Diarylcarbene complexes of chromium from diazo precursors: synthesis and reaction with electron-rich alkynes

Article abstract of DOI:10.1021/om971086g

By reaction with pentacarbonyl(η²-cis-cyclooctene)chromium(0) (1) various diaryl diazo compounds have been converted into the corresponding chromium carbene complexes 9-15, 18, and 19 which, in certain cases, show extraordinary low-field ¹

Full text of DOI:10.1021/om971086g

Organometallics 1998, 17, 4353-4361
4353
Dia r ylca r ben e Com p lexes of Ch r om iu m fr om Dia zo
P r ecu r sor s: Syn th esis a n d Rea ction w ith Electr on -Rich
Alk yn es1
J u¨rgen Pfeiffer† and Karl Heinz Do¨tz*
Kekule´-Institut fu¨r Organische Chemie und Biochemie, Universita¨t Bonn,
Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany
Received December 10, 1997
By reaction with pentacarbonyl(η2-cis-cyclooctene)chromium(0) (1) various diaryl diazo
compounds have been converted into the corresponding chromium carbene complexes 9-15,
18, and 19 which, in certain cases, show extraordinary low-field 13C NMR shifts (>400 ppm)
for the carbene carbon atoms. The carbene complexes obtained by this “diazo route” undergo
insertion of nucleophilic alkynes such as 1-(diethylamino)-1-propyne or ethoxyethyne into
the metal-carbene bond to yield the R,â-unsaturated carbene complexes 20-28 by C2
homologization.
Sch em e 1. Syn th esis of F isch er -Typ e Ca r ben e
Com p lexes
In tr od u ction
Fischer-type carbene complexes have become valuable
tools for stereoselective carbon-carbon bond formation
over the last two decades.2 Since their invention,
several strategies have been developed for the synthesis
of this class of compounds. The two most important
synthetic pathways are the classical Fischer route3
(Scheme 1, A) and the dianion route, developed by
Semmelhack and Hegedus (Scheme 1, B),4 both based
upon complementary strategies of electrophile/nucleo-
phile combinations starting from the M(CO)6 complexes
(M ) Cr, Mo, W).
Following an earlier approach to C5H5(CO)(L)MdCPh2
(M ) Mn, L ) CO; M ) Cr, L ) NO)5 or to ruthenium
complexes,6 we focused our interest on the preparation
of pentacarbonyl carbene complexes from diazo precur-
sors and group 6 metal complexes (CO)5M-L, bearing
the weakly bonded ligand L (M ) Cr, W; L ) e.g. THF,
cis-cyclooctene). Recently, we reported the synthesis of
the first tricyclic carbene complexes from diazo precur-
sors and pentacarbonyl(η2-cis-cyclooctene)chromium(0)
(1) and their benzannulation reaction with 1-hexyne.7
We extended this route to a variety of aryl diazo
compounds in order to elucidate the scope of this
complementary approach to metal carbenes which we
subsequently exploited in carbon-carbon bond forma-
tion using electron-rich alkynes.
† Present address: Institut fu¨r Anorganische Chemie der Technis-
chen Universita¨t Wien, Getreidemarkt 9/153, A-1060 Wien, Austria.
(1) Reactions of Complex Ligands. 79. Part 78: Pfeiffer, J .; Do¨tz,
K. H. Angew. Chem., Int. Ed. Engl. 1997, 36, 2828.
(2) For reviews see: (a) Do¨tz, K. H.; Fischer, H.; Hofmann, P.;
Kreissl, F. R.; Schubert, U.; Weiss, K. Transition Metal Carbene
Complexes; VCH: Weinheim, Germany, 1983. (b) Do¨tz, K. H. Angew.
Chem., Int. Ed. Engl. 1984, 23, 587. (c) Hegedus, L. S. In Comprehen-
sive Organometallic Chemistry II; Abel, E. W., Stone F. G. A., Wilkinson
G., Eds.; Pergamon Press: Oxford, U.K., 1995; Vol. 12, p 549. (d) Wulff,
W. D. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I.,
Eds.; Pergamon Press: Oxford, U.K., 1991; Vol. 5, p 1065. (e) Wulff,
W. D. In Comprehensive Organometallic Chemistry II; Abel, E. W.,
Stone, F. G. A., Wilkinson G., Eds.; Pergamon Press: Oxford, U.K.,
1995; Vol. 12, p 469. (f) Harvey, D. F., Sigano, D. M. Chem. Rev. 1996,
96, 271. (g) de Meijere, A. Pure Appl. Chem. 1996, 68, 61. (h) Barluenga,
J . Pure Appl. Chem. 1996, 68, 543. (i) Aumann, R.; Nienaber, H. Adv.
Organomet. Chem. 1997, 41, 163.
(3) (a) Fischer, E. O.; Maasbo¨l, A. Angew. Chem., Int. Ed. Engl. 1964,
3, 580. (b) Fischer, E. O.; Selmayr, T.; Kreissl, F. R. Chem. Ber. 1977,
110, 2947. (c) So¨derberg, B. C.; Hegedus, L. S.; Sierra, M. A. J . Am.
Chem. Soc. 1990, 112, 4364.
(4) (a) O¨ fele, K. Angew. Chem., Int. Ed. Engl. 1968, 7, 950. (b) Rees,
C. W.; von Angerer, E. J . Chem. Soc., Chem. Commun. 1972, 420. (c)
Imwinkelried, R.; Hegedus, L. S. Organometallics 1988, 7, 702. (d)
Schwindt, M. A.; Miller, J . R.; Hegedus, L. S. J . Organomet. Chem.
1991, 413, 143. (e) Schwindt, M. A.; Lejon, T.; Hegedus, L. S.
Organometallics 1990, 9, 2814. (f) Semmelhack, M. F.; Lee, G. R.
Organometallics 1987, 6, 1839.
Resu lts a n d Discu ssion
Rea ction of Ar yl Dia zo Com p ou n d s w ith Ch r o-
m iu m a n d Tu n gsten Com p lexes (CO)5M-L (M )
Cr , W; L ) cis-Cycloocten e, THF ). Addition of a
solution of the diaryl diazo compounds 2-5 in PE/CH2-
Cl2 (9/1 v/v; PE ) petroleum ether) to a suspension of
(6) (a) Schwab, P.; France, M. B.; Ziller, J . W.; Grubbs, R. H. Angew.
Chem., Int. Ed. Engl. 1995, 34, 2039. (b) Schwab, P.; Ziller, J . W.;
Grubbs, R. H. J . Am. Chem. Soc. 1996, 118, 100.
(7) Do¨tz, K. H.; Pfeiffer, J . J . Chem. Soc., Chem. Commun. 1996,
895.
(5) (a) Herrmann, W. A., Angew. Chem., Int. Ed. Engl. 1974, 13,
599. (b) Herrmann, W. A. Chem. Ber. 1975, 108, 486. (c) Herrmann,
W. A.; Hubbard, J . L.; Bernal, I.; Korp, J . D.; Haymore, B. L.; Hillhouse,
G. L. Inorg. Chem. 1984, 23, 2978.
S0276-7333(97)01086-8 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 09/04/1998

4354 Organometallics, Vol. 17, No. 20, 1998
Pfeiffer and Do¨tz
Sch em e 2. Syn th esis of Tr icyclic Dia r ylca r ben e
Sch em e 3. Syn th esis of th e P en ta cyclic Ca r ben e
Com p lex 15
Com p lexes 9-14
1
The H NMR spectrum of 15 is characterized by two
AX systems corresponding to the cyclopropyl protons (δ
3
4.29, 5.52; J HH ) 3.33 Hz) and the alkene protons of
3
the spiro-linked indene unit (δ 5.27, 6.76; J HH ) 5.66
Hz). Most indicative for the formation of the cyclopro-
pane skeleton are the 13C NMR signals at 77.08 (s),
67.45 (d, 178.3 Hz), and 47.79 (d, 178.6 Hz) ppm. We
assume an exo stereochemistry of the spirocyclic struc-
ture, since no characteristic upfield shift of the inde-
nylidene arene protons H-6′′ and H-7′′ is observed as
expected for an endo cycloadduct due to anisotropy
arising from the ring current of the indylidene complex
moiety.
Reaction of the unbridged diaryl diazo compounds 16
and 17 with cyclooctene complex 1 gave similar good
yields of diarylcarbene complexes 18 and 19, respec-
tively (Scheme 4).
pentacarbonyl(η2-cis-cyclooctene)chromium(0) (1) in CH2-
Cl2 at -5 °C over 8 h was accompanied by evolution of
nitrogen and afforded intensely colored reaction mix-
tures. Crystallization at -78 °C followed by chromato-
graphic workup on silica gel led to the tricyclic diaryl-
carbene complexes 9-12 in good yields along with the
corresponding azines 9a -12a as the major byproducts
(Scheme 2). Reaction of 9-diazo-(9H)-thioxanthene (6)
also resulted in formation of an intensely blue reaction
mixture, but the corresponding thioxanthenylidene
complex could not be isolated; decomposition occurred
during chromatographic workup, giving only the azine
13a . In the case of 9-diazo-9,10-dihydro-10,10-dimethyl-
anthracene (7), the reaction required temperatures
above +5 °C, the dark red color of the reaction mixture
diminished within a few minutes after the addition of
7 was completed, and again, only the corresponding
azine 14a could be obtained.
The choice of the cis-cyclooctene complex as a source
for the metal fragment is crucial. When 9-diazo-(9H)-
(8) Assignment of the 13C NMR signals was achieved by subtraction
of the resonances known for 1.23 Spectroscopic data obtained after
column chromatographic workup (eluent dichloromethane) for bis[9-
(9H)-th ioxa n th en ylid en e]a zin e (13a ): orange solid; Rf 0.7 (CH2Cl2);
mp 282 °C; 1H NMR (500 MHz, CDCl3) δ 7.32-7.42 (m, 6H, Ar H),
3
7.43-7.48 (m, 4H, Ar H), 7.56 (d, 2H, J HH ) 7.77 Hz, Ar H), 8.10 (d,
3
3
2H, J HH ) 7.93 Hz, Ar H), 8.18 (d, 2H, J HH ) 7.34 Hz, Ar H); 13C
NMR (125.6 MHz, CDCl3) δ 125.20 (2C, Ar Ct), 125.43 (2C, Ar Ct),
126.11 (2C, Ar Ct), 126.70 (2C, Ar Ct), 127.49 (2C, Ar Ct), 127.62 (2C,
Ar Cq), 128.88 (2C, Ar Ct), 129.77 (2C, Ar Ct), 131.86 (2C, Ar Ct), 132.63
(2C, Ar Cq), 132.69 (2C, Ar Cq), 135.09 (2C, Ar Cq), 150.12 (2C, CdN);
FT-IR (KBr) 3057 (m, CH), 1577 (s, CdN), 1544 (s, CdN), 1462 (s),
1435 (s), 1070 (m), 768 (s), 732 (vs) cm-1; MS (EI) m/z (%) 420 (M+,
100), 387 (12), 343 (35), 236 (52), 210 (19), 196 (24), 152 (51); HR-MS
calcd for C26H16N2S2 420.0755, found 420.0760 (M+).
