Reactions of complex ligands Part 91. Application of ring closing metathesis to Fischer-type carbene complexes: Synthesis and structure of medium-sized chromium oxacycloalkenylidenes

Article abstract of DOI:10.1016/S0022-328X(00)00095-4

Six- and seven-membered pentacarbonyl(2-oxacycloalkenylidene) chromium complexes 17 and 6 have been synthesized in moderate to good yields from alkenyloxy(methyl)carbene complex precursors applying an α-alkylation/ruthenium based ring closing metathesis sequence. The ring-closure is hampered for β-alkylated vinylcarbene complexes which may undergo competing intermolecular cross metathesis at the alkenyloxy terminus in low yield.

Full text of DOI:10.1016/S0022-328X(00)00095-4

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 606 (2000) 26–36
Reactions of complex ligands
Part 91ꢀ. Application of ring closing metathesis to Fischer-type
carbene complexes: synthesis and structure of medium-sized
chromium oxacycloalkenylidenes
Jan Su¨ltemeyer a, Karl Heinz Do¨tz a,*, Heike Hupfer b, Martin Nieger b
a Kekule´-Institut fu¨r Organische Chemie und Biochemie der Rheinischen Friedrich-Wilhelms-Uni6ersita¨t, Gerhard-Domagk-Strasse 1,
D-53121 Bonn, Germany
b Institut fu¨r Anorganische Chemie der Rheinischen Friedrich-Wilhelms-Uni6ersita¨t, Gerhard-Domagk-Strasse 1, D-53121 Bonn, Germany
Received 8 December 1999; received in revised form 31 January 2000
Abstract
Six- and seven-membered pentacarbonyl(2-oxacycloalkenylidene) chromium complexes 17 and 6 have been synthesized in
moderate to good yields from alkenyloxy(methyl)carbene complex precursors applying an a-alkylation/ruthenium based ring
closing metathesis sequence. The ring-closure is hampered for b-alkylated vinylcarbene complexes which may undergo competing
intermolecular cross metathesis at the alkenyloxy terminus in low yield. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Carbene complexes; Crotonates; Ring closing metathesis; Cross-metathesis
1. Introduction
ligands as exploited in aldol reactions [8], on a,b-unsat-
urated carbene ligands activated for Michael-type addi-
tion [9], on [n+2] cycloaddition reactions [10], or on
metal-centered three-component cycloaddition reac-
tions such as the chromium-mediated benzannulation
reaction [11]. We now report on the synthesis of alkeny-
l(alkenyloxy)carbene complexes of chromium and on
their potential for ring closing metathesis.
Within a few years ring closing metathesis (RCM)
has been developed to a flexible and efficient methodol-
ogy for the synthesis of small, medium and large homo-
and heterocycles [2]. The easy to handle ruthenium-
based catalyst introduced by Grubbs [3] and more
recent variations thereof [4] tolerate various functional
groups including heteroatoms and, thus, find increasing
application in the synthesis of macrocycles as convinc-
ingly demonstrated in examples of biological impor-
tance [5]. We became interested in whether the Grubbs
catalyst is compatible with another metal alkylidene
moiety as provided by a Fischer-type metal carbene
bearing alkene termini in both carbene side chains.
Carbonyl carbene complexes [6] provide a variety of
more conventional or unique methodologies for
stereoselective carbonꢀcarbon bond formation; they
may be based on the a-CH acidity [7] of alkyl carbene
2. Synthesis of 2-oxacyclohept-4-enylidene complexes
The synthesis of suitable RCM precursors follows a
two-step sequence based on the alcoholysis of the acet-
oxy(methyl)carbene complex [12], generated in situ
from tetramethylammonium acetyl(pentacarbonyl)-
chromate (1) and acetyl bromide [13], and subsequent
tandem deprotonation/alkylation of the alkenyl-
oxy(methyl)carbene complexes 2, 3 [14]. This protocol
afforded alkenyloxy(butenyl)carbene complexes 4, 5 in
63 and 56% overall yields (Scheme 1). The number of
methylene spacers in the alkenyloxycarbene side
chain turned out to be crucial for ring closing
ꢀ For Part 90, see Ref. [1].
* Corresponding author. Tel.: +49-228-735609; fax: +49-228-
735813.
E-mail address: doetz@uni-bonn.de (K.H. Do¨tz)
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00095-4

J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
27
metathesis. The allyloxycarbene complex 4 underwent
clean cyclization in dichoromethane at room tempera-
ture in the presence of 7.5 mol% Grubbs catalyst 7 to
give a 81% yield of chromium 2-oxacyclo-4-heptenyli-
dene 6. The butenyloxycarbene complex analogue 5,
however, eluded ring closure even under more forcing
or high dilution conditions. This result is consistent
with the well-documented reluctance along the forma-
tion of eight-membered rings by RCM [15] reflecting
severe transannular repulsive interactions in the transi-
tion state [16].
The a-CH acidity of oxacycloheptenylidene complex
6 was expected to allow for an exocyclic modification
as required for ligand-centered conjugate addition,
[n+2] cycloaddition or metal-centered benzannulation
reactions. The standard deprotonation/exo-methylena-
tion protocol applying a methyleneiminium electrophile
[17], however, failed to give satisfactory yields. Thus,
we persued an alternative approach which started from
2-bromo-1,4-diene 8 [18]; lithiation and addition to
hexacarbonyl chromium followed by metathesis with
tetramethylammonium bromide afforded acyl chromate
9; activation for nucleophilic attack by acylation with
pivaloyl chloride and alcoholysis using allyl alcohol
gave metal carbene triene 10. At room temperature it
slowly undergoes decarbonylation and chelation via the
allyloxy side chain to form a stable five-membered
carbene chelate complex [19]. In order to avoid this
unfavourable process and to retain the uncoordinated
terminal alkene moiety, the ring closing metathesis
was performed at 0°C, which finally afforded red crys-
tals of exo-benzylidene complex 11 as a single E-iso-
mer after chromatographic workup in moderate yield
(Scheme 2).
Scheme 1. Synthesis and ring closing metathesis of alkenyloxy(butenyl)carbene complexes.
Scheme 2. Synthesis of exo-benzylidene complex 11.

28
J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
center in 11 for the sp3 carbon atom in 6; the angle
between the C(3)ꢀC(4)ꢀC(5) plane and the
C(2)ꢀO(2)ꢀC(1)ꢀC(6) plane is nearly identical for both
complexes (121.7 (3) for 6, 121.4 (3) for 11). The
Table 2
Bond angles and torsion angles (°) in 2-oxacycloheptenylidene com-
plexes 6 and 11
Angle
6
11
CrꢀC(1)ꢀC(6)
125.0(9)
119.6(9)
115.3(1)
113.0(1)
110.1(1)
−23.3(1)
−24.3(1)
−2.1(2)
−2.8(3)
−9.7(2)
123.6(1)
121.7(1)
114.4(1)
112.5(2)
113.6(1)
−8.7(2)
−19.6(2)
−5.1(2)
0.0(3)
−6.5(3)
−73.8(2)
179.6(2)
50.1(3)
CrꢀC(1)ꢀO(2)
O(2)ꢀC(1)ꢀC(6)
O(2)ꢀC(2)ꢀC(3)
Fig. 1. Molecular structure of 2-oxacycloheptenylidene complex 6.
