t, J ˆ
7.1 Hz, 3H; CH3), 1.01 ppm (s, 9H; 3CH3); 13C NMR (50 MHz, CDCl3):
ˆ
d ˆ 357.9 (Cr C), 223.5 (COtrans), 215.9 (COcis), 148.5 (Cipso), 121.7 (Cq),
1
120.9, 107.3 (CH aromatic), 78.7 (OCH2), 63.4 (CH2), 41.5 (Cq), 24.1 (CH3),
36: M.p. 120 122 8C; H NMR (300 MHz, CDCl3): d ˆ 7.76 7.73 (m, 2H;
14.2 ppm (CH3); IR (CCl4): nÄ ˆ 2062, 1985, 1946, 1489, 1238 cmÀ1
;
ArH), 7.40 7.38 (m, 3H; ArH), 6.82 (d, J ˆ 7.2 Hz, 2H; ArH), 6.38 (brs,
2H; ArH), 3.16 ppm (s, 4H; 2CH2); 13C NMR (50 MHz, [D6]DMSO): d ˆ
elemental analysis calcd (%) for C20H20CrO8: C 54.55, H 4.58. C 57.40;
found: C 54.74, H 4.81.
ˆ
153.5 (C N), 140.7, 135.7, 134.1, 130.7, 128.2, 126.6, 121.2, 119.4 (aromatic C
and CH), 30.2 ppm (2CH2); IR (KBr): nÄ ˆ 3421, 1635, 1593, 1560, 1550,
1458 cmÀ1; elemental analysis calcd (%) for C19H14N2: C 84.42, H 5.22, N
10.36; found: C19H14N2 C 84.29, H 5.13, N 10.47.
Synthesis of 2-substituted perimidines. General procedure:
In a typical experiment, the carbene complex was dissolved in anhydrous
CH2Cl2 and 1,8-diaminonaphtalene was added. The mixture reaction was
stirred at room temperature under an argon atmosphere until the starting
material had disappeared (checked by TLC). The solvent was removed in
vacuo, and the crude reaction mixture was purified by flash column
chromatography on silica gel under argon pressure.
2-[3-(1H-perimidin-2-yl)phenyl]-1H-perimidine (38): Following the gen-
eral procedure, biscarbene complex 37 (160 mg, 0.24 mmol), 1,8-diamino-
naphtalene (80 mg, 0.51 mmol), and CH2Cl2 (15 mL) gave, after 1.5 h,
perimidine 38 (98 mg, 100%) as a dark yellow solid and carbene complex
32a (73 mg, 58%).
2-Phenyl-1H-perimidine (33a)
38: M.p. 2218C (decomp); 1H NMR (300 MHz, CDCl3): d ˆ 10.84 (s, 2H),
8.63 (s, 1H; ArH), 8.18 (d, J ˆ 6.6 Hz, 2H; ArH), 7.72 (t, J ˆ 6.5 Hz, 1H;
ArH), 7.22 7.05 (m, 8H; ArH), 6.76 (d, J ˆ 6.2 Hz, 2H; ArH), 6.60 ppm (d,
Method A: Following the general procedure, a solution of carbene complex
1a (150 mg, 0.43 mmol) and 1,8-diaminonaphtalene (68 mg 0.43 mmol) in
CH2Cl2 (15 mL) gave, after 24 h, perimidine 33a (84 mg, 80%) as an orange
solid and carbene complex 32a (90 mg , 80%).
J ˆ 4.6 Hz, 2H; ArH); 13C NMR (125 MHz, [D6]DMSO): d ˆ 152.4 (C N),
ˆ
144.8, 138.4, 135.1, 133.8, 129.2, 128.9, 128.6, 128.0, 125.4, 121.6, 119.4, 117.8,
114.0, 102.9 ppm (aromatic C and CH); IR (KBr): 3335, 3047, 1634, 1593,
1373 cmÀ1; elemental analysis calcd (%) for C18H18N4: C 81.93, H 4.42, N
13.65; found: C 82.10, H 4.45, N 13.86.
Method B: A solution of carbene complex 1b (150 mg, 0.31 mmol) and 1,8-
diaminonaphtalene (49 mg, 0.31 mmol) in CH2Cl2 (15 mL) gave, after 7.5 h,
perimidine 33a (74 mg, 97%) and carbene complex 32b (112 mg, 91%).