To support the formation of 13 and 14 by NMR
spectroscopy, equimolar amounts of 1 and 6 or 7,
respectively, were dissolved in CDCl3 at -30 °C and
warmed to room temperature for 5 min. After the
(9) Assignment of the 13C NMR signals was achieved by subtraction
of the resonances known for 123 and 14a . Spectroscopic data obtained
after decomposition of 14 and column chromatographic workup (eluent
dichloromethane) for bis(9,10-d ih yd r o-10,10-d im eth yl-9-a n th r a ce-
n ylid en e)a zin e (14a ): orange solid; Rf 0.45 (CH2Cl2); mp 212 °C; 1
H
1
temperature was lowered to -30 °C again, H and 13C
3
NMR (500 MHz, CDCl3) δ 1.71 (s, 12H, CH3), 7.27 (t, 2H, J HH ) 7.55
3
3
NMR spectra of the samples were recorded. Subtraction
of the known resonances of 1, 13a , and 14a , respec-
tively, allowed the unambiguous identification of the
carbene complexes 138 and 14.9
Hz, Ar H), 7.32 (t, 2H, J HH ) 7.43 Hz, Ar H), 7.38 (t, 2H, J HH ) 7.75
Hz, Ar H), 7.39 (t, 2H, 3J HH ) 7.80 Hz, Ar H), 7.58 (d, 2H, 3J HH ) 7.35
Hz, Ar H), 7.64 (d, 2H, 3J HH ) 7.84 Hz, Ar H), 8.06 (d, 2H, 3J HH ) 7.85
Hz, Ar H), 8.19 (d, 2H, J HH ) 7.60 Hz, Ar H); 13C NMR (125.6 MHz,
3
CDCl3) δ 31.59 (4C, CH3), 39.54 (2C, C-10, C-10′), 123.89 (2C, Ar Ct),
124.28 (2C, Ar Ct), 125.55 (2C, Ar Ct), 126.14 (2C, Ar Ct), 126.60 (2C,
Ar Ct), 129.08 (2C, Ar Ct), 129.57 (2C, Ar Cq), 129.85 (2C, Ar Ct), 130.44
(2C, Ar Ct), 134.41 (2C, Ar Cq), 145.99 (2C, Ar Cq), 148.05 (2C, Ar Cq),
149.24 (2C, CdN); FT-IR (KBr) 3057 (m), 2969 (m), 1591 (s, CdN),
1560 (s, CdN), 1476 (s), 1448 (s), 1261 (s), 792 (s), 756 (vs), 669 (s)
Surprisingly, reaction of 1-diazo-(1H)-indene (8) with
cyclooctene complex 1 did not yield the expected 1(1H)-
indenylidene complex; instead, the pentacarbonylchro-
mium carbene complex 15 was formed, arising from the
incorporation of two indene moieties. Spectroscopic data
indicated the formation of a novel pentacyclic carbon
skeleton (Scheme 3).
cm-1; MS (EI) m/z (%) 440 (M+, 66), 425 (M+ - CH3, 100), 410 (M+
-
2CH3, 40), 395 (M+ - 3CH3, 18), 246 (22), 207 (37), 191 (28), 149 (25);
HR-MS calcd for C32H28N2 440.2252, found 440.2254 (M+). Anal. Calcd
for C32H28N2: C, 87.24; H, 6.41; N, 6.36. Found: C, 87.06; H, 6.35; N,
6.24.

Diarylcarbene Complexes of Chromium
Organometallics, Vol. 17, No. 20, 1998 4355
Sch em e 4. Syn th esis of Dia r ylca r ben e Com p lexes
18 a n d 19
complex 9 and the spiro compound 15 show upfield
chemical shifts for the carbene carbon atom compared
to those found for the unbridged pentacarbonyl(diphe-
nylcarbene)chromium(0) (399.4 ppm).12 This result
reflects the rigid, almost planar fluorenylidene and
indenylidene moiety, respectively, resulting in an opti-
mal overlap of the arene π orbital and the p orbital at
the carbene carbon atom. In contrast, this interaction
is hampered in carbene complexes 11 and 12 bearing a
nonplanar seven-membered central carbocycle.13 Thus,
to the best of our knowledge, these two complexes
exhibit the largest downfield shifts observed for metal-
coordinated carbene carbon atoms so far (419.1 and
404.2 ppm, respectively).
In ser tion Rea ction of 1-(Dieth yla m in o)-1-p r o-
p yn e w ith 9-12, 15, 18, a n d 19. Insertion of nucleo-
philic alkynes such as ynamines and ynol ethers into a
metal-carbene bond is a straightforward approach to
R,â-unsaturated carbene complexes.14 To explore the
reactivity of the carbene complexes obtained from diazo
precursors, 9-12, 15, 18, and 19 were treated with
equimolar amounts of the ynamine Et2NCtCMe. Reac-
tion of 9, 10, and 15 occurred smoothly at -60 °C in
CH2Cl2 within 2 min, whereas the unbridged diarylcar-
bene complexes 18 and 19 required temperatures above
-20 °C. This reduced reactivity is presumably a
consequence of the free rotation of the aryl substituents,
hampering the approach of the ynamine. Surprisingly,
reaction of 11 and 12 with 1-(dimethylamino)-1-propyne
did not occur below room temperature, and even under
these conditions, the dibenzocycloheptenylidene complex
12 gave only a low yield, whereas no insertion product
from 11 could be obtained at all. Chromatographic
workup on silica gel afforded the R,â-unsaturated ami-
nocarbene complexes 20-25 in moderate to good yields
(Scheme 5).
The ynamine insertion into the chromium-carbene
carbon bond of complexes bearing unsymmetric carbene
ligands such as 15 and 18 results in the formation of
diastereomers differing in the configuration of the newly
formed CdC bond. The diastereomers of 23 (ratio 3.4:
1) could be separated by fractional crystallization from
hexane at -78 °C, whereas in the case of 24 (ratio 5.6:
1), only the major isomer could be obtained as a
diastereomerically pure sample. According to previous
work on the stereoselectivity of the ynamine inser-
tion,14d,15 the major isomers are presumed to adopt the
E configuration.
Ta ble 1. 13C NMR Ch em ica l Sh ifts for th e
Ca r ben e a n d Ca r bon yl Ca r bon Atom s in 9-15, 18
a n d 19
compd
δCO
δCO
δC
cis
trans
carbene
9
10
11
12
13
14
15
18
19
217.45
218.55
215.22
214.53
215.49
216.73
216.56
216.49
216.71
238.78
230.03
234.74
237.37
235.39
233.65
232.85
234.24
233.47
361.29
314.94
419.14
404.24
357.80
378.64
370.89
385.77
380.18
fluorene (2) and 9-diazo-(9H)-xanthene (3) were reacted
with (CO)5Cr-THF, the fluorenylidene complex 9 could
be obtained only in poor yield (8%), whereas reaction of
3 only gave azine 10a . The reactions of 2 and 3 with
the analogous tungsten complexes (CO)5W-L (L ) cis-
cyclooctene, THF) did not afford the expected tungsten
carbene complexes at all; instead, the azines 9a and 10a
were obtained in 81-88% yield.
The formation of the carbene complexes 9-15, 18, and
19 can be rationalized either in terms of an electrophilic
attack of the Lewis acid Cr(CO)5 at the diazo carbon
atom followed by loss of molecular nitrogen or by side-
on10 or end-on11 coordination of the diazo compound at
the Cr(CO)5 fragment followed by metal migration.7
The spectroscopic properties and thermal stabilities
of the carbene complexes 9-15 depend on the ability of
the carbene substituents to stabilize the electron defi-
ciency at the carbene carbon atom. This capability is
controlled by the arene-bridging, electron-releasing het-
eroatom as well as by the geometry of the central ring
system bearing the pentacarbonylmetal fragment and
is reflected by the 13C NMR shifts (Table 1).
The 1H NMR spectra of carbene complexes 20-25 are
characterized by a fine structure (doublets of quartets)
of the NCH2 proton resonances, which adopt the shape
of a pseudosextet due to the fact that the coupling
(12) Fischer, E. O.; Held, W.; Kreissl, F. R.; Frank, A.; Huttner, G.
Chem. Ber. 1977, 110, 656.
(13) Crystal structures are known for the analogous ketones: (a)
Oddon, Y.; Darbon, N.; Reboul, J . P.; Cristeau, B.; Soyfer, J . C.; Pe`pe
G. Acta Crystallogr. 1984, C40, 524. (b) Reboul, J . P.; Soyfer, J . C.;
Cristeau, B.; Darbon, N.; Oddon, Y.; Pe`pe, G. Acta Crystallogr. 1983,
C39, 600.
(14) (a) Do¨tz, K. H.; Kreiter, C. G. J . Organomet. Chem. 1975, 99,
309. (b) Do¨tz, K. H.; Kreiter, C. G. Chem. Ber. 1976, 109, 2026. (c)
Do¨tz, K. H. Chem. Ber. 1977, 110, 78. (d) Do¨tz, K. H.; Pruskil, I. J .
Organomet. Chem. 1977, 132, 115. (e) Aumann, R.; Heinen, H.;
Hinterding, P.; Stra¨ter, N.; Krebs, B. Chem. Ber. 1991, 124, 1229. (f)
Aumann, R.; Heinen, H.; Goddard, R.; Kru¨ger, C. Chem. Ber. 1991,
124, 2587. (g) Do¨tz, K. H.; Ehlenz, R.; Paetsch, D. Angew. Chem., Int.
Ed. Engl. 1997, 36, 2376.
Accordingly, the xanthenylidene complex 10 can be
regarded as a vinylogous aryloxycarbene complex. As
a consequence, 10 can be handled at room temperature
and benzannulation requires gentle warming above
ambient temperature (40 °C).7 The fluorenylidene
(10) Nakamura, A.; Yoshida, T.; Cowie, M.; Otsuka, S.; Ibers, J . A.
J . Am. Chem. Soc. 1977, 99, 2108.
(11) (a) Herrmann, W. A. J . Organomet. Chem. 1975, 84, C25. (b)
Dahl-Schramm, K.; Ibers, J . A. J . Am. Chem. Soc. 1978, 100, 2932.
(15) Pruskil, I. Ph.D. Thesis, TU Munich, 1980.

4356 Organometallics, Vol. 17, No. 20, 1998
Pfeiffer and Do¨tz
Sch em e 5. Yn a m in e In ser tion Rea ction s of
Ca r ben e Com p lexes 9, 10, 12, 15, 18, a n d 19
F igu r e 1. Stereochemical preference in the ynamine
insertion reaction with 22.