C(1)ꢀC(6)ꢀC(5)
C(1b)ꢀCrꢀC(1)ꢀC(6)
C(1c)ꢀCrꢀC(1)ꢀO(2)
C(6)ꢀC(1)ꢀO(2)ꢀC(2)
C(2)ꢀC(3)ꢀC(4)ꢀC(5)
C(3)ꢀC(4)ꢀC(5)ꢀC(6)
CrꢀC(1)ꢀC(6)ꢀC(7)
C(1)ꢀC(6)ꢀC(7)ꢀC(8)
C(6)ꢀC(7)ꢀC(8)ꢀC(9)
Table 3
Crystallographic and data collection parameters for complexes 6 and
11
6
11
Fig. 2. Molecular structure of exo-benzylidene complex 11.
Empirical formula
Formula weight
Temperature (K)
C
288.17
123(2)
0.71073
(Mo–Ka)
Triclinic
11H8O6Cr
C18H12O6Cr
376.28
123(2)
0.71073
(Mo–Ka)
Triclinic
Table 1
,
Selected bond lengths (A) in 2-oxacycloheptenylidene complexes 6
and 11
,
Wavelength (A)
Crystal system
Space group
(
(
Bond
6
11
P1 (no.2)
P1 (no.2)
,
a (A)
7.4188(5)
9.3844(7)
9.5291(6)
99.417(3)
111.380(3)
94.540(3)
602.45(7)
2
9.3914(4)
9.8758(4)
10.0074(5)
91.289(3)
90.405(2)
114.127(2)
846.73(7)
2
,
b (A)
CrꢀC(1a)
CrꢀC(1b)
CrꢀC(1c)
CrꢀC(1d)
CrꢀC(1e)
CrꢀC(1)
C(1)ꢀO(2)
C(1)ꢀC(6)
C(3)ꢀC(4)
C(6)ꢀC(7)
1.895(2)
1.900(1)
1.902(2)
1.908(1)
1.902(2)
2.014(1)
1.313(2)
1.499(2)
1.320(2)
1.901(2)
1.914(2)
1.896(2)
1.909(2)
1.912(2)
2.006(2)
1.319(2)
1.488(2)
1.324(3)
1.337(2)
,
c (A)
h (°)
i (°)
k (°)
3
,
V (A )
Z
Dcalc. (g cm−3
)
1.589
0.965
0.50×0.35
1.476
0.706
0.30×0.20×0.10
v (mm−1
)
Crystal dimension (mm)
×0.20
28.30
7322
2qmax (°)
Number of reflections
recorded
28.27
12839
3. Molecular structure of 2-oxacycloheptenylidene com-
plexes 6 and 11
Number of non-equivalent
reflections recorded
Rmerg
2775
4004
0.0363
163
0.0416
226
In order to elucidate the conformation of the unsatu-
rated medium-sized oxacycloalkylidene ring the molec-
ular structure of complexes 6 and 11 was established by
X-ray analysis (Figs. 1 and 2, Tables 1–3). Suitable
crystals have been grown from saturated solutions in
n-hexane at −28°C. In both cases the oxacylohep-
tenylidene ring adopts similar half-chair conformations
irrespective of the substitution of the a-sp2 carbon
Number of parameters
refined
b
R1a; wR
0.0257; 0.0738
1.10
0.312/−0.373
0.0358; 0.0933
1.04
0.443/−0.827
Goodness-of-fit c
−3
,
Final max, min Dz (e A
)
a R1=ꢀ(ꢁꢁFoꢁ−ꢁFcꢁꢁ)/ꢀ ꢁFoꢁ (for I\2| (I)).
b wR=[ꢀ wꢁFo2ꢁ2]1. /2
c Goodness-of-fit={ꢀ [wꢁF2oꢁ−ꢁF2cꢁ)2]/(Nobs−Nparams)}1. /2

J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
29
Scheme 3. Reactions of chromium alkenyloxy(2-propenyl)carbenes under RCM-conditions.
majority of the pentacarbonyl carbene complexes adopt
solid state conformations in which the carbene ligand
bisects the angle of the cis-M(CO)2 fragment [20]. In
complexes 6 and 11, however, the bisecting angle is
reduced to 23.3° (for 6) and 8.7° (for 11), which is
probably due to a rather flat potential for the rotation
around the metalꢀcarbene bond and intermolecular in-
teractions between the hydrogen atoms of the seven-
membered ring and oxygen atoms of the CO-ligands.
catalyst resulting in its deactivation. Experimental sup-
port for this idea was provided by the isolation of
dicarbonyl (dichloro) bis (tricyclohexylphosphine) ruthe-
nium as a byproduct in the metathesis of an allylhex-
onate-6-oxy carbene complex under similar conditions.
The undesired chelation is suppressed if another meth-
ylene spacer is incorporated into the alkenyloxycarbene
side chain as observed for the butenyloxycarbene com-
plex 14; this result reflects the reduced propensity to
form homologous six-membered carbene chelates [21].
Instead, the desired ruthenium-catalyzed cyclization oc-
curs to give chromium 2-oxacyclohexenylidene 17 in
fair yield; obviously, the driving force for the ring
closure overrules the complications which may be ex-
pected for the electron-deficient vinylcarbene moiety
bearing an additional alkyl substituent [22]. This reac-
tion indicates that RCM may be applied to electron
deficient double bonds under mild conditions using
catalyst 7, and refines earlier reports on N-allyl lactam
acrylates [23] or a-methylene g-lactones [24], which
required cyclization temperatures above 100°C or even
refuse to undergo ring closure. Surprisingly, no RCM-
product was detected from the reaction of the ho-
mologous 4-pentenyloxycarbene complex 15 under
identical conditions; instead, the 4-octenyldioxy bridged
biscarbene complex 18 was isolated as a mixture of
E/Z-isomers in low yield; 67% of the starting material
were recovered. An additional experiment carried out
with a 3 mM solution of complex 15 in dichloro-
methane further indicated that cross-metathesis over-
rules ring closing metathesis even under high dilution
conditions.
4. Cyclization of a,b-unsaturated carbene complexes
In order to probe the influence of the electron-accep-
tor properties of the metal carbene moiety on the
propensity of adjacent CꢁC bonds for ring closing
metathesis, we extended our studies to a serie of E-
propenylcarbene complexes. Alkenyloxycarbene com-
plexes 13–15 were synthesized by alcoholysis of the
acetoxycarbene complex intermediate generated from
2-butenoylchromate 12. Their tendency to undergo ring
closing metathesis turned out to depend on the length
of the methylene spacer separating the alkene terminus
and the oxycarbene functionality. Allyloxycarbene
complex 13 failed to undergo cyclization under our
standard conditions due to a competing decarbonyla-
tion/chelation sequence which blocked the terminal
alkene and produced the stable five-membered carbene
chelate 16 in low yield (Scheme 3) with 81% of the
starting material recovered. The reluctance of
chromium allyloxycarbene for ring closing metathesis
may be rationalized in terms of a carbonylation of the

30
J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
Table 4
hydride (methylene chloride), lithium aluminium hy-
dride (petroleum ether, b.p. 40–60°C; diethyl ether) and
saturated with argon. Silica gel [(E. Merck silica gel 60
(0.63–0.200)] was degassed at high vacuum and stored
under argon prior to use for chromatography.