33a: M.p. 187 188 8C; 1H NMR (300 MHz, CDCl3): d ˆ 7.78 (m, 2H;
ArH), 7.44 7.37 (m, 3H; ArH), 7.14 7.04 (m, 4H; ArH), 6.53 ppm (brs,
2H; ArH); 13C NMR (50 MHz, CDCl3): d ˆ 152.7, 135.4, 134.0, 131.0, 128.9,
128.3, 126.2, 121.8, 119.8 ppm; IR (KBr): nÄ ˆ 3051, 1636, 1597, 1566, 1404,
‡
‡
1371 cmÀ1; MS (70 eV): m/z (%): 245 (22) [M‡1] , 244 (100) [M] , 166
(32), 122 (18); elemental analysis calcd (%) for C17H12N2: C 83.58, H 4.95, N
11.47; found: C 83.71, H 4.86, N 11.35.
Acknowledgements
Financial support by the Spanish Ministerio de Ciencia y TecnologÌa (Grant
BQU2001 1283) and the Comunidad Auto noma de Madrid (Grant 07M/
0043/2002) is gratefully acknowledged. J.C.D.A. and I.F. thank the
Ministerio de Educacion y Ciencia (Spain) for a predoctoral fellowship.
¬
2-tert-Butyl-1H-perimidine (33c): Following the general procedure, a
solution of carbene complex 1c (160 mg, 0.48 mmol) and 1,8-diamino-
naphtalene (76 mg, 0.48 mmol) in CH2Cl2 (16 mL) gave, after 24 h,
perimidine 33c as a yellow solid (83 mg, 77%) and carbene complex 32a
(79 mg, 62%).
¬
33c: M.p. 162 163 8C; 1H NMR (300 MHz, CDCl3): d ˆ 7.19 6.98 (m, 4H;
ArH), 6.46 (brs, 2H; ArH), 1.27 ppm (s, 9H; CH3); 13C NMR (50 MHz,
CDCl3): d ˆ 161.7, 140.8, 135.2, 128.1, 121.4, 119.2, 108.2 (aromatic C and
CH), 36.6 (Cq), 28.0 ppm (CH3); IR (CCl4): nÄ ˆ 3452, 2966, 1634, 1599,
1406, 1373 cmÀ1; elemental analysis calcd (%) for C15H16N2: C 80.32, H 7.19,
N 12.49; found: C 80.15, H 7.25, N 12.63.
¬
ƒ
[1] M. A. Sierra, M. J. Mancheno, J. C. Del Amo, I. Fernandez, M.
¬
Gomez-Gallego, M. R. Torres, Organometallics 2003, 22, 384 386.
[2] This is in agreement with the statement of the isolobal analogy
principle. See: a) R. Hoffmann, Science 1981, 211, 995 1002; b) An-
gew. Chem. 1982, 94, 725 739; R. Hoffmann, Angew. Chem. Int. Ed.
Engl. 1982, 21, 711 724.
¬
¬
[3] Reviews: a) J. Barluenga, J. Florez, F. J. Fanƒanas, J. Organomet. Chem.
2001, 624, 5 17; b) A. de Meijere, H. Schirmer, M. Duetsch, Angew.
Chem. 2000, 112, 4142 4162; Angew. Chem. Int. Ed. 2000, 39, 3965
4002; c) R. Aumann, H. Nienaber, Adv. Organomet. Chem. 1997, 41,
163 242.
2-Ferrocenyl-1H-perimidine (33d): Following the general procedure, a
solution of carbene complex 1d (150 mg, 0.32 mmol) and 1,8-diamino-
naphtalene (52 mg, 0.32 mmol) in CH2Cl2 (15 mL) gave, after 24 h,
perimidine 33d (113 mg, 100%) as an orange solid and carbene complex
32a (72 mg, 83%).
[4] Selected reviews in the chemistry and synthetic applications of Fischer
carbene complexes: a) K. H. Dˆtz, H. Fischer, P. Hofmann, F. R.
Kreissel, U. Schubert, K. Weiss, Transition Metal Carbene Complexes,
Verlag Chemie, Deerfield Beach, Florida, 1983; b) K. H. Dˆtz,
Angew. Chem. 1984, 96, 573; Angew. Chem. Int. Ed. Engl. 1984, 23,
587 608; c) W. D. Wulff in Comprehensive Organometallic Chemis-
try II, Vol. 12 (Eds.: E. W. Abel, F. G. A. Stone, G. Wilkinson),
Pergamon, Oxford, 1995, p. 470; d) D. F. Harvey, D. M. Sigano, Chem.
Rev. 1996, 96, 271 288; e) L. S. Hegedus, Tetrahedron 1997, 53, 4105
4128; f) M. A. Sierra, Chem. Rev. 2000, 100, 3591 3637.