2
constants J HH are almost twice as large as the coupling
3
constants J HH. This fine structure indicates the dias-
tereotopy of the NCH2 protons due to the presence of
atropisomers as a consequence of a restricted rotation
along the R-Calkene-Ccarbene bond14d,16 which may be
separable in certain cases.17 Due to the nonplanarity
of the central seven-membered ring,18 the NMR spectra
of 22 show the presence of two diastereomers (ratio 4.6:
1) which, however, could not be separated.
As a result of the planarity of the fluorenylidene
system and the conformational flexibility of the xan-
thene moiety, respectively,19 the atropisomers of carbene
complexes 20 and 21 represent pairs of atropisomeric
enantiomers. When solutions of 20 and 21 were sub-
jected to chiral HPLC (Chiracel OD), equal amounts of
both enantiomers were observed in both cases.20
The preference of one diastereomer of 22 over the
other may be explained in terms of the tilted tricyclic
ligand in 12 favoring the approach of the ynamine from
the lower (convex) face. As a result, the thermodynami-
cally less stable isomer bearing the arene rings and the
(CO)5Cr fragment syn to each other is formed as the
major diastereomer, as established by NMR-spectros-
copy (Figure 1). A mixture of the syn and anti isomers
was warmed in a NMR tube to 50 °C, and 1H NMR
F igu r e 2. Stereoisomers of 26 at -40 °C.
spectra were recorded every 10 min to monitor the
isomer ratio. Within 110 min the isomer ratio changed
from 4.6:1 to 0.94:1. After this period, integration of
the signals became inaccurate due to decomposition.
In ser tion Rea ction of Eth oxyeth yn e w ith 9, 10,
a n d 15. To explore the insertion of the less nucleophilic
ynol ethers into the metal-carbene carbon bond of
polycyclic arylcarbene complexes, compounds 9, 10, and
15, respectively, were treated with equimolar amounts
of ethoxyethyne. The reactions were run in CH2Cl2 at
-20 °Csreflecting the lower reactivity of the ynol ether
compared to that of 1-(diethylamino)-1-propynesand led
to reddish brown solutions within 2 h. Chromato-
graphic workup on silica gel afforded the R,â-unsatur-
ated alkoxycarbene complexes 26-28 as brown oils in
moderate yields (Scheme 6). Again, reaction with
spiroindene complex 15 afforded two diastereomers
(ratio 1.6:1) the major of which could be obtained in pure
form by fractional crystallization.
(16) (a) Fischer, E. O.; Aumann, R. Chem. Ber. 1968, 101, 954. (b)
Fischer, E. O.; Brunner, H.; Doppelberger, J .; Lappus, M. J . Orga-
nomet. Chem. 1976, 112, 66.
(17) Kretschik, O. Ph.D. Thesis, Universita¨t Bonn, 1996.
(18) The nonplanarity of the dibenzo[a,d]cycloheptenylidene system
in the solid state has been established by several X-ray crystal
structure analyses, e.g. the ketone.13 The temperature for the inversion
of this tricyclic carbon skeleton has been found to be as high as 250
°C; see: Scho¨nberg, A.; Sodke, U.; Praefcke, K. Chem. Ber. 1969, 102,
1453. The separation of enantiomersswhich are conformationally
stable at room temperaturesresulting from the nonplanarity of the
dibenzo[a,d]cycloheptenylidene system has been reported; see: Eb-
nother, A.; J ucker, E.; Stoll, A. Helv. Chim. Acta 1965, 48, 1237.
(19) (a) Aroney, M. J .; Hoskins, G. M.; LeFevre, R. J . Chem. Soc. B
1969, 980. (b) McKinley, S. V.; Grieco, P. A.; Young, A. E.; Freedman,
H. H. J . Am. Chem. Soc. 1970, 92, 5900.
(20) Retention times: 20, 7.95, 9.83 min; 21, 6.75, 7.98 min.

Diarylcarbene Complexes of Chromium
Organometallics, Vol. 17, No. 20, 1998 4357
Sch em e 6. Yn ol Eth er In ser tion Rea ction s of
Ca r ben e Com p lexes 9, 10, a n d 15
metal carbene allows insertion reactions of nucleophilic
alkynes and has been exploited in the synthesis of
tricyclic exo-alkenyl carbene complexes, some of which
are promising precursors for tetracyclic arenes with a
defined substitution pattern.22
Exp er im en ta l Section
All operations were performed using flame-dried glassware
and an atmosphere of argon. Solvents (petroleum ether, bp
40-60 °C) were dried by distillation from sodium hydride or
calcium hydride and saturated with argon. Silica gel (Merck,
0.063-0.200 mm) was degassed under high vacuum and stored
under argon. The separation of the atropisomers of 20 and
21 was performed with a Knauer HPLC system using a
Chiracel OD column (4.6 × 250 mm) from Daicel Chemical
Industries Ltd. (λdetector 400 nm, n-hexane/2-propanol (9/1 v/v)).
Pentacarbonyl(η2-cis-cyclooctene)chromium(0) (1)23 and -tung-
sten(0) (1a ),24 9-diazo-(9H)-fluorene (2),25 9-diazo-(9H)-xan-
thene (3),26 5-diazo-(5H)-dibenzo[a,d]cycloheptane (4),27 5-diazo-
(5H)-dibenzo[a,d]cycloheptene (5),28 9-diazo-(9H)-thioxanthene
(6),26 9-diazo-9,10-dihydro-10,10-dimethylanthracene (7),29 1-di-
azo-(1H)-indene (8),30 (4-methoxyphenyl)phenyldiazomethane
(16),31 and bis(4-methoxyphenyl)diazomethane (17)31 were
prepared according to the literature.
Gen er a l P r oced u r e for th e Syn th esis of th e Ca r ben e
Com p lexes 9-15, 18, a n d 19. A solution of 5 mmol of
the diazo compounds 2-8, 16, and 17 (for the preparation of
15: 10 mmol t 1.42 g of 8) in 100 mL of petroleum ether/
dichloromethane (9/1 v/v) was added over 8 h to a stirred
suspension of 5 mmol (1.51 g) of pentacarbonyl(η2-cis-cy-
clooctene)chromium(0) (1) in 10 mL of dichloromethane cooled
to -10 °C. The workup was performed according to one of
the following procedures.
P r oced u r e A. The reaction mixture was cooled to -78 °C
for 4 days. Then the precipitate was filtered off at the same
temperature and washed with 40 mL of petroleum ether/
dichloromethane (2/1 v/v) at -20 °C, leaving most of the azines
undissolved. The washing liquid was adsorbed on 50 mL of
silica gel at -40 °C. Purification by column chromatography
(-40 °C, SiO2, eluents petroleum ether/dichloromethane (2/1)
for 9 and 11-15, petroleum ether/chloroform (2/1) for 10)
afforded the carbene complexes. The mother liquors resulting
from the crystallization were also adsorbed on 50 mL of silica
gel at -40 °C and separated by column chromatography (-40
°C, SiO2; eluent petroleum ether/dichloromethane (6/1)).
P r oced u r e B. The reaction mixture was adsorbed on 50
mL of silica gel at -25 °C and purified by column chromatog-
raphy (-25 °C, SiO2; eluent petroleum ether/dichloromethane
(2/1)).
NMR spectra of 26 and 27 recorded at -40 °C allowed
us to detect E/Z isomers due to restricted rotation along
the carbene carbon-oxygen bond under these conditions
(E/Z ratio: for 26, 2.4:1; for 27, 1.2:1). According to
previous work,21 the major isomers are presumed to
adopt the E configuration. In both cases, the CH2
protons of the major isomers are magnetically inequiva-
lent, indicating the presence of atropisomeric enanti-
omers (Figure 2) due to the restricted rotation around
the R-Calkene-Ccarbene bond.
P en ta ca r bon yl[9(9H)-flu or en ylid en e]ch r om iu m (0) (9).
The workup was carried out according to procedure A. Wash-
ing of the precipitate yielded 0.09 g (0.25 mmol, 10% based on
2) of the bis[9-(9H)-fluorenylidene]azine compound 9a as an
Con clu sion s
(22) (a) Do¨tz, K. H.; Pruskil, I. Chem. Ber. 1978, 111, 2059. (b) Do¨tz,
K. H.; Neugebauer, D. Angew. Chem., Int. Ed. Engl. 1978, 17, 851.
(23) Grevels, F. W.; Skibbe, V. J . Chem. Soc., Chem. Commun. 1984,
681.
(24) Dalla Riva Toma, J . M.; Toma, P. H.; Fanwick, P. E.; Bergstrom,
D. E.; Byrn, S. R. J . Crystallogr. Spectrosc. Res. 1993, 23, 41.
(25) Scho¨nberg, A.; Awad, W.; Latif, N. J . Chem. Soc. 1951, 1368.
(26) (a) Lapin, S. C.; Schuster, G. B. J . Am. Chem. Soc. 1985, 107,
4243. (b) Holton, T. C. Ph.D. Thesis, The Ohio State University, 1970.
(27) Moritani, I.; Murahashi, S.-I.; Yoshinaga, K.; Ashitaka, H. Bull.
Chem. Soc. J pn. 1967, 40, 1506.
(28) Murahashi, S.-I;, Moritani, I.; Nishino, M. Tetrahedron 1971,
27, 5131.
(29) (a) Davies, M. A.; Winthrop, S. O;, Thomas, R. A.; Herr, F.;
Charest, M.-P.; Gaudry, R. J . Med. Chem. 1964, 7, 8. (b) Wright, B.
B.; Platz, M. S. J . Am. Chem. Soc. 1984, 106, 4175.
(30) Rewicki, D.; Tuchscherer, C. Angew. Chem., Int. Ed. Engl.
1972, 11, 44.
The diazo route based on a cis-η2-cyclooctene-stabi-
lized pentacarbonylchromium fragment provides a
straightforward approach to carbonyl complexes bearing
oligocyclic carbene ligands. This methodology allows
the synthesis of either bridged or nonbridged (di)-
arylcarbene complexes, the electrophilicity of which can
be controlled by the bridge connecting the aryl substit-
uents. Nonplanar tricyclic systems such as the diben-
zocycloheptylidene complex 11 exhibit unprecedented
downfield shifts for the carbene carbon atoms in the 13
C
NMR spectra. The electrophilic nature of this type of
(21) Kreiter, C. G.; Fischer, E. O. Angew. Chem., Int. Ed. Engl. 1969,
8, 761.
(31) Back, C.; Praefke, K. Chem. Ber. 1979, 112, 2744.

4358 Organometallics, Vol. 17, No. 20, 1998
Pfeiffer and Do¨tz
orange solid. The workup of the washing liquids yielded 0.89
g (2.5 mmol, 50%) of 9 as a dark green solid followed by 0.03
g (0.09 mmol, 4% based on 2) of 9,9′-bis(fluorenylidene) species
9b as a dark red solid. The workup of the mother liquor
yielded 0.24 g (0.8 mmol, 16%) of 1 followed by 0.3 g (0.85
mmol, 17%) of 9.