Competetive metathesis reactions of alkenyl E-crotonates
Crotonate
Lacton (%)
Dimer (%)
n=1:19
n=2:20
n=3:21
22:8
23:15
24:0
25:40
26:60
27:69
5.2. Single-crystal X-ray diffraction analysis of 6 and
11
To further evaluate the unexpected preference of
cross-metathesis over ring closing metathesis observed
for 15 we included alkenyl E-crotonates 19–21 which
represent the isolobal analogues [25] of the aforemen-
tioned propenylcarbene complexes into a comparative
study under similar conditions. The results outlined in
Table 4 demonstrate that cross-metathesis is the fa-
voured reaction path leading to bisesters 25–27. The
unsaturated lactones 22–24 resulting from competitive
ring closing metathesis were isolated only as minor
products. This trend indicates that RCM is hampered
for alkenes conjugated with potent electron-acceptor
groups especially when additional substituents increase
their steric bulk. The results obtained for pairs of
analogous metal carbenes 14/15 and esters 20/21 ap-
pear inconsistent at first glance. However, the straight-
forward cyclization of chromium butenyloxycarbene
14, which contrasts the poor selectivity observed for its
crotonate analogue 20, may reflect the steric bulk of the
pentacarbonylchromium fragment which forces the bu-
tenyl side chain in a conformation allowing a closer
proximity of both alkene moities which is an obvious
requisite for RCM. This behaviour could be described
as an organometallic variant of the Thorpe–Ingold
effect [26]. On the other hand, the reluctance of the
homologous carbene complex 15 towards ring closing
metathesis suggests that the pentenyloxy side chain is
too long to adjust the proper distance to the vinylcar-
bene substituent required for successful RCM steps.
Crystals of 6 and 11 were grown at −28°C in
hexane. Selected structural parameters are summarized
in Tables 1 and 2, crystallographic data are given in
Table 3. Data were collected on a Nonius Kappa-CCD
diffractometer. An empirical absorption correction was
applied for complex 11 (minimum/maximum transmis-
sions 0.8161/0.9119). The structures of 6 and 11 were
solved by direct methods (SHELXS-97) [27] and refined
by full-matrix least-squares on F2. All non-hydrogen
atoms were refined anisotropically on F2 and hydrogen
atoms were localized by difference electron density
determination and refined using
a riding model
(SHELXL-97) [28]. For better comparison of the molecu-
lar structures the original atom labeling given in the
Cambridge Data Center has been changed in this
article.
5.3. Instruments
IR: Nicolet Magna 550 FT-IR. NMR: Bruker DRX-
500, AM-400, AM-250. MS (EI): Kratos MS 50 (70
eV). Elemental analysis: Elementaranalysesysteme
Vario EL.
5.4. Reagents
The following chemicals were prepared according to
literature procedures: tetramethylammonium[acetyl-
(pentacarbonyl)]chromate(−I) (1) [29], pentacarbonyl-
[allyloxy(methyl)carbene]chromium(0) (2) [12], pen-
tacarbonyl[3-butenyloxy(methyl)carbene]chromium(0)
(3) [12], 4-bromo-5-phenyl-1,4-pentene (8) [18] and
alkenyl crotonates (19–21) [30].
5.4.1. Synthesis of the metathesis precursors
5.4.1.1. Synthesis of acyl(pentacarbonyl)chromates 9 and
12. Tetramethylammonium[(2 - E - benzylidene - 4 - pen-
tenoyl)pentacarbonyl]chromate(-I): (9) 2.2 Equivalents
(10.1 mmol, 5.94 ml) of tert-butyllithium (1.7 M solu-
tion in hexane) were added at −78°C to a solution of
1.03 g (4.6 mmol) 4-bromo-5-phenyl-1,4-pentene in 100
ml of diethyl ether. The solution was stirred at this
temperature for 2 h, one equivalent (4.6 mmol, 1.01 g)
hexacarbonyl chromium was added and the reaction
mixture was allowed to warm to room temperature
(r.t.) over 2 h. The solvent was evaporated and the
residue was dissolved in 50 ml of argon-saturated wa-
5. Experimental
5.1. General reaction conditions
All reactions were carried out under dry argon using
Schlenk techniques. The solvents used for reactions and
chromatography were dried by distillation from calcium

J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
31
were added dropwise at −78°C to a solution of 1
mmol of the alkenyloxy(methyl)carbene complex 2 or
3 in 50 ml of diethyl ether. The solution was stirred
for 1 h at this temperature. 1.5 Equivalents (252 mg,
0.14 ml) allyl iodide were added dropwise, and the
reaction mixture was allowed to warm to r.t. over 2 h.
Removal of the solvent and chromatographic work-up
using petroleum ether/dichloromethane (3:1) afforded
complexes 4 or 5 as yellow oils.
ter. 1.5 Equivalents (1.06 g) of tetramethylammonium
bromide were added, and the orange solution was
stirred for 30 min at r.t. The mixture was extracted 3
times with 30 ml of CH2Cl2, the organic layers were
dried over MgSO4 and the solvent was evaporated to
give 1.3 g (2.9 mmol, 64%) of a deep red oil. The
crude product was not further purified. IR (CH2Cl2):
1
w(CO)=2031 w, 1898 vs cm−1. H-NMR (250 MHz,
CDCl3): l 3.09 (d, 3J=5.1 Hz, 2H, CCH2CHCH2),
3.23 (s, 12H, N(CH3)4), 4.97 (d, 3JZ=9.9 Hz, 1H,
CHCH2), 5.02 (d, 3JE=16.8 Hz, 1H, CHCH2), 5.86
Pentacarbonyl[allyloxy(3-butenyl)carbene]chromium-
(0) (4): Yield: 243 mg (0.77 mmol, 77%). Rf=0.4
(petroleum ether). IR (petroleum ether): w(CO)=2064
3
3
3
(ddt, JE=16.8, JZ=9.9, J=5.1 Hz, 1H, CHCH2),
6.98 (s, 1H, CHPh), 7.21–7.40 (m, 5H, ArꢀH) ppm.
13C-NMR (31.25 MHz, CDCl3): l 31.4 (N(CH3)4),
56.6 (CH2CHCH2), 114.8 (CHCH2), 128.2 (meta-
ArꢀC), 18.8 (ortho-ArꢀC), 136.8 (ipso-ArꢀC), 138.0
(CCHPh), 155.5 (CCHPh), 223.1 (cis-CO), 228.0
(trans-CO), 297.3 (CrꢁC) ppm.
1
m, 1961 s, 1948 vs cm−1. H-NMR (500 MHz, CDCl3):
3
l 2.25 (td, J=7.5, 6.9 Hz, 2H, CH2CH2CHCH2), 3.4
3
3
(t, J=7.5 Hz, 2H, CH2CH2CHCH2), 4.99 (d, JZ=
3
10.5 Hz, 1H, CH2CH2CHCH2), 5.02 (d, JE=18.1 Hz,
1H, CH2CH2CHCH2), 5.46 (d, 3JZ=10.6 Hz, 1H, OCH2-
CHCH2), 5.51 (d, 3J=4.7 Hz, 2H, OCH2CHCH2),
3
5.53 (d, JE=16.7 Hz, 1H, OCH2CHCH2), 5.74 (ddt,
3JE=18.1, 3JZ=10.5, 3J=6.9 Hz, 1H, CH2CH2-
Tetramethylammonium[(E - but - 2 - enoyl)pentacar-
bonyl]chromate (12): 2.2 Equivalents (90.86 mmol,
53.3 ml) of tert-butyllithium (1.7 M solution in hex-
ane) were added dropwise at −78°C to a solution of
5 g (41.3 mmol) 1-bromo-propene in 200 ml of diethyl
ether. After the solution was stirred at this tempera-
ture for 2.5 h, one equivalent (41.3 mmol, 9.09 g)
hexacarbonyl chromium was added and the reaction
mixture was allowed to warm to r.t. over 2 h. The
solvent was evaporated and the residue was dissolved
in 120 ml of argon-saturated water. Then 1.5 equiva-
lents (6.99 g) of tetramethylammonium bromide were
added and the orange solution was stirred for 30 min
at r.t. The mixture was extracted three times with 50
ml of CH2Cl2, the organic layers were dried over
MgSO4, filtered and concentrated. After addition of
100 ml of petroleum ether the precipitate was filtered
and dried in vacuo to yield 9.45 g (28.2 mmol, 68%)
of a red solid. Recrystallization from water afforded
dark red crystals. IR (CH2Cl2): w(CO)=2030 w, 1897
3
3
3
CHCH2), 6.15 (ddt, JE=16.7, JZ=10.6, J=4.7 Hz,
1H, OCH2CHCH2) ppm. 13C-NMR (125 MHz,
CDCl3): l 30.39 (CH2CH2CHCH2), 61.9 (CH2CH2-
CHCH2), 82.01 (OCH2), 115.81 (CH2CH2CHCH2),
120.46 (OCH2CHCH2), 130.70 (OCH2CHCH2), 136.27
(CH2CH2CHCH2), 216.20 (cis-CO), 223.02 (trans-
CO), 360.23 (CrꢁC) ppm. MS (EI): m/z (%): 316 (13)
[M+], 232 (19) [M+−3CO], 176 (34) [M+−5CO],
135 (22) [M+−5CO, ꢀC3H5], 94 (21). HRMS: Calc.