33d: M.p. 253 255 8C; 1H NMR (300 MHz, CDCl3): d ˆ 7.14 7.04 (m, 4H;
ArH), 6.62 (d, J ˆ 6.2 Hz, 2H; ArH), 4.87 (brs, 2H; CH), 4.31 (brs, 2H;
CH), 4.19 ppm (s, 5H; Cp); 13C NMR (125 MHz, [D6]DMSO): d ˆ 155.1
ˆ
(C N), 145.3, 138.4, 135.1, 128.9, 127.9, 121.2, 118.3, 117.2, 113.0, 102.0
(aromatic C and CH), 77.1 (Cq Fc), 70.2 (CH Fc), 69.5 (Cp), 67.6 ppm (CH
Fc); IR (KBr): nÄ ˆ 3422, 1636, 1593, 1412, 1373 cmÀ1; MS (EI): m/z (%): 352
‡
(100) [M] , 286 (71), 176 (16), 56 (10); elemental analysis calcd (%) for
C21H16FeN2: C 71.61, H 4.58, N 7.95; found: C 71.78, H 4.44, N 8.03.
2-Propyl-1H-perimidine (33e): Following the general procedure, a solution
of carbene complex 1e (150 mg, 0.48 mmol) and 1,8-diaminonaphtalene
(76 mg, 0.48 mmol) in CH2Cl2 (15 mL) gave, after 24 h, the perimidine 33e
(73 mg, 72%) as a yellow solid and carbene complex 32a (84 mg, 66%).
33e: M.p. 157 159 8C; 1H NMR (300 MHz, CDCl3): d ˆ 7.09 7.00 (m, 4H;
ArH), 6.43 (d, J ˆ 6.8 Hz, 2H; ArH), 4.62 (brs, 1H; NH), 2.26 (t, J ˆ 7.5 Hz,
2H; CH2), 1.70 (sextuplet, J ˆ 7.6 Hz, 2H; CH2), 0.97 ppm (t, J ˆ 7.3 Hz,
¬
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[5] a) M. Gomez-Gallego, M. J. Mancheno, P. RamÌrez, C. Pinar, M. A.
Sierra, Tetrahedron 2000, 56, 4893 4905; b) M. J. Manchenƒo, M. A.
¬
Sierra, M. Gomez-Gallego, P. RamÌrez, Organometallics 1999, 18,
¬
¬
3252 3254; c) J. Barluenga, E. Rubio, J. A. Jo pez-PelegrÌn, M. Tomas,
Angew. Chem. 1999, 111, 1163 1165; Angew. Chem. Int. Ed. 1999, 38,
1091 1093.
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¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
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Reaction of Alkoxyalkynylchromium Carbenes with Aromatic Dinucleophiles
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[6] J. M. Moreto, S. Ricart, K. H. Dˆtz, E. Molins, Organometallics 2001,
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[7] a) F. Camps, A. Llebaria, J. M. Moreto, S. Ricart, J. M. Vinƒas, J. Ros,
¬
R. Yanez, J. Organomet. Chem. 1991, 401, C17 C19V; b) F. Camps, A.
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[8] For reviews on the chemistry of a,b-unsaturated carbene complexes,
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[10] The addition of simple amines to a,b-unsaturated Group 6 carbene
complexes was one of the earlier reactions reported for these classes
of compounds, see: a) E. O. Fischer, F. R. Kreissl, J. Organomet.
Chem. 1972, 35, C47 C51; b) E. O. Fischer, H. J. Kalder, J. Organo-
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[17] The Aumann reaction, namely, the reaction of an alkoxyalkyl Group 6
carbene complex with an aldehyde lacking an a hydrogen, TMSCl,
and Et3N to yield an a,b-unsaturated complex is the standard method
to prepare this kind of compounds. R. Aumann, H. Heinen, Chem.
Ber. 1987, 120, 537 540.
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[11] a) I. Fernandez, M. A. Sierra, M. J. Mancheno, M. Gomez-Gallego, S.
[18] For recent articles about the properties of these compounds, see: a) X.
Bu, L. W. Deady, G. J. Finlay, B. C. Baguley, W. A. Denny, J. Med.
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Ricart, Organometallics 2001, 20, 4304 4306; b) I. Ferna ndez, M. J.
Manchenƒo, M. Gomez-Gallego, M. A. Sierra, Org. Lett. 2003, 5,
1237 1250.
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[12] M. J. Mancheno, P. RamÌrez-Lopez, M. Gomez-Gallego, M. A. Sierra,
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[13] R. Aumann, R. Frˆhlich, S. Kotila, Organometallics 1996, 15, 4842
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[14] Some examples of Group 6 isocyanide complexes: a) M. Balbo-Block,
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c) C.-Y. Liu, D.-Y. Chen, G.-H. Lee, S.-M. Peng, S.-T. Liu, Organo-
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Ed. Engl. 1994, 33, 1315 1331.
Received: May 14, 2003 [F5138]
Chem. Eur. J. 2003, 9, 4943 4953
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¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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