12: black solid, 1.28 g (67%); Rf 0.6 (petroleum ether/CH2-
Cl2 2/1); 1H NMR (500 MHz, CDCl3, 253 K)32 δ 6.88 (s, 2H,
H-10, H-11), 7.10-7.55 (m, 8H, Ar H); 13C NMR (100.6 MHz,
CDCl3, 253 K) δ 119.58 (2C, Cq), 123.28 (2C), 126.98 (2C),
128.01 (2C), 128.29 (2C), 131.86 (2C) (10C, Ar Ct, C-10 and
C-11), 162.68 (2C, Cq), 214.53 (4C, COcis), 237.37 (1C, COtrans),
404.24 (1C, Ccarbene); FT-IR (hexane) (νCdO) 2068 (m, A1), 1987
(vs, E), 1958 (m, A1) cm-1; MS (EI) m/z (%) 354 (M+ - CO, 5),
298 (M+ - 3CO, 8), 270 (M+ - 4CO, 12), 242 (M+ - 5CO, 21),
190 (M+ - 5CO - Cr, 100), 52 (Cr+, 41); HR-MS calcd for
9: dark green solid, 1.19 g (67%); Rf 0.45 (petroleum ether/
1
3
CH2Cl2); H NMR (500 MHz, CDCl3, 253 K) δ 7.26 (d, J HH
)
3
7.49 Hz, 2H, H-4, H-5), 7.29 (t, J HH ) 7.89 Hz, 2H, Ar H),
3
3
7.35 (t, J HH ) 7.32 Hz, 2H, Ar H), 8.05 (d, J HH ) 7.55 Hz,
2H, H-1, H-8); 13C NMR (100.6 MHz, CDCl3, 253 K) δ 118.06
(2C, Ar C), 128.95 (2C, Ar C), 132.51 (2C, Ar C), 133.66 (2C,
Ar C), 136.52 (2C, C-4a, C-4b), 148.21 (2C, C-8a, C-9a), 217.45
(4C, COcis), 238.78 (1C, COtrans), 361.29 (1C, Ccarbene); FT-IR
C
19H10CrO4 353.9984, found 353.9944 (M+ - CO).
exo-P en tacar bon yl{spir o-(1′′H)-in den o-(1′′,1′)cyclopr op-
[2′,3′-b]-1(1H)-in d ylid en e}ch r om iu m (0) (15). The workup
was carried out according to procedure A. The workup of the
precipitate yielded 0.86 g (2.04 mmol, 41%) of 15 as a black
solid. The workup of the mother liquor afforded 0.23 g (0.76
mmol, 15%) of 1 followed by 0.12 g (0.28 mmol, 6%) of 15.
15: black solid, 0.98 g (47%); Rf 0.7 (petroleum ether/CH2-
(hexane) (νCdO) 2060 (m, A1), 1972 (vs, E), 1946 (sh, A1) cm-1
;
MS (EI) m/z (%) 356 (M+, 27), 328 (M+- CO, 100), 300 (M+-
2CO, 17), 272 (M+- 3CO, 1), 216 (M+- 5CO, 54), 164 (M+-
5CO - Cr, 5), 52 (Cr+, 5); HR-MS calcd for C18H8CrO5
355.9777, found 355.9758 (M+).
1
3
Cl2 2/1); H NMR (250 MHz, CDCl3, 253 K) δ 4.29 (d, J HH
)
3
P en t a ca r b on yl[9(9H )-xa n t h en ylid en e]ch r om iu m (0)
(10). The workup was carried out according to procedure A.
Washing of the precipitate yielded 0.45 g (1.16 mmol, 46%
based on 3) of the bis[9-(9H)-xanthenylidene]azine species 10a
as an orange solid. The workup of the washing solutions
afforded 0.84 g (2.25 mmol, 45%) of 10 as a black solid. The
workup of the mother liquor gave 0.67 g (2.2 mmol, 44%) of 1
followed by 0.15 g (0.4 mmol, 8%) of 10.
3.33 Hz, 1H, H-3), 5.27 (d, J HH ) 5.66 Hz, 1H, H-2′′), 5.51 (d,
3J HH ) 3.33 Hz, 1H, H-2), 6.76 (d, J HH ) 5.66 Hz, 1H, H-3′′),
3
7.28-7.33 (m, 3H, Ar H), 7.40-7.45 (m, 2H, Ar H), 7.54-7.60
(m, 2H, Ar H), 8.46 (d, J HH ) 8.29 Hz, 1H, Ar H); 13C NMR
3
1
(125.6 MHz, CDCl3, 263 K) δ 47.54 (d, J CH ) 178.3 Hz, 1C,
C-3), 67.19 (d, J CH ) 178.6 Hz, 1C, C-2), 77.08 (s, 1 C, C-1′),
1
118.24 (d), 121.16 (d), 124.13 (d), 124.95 (d), 127.37 (d), 128.00
(d), 130.72 (d), 132.54 (d), 133.09 (d), 135.01 (d) (10C, Ar Ct,
C-2′′ and C-3′′), 142.02 (1C, Cq), 144.05 (1C, Cq), 144.73 (1C,
Cq), 153.77 (1C, Cq), 216.56 (4C, COcis), 232.85 (1C, COtrans),
370.89 (1C, Ccarbene); FT-IR (hexane) (νCdO) 2056 (m, A1), 1976
(m, A1), 1964 (s, E) cm-1; MS (EI) m/z (%) 420 (M+, 1), 392
(M+ - CO, 1), 364 (M+ - 2CO, 1), 336 (M+ - 3CO, 2), 308 (M+
- 4CO, 3), 280 (M+ - 5CO, 18), 228 (M+ - 5CO - Cr, 100),
115 (C9H7+, 14), 52 (Cr+, 46); HR-MS calcd for C23H12CrO5
420.0090, found 420.0090 (M+).
10: black solid, 0.99 g (54%); Rf 0.55 (petroleum ether/CHCl3
1
1/1); mp 83 °C dec; H NMR (500 MHz, CDCl3, 253 K) δ 7.68
(d, 3J HH ) 8.60 Hz, 2H, H-4, H-5), 7.69 (t, 3J HH ) 8.65 Hz, 2H,
3
3
Ar H), 7.90 (t, J HH ) 7.54 Hz, 2H, Ar H), 9.19 (d, J HH ) 8.44
Hz, 2H, H-1, H-8); 13C NMR (100.6 MHz, CDCl3, 253 K) δ
118.94 (2C, Ar C), 125.14 (2C, Ar C), 136.85 (2C, Ar C), 140.42
(2C, Ar C), 140.65 (2C, Cq), 141.01 (2C, Cq), 218.55 (4C, COcis),
230.03 (1C, COtrans), 314.94 (1C, Ccarbene); FT-IR (hexane) (νCdO
)
2045 (m, A1), 1945 (vs, E), 1903 (sh, A1) cm-1; MS (EI): m/z
(%) 372 (M+, 8), 344 (M+ - CO, 4), 316 (M+ - 2CO, 3), 260
(M+ - 4CO, 5), 232 (M+ - 5CO, 38), 180 (M+ - 5CO - Cr,
100), 52 (Cr+, 5); HR-MS calcd for C18H8CrO6 371.9726, found
371.9702 (M+). Anal. Calcd for C18H8CrO6: C, 58.08; H, 2.17.
Found: C, 57.84; H, 2.41.
P en ta ca r bon yl{5(5H)-d iben zo[a ,d ]cycloh ep tylid en e}-
ch r om iu m (0) (11). The workup was carried out according
to procedure A. The workup of the precipitate yielded 0.6 g
(1.56 mmol, 31%) of 11 as a black solid. The workup of the
mother liquor gave 0.54 g (1.8 mmol, 36%) of 1 followed by
0.43 g (1.12 mmol, 22%) of 11.
11: black solid, 1.14 g (53%); Rf 0.65 (petroleum ether/CH2-
Cl2 1/1); 1H NMR (500 MHz, CDCl3, 253 K)32 δ 3.10 (s, 4H,
H-10, H-11), 7.00-7.40 (m, 8H, Ar H); 13C NMR (125.6 MHz,
CDCl3, 253 K) δ 32.39 (2C, C-10, C-11), 123.92 (2C, Ar C),
125.04 (2C, Cq), 125.43 (2C, Ar C), 128.53 (2C, Ar C), 128.92
(2C, Ar C), 165.05 (2C, Cq), 215.22 (4C, COcis), 234.74 (1C,
COtrans), 419.14 (1C, Ccarbene); FT-IR (hexane) (νCdO) 2066 (m,
A1), 1981 (vs, E), 1960 (m, A1) cm-1; MS (EI) m/z (%) 356 (M+
P en t a ca r b on yl[(4-m et h oxyp h en yl)p h en ylca r b en e]-
ch r om iu m (0) (18). The workup according to procedure B
yielded 0.38 g (1.27 mmol, 25%) of 1 followed by 1.26 g (3.25
mmol, 65%) of 18.
18: black solid, 1.26 g (65%); Rf 0.4 (petroleum ether/CH2-
Cl2 2/1); 1H NMR (500 MHz, CDCl3, 253 K) δ 3.91 (s, 3H,
3
3
OCH3), 6.81 (d, J HH ) 7.45 Hz, 2H, H-2′, H-6′), 6.91 (d, J HH
3
) 8.79 Hz, 2H, H-3, H-5), 7.27 (t, J HH ) 7.45 Hz, 1H, H-4′),
3
3
7.35 (t, J HH ) 7.45 Hz, 2H, H-3′, H-5′), 7.43 (d, J HH ) 8.79
Hz, 2H, H-2, H-6); 13C NMR (125.6 MHz, CDCl3, 253 K) δ 55.76
(1C, OCH3), 113.15 (2C, C-3, C-5), 121.23 (2C, Ar C), 127.13
(2C, Ar C), 127.77 (1C, C-4′), 132.06 (2C, Ar C), 153.93 (1C,
C-4), 165.02, 165.22 (2C, C-1, C-1′), 216.49 (4C, COcis), 234.24
(1C, COtrans), 385.77 (1C, Ccarbene); FT-IR (hexane) (νCdO) 2055
(m, A1), 1966 (vs, E), 1956 (sh, A1) cm-1; MS (EI) m/z (%) 360
(M+ - CO, 24), 304 (M+ - 3CO, 22), 276 (M+ - 4CO, 74), 248
(M+ - 5CO, 79), 196 (M+ - 5CO - Cr, 100), 181 (M+ - 5CO
- Cr - CH3, 72), 165 (M+ - 5CO - Cr - OCH3, 25); HR-MS
calcd for C18H12CrO5 360.0090, found 360.0085 (M+ - CO).
P en t a ca r b on yl[b is(4-m et h oxyp h en yl)ca r b en e]ch r o-
m iu m (0) (19). Workup according to procedure B yielded 0.36
g (1.2 mmol, 24%) of 1 followed by 1.37 g (3.3 mmol, 66%) of
19.