for M+: 316.0039; Found 316.0032. Anal. Found: C,
49.45; H, 3.72. C13H12O6Cr (316.23). Calc.: C, 49.38;
H, 3.82%.
Pentacarbonyl[3-butenyl-(3-butenyloxy)carbene]chro-
mium(0) (5): Yield: 274 mg (0.83 mmol, 83%). Rf=0.4
(petroleum ether). IR (petroleum ether): w(CO)=2064
1
m, 1948 vs cm−1. H-NMR (500 MHz, CDCl3): l 2.21
3
(td, J=7.5, 6.8 Hz, 2H, CCH2CH2CHCH2), 2.74 (td,
3
3J=6.5 Hz, 2H, OCH2CH2CHCH2), 3.40 (t, J=7.5
Hz, 2H, CCH2CH2CHCH2), 4.98 (d, 3JZ=10.2 Hz, 1H,
CCH2CH2CHCH2), 5.02 (d, 3JE=16.8 Hz, 1H,
vs cm−1 1H-NMR (250 MHz,CD2Cl2): l 1.70 (d,
.
3
CCH2CH2CHCH2), 5.05 (t, J=6.5 Hz, 2H, OCH2),
3J=6.3 Hz, 3H, CH3), 3.34 (s, 12H, N(CH3)4), 5.75
(dq, 3J=15.1; 6.3 Hz, 1H, CHꢁCHCH3), 6.43 (d,
3J=15.1 Hz, 1H, CHꢁCHCH3) ppm. 13C-NMR
5.19 (dd, 3JZ=10.2, 2J=1.3 Hz, 1H, OCH2-
CH2CHCH2), 5.23 (dd, 3JE=17.1, 2J=1.3 Hz, 1H,
OCH2CH2CHCH2), 5.74 (ddt, 3JE=16.8, 3JZ=10.2,
(31.25 MHz, CD2Cl2):
l
14.17 (CH3), 55.97
3
3J=6.8 Hz, 1H, CCH2CH2CHCH2), 5.89 (ddt, JE=
(N(CH3)4), 111.59 (CHꢁCHCH3), 147.88 (CHꢁ
CHCH3), 224.72 (cis-CO), 229.68 (trans-CO), 292.73
(CrꢁC) ppm. MS (EI): m/z (%): 220 (21) [M+−4CO],
192 (3) [M+−5CO]. Anal. Found: C, 46.50; H, 5.00;
N, 4.19. C13H17O6NCr (335.289) Calc.: C, 46.57; H,
5.11; N, 4.18%.
3
3
17.1, JZ=10.2, J=6.5 Hz, 1H, OCH2CH2CHCH2)
ppm. 13C-NMR (125 MHz, CDCl3):
l
30.28
(CCH2CH2CHCH2), 33.66 (OCH2CH2), 61.95 (CCH2),
80.68 (OCH2), 115.72 (OCH2CH2CHCH2), 118.47
(CCH2CH2CHCH2),
132.78
(OCH2CH2CHCH2),
136.38 (CCH2CH2CHCH2), 216.31 (cis-CO), 223.08
(trans-CO), 359.68 (CrꢁC) ppm. MS (EI): m/z (%): 330
(8) [M+], 302 (5) [M+−CO], 246 (12) [M+−3CO],
218 (8) [M+−4CO], 190 (62) [M+−5CO], 107 (22), 55
(100). HRMS: Calc. for M+−5CO: 190.0449, Found:
190.0434%.
5.4.1.2. [(Alkenyloxy)3-butenylcarbene]pentacarbonyl-
chromium complexes 4, 5 and 10. General procedure
for C-allylation of (alkenyloxy)methylcarbene com-
plexes 2, 3: 1.1 Equivalents (0.63 ml) n-butyllithium

32
J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
3
3
Pentacarbonyl[allyloxy(2-E-benzylidene-3-butenyl)-
OCH2CHCH2), 6.39 (dq, JE=14.9, J=6.9 Hz, 1H,
CHCHCH3), 7.33 (dq, 3JE=14.9, 4J=1.5 Hz, 1H,
CHCHCH3) ppm. 13C-NMR (125 MHz, CDCl3): l
18.15 (CH3), 80.26 (OCH2), 119.83 (CHCH2), 131.32
(CHCH2), 132.87 (CHCHCH3), 145.73 (CHCHCH3),
216.62 (cis-CO), 223.92 (trans-CO), 333.99 (CrꢁC)
ppm. MS (EI): m/z (%): 302 (7) [M+], 274 (4) [M+−
CO], 246 (14) [M+−2CO], 218 (6) [M+−3CO], 190
(26) [M+−4CO], 162 (17) [M+−5CO], 121 (18), 52
(100). HRMS: Calc. for M+: 301.9883; Found:
301.9885.
carbene]chromium(0) (10): One equivalent (153 mg,
0.16 ml) of pivaloyl chloride was added at −20°C to a
solution of 557 mg (1.27 mmol) tetramethylammo-
nium[(2 - E - benzylidene - 4 - pentenoyl)pentacarbonyl]-
chromate(−I) (7) in 70 ml of CH2Cl2. The mixture was
stirred for 30 min at this temperature and two equiva-
lents of allyl alcohol were added dropwise to the dark
brown solution. The solution was allowed to warm to
0°C over 2 h. The solvent was evaporated and the
residue was purified by chromatography at −5°C using
petroleum ether/dichloromethane (3:1) to give 272 mg
(0.62 mmol, 49%) of a red oil. IR (petroleum ether):
Pentacarbonyl [3-butenyloxy(E-1-propenyl)carbene]-
chromium(0) (14): Yield: 487 mg (1.54 mmol, 77%).
Rf=0.7 (petroleum ether/CH2Cl2 3/1). IR (petroleum
1
w(CO)=2059 m, 1945 vs cm−1. H-NMR (500 MHz,
CDCl3): l 3.37 (d, 3J=6.1 Hz, 2H, CCH2CHCH2),
5.09 (d, 3JE=18.0 Hz, 1H, CCH2CHCH2), 5.12 (d,
3JZ=10.3 Hz, 1H, CCH2CHCH2), 5.45–5.49 (m, 2H,
OCH2), 5.51 (d, 3JZ=10.4 Hz, 1H, OCH2CHCH2),
ether): w(CO)=2059 m, 1945 vs cm−1. H-NMR (500
1
3
MHz, CDCl3): l 1.86 (d, J=6.8 Hz, 3H, CH3), 2.73
3
(m, 2H, OCH2CH2), 5.00 (t, J=6.0 Hz, 2H, OCH2),
3
3
5.18 (d, JZ=10.4 Hz, 1H, CHCH2), 5.22 (d, JE=17.3
3
5.59 (d, JE=17.2 Hz, 1H, OCH2CHCH2), 5,85 (ddt,
3
3
Hz, 1H, CHCH2), 5.90 (dq, 3JZ=14.8, 3J=6.8 Hz, 1H,
3JE=18.0, JZ=10.3, J=6.1 Hz, 2H, CCH2CHCH2),
6.22 (ddt, 3JE=17.2, 3JZ=10.4, 3J=5.7 Hz, 2H,
OCH2CHCH2), 7.03 (s, 1H, CCHPh), 7.32-7.43 (m,
5H, ArꢀH) ppm. 13C-NMR (125 MHz,CDCl3): l 33.91
(CCH2CHCH2), 80.97 (OCH2), 117.29 (CHCH2),
120.39 (CH CH2), 126.66, 128.12, 128.26, 128.48,
129.09, 130.81 (all CH), 134.24 (ipso-ArC), 134.24
(CrꢁCC), 216.33 (cis-CO), 223.72 (trans-CO), 350.62
(CrꢁC) ppm. MS (EI): m/z (%): 404 (20) [M+], 376 (40)
[M+−CO], 348 (8) [M+−2CO], 320 (12) [M+−
3CO], 292 (20) [M+−4CO], 264 (20) [M+−5CO], 236
(40) [M+−6CO], 212 (40) [M+−5CO, ꢀCr], 194 (100),
171 (62) [M+−5CO, ꢀCr, ꢀC3H5], 141 (35), 128 (95),
115 (52), 91 (39), 69 (50), 52 (87). HRMS: Calc. for
[M+−5CO]: 264.0606, Found: 264.0607%.
3
3
3
CHCHCH3), 5.34 (ddt, JE=17.3, JZ=10.4, J=6.4
Hz, 1H, CHCH2), 7.31 (d, JZ=14.8 Hz, CHCHCH3)
3
ppm. 13C-NMR (125 MHz, CDCl3): l 18.08 (CH3),
33.81 (OCH2CH2), 78.87 (OCH2), 118.15 (CHCH2),
132.43 (CHCHCH3), 133.27 (CHCH2), 145.80
(CHCHCH3), 216.73 (cis-CO), 223.96 (trans-CO),
333.57 (CrꢁC) ppm. MS (EI): m/z (%): 319 (60) [M+],
288 (5) [M+−CO], 260 (12) [M+−2CO], 232 (50)
[M+−3CO], 204 (22) [M+−4CO], 176 (55) [M+−
5CO], 93 (20), 52 (70). HRMS: Calc. for M+: 316.0024;
Found: 316.0032%.
Pentacarbonyl [4 - pentenyloxy(E - 1 - propenyl)car-
bene]chromium(0) (15): Yield: 528 mg (0.16 mmol,
80%). Rf=0.7 (petroleum ether/CH2Cl2 3/1). IR
(petroleum ether) w(CO)=2059 m, 1934 vs cm−1. H-
1
3
4
5.4.1.3. [Alkenyloxy(E - 1 - propenyl)carbene]pentacar-
bonylchromium complexes 13–15. General procedure:
One equivalent (246 mg, 0.15 ml) of acetyl bromide was
added at −40°C to a solution of 670 mg (2 mmol) 12
in 100 ml of dichloromethane. After stirring the mixture
for 10 min at this temperature, two equivalents of the
alcohol were added dropwise to the dark brown solu-
tion, which subsequently was allowed to warm to room
temperature over a period of 2 h. Removal of the sol-
vent and chromatographical work-up using petroleum
ether/dichloromethane (3:1) as eluent afforded com-
plexes 13–15 as red oils.
NMR (250 MHz, CDCl3): l 1.88 (dd, J=6.6, J=1.4
Hz, 3H, CH3), 2.08 (tt, J=6.5 Hz, 2H, OCH2CH2),
3
3
2.29 (dt, J=6.6, 6.5 Hz, 2H, OCH2CH2CH2), 4.95 (t,
3J=6.5 Hz, 2H, OCH2), 5.05 (dd, JZ=10.4, J=1.6
3
2
Hz, 1H, CHCH2), 5.09 (dd, 3JE=17.0, 2J=1.6 Hz, 1H,
3
3
3
CHCH2), 5.87 (ddt, JE=17.0, JZ=10.4, J=6.6 Hz,
1H, CHCH2), 6.34 (dq, 3JE=14.9 Hz, 1H,
CHCHCH3), 7.29 (dq, 3JE=14.9, 2J=1.4 Hz, 1H,
CHCHCH3) ppm. 13C-NMR (31.25 MHz, CDCl3): l
18.12 (CH3), 28.64 (CH2), 30.12 (CH2), 79.42 (OCH2),
115.97 (CHCH2), 132.61 (CHCHCH3), 136.84
(CHCH2), 145.73 (CHCHCH3), 216.79 (cis-CO),
224.01 (trans-CO), 333, 75 (CrꢁC) ppm. MS (EI): m/z
(%): 330 (9) [M+], 302 (2) [M+−CO], 374 (6) [M+−
2CO], 246 [M+−3CO], 218 (30) [M+−4CO], 190 (79)
[M+−5CO], 148 (23) [M+−5CO, ꢀOCH2], 93 (34
[M+−5CO, ꢀOCH2, ꢀC4H7], 52 (100). HRMS: Calc.
for M+−5CO: 190.0450; Found: 190.0447. Anal.
Found: C, 50.78; H, 4.34. C14H14O6Cr (330.26) Calc.:
C, 50.92; H, 4.27%.
Pentacarbonyl [allyloxy(E-1-propenyl)carbene]chro-
mium(0) (13): Yield: 369 mg (1.22 mmol, 61%). Rf=0.7
(petroleum ether/CH2Cl2 3/1). IR (petroleum ether):
1
w(CO)=2059 m, 1942 vs) cm−1. H-NMR (CDCl3): l
1.88 (dd, 3J=6.9, 4J=1.5 Hz, 3H, CH3), 5.42 (dd,
2
3
3JZ=10.5, J=1.1 Hz, 1H, CHꢁCH2), 5.47 (dd, J=
4
3
5.7, J=1.0 Hz, 2H, OCH2CHCH2), 5.49 (ddt, JE=
16.6, 2J=1.1, 4J=1.0 Hz, 1H, OCH2CHCH2), 6.15
(ddt, 3JE=16.6, 3JZ=10.5, 3J=5.7 Hz, 1H,

J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
33
5.4.2. Metathesis reactions
General procedure for the metathesis of alkenyl-
oxy(propenyl)carbene complexes 13–15: 20 mg (5
mol%) of catalyst 7 were added at r.t. to a solution of
0.5 mmol of the complexes 13–15 in 50 ml of
dichloromethane. The reaction mixture was stirred for 3
h at this temperature before additional 20 mg (5 mol%)
7 were added. After 3 h the solvent was evaporated and
chromatographic work-up at −5°C using petroleum
ether/dichloromethane (3:1) afforded complexes 16–18.