- CO, 1), 300 (M+ - 3CO, 1), 272 (M+ - 4CO, 3), 244 (M+
-
5CO, 2), 192 (M+ - 5CO - Cr, 60), 191 (M+ - 5CO - Cr - H,
100), 165 (C13H9+, 40), 52 (Cr+, 9); HR-MS calcd for C19H12
-
CrO4 356.0141, found 356.0142 (M+ - CO).
19: black solid, 1.37 g (66%); Rf 0.3 (petroleum ether/CH2-
Cl2 2/1); 1H NMR (250 MHz, CDCl3, 253 K) δ 3.95 (s, 6H,
OCH3), 6.85 (d, 3J HH ) 7.28 Hz, 4H, H-3, H-5, H-3′, H-5′), 7.15
P en tacar bon yl{5(5H)-diben zo[a ,d]cycloh epten yliden e}-
ch r om iu m (0) (12). The workup was carried out according
to procedure A. The workup of the precipitate yielded 1.11 g
(2.9 mmol, 58%) of 12 as a black solid and 0.04 g of an
unidentified cis-tetracarbonyl chromium complex. The workup
of the mother liquor afforded 0.34 g (1.13 mmol, 23%) of 1
followed by 0.17 g (0.45 mmol, 9%) of 12.
3
(d, J HH ) 7.28 Hz, 4H, H-2, H-6, H-2′, H-6′); 13C NMR (62.5
MHz, CDCl3, 253 K) δ 55.62 (2C, OCH3), 112.47 (4C, C-3, C-5,
C-3′, C-5′), 129.48 (4C, C-2, C-6, C-2′, C-6′), 157.34 (2C, C-4,
C-4′), 162.78 (2C, C-1, C-1′), 216.71 (4C, COcis), 233.47 (1C,
COtrans), 380.18 (1C, Ccarbene); FT-IR (hexane) (νCdO) 2051 (m,
A1), 1961 (vs, E), 1949 (sh, A1) cm-1; MS (EI) m/z (%) 390 (M+
- CO, 15), 334 (M+ - 3CO, 14), 306 (M+ - 4CO, 9), 278 (M+
- 5CO, 12), 226 (M+ - 5CO - Cr, 39), 211 (M+ - 5CO - Cr
- CH3, 41), 80 (CrCO+, 100), 52 (Cr+, 5); HR-MS calcd for
(32) No NMR spectra free of impurities could be obtained for
compounds 11, 12, and 22. The thermolability of 11 and 12 requires
temperatures below -40 °C during workup, preventing sufficient
removal of the solvent; in the case of 22, traces of the solvent remained
in the samples due to the oily to waxy consistence.
C
19H14CrO6 390.0195, found 390.0203 (M+ - CO).

Diarylcarbene Complexes of Chromium
Organometallics, Vol. 17, No. 20, 1998 4359
3
3
NMR Sp ectr oscop ic Evid en ce for th e Ca r ben e Com -
p lexes 13 a n d 14. A 0.1 mmol amount of diazo compound 6
or 7, respectively, and 0.1 mmol (0.03 g) of pentacarbonyl(η2-
cis-cyclooctene)chromium(0) (1) were dissolved in 4 mL of
CDCl3 at -30 °C. The mixture was warmed to room temper-
ature, stirred for 5 min, and cooled to -30 °C again. A sample
NCHH), 7.02 (d, J HH ) 6.43 Hz, 2H, Ar H), 7.13 (t, J HH
)
)
3
7.43 Hz, 2H, Ar H), 7.16-7.30 (m, 3H, Ar H), 7.54 (d, J HH
7.83 Hz, 1H, Ar H); 13C NMR (100.6 MHz, CDCl3) δ 12.94 (1C,
NCH2CH3), 13.17 (1C, NCH2CH3), 20.60 (1C, CH3), 48.11 (1C,
NCH2), 52.84 (1C, NCH2), 112.99 (1C, C-9′), 116.47 (1C, Ar
C), 116.50 (1C, Ar C), 122.52 (1C, Ar C), 122.63 (1C, Ar C),
127.17 (1C, Ar C), 128.11 (1C, Ar C), 128.16 (1C, Ar C), 128.47
(1C, Ar C), 124.18, 125.03 (2C, C-8a′, C-9a′), 140.39 (1C, C-1),
152.72, 154.11 (2C, C-4a′, C-4b′), 216.67 (4C, COcis), 222.38 (1C,
COtrans), 273.67 (1C, Ccarbene); FT-IR (hexane) (νCdO) 2051 (m,
A1), 1973 (w, B), 1937 (vs, E), 1911 (s, A1) cm-1; FT-IR (KBr)
2965 (m, νC-H), 1523, 1450 (m, νCdC), 1261 (s, νC-O-C), 1103,
1023 (s), 798 (s), 754 (m), 671 (m) cm-1; MS (EI) m/z (%) 427
(M+ - 2CO, 12), 399 (M+ - 3CO, 4), 371 (M+ - 4CO, 17), 343
(M+ - 5CO, 33), 291 (M+ - 5CO - Cr, 48), 276 (M+ - 5CO -
Cr - CH3, 30), 219 (M+ - 5CO - Cr - CH3 - C2H5 - C2H4,
100), 52 (Cr+, 39); HR-MS calcd for C23H21CrNO4 427.0876,
found 427.0878 (M+ - 2CO). Anal. Calcd for C25H21CrNO6:
C, 62.11; H, 4.38; N, 2.90. Found: C, 61.88; H, 4.13; N, 2.97.
1
was transferred into an NMR tube, and H NMR and 13C NMR
spectra were recorded at -30 °C.
P en ta ca r bon yl[9(9H)-th ioxa n th en ylid en e]ch r om iu m -
(0) (13): 1H NMR (500 MHz, CDCl3, 243 K) δ 7.45 (t, 2H, 3J HH
3
) 7.46 Hz, Ar H), 7.51 (t, 2H, J HH ) 7.41 Hz, Ar H), 7.60 (d,
3
3
2H, J HH ) 7.85 Hz, Ar H), 8.37 (d, 2H, J HH ) 7.94 Hz, H-1,
H-8); 13C NMR (125.6 MHz, CDCl3, 243 K) δ 118.92 (2C, C-4a,
C-4b), 124.31 (2C, Ar Ct), 126.34 (2C, Ar Ct), 130.65 (2C, Ar
Ct), 132.20 (2C, Ar Ct), 154.96 (2C, C-8a, C-9a), 215.49 (4C,
COcis), 235.39 (1C, COtrans), 357.80 (1C, Ccarbene).8
P en ta ca r bon yl(9,10-d ih yd r o-10,10-d im eth yl-9-a n th r a -
cen ylid en e)ch r om iu m (0) (14): 13C NMR (125.6 MHz, CDCl3,
243 K) δ 31.31 (2C, CH3), 39.67 (1C, C-10), 122.60 (2C, ArCt),
126.34 (2C, ArCt), 130.51 (2C, ArCt), 131.60 (2C, C-4a, C-10a),
131.69 (2C, ArCt), 158.64 (2C, C-8a, C-9a), 216.73 (4C, COcis),
233.65 (1C, COtrans), 378.64 (1C, Ccarbene).9
Gen er a l P r oced u r e for th e Rea ction of th e Ca r ben e
Com p lexes 9-12, 15, 18, a n d 19 w ith Et2NCtCMe. To a
stirred solution of 1 mmol of the carbene complex in 20 mL of
dichloromethane (9, 10, and 15, -60 °C; 18 and 19, -20 °C;
11 and 12, room temperature) was added 1 mmol (0.11 g) of
1-(diethylamino)-1-propyne in 2 mL of dichloromethane over
2 min. After consumption of the starting material (TLC
control) and removal of the solvent under reduced pressure,
the residue was purified by column chromatography (-10 °C;
eluents petroleum ether/dichloromethane (2/1) for 20, 21, and
23, petroleum ether/dichloromethane (1/1) for 24, petroleum
ether/dichloromethane (1/3) for 25, and dichloromethane for
22). Complexes 20, 21, and 23-25 were obtained as yellow
solids, whereas 22 had an oily to waxy consistence.
(syn /a n ti)-P en t a ca r b on yl{(d iet h yla m in o){1-[5′(5′H )-
d i b e n z o [a ,d ]c y c lo h e p t e n y li d e n e ]e t h y l}c a r b e n e }-
ch r om iu m (0) (22): yellow oily wax, 0.27 g (27%, syn/anti )
4.9); Rf 0.65 (CH2Cl2); 1H NMR (500 MHz, CDCl3) syn isomer32
3
3
δ 1.40 (t, J HH ) 7.23 Hz, 3H, NCH2CH3), 1.54 (t, J HH ) 7.15
2
Hz, 3H, NCH2CH3), 1.81 (s, 3H, CH3), 3.71 (dq, J HH ) 13.82
3
2
Hz, J HH ) 6.84 Hz, 1H, NCHH), 3.91 (dq, J HH ) 13.87 Hz,
3J HH ) 6.90 Hz, 1H, NCHH), 4.37 (dq, J HH ) 13.88 Hz, J HH
2
3
) 6.94 Hz, 1H, NCHH), 4.84 (dq, 2J HH ) 13.69 Hz, 3J HH ) 6.84
3
Hz, 1H, NCHH), 6.80 (d, J HH ) 7.42 Hz, 1H, Ar H), 6.97 (d,
3J HH ) 11.83 Hz, 1H, dCH), 7.01 (d, J HH ) 11.83 Hz, 1H,
3
dCH), 7.19 (t, 3J HH ) 8.36 Hz, 1H, Ar H), 7.21 (d, 3J HH ) 6.67
3
Hz, 1H, Ar H), 7.25 (t, J HH ) 7.66 Hz, 1H, Ar H), 7.30 (d,
3J HH ) 6.59 Hz, 1H, Ar H), 7.31 (t, 3J HH ) 6.65 Hz, 1H, Ar H),
3
3
7.35 (d, J HH ) 7.45 Hz, 1H, Ar H), 7.37 (t, J HH ) 7.87 Hz,
3
1H, Ar H), anti isomer δ 0.74 (t, J HH ) 7.21 Hz, 3H,
3
NCH2CH3), 0.96 (t, J HH ) 7.18, 3H, NCH2CH3), 1.88 (s, 3H,
2
3
CH3), 2.81 (dq, J HH ) 13.83 Hz, J HH ) 6.98 Hz, 1H, NCHH),
(()-P e n t a c a r b o n y l {(d i e t h y l a m i n o ){1 -[9 ′(9 ′H )-
flu or en ylid en e]eth yl}ca r ben e}ch r om iu m (0) (20): yellow
solid, 0.24 g (51%); Rf 0.45 (petroleum ether/CH2Cl2 2:1); mp
2
3
3.77 (dq, J HH ) 14.02 Hz, J HH ) 6.92 Hz, 1H, NCHH), 4.07
2
3
(dq, J HH ) 13.83 Hz, J HH ) 6.98 Hz, 1H, NCHH), 4.35 (dq,
2J HH ) 14.02 Hz, 3J HH ) 6.92 Hz, 1H, NCHH), 6.65 (d, 3J HH
)
1
3
65-68 °C dec; H NMR (400 MHz, CDCl3) δ 1.09 (t, J HH
)
3
7.37 Hz, 3H, NCH2CH3), 1.57 (t, 3J HH ) 7.08 Hz, 3H, NCH2CH3),
7.56 Hz, 1H, Ar H), 6.83 (d, J HH ) 10.81 Hz, 1H, dCH), 6.85
(d, 3J HH ) 10.81 Hz, 1H, dCH);33 13C NMR (100.6 MHz, CDCl3)
syn isomer δ 14.49 (1C, NCH2CH3), 15.14 (1C, NCH2CH3),
18.50 (1C, CH3), 50.21 (1C, NCH2), 53.09 (1C, NCH2), 125.48
(1C, C-5′), 127.13 (1C), 127.25 (1C), 127.68 (1C), 127.80 (1C),
128.07 (1C), 128.88 (1C), 129.65 (1C), 130.10 (1C), 131.73 (1C),
131.79 (1C) (10C, Ar C, C-10′ and C-11′), 135.16, 135.73,
137.89, 138.94, 145.57 (5C, C-1, C-4a′, C-5a′, C-9a′, C-11a′),
217.34 (4C, COcis), 223.71 (1C, COtrans), 276.22 (1C, Ccarbene),
anti isomer: δ 13.05 (1C, NCH2CH3), 14.57 (1C, NCH2CH3),
20.96 (1C, CH3), 48.01 (1C, NCH2), 54.42 (1C, NCH2), 120.92
(1C, C-5′), 126.33 (1C), 127.07 (1C), 128.26 (1C), 128.34 (1C),
128.68 (1C), 129.76 (1C), 130.57 (1C), 130.88 (1C), 131.45 (1C),
131.95 (1C) (10C, Ar C, C-10′ and C-11′), 134.06, 134.42,
138.02, 139.64, 145.00 (5C, C-1, C-4a′, C-5a′, C-9a′, C-11a′),
218.35 (4C, COcis), 223.27 (1C, COtrans), 272.63 (1C, Ccarbene);
FT-IR (hexane) (νCdO) 2053 (m, A1), 1971 (m, B), 1939, 1930
2
3
2.52 (s, 3H, CH3), 3.56 (dq, J HH ) 13.99 Hz, J HH ) 7.08 Hz,
2
3
1H, NCHH), 3.76 (dq, J HH ) 13.99 Hz, J HH ) 7.08 Hz, 1H,
3
NCHH), 4.43 (q, J HH ) 7.37 Hz, 2H, NCH2), 7.25 (m, 1H, Ar
3
H), 7.32 (m, 2H, Ar H), 7.38 (m, 2H, Ar H), 7.76 (d, J HH
)
7.04 Hz, 1H, Ar H), 7.86 (m, 1H, Ar H), 7.88 (m, 1H, Ar H);
13C NMR (100.6 MHz, CDCl3) δ 12.96 (1C, NCH2CH3), 13.12
(1C, NCH2CH3), 21.59 (1C, CH3), 48.60 (1C, NCH2CH3), 52.99
(1C, NCH2CH3), 119.58 (1C, Ar C), 119.85 (1C, Ar C), 120.81
(1C, C-9′), 124.45 (1C, Ar C), 125.46 (1C, Ar C), 126.08 (1C,
Ar C), 126.85 (1C, Ar C), 126.99 (1C, Ar C), 127.09 (1C, Ar C),
136.97, 138.21, 138.93, 140.31, 145.61 (5C, C-1, C-4a′, C-4b′,
C-8a′, C-9a′), 216.54 (4C, COcis), 222.38 (1C, COtrans), 272.00
(1C, Ccarbene); FT-IR (hexane) (νCdO) 2055 (m, A1), 1977 (m, B),
1939, 1930 (vs, E) cm-1; FT-IR (KBr) 2981 (m, νC-H), 1612 (w),
1591 (w), 1516, 1446 (m, νCdC), 781 (m), 732 (m), 653 (s) cm-1
;
MS (EI) m/z (%) 411 (M+ - 2CO, 12), 383 (M+ - 3CO, 9), 355
(M+ - 4CO, 21), 327 (M+ - 5CO, 100), 275 (M+ - 5CO - Cr,
22), 256 (M+ - 5CO - NEt2, 30), 203 (M+ - 5CO - Cr - NEt2
- H, 15), 52 (Cr+, 67); HR-MS calcd for C23H21CrNO3 411.0927,
found 411.0924 (M+ - 2CO). Anal. Calcd for C25H21CrNO5:
C, 64.24; H, 4.53; N, 3.00. Found: C, 64.08; H, 4.83; N, 2.87.
(()-P e n t a c a r b o n y l {(d i e t h y l a m i n o ){1 -[9 ′(9 ′H )-
xa n th en ylid en e]eth yl}ca r ben e}ch r om iu m (0) (21): yellow
solid, 0.25 g (52%); Rf 0.5 (petroleum ether/CH2Cl2 2/1); mp
(vs, E) cm-1; MS (EI) m/z (%) 437 (M+ - 2CO, 6), 409 (M+
-
3CO, 2), 381 (M+ - 4CO, 10), 353 (M+ - 5CO, 100), 301 (M+
+
- 5CO - Cr, 12), 229 (M+ - 5CO - NEt2, 55), 191 (C15H11
,
44); HR-MS calcd for C25H23CrNO3 437.1083, found 437.1083
(M+ - 2CO).
(E/Z)-P e n t a ca r b on yl{(d ie t h yla m in o)[1′′′-(exo-sp ir o-
(1′′H)-in den o-(1′′,1′)-cyclopr op[2′,3′-b]-1(1H)-in den yliden e)-
eth yl]ca r ben e}ch r om iu m (0) (23) (F igu r e 3): yellow solid,
0.38 g (73%, E/Z ) 3.4); Rf 0.4 (petroleum ether/CH2Cl2 2/1);
mp 73-75 °C dec; 1H NMR (500 MHz, CDCl3)34 E isomer δ
1
3
72 °C dec; H NMR (400 MHz, CDCl3) δ 1.19 (t, J HH ) 7.15
3
Hz, 3H, NCH2CH3), 1.48 (t, J HH ) 7.08 Hz, 3H, NCH2CH3),
2
3
2.19 (s, 3H, CH3), 3.51 (dq, J HH ) 14.10 Hz, J HH ) 7.15 Hz,
2
3
1H, NCHH), 3.98 (dq, J HH ) 14.10 Hz, J HH ) 7.15 Hz, 1H,
(33) The signals of the aromatic protons of the anti isomer are
covered by the signals of the syn isomer.
(34) Assignment according to H,H- and C,H-COSY experiments.
2
3
NCHH), 4.15 (dq, J HH ) 13.89 Hz, J HH ) 7.08 Hz, 1H,
2
3
NCHH), 4.43 (dq, J HH ) 13.89 Hz, J HH ) 7.08 Hz, 1H,

4360 Organometallics, Vol. 17, No. 20, 1998
Pfeiffer and Do¨tz
8.25 Hz, 2H, Ar H);35 13C NMR (125.6 MHz, CDCl3) E isomer
δ 13.17 (1C, NCH2CH3), 13.59 (1C, NCH2CH3), 20.63 (1C, CH3),
48.97 (1C, NCH2), 52.60 (1C, NCH2), 55.21 (1C, OCH3), 113.71
(2C, C-3′, C-5′), 126.06 (s, 1C, C-1), 127.18 (d, 1C, C-4′′), 127.73
(d, 2C, C-2′′, C-6′′), 129.09 (d, 2C, C-3′′, C-5′′), 131.10 (2C, C-2′,
C-6′), 133.84 (1C, Cq), 140.78 (1C, Cq), 143.66 (1C, C-2), 158.31
(1C, C-4′), 217.09 (4C, COcis), 222.86 (1C, COtrans), 276.37 (1C,
C
carbene), Z isomer δ 13.22 (1C, NCH2CH3), 13.53 (1C, NCH2CH3),
20.52 (1C, CH3), 48.75 (1C, NCH2), 53.20 (1C, NCH2), 55.23
(1C, OCH3), 113.17 (2C, C-3′, C-5′), 125.54 (1C, C-1), 126.70
(1C, C-4′′), 128.35 (2C, C-2′′, C-6′′), 129.94 (2C, C-3′′, C-5′′),
130.32 (2C, C-2′, C-6′), 133.03 (1C, Cq), 141.81 (1C, Cq), 142.35
(1C, C-2), 158.86 (1C, C-4′), 217.20 (4C, COcis), 222.81 (1C,
COtrans), 276.32 (1C, Ccarbene); FT-IR (hexane) (νCdO) 2053 (m,
A1), 1971 (w, B1), 1940, 1928 (vs, E), 1912 (s, A1) cm-1; MS
(EI) m/z (%) 443 (M+ - 2CO, 9), 387 (M+ - 4CO, 2), 359 (M+
- 5CO, 33), 307 (M+ - 5CO - Cr, 54), 292 (M+ - 5CO - Cr
- CH3, 100), 235 (M+ - 5CO - Cr - NEt2, 45), 52 (Cr+, 24);
HR-MS calcd for C24H25CrNO4 443.1189, found 443.1197 (M+
- 2CO). Anal. Calcd for C26H25CrNO6: C, 62.52; H, 5.09; N,
2.80. Found: C, 62.11; H, 4.82; N, 3.02.
F igu r e 3. Atom labeling of (E/Z)-23.