Cis-Tetracarbonyl[h2-allyloxy(E-1-propenyl)carbene]
chromium(0) (16): Yield 11 mg (0.04 mmol, 8%) as a
red oil. Rf=0.6 (petroleum ether/dichloromethane
(3:1)). IR (petroleum ether): w(CO)=2054 w, 2023 m,
Pentacarbonyl[(2-oxacyclohept-4-enyl)carbene]chro-
mium(0) (6): 69 mg (5 mol%) of catalyst 7 were added
at r.t. to a solution of 528 mg (1.67 mmol) of complex
4 in 55 ml of dichloromethane. The reaction mixture
was stirred for 3 h and additional 35 mg (2.5 mol%) 7
were added. After additional 3 h the solvent was evapo-
rated and chromatographic work-up at −5°C using
petroleum ether/dichloromethane (3:1) afforded 390 mg
(1.36 mmol, 81%) 6 a as yellow solid along with 110 mg
(0.35 mmol, 17%) of the starting compound 4. Recrys-
tallization from hexane afforded yellow crystals. Rf=
0.5 (petroleum ether/dichloromethane (3:1)). IR
(petroleum ether): w(CO)=2065 m, 1963 s, 1950 vs
1
1942 s cm−1. H-NMR (500 MHz, CDCl3): l 1.93 (d,
1
cm−1. H-NMR (500 MHz, CDCl3): l 2.50 (m, 2H,
3J=6.4 Hz, 3H, CH3), 3.08 (d, 3JZ=8.8 Hz, 1H,
CHCH2), 3.29 (d, 3JE=13.3 Hz, 1H, CHCH2), 4.75
(dd, 2J=11.9, 3J=4.7 Hz, 1H, OCH2), 4.89 (dddd,
3JE=13.3, 3JZ=8.8, 3J=4.7; 4.3 Hz, 1H, CHCH2),
3
CrꢁCH2CH2), 3.72 (t, J=6.6 Hz, 2H, CrꢁCCH2CH2),
5.21 (m, 2H, OCH2), 5.68 (m, 1H, OCH2CHCH), 5.8
3
3
(dt, JZ=10.9, J=3.5 Hz, 1H, OCH2CH) ppm. 13C-
NMR (125 MHz, CDCl3): l 24.16 (CrꢁCCH2CH2),
52.03 (CrꢁCCH2CH2), 71.21 (OCH2), 122.61 (ꢁCH),
133.67 (ꢁCH), 216.46 (cis-CO), 223.96 (trans-CO),
361.76 (CrꢁC) ppm. MS (EI): m/z (%): 288 (25) [M+],
260 (12) [M+−CO], 232 (11) [M+−2CO], 204 (12)
[M+−3CO], 176 (38) [M+−4CO], 148 (95) [M+−
5CO], 120 (20) [M+−5CO, ꢀC2H4], 80 (30), 52 (100).
HRMS: Calc. for M+: 287.9726; Found: 287.9719%.
Pentacarbonyl[(7-E-benzylidene-2-oxacyclohept-4-
enyl)carbene]chromium(0) (11): 10 mg (5 mol%) cata-
lyst 7 were added at 0°C to a solution of 271 mg (0.62
mmol) of complex 10 in 20 ml of dichloromethane. The
reaction mixture was stirred for 3 h at this temperature
before additional 10 mg (5 mol%) 7 were added. After
4 additional hours the solvent was evaporated and
chromatographic work-up at −5°C using petroleum
ether/dichloromethane (3:1) afforded 95.6 mg (0.25
mmol, 41%) 11 as yellow solid along with 57.0 mg (0.13
mmol, 21%) of starting material 10. Recrystallization
from hexane afforded red crystals. Rf=0.6 (petroleum
ether/dichloromethane (3:1)). IR (petroleum ether):
2
3
5.12 (dd, J=11.9, J=4.3 Hz, 1H, OCH2), 6.75 (dq
3JZ=15.4, 3J=6.4 Hz, 1H, CHCHCH3), 6.84 (d,
3JZ=15.4 Hz, 1H, CHCHCH3) ppm. 13C-NMR (125
MHz, CDCl3): l 18.96 (CH3), 65.67 (CHCH2), 81.95
(OCH2), 95.56 (CHCH2), 141.34 (CHCHCH3), 142.57
(CHCHCH3), 221, 35, 221.75, 227.40, 231.17 (CO),
335.62 (CrꢁC) ppm. MS (EI): m/z (%): 274 (2) [M+],
246 (4) [M+−CO], 190 (6) [M+−3CO], 162 (5) [M+
−4CO], 149 (10) [M+−3CO, ꢀC3H5], 108 (14) [M+−
3CO, ꢀC3H5, ꢀC3H5], 80 (50), 52 (90). 122 mg (0.4 mml,
81%) of starting material 13 were reisolated.
Pentacarbonyl[(2 - oxacyclohex - 5 - enyl)carbene]chro-
mium(0) (17): Yield: 66 mg (0.24 mmol, 48%) as red
crystals. Rf=0.4 (petroleum ether/dichloromethane
(3:1)). IR (petroleum ether): w(CO)=2061 m, 1946 vs
1
3
cm−1. H-NMR (500 MHz, CDCl3): l 2.35 (td, J=
6.8; 5.0 Hz, 2H, OCH2CH2), 4.42 (t, 3J=6.8 Hz,
2H, OCH2), 5.95 (dt, 3JZ=9.8, 3J=5.0 Hz, 1H,
3
CHCHCH2), 7.57 (d, JZ=9.8 Hz, 1H, CHCHCH2)
ppm. 13C-NMR (125 MHz, CDCl3):
l
23.02
(OCH2CH2), 68.01 (OCH2), 124.73 (CHCHCH2),
138.74 (CHCHCH2), 216.61 (cis-CO), 225.05 (trans-
CO), 324.36 (CrꢁC) ppm. MS (EI): m/z (%): 274 (14)
[M+], 246 (9) [M+−CO], 218 (6) [M+−2CO], 190
(13) [M+−3CO], 162 (20) [M+−4CO], 134 (97) [M+
−5CO], 80 (21), 52 (100). HRMS: Calc. for M+−
5CO: 133.9824; Found: 133.9826. 53 mg (0.16 mml,
33%) of starting material 14 were reisolated.
w(CO)=2065 m, 1965 s, 1955 vs cm−1. H-NMR (500
1
MHz, CDCl3):
l
3.24 (d, 3J=3.2 Hz, 2H,
3
OCH2CHCHCH2), 5.16 (d, J=4.7 Hz, 2H, OCH2),
3
3
5.82 (dt, JZ=10.2, J=4.7 Hz, 1H, OCH2CH), 5.88
3
3
(dt, JZ=10.2, J=3.2 Hz, 1H, OCH2CHCHC), 6.45
(s, 1H, CCHPh), 7.25–7.4 (m, 5H, HꢀAr) ppm. 13C-
NMR (125 MHz, CDCl3): l 27.54 (CH2CHCHCH2O),
71.46 (OCH2), 123.18 (CHCH), 127.46 (CCH), 127.94
(para-ArꢀC), 128.62 (meta-ArꢀC), 128.98 (ortho-ArꢀC),
132.23 (CHꢁCH), 134.33 (ipso-ArꢀC), 150.39 (CrꢁCC),
216.19 (cis-CO), 224.39 (trans-CO), 354.89 (CrꢁC)
ppm. MS (EI): m/z (%): 376 (3) [M+], 348 (10) [M+−
CO], 320 (2) [M+−2CO], 292 (13) [M+−3CO], 264
(20) [M+−4CO], 236 (30) [M+−5CO], 182 (33) [M+
−5CO, ꢀC4H6]. HRMS: Calc. for M+: 376.0039;
Found 376.0039%. Anal. Calc.: C, 57.46. H, 3.21.
Found: C, 57.51; H, 3.31. C18H12O6Cr (376.0)%.
4-Octen-1,8-dioxy-{bis-[pentacarbonyl(E-1-propenyl-
carbene)chromium(0)]} (18): Yield: 31.6 mg (0.05
mmol, 20%) as a red oil; E/Z-ratio: 3:1. Rf=0.6
(petroleum ether/dichloromethane (3:1)). IR (petroleum
1
ether): w(CO)=2061 m, 1946 vs cm−1. E-isomer: H-
3
4
NMR (500 MHz, C6D6): l 1.33 (dd, J=7.0, J=1.6
Hz, 6H, CH3, CH‘3), 1.63 (tt, 3J=6.5 Hz, 4H,
OCH2CH2, OCH2CH%), 1.98–2.06 (m, 4H, OCH2-
2
CH2CH2, OCH2CH2CH%), 4.64 (t, 3J=6.4 Hz, 4H,
2
OCH2, OCH%), 5.30 (tt, 3J=3.7, 4J=1.5 Hz, 2H,
2

34
J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
OCH2CH2CH2CH, OCH2CH2CH2CH%), 6.15 (dq,
OCH2CH%) 144.89 (OCCHCH, OCCHCH%), 165.72
(CO,CO%) ppm. FABMS: m/z: 225 [M++H]. 5H-fu-
ran-2-one 22. Yield: 7 mg (0,08 mmol, 8%). The analyt-
ical data for 22 correspond to the data given in
literature [31].
3
3JE=14.8, J=7.0 Hz, 2H, CHCHCH3, CHCHCH3%),
3
7.19 (d, JE=14.8, 2H, CHCHCH3) ppm. 13C-NMR
(125 MHz, C6D6): l 17.70 (CH3, CH3%), 28.91 (2×
CH2), 29.03 (2×CH2), 79.44 (CH2O, CH2O%), 128.29
(CHCHCH3, CHCHCH%3), 130.09 (OCH2CH2CH2CH,
OCH2CH2CH2CH%), 145.63 (CHCHCH3, CHCH-
CH3‘), 217.23 (cis-CO, cis-CO%), 224.14 (trans-CO,
Metathesis of butenylcrotonate (20): 1,6-bis-E-
crotonyloxy-hex-3-ene (26): Yield: 151 mg (0.6 mmol,
60%); E/Z-ratio: 1.8:1. Rf=0.6 (petroleum ether/di-
ethyl ether (3:1)). E-isomer: 1H-NMR (250 MHz, C6D6):
1
trans-CO%), 333.80 (CrꢁC, CrꢁC%) ppm. Z-isomer: H-
3
4
3
4
NMR (500 MHz, C6D6): l 1.36 (dd, J=7.0, J=1.6
l 1.40 (dd, J=6.9, J=1.5 Hz, 6H, CH3, CH3%), 2.20
Hz, 6H, CH3, CH3%), 1.63 (tt, 3J=6.5 Hz, 4H,
(m, 4H, OCH2CH2, OCH2CH%), 4.07 (t, J=6.7 Hz,
3
2
3
4
OCH2CH2, OCH2CH%), 1.98–2.06 (m, 4H, OCH2-
4H, OCH2, OCH%2), 5.31 (tt, J=4.0, J=1.5 Hz, 2H,
2
CH2CH2, OCH2CH2CH%), 4.61 (t, 3J=6.4 Hz, 4H,
OCH2CH2CH, OCH2CH2CH%), 5.83 (dq, 3JE=15.0,
2
OCH2, OCH%), 5.35 (tt, 3J=4.8, 4J=1.2 Hz, 2H,
4J=1.5 Hz, 2H, CCHCH, CCHCH‘), 6.95 (dq, JE=
3
2
3
OCH2CH2CH2CH, OCH2CH2CH2CH%), 6.15 (dq,
15.0, J=6.9 Hz, 2H, CCHCH, CCHCH%) ppm. 13C-
3
3JE=14.8, J=7.0 Hz, 2H, CHCHCH3, CHCHCH3%),
NMR (62.5 MHz, C6D6): l 17.53 (CH3, CH3%), 32.41
(OCH2CH2, OCH2CH2%), 63.49 (OCH2, OCH2%), 123.12
(CCHCH, CCHCH%), 128.56 (OCH2CH2CH, OCH2-
CH2CH%), 144.28 (CCHCH, CCHCH%), 165.92 (CO,
CO%) ppm. Z-isomer: 1H-NMR (250 MHz, C6D6): l
3
7.17 (d, JE=14.8, 2H, CHCHCH3) ppm. 13C-NMR
(125 MHz, C6D6): l 17.70 (CH3, CH3%), 23.69 (2×
CH2), 29.13 (2×CH2), 79.34 (CH2O, CH2O%), 128.29
(CHCHCH3, CHCHCH%3), 129.48 (OCH2CH2CH2CH,
OCH2CH2CH2CH%), 145.71 (CHCHCH3, CHCHCH%3),
217.36 (cis-CO, cis-CO%), 224.17 (trans-CO, trans-CO%),
333.93 (CrꢁC, CrꢁC%) ppm. FABMS: m/z: 632 [M+],
492 [M+−5CO], 408 [M+−8CO], 380 [M+−9CO],
352 [M+−10CO]. 110 mg (0.34 mml, 67%) of starting
material 15 were reisolated.
1.40 (dd, 3J=6.9, 4J=1.5 Hz, 6H, CH3, CH3%), 2.20 (m,
3
4H, OCH2CH2, OCH2CH%), 4.07 (t, J=6.7 Hz, 4H,
2
OCH2, OCH%2), 5.39 (tt, 3J=5.0, 4J=1.2 Hz, 2H,
OCH2CH2CH, OCH2CH2CH%), 5.83 (dq, 3JE=15.0,
4J=1.5 Hz, 2H, CCHCH, CCHCH%), 6.95 (dq, JE=
3
15.0, J=6.9 Hz, 2H, CCHCH, CCHCH%) ppm. 13C-
3
General procedure for the metathesis of the alkenyl
crotonates 19–21: 41 mg (5 mol%) of catalyst 7 were
added at r.t. to a solution of 1 mmol alkenyl crotonate
in 100 ml dichloromethane. The reaction mixture was
stirred for 3 h before additional 41 mg (5 mol%) 7 were
added. After 3 h the solvent was evaporated, and
chromatographic work-up using petroleum ether/di-
ethyl ether (3:1) afforded the products as colourless
oils.
NMR (62.5 MHz, C6D6): l 17.53 (CH3, CH3%), 27.21
(OCH2CH2, OCH2CH2%), 63.38 (OCH2, OCH2%), 123.12
(CCHCH,
CCHCH%),
128.56
(OCH2CH2CH,
OCH2CH2CH%), 144.36 (CCHCH, CCHCH%), 165.92
(CO, CO%) ppm. FABMS: m/z: 253 [M++H], 167
[M++H, ꢀC4O2H6]. 5,6-Dihydro-pyran-2-one (23).