3
3
1.33 (t, J HH ) 6.95 Hz, 3H, NCH2CH3), 1.48 (t, J HH ) 7.01
Hz, 3H, NCH2CH3), 2.37 (s, 3H, CH3), 2.91 (d, 3J HH ) 5.80 Hz,
2
3
1H, H-3), 3.12 (dq, J HH ) 13.84 Hz, J HH ) 6.95 Hz, 1H,
3
2
NCHH), 3.77 (d, J HH ) 5.80 Hz, 1H, H-2), 3.95 (dq, J HH
)
3
2
13.84 Hz, J HH ) 6.95 Hz, 1H, NCHH), 4.10 (dq, J HH ) 13.77
3
2
Hz, J HH ) 7.01 Hz, 1H, NCHH), 4.18 (dq, J HH ) 13.77 Hz,
3J HH ) 7.01 Hz, 1H, NCHH), 5.67 (d, J HH ) 5.65 Hz, 1H,
3
H-2′′), 6.87 (d, 3J HH ) 5.65 Hz, 1H, H-3′′), 7.00 (d, 3J HH ) 7.39
Hz, 1H, H-4′′), 7.18 (d, 3J HH ) 7.41 Hz, 1H, H-5′′), 7.25 (d, 3J HH
3
) 7.43 Hz, 1H, H-6′′), 7.26 (d, J HH ) 7.44 Hz, 1H, H-5), 7.32
3
3
(d, J HH ) 7.55 Hz, 1H, H-7′′), 7.35 (t, J HH ) 7.44 Hz, 1H,
3
3
P e n t a ca r b on yl{(d ie t h yla m in o)[1,1-b is(4′-m e t h oxy-
p h en yl)-2-p r op en yl]ca r ben e}ch r om iu m (0) (25): yellow
solid, 0.34 g (65%); Rf 0.5 (petroleum ether/CH2Cl2 1/3). 1H
H-6), 7.36 (d, J HH ) 7.49 Hz, 1H, H-4), 7.72 (d, J HH ) 7.79
3
Hz, 1H, H-7). Z isomer δ 1.12 (t, J HH ) 7.09 Hz, 3H,
3
NCH2CH3), 1.59 (t, J HH ) 7.05 Hz, 3H, NCH2CH3), 2.05 (s,
3
2
3
NMR (500 MHz, CDCl3) δ 1.39 (t, J HH ) 7.06 Hz, 3H,
3H, CH3), 3.43 (dq, J HH ) 13.90 Hz, J HH ) 7.09 Hz, 1H,
3
3
3
NCH2CH3), 1.51 (t, J HH ) 7.25 Hz, 3H, NCH2CH3), 1.89 (s,
NCHH), 3.58 (d, J HH ) 6.04 Hz, 1H, H-3), 3.70 (d, J HH
)
2
3
2
3
3H, CH3), 3.68 (dq, J HH ) 13.94 Hz, J HH ) 7.06 Hz, 1H,
NCHH), 3.79 (s, 3H, OCH3), 3.86 (s, 3H, OCH3), 4.12 (dq, 2J HH
) 14.57 Hz, 3J HH ) 7.25 Hz, 1H, NCHH), 4.15 (dq, 2J HH ) 14.57
6.04 Hz, 1H, H-2), 3.90 (dq, J HH ) 13.90 Hz, J HH ) 7.09 Hz,
2
3
1H, NCHH), 4.25 (dq, J HH ) 13.72 Hz, J HH ) 7.05 Hz, 1H,
2
3
NCHH), 4.51 (dq, J HH ) 13.72 Hz, J HH ) 7.05 Hz, 1H,
3
2
3
3
Hz, J HH ) 7.25 Hz, 1H, NCHH), 4.43 (dq, J HH ) 13.94 Hz,
NCHH), 5.98 (d, J HH ) 5.66 Hz, 1H, H-2′′), 6.89 (d, J HH
)
)
3J HH ) 7.06 Hz, 1H, NCHH), 6.77 (d, J HH ) 8.74 Hz, 2H, Ar
3
3
5.66 Hz, 1H, H-3′′), 7.10-7.35 (m, 7H, Ar H), 7.42 (d, J HH
3
3
7.25 Hz, 1H, Ar H). 13C NMR (125.6 MHz, CDCl3)34 E isomer
δ 13.73 (q, 1C, NCH2CH3), 13.91 (q, 1C, NCH2CH3), 19.19 (q,
H), 6.83 (d, J HH ) 8.74 Hz, 2H, Ar H), 6.93 (d, J HH ) 8.55
Hz, 2H, Ar H), 7.20 (d, J HH ) 8.54 Hz, 2H, Ar H); 13C NMR
3
1C, CH3), 35.53 (d, 1J CH ) 170.9 Hz, 1C, C-3), 38.36 (d, 1J CH
)
(125.6 MHz, CDCl3) δ 13.21 (1C, NCH2CH3), 13.52 (1C,
NCH2CH3), 20.54 (1C, CH3), 48.79 (1C, NCH2), 52.54 (1C,
NCH2), 55.20 (1C, OCH3), 55.22 (1C, OCH3), 113.13 (2C, Ar
C), 113.65 (2C, Ar C), 125.73 (1C, C-1), 130.32 (2C, Ar C),
131.10 (2C, Ar C), 133.46 (1C, C-1′), 134.05 (1C, C-1′), 142.53
(1C, C-2), 158.25 (1C, C-4′), 158.84 (1C, C-4′), 217.11 (4C,
COcis), 222.86 (1C, COtrans), 276.48 (1C, Ccarbene); FT-IR (hexane)
(νCdO) 2052 (m, A1), 1971 (w, B1), 1938, 1928 (vs, E), 1911 (s,
A1) cm-1; MS (EI) m/z (%) 473 (M+ - 2CO, 9), 417 (M+ - 4CO,
175.3 Hz, 1C, C-2), 49.22 (1C, C-1′′), 49.32 (t, 1C, NCH2), 52.96
(t, 1C, NCH2), 116.93 (d, 1C, C-4′′), 121.23 (d, 1C, C-4), 123.09
(1C, C-1′′′), 124.07 (d, 1C, C-5′′), 124.14 (d, 1C, C-7), 124.73
(d, 1C, C-7′′), 125.82 (d, 1C, C-6′′), 126.99 (d, 1C, C-6), 127.46
(d, 1C, C-5), 131.10 (d, 1C, C-3′′), 134.31 (d, 1C, C-2′′), 139.07,
143.31, 143.34, 144.83, 146.43 (5C, C-3a, C-7a, C-3a′′, C-7a′′,
C-1), 217.16 (4C, COcis), 223.53 (1C, COtrans), 275.01 (1C,
C
carbene); Z isomer δ 13.17 (q, 1C, NCH2CH3), 13.69 (q, 1C,
2), 389 (M+ - 5CO, 35), 337 (M+ - 5CO - Cr, 64), 322 (M+
-
1
NCH2CH3), 20.47 (q, 1C, CH3), 37.42 (d, J CH ) 173.4 Hz, 1C,
5CO - Cr - CH3, 100), 265 (M+ - 5CO - Cr - NEt2, 60), 52
(Cr+, 13); HR-MS calcd for C25H27CrNO5 473.1294, found
473.1288 (M+ - 2CO). Anal. Calcd for C27H27CrNO7: C,
61.24; H, 5.14; N, 2.65. Found: C, 61.09; H, 5.19; N, 2.47.
Gen er a l P r oced u r e for th e Rea ction s of th e Ca r ben e
Com p lexes 9, 10, a n d 15 w ith Eth oxyeth yn e. To a stirred
solution of 1 mmol of the carbene complexes 9, 10, and 15,
respectively, in 20 mL of CH2Cl2, cooled to -20 °C, was added
a solution of 0.07 g (1 mmol) of ethoxyethyne in 2 mL of CH2-
Cl2 over 5 min. After 2 h the reaction was complete, yielding
a reddish brown solution. Removal of the solvent under
reduced pressure and column chromatographic workup (-20
°C, eluent petroleum ether/dichloromethane 2/1) gave 26-28
as brown or red oils.
1
C-3), 38.42 (d, J CH ) 175.3 Hz, 1C, C-2), 47.35 (t, 1C, NCH2),
49.30 (s, 1C, C-1′′), 53.20 (t, 1C, NCH2), 117.45 (d, 1C, Ar C),
121.45 (d, 1C, Ar C), 124.24 (d, 1C, Ar C), 124.79 (d, 1C, Ar
C), 125.72 (d, 1C, Ar C), 126.08 (d, 1C, Ar C), 126.32 (d, 1C,
Ar C), 127.01 (d, 1C, Ar C), 127.48 (s, 1C, C-1′′′), 130.95 (d,
1C, C-3′′), 134.91 (d, 1C, C-2′′), 139.21, 141.01, 143.20, 144.38,
146.50 (5C, C-3a, C-7a, C-3a′′, C-7a′′, C-1), 216.92 (4C, COcis),
222.54 (1C, COtrans), 273.51 (1C, Ccarbene); FT-IR (hexane) (νCdO
)
;
2054 (m, A1), 1974 (m, B1), 1941, 1932 (vs, E), 1913 (s, A1) cm-1
MS (EI) m/z (%) 503 (M+ - CO, 5), 475 (M+ - 2CO, 6), 447
(M+ - 3CO, 8), 419 (M+ - 4CO, 10), 391 (M+ - 5CO, 100),
339 (M+ - 5CO-Cr, 52), 324 (M+ - 5CO-Cr-CH3, 55), 310
(M+ - 5CO - Cr - C2H5, 19), 267 (M+ - Cr-5CO - NEt2, 30);
HR-MS calcd for C27H25CrNO2 447.1290, found 447.1287 (M+
- 3CO). Anal. Calcd for C30H25CrNO5: C, 67.79; H, 4.74; N,
2.64. Found: C, 67.73; H, 5.07; N, 2.29.
P en ta ca r bon yl{eth oxy[9(9H)-flu or en ylid en em eth yl]-
ca r ben e}ch r om iu m (0) (26): red oil, 0.20 g (47%); Rf 0.45
(petroleum ether/CH2Cl2 2/1); 1H NMR (500 MHz, CDCl3, 298
(E/Z)-P en t a ca r b on yl{(d iet h yla m in o)[1-(4′-m et h oxy-
p h en yl)-1-p h en yl-2-p r op en yl]ca r ben e}ch r om iu m (0) (24):
yellow solid, 0.29 g (58%, E/Z ) 5.6); Rf 0.45 (petroleum ether/
CH2Cl2 1/1). 1H NMR (500 MHz, CDCl3) E isomer δ 1.39 (t,
3
K) δ 1.56 (t, 3H, J HH ) 7.15 Hz, CH3), 4.85 (b, 2H, OCH2),
3
3
7.24 (t, 1H, J HH ) 7.55 Hz, Ar H), 7.29 (d, 1H, J HH ) 7.35
3
Hz, Ar H), 7.31 (d, 1H, J HH ) 7.55 Hz, Ar H), 7.36 (t, 2H,
3J HH ) 7.03 Hz, 3H, NCH2CH3), 1.49 (t, J HH ) 6.86 Hz, 3H,
3
3J HH ) 6.95 Hz, Ar H), 7.58 (s, 1H, CdC(R)H), 7.66 (d, 2H,
2
3
3J HH ) 7.85 Hz, Ar H), 7.67 (t, 1H, J HH ) 7.70 Hz, Ar H). H
NMR (500 MHz, CDCl3, 233 K, E/Z ) 2.4:1) δ 1.55 (b, 3H,
CH3(E)), 1.73 (b, 3H, CH3(Z)), 4.57 (b, 1H, OCHH(E)), 4.69 (b,
1H, OCHH(E)), 5.35 (b, 2H, OCH2(Z)), 7.20-7.80 (m, 18H, Ar
3
1
NCH2CH3), 1.92 (s, 3H, CH3), 3.68 (dq, J HH ) 13.95 Hz, J HH
2
) 7.03 Hz, 1H, NCHH), 3.86 (s, 3H, OCH3), 4.09 (dq, J HH
)
3
2
13.95 Hz, J HH ) 7.03 Hz, 1H, NCHH), 4.21 (dq, J HH ) 13.81
3
2
Hz, J HH ) 6.86 Hz, 1H, NCHH), 4.43 (dq, J HH ) 13.81 Hz,
3J HH ) 6.86 Hz, 1H, NCHH), 6.90-6.96 (m, 4H, Ar H), 7.16-
7.27 (m, 5H, Ar H); Z isomer δ 1.86 (s, 3H, CH3), 3.78 (s, 3H,
(35) The signals of the aromatic protons of the Z isomer are partially
covered by the signals of the E isomer.
3
3
OCH3), 6.72 (d, J HH ) 8.35 Hz, 2H, Ar H), 6.79 (d, J HH
)

Diarylcarbene Complexes of Chromium
and CdC(R)H(E Z)); 13C NMR (125.6 MHz, CDCl3,
Organometallics, Vol. 17, No. 20, 1998 4361
H(E
(E/Z)-P en tacar bon yl{eth oxy[1-(exo-spir o-(1′′H)-in den o-
(1′′,1′)-c y c lo p r o p [2′,3′-b ]-1(1H )-in d y lid e n e )m e t h y l]-
ca r ben e}ch r om iu m (0) (E/Z-28): red solid, 0.18 g (36%, E/Z
) 1.6:1); Rf 0.7 (petroleum ether/dichloromethane 2/1); 1H
+
Z)
+
298 K) δ 15.04 (1C, CH3), 76.20 (1C, OCH2), 120.11 (2C, Ar
C), 120.29 (1C, Ar C), 120.84 (1C, Ar C), 124.36 (1C, Ar C),
127.34 (1C, Ar C), 127.37 (1C, Ar C), 129.21 (1C, Ar C), 129.54
(1C, Ar C), 131.67, 135.09, 137.99, 140.54, 141.42 (5C, C-4a,
C-4b, C-8a, C-9, C-9a), 215.83 (4C, COcis), 224.17 (1C, COtrans),
346.51 (1C, Ccarbene); 13C NMR (125.6 MHz, CDCl3, 233 K) E
isomer δ 15.89 (1C, CH3), 76.56 (1C, OCH2), 120.91, 121.09,
121.46, 124.30, 127.99, 128.31, 129.68, 130.11, 131.09 (9C, Ar
C and C)C(R)H), 130.03, 135.31, 137.90, 140.65, 141.36 (5C,
C-4a, C-4b, C-8a, C-9, C-9a), 216.42 (4C, COcis), 225.31 (1C,
COtrans), 347.39 (1C, Ccarbene); Z isomer δ 15.57 (1C, CH3), 78.29
(1C, OCH2), 120.75, 120.98, 121.72, 123.74 (2C), 125.24, 126.77,
127.67, 127.91 (9C, Ar C and CdC(R)H), 135.46, 135.56,
138.81, 141.14, 142.21 (5C, C-4a, C-4b, C-8a, C-9, C-9a), 216.20
(4C, COcis), 224.40 (1C, COtrans), 344.41 (1C, Ccarbene); FT-IR
(hexane) (νCdO) 2064 (m, A1), 1989 (w, B), 1965 (vs, E), 1951
(vs, A1) cm-1; MS (EI) m/z (%) 426 (M+, 5), 370 (M+ - 2CO,
20), 342 (M+ - 3CO, 17), 314 (M+ - 4CO, 26), 286 (M+ - 5CO,
85), 242 (M+ - 5CO - OC2H5 - H, 75), 52 (Cr+, 100); HR-MS
calcd for C22H14CrO6 426.0195, found 426.0184 (M+).
3
NMR (500 MHz, CDCl3) E isomer δ 0.89 (t, 3H, J HH ) 7.07
Hz, CH3), 3.86 (d, 1H, 3J HH ) 4.97 Hz, H-3), 3.95 (dd, 1H, 3J HH
4
2
) 4.97 Hz, J HH ) 1.05 Hz, H-2), 4.78 (dq, 1H, J HH ) 10.38
3
2
Hz, J HH ) 7.07 Hz, OCHH), 4.85 (dq, 1H, J HH ) 10.38 Hz,
3
3J HH ) 7.07 Hz, OCHH), 5.53 (d, 1H, J HH ) 5.66 Hz, H-2′′),
3
4
6.82 (dd, 1H, J HH ) 5.66 Hz, J HH ) 0.59 Hz, H-3′′), 7.16 (d,
1H, 3J HH ) 7.45 Hz, Ar H), 7.24 (t, 1H, 3J HH ) 7.25 Hz, Ar H),
3
7.29 (t, 1H, J HH ) 7.40 Hz, Ar H), 7.34-7.40 (m, 4H, Ar H),
3
4
7.74 (d, 1H, J HH ) 6.95 Hz, Ar H), 8.05 (d, 1H, J HH ) 1.05
3
Hz, CdC(R)H); Z isomer δ 1.60 (t, 3H, J HH ) 7.09 Hz, CH3),
3
3
3.87 (d, 1H, J HH ) 5.02 Hz, H-3), 4.05 (dd, 1H, J HH ) 5.02
4
Hz, J HH ) 1.14 Hz, H-2), 4.80 (m, 1H, OCHH), 4.96 (dq, 1H,
2J HH ) 10.31 Hz, J HH ) 7.09 Hz, OCHH), 6.16 (d, 1H, J HH
)
3
3
3
5.46 Hz, H-2′′), 6.72 (t, 1H, J HH ) 7.68, Ar H), 6.89 (d, 1H,
3J HH ) 5.46 Hz, H-3′′), 7.98 (d, 1H, J HH ) 7.65 Hz, Ar H),
3
8.16 (d, 1H, 4J HH ) 1.14 Hz, CdC(R)H);35 13C NMR (125.6 MHz,
1
CDCl3) E isomer δ 14.34 (q, 1C, CH3), 39.65 (d, 1C, J HH
)
1
176.3 Hz, C-2 or C-3), 40.87 (d, 1C, J CH ) 180.4 Hz, C-2 or
C-3), 57.48 (s, 1C, C-1′′), 76.40 (t, 1C, OCH2), 117.78, 121.53,
122.38, 124.87, 125.11, 126.89, 127.43, 131.46, 132.35, 133.08,
133.29 (11C, Ar C and C)C(R)H), 139.72, 141.52, 142.90,
145.42, 148.14 (s, 5C, C-1, C-3a, C-7a, C-3a′′, C-7a′′), 216.88
(s, 4C, COcis), 224.31 (s, 1C, COtrans), 328.23 (s, 1C, Ccarbene); Z
isomer δ 14.82 (1C, CH3), 37.36, 38.17 (2C, C-2, C-3), 52.04
(1C, C-1′′), 75.86 (1C, OCH2), 216.46 (4C, COcis), 223.92 (1C,
COtrans), 328.09 (1C, Ccarbene);37 FT-IR (hexane) (νCdO) 2055 (m,
A1), 1979 (w, B), 1954 (vs, E), 1946 (vs, A1) cm-1; MS (EI) m/z
(%) 490 (M+, 0.2), 462 (M+ - CO, 0.2), 434 (M+ - 2CO, 0.2),
406 (M+ - 3CO, 2), 378 (M+ - 4CO, 0.4), 350 (M+ - 5CO, 40),
298 (M+ - 5CO - Cr, 9), 253 (M+ - 5CO - Cr - OCH2CH3,
P en ta ca r bon yl{eth oxy[9(9H)-xa n th en ylid en em eth yl]-
ca r ben e}ch r om iu m (0) (27): brown oil, 0.18 g (41%); Rf 0.75
(petroleum ether/dichloromethane 2/1). 1H NMR (500 MHz,
3
CDCl3, 298 K) δ 1.45 (t, 3H, J HH ) 7.05 Hz, CH3), 4.69 (q,
3
3
2H, J HH ) 7.05 Hz, OCH2), 7.15 (t, 1H, J HH ) 7.15 Hz, Ar
3
H), 7.16 (d, 1H, J HH ) 7.17 Hz, Ar H), 7.24-7.28 (m, 4H, Ar
3
H), 7.39-7.44 (m, 2H, Ar H and CdC(R)H), 7.77 (d, 1H, J HH
1
) 8.64 Hz, Ar H); H NMR (500 MHz, CDCl3, 233 K, E/Z )
1.2:1) δ 1.2-1.6 (m, 6H, CH3(E + Z)), 4.10 (b, 1H, OCHH(E)), 4.65
(b, 1H, OCHH(E)), 5.00 (b, 2H, OCH2(Z)), 7.00-7.80 (m, 18H,
Ar H(E + Z) and CdC(R)H(E + Z)); 13C NMR (125.6 MHz, CDCl3,
298 K) δ 14.73 (1C, CH3), 75.66 (1C, OCH2), 117.26, 117.40,
123.35, 123.59, 124.32 (2C), 128.53, 130.21, 130.58 (9C, Ar C
and C)C(R)H), 119.88 (1C, Cq), 121.41 (1C, Cq), 130.88 (1C,
Cq), 152.27, 152.44 (2C, C-4a, C-4b), 216.47 (4C, COcis), 224.15
(1C, COtrans), 343.52 (1C, Ccarbene); 13C NMR (125.6 MHz, CDCl3
11), 115 (C7H9+, 100), 80 (CrCO+, 35); HR-MS calcd for C22H18
-
CrO 350.0762, found 350.0772 (M+ - 5CO).
Ack n ow led gm en t. Support by the Fonds der Che-
mischen Industrie and the Graduiertenkolleg “Spek-
troskopie isolierter und kondensierter Moleku¨le” is
gratefully acknowledged.
233 K) δ 14.53, 14.77 (2C, CH3(E
Z)), 75.09, 76.34 (2C,
+
OCH2(E
Z)), 216.94 (8C, COcis(E
Z)), 224.69, 225.24 (2C,
+
+
COtrans(E
Z)), 337.89, 346.39 (2C, Ccarbene(E
Z));36 FT-IR
+
+
(hexane) [ν(CdO)] 2059 (m, A1), 1983 (w, B), 1956 (vs, E), 1946
(vs, A1) cm-1; MS (EI) m/z (%) 442 (M+, 2), 414 (M+ - CO, 4),
386 (M+ - 2CO, 14), 358 (M+ - 3CO, 10), 330 (M+ - 4CO,
30), 302 (M+ - 5CO, 55), 250 (M+ - 5CO - Cr, 17), 245 (30),
205 (M+ - 5CO - Cr - OEt, 100), 52 (Cr+, 85); HR-MS calcd
for C22H14CrO7 442.0145, found 442.0120 (M+). Anal. Calcd
for C22H14CrO7: C, 59.74; H, 3.19. Found: C, 59.74; H, 3.91.
Su p p or tin g In for m a tion Ava ila ble: 1H and 13C NMR
spectra for all compounds described (45 pages). Ordering
information is given on any current masthead page.
OM971086G
(37) The signals of the aromatic carbon atoms of the Z isomer are
covered by the signals of the E isomer.
(36) The signals in the aromatic region are not resolved.