Yield: 15 mg (0.15 mmol, 15%). The analytical data for
23 correspond to the data given in literature [32]
Metathesis of butenylcrotonate (21): 1,8-bis-E-
crotonyloxy-oct-4-ene (27): Yield: 193 mg (0.69 mmol,
69%); E/Z-ratio: 3:1. Rf=0.6 (petroleum ether/diethyl
Metathesis of allylcrotonate (19): 1,4-bis-E-crotonyl-
oxy-but-2-ene (25): Yield: 90 mg (0.4 mmol, 40%);
E/Z-ratio: 5:1. Rf=0.6 (petroleum ether/diethyl ether
1
ether (3:1)). E-isomer: H-NMR (500 MHz, C6D6): l
1
3
4
(3:1)). E-isomer: H-NMR (500 MHz, C6D6): l 1.34
1.38 (dd, J=6.7, J=1.5 Hz, 6H, CH3, CH3%), 1.57 (tt,
3
4
3
(dd, J=7.0, J=1.5 Hz, 6H, CH3, CH3%), 4.50 (dd,
3J=6.8 Hz, 4H, OCH2CH2, OCH2CH%), 1.94 (td, J=
2
3J=3.0, 4J=1.5 Hz, 4H, OCH2, OCH%), 5.66 (tt,
6.8, 4.0 Hz, 4H, OCH2CH2CH2, OCH2CH2CH%), 4.13
2
2
3J=3.0, J=1.5 Hz, 2H, OCH2CH2, OCH2CH%), 5.79
(t, J=6.8 Hz, 4H, OCH2, OCH%2), 5.29 (tt, J=4.0,
4
3
3
2
(dq, 3JE=15.0, 4J=1.5 Hz, 2H, CCH, CCH%), 6.93
(dq, 3JE=15.0, 3J=7.0 Hz, 2H, OCCHCH, OC-
CHCH%) ppm. 13C-NMR (125 MHz, C6D6): l 17.68
(CH3, CH3%), 63.75 (OCH2 OCH2%), 122.95 (OCCHCH,
OCCHCH%), 128.43 (OCH2CH, OCH2CH%), 144.89
(OCCHCH, OCCHCH%), 165.72 (CO,CO%) ppm. Z-iso-
4J=1.5 Hz, 2H, OCH2CH2CH2CH, OCH2CH2CH2-
3
4
CH%), 5.85 (dq, JE=15.5, J=1.5 Hz, 2H, CCHCH,
CCHCH%), 6.97 (dq, 3JE=15.5, 3J=6.7 Hz, 2H,
CCHCH, CCHCH%) ppm. 13C-NMR (125 MHz, C6D6):
l 17.5 (CH3, CH3%), 28.84 (2×CH2), 29.15 (2×CH2),
63.51 (OCH2, OCH2%), 123.21 (CCHCH, CCHCH%),
130.07 (OCH2CH2CH2CH, OCH2CH2CH2CH%), 144.20
(CCHCH, CCHCH%), 166.01 (CO, CO%) ppm. Z-iso-
1
3
mer: H-NMR (500 MHz, C6D6): l 1.34 (dd, J=7.0,
4J=1.5 Hz, 6H, CH3, CH3%), 4.67 (dd, J=4.0, J=1.2
Hz, 4H, OCH2, OCH%), 5.62 (tt, J=4.0, J=1.2 Hz,
2H, OCH2CH2, OCH2CH%), 5.79 (dq, JE=15.0, J=
1.5 Hz, 2H, CCH, CCH%), 6.93 (dq, JE=15.0, J=7.0
Hz, 2H, OCCHCH, OCCHCH%) ppm. 13C-NMR (125
MHz, C6D6): l 17.68 (CH3, CH%3), 69.92 (OCH2 OCH%2),
122.95 (OCCHCH, OCCHCH%), 128.58 (OCH2CH,
3
4
3
4
1
3
mer: H-NMR (500 MHz, C6D6): l 1.39 (dd, J=6.7,
2
3
4
3
4J=1.5 Hz, 6H, CH3, CH3%), 1.57 (tt, J=6.8 Hz, 4H,
OCH2CH2, OCH2CH%), 1.20 (td, J=6.8, 4.8 Hz, 4H,
OCH2CH2CH2, OCH2CH2CH%), 4.11 (t, J=6.8 Hz,
2
3
3
3
2
3
2
3
4
4H, OCH2, OCH%2), 5.31 (tt, J=4.8, J=1.2 Hz, 2H,
OCH2CH2CH2CH, OCH2CH2CH2CH%), 5.85 (dq, 3JE=

J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
35
4
15.5, J=1.5 Hz, 2H, CCHCH, CCHCH%), 6.97 (dq,
troskopie isolierter und kondensierter Moleku¨le) and
from the Fonds der Chemischen Industrie is gratefully
acknowledged.
3JE=15.5, J=6.7 Hz, 2H, CCHCH, CCHCH%) ppm.
3
13C-NMR (125 MHz, C6D6): l 17.5 (CH3, CH%3), 23.79
(2×CH2), 28.90 (2×CH2), 63.48 (OCH2, OCH2%), 123.17
(CCHCH, CCHCH%), 129.59 (OCH2CH2CH2CH,
OCH2CH2CH2CH%), 144.13 (CCHCH, CCHCH%),
166.01 (CO, CO%) ppm. FABMS: m/z: 281 [M++H], 195
[M++H, ꢀC4O2H6], 167 [M++H, ꢀC4O2H6, ꢀC2H4].
References
[1] K.H. Do¨tz, A. Koch, B. Weyershausen, H. Hupfer, M. Nieger,
Tetrahedron, in press.
[2] Recent reviews: (a) R.H. Grubbs, S. Chang, Tetrahedron 54
(1998) 4413. (b) M. Schuster, S. Blechert, Angew. Chem. 109
(1997) 2124; Angew. Chem. Int. Ed. Engl. 36 (1997) 2036. (c)
S.K. Armstrong, J. Chem. Soc. Perkin Trans. 1 (1998) 371. (d)
C. Pariya, K.N. Jayaprakash, A. Sarkar, Coord. Chem. Rev. 168
(1998) 1.
6. Conclusions
We have demonstrated, in principle, that the metal
carbene moiety in the Grubbs ruthenium-based RCM
catalyst is compatible with another electrophilic metal
carbene functionality as present in Fischer-type car-
bonyl carbene complexes. The propensity for ring clos-
ing metathesis within the alkenyl(alkenyloxy)carbene
ligand depends on both the length of the spacers sepa-
rating the alkene termini and the carbene carbon atom
and the alkene substitution pattern. Whereas the allyl-
oxy complex 13 prefers intramolecular chelation result-
ing in a stable tetracarbonyl carbene chelate complex 16,
its homoallyl analogue 14 undergoes ring closing
metathesis probably assisted by the bulky Cr(CO)5
fragment which may favour the proximity of both
alkene termini required for RCM. The conformative
assistance of the metal carbonyl group decreases with
insertion of another methylene spacer as suggested by
the pentenyloxycarbene complex 15 which prefers the
formation of a dinuclear cross-metathesis product 18
over RCM. The pronounced selectivity observed for the
alkenyloxy(alkenyl)carbene complex homologues obvi-
ously requires the use of tailored RCM catalysts. Recent
advances in this direction have been reported by Herr-
mann who has developed promising imidazolylidene–
phosphine complexes for application in RCM [4a].
[3] P. Schwab, R.H. Grubbs, J.W. Ziller, J. Am. Chem. Soc. 118
(1996) 100.
[4] (a) T. Weskamp, F.J. Kohl, W. Hieringer, D. Gleich, W.A.
Herrmann, Angew. Chem. 111 (1999) 2573; Angew. Chem. Int.
Ed. Engl. 38 (1999) 2416. (b) M. Scholl, T.M. Trnka, J.P.
Morgan, R.H. Grubbs, Tetrahedron Lett. 40 (1999) 2247. (c) A.
Fu¨rstner, M. Picquet, C. Bruneau, P.H. Dixneuf, Chem. Com-
mun. (1998) 1315.
[5] (a) K.C. Nicolaou, Y. He, D. Vourloumis, H. Vallberg, F.
Roschangar, F. Sarabia, S. Ninkovic, Z. Yang, J.I. Trujillo, J.
Am. Chem. Soc. 119 (1997) 7960. (b) A. Fu¨rstner, K. Lange-
mann, J. Am. Chem. Soc. 119 (1997) 9130.
[6] Reviews: (a) K.H. Do¨tz, Angew. Chem. 96 (1984) 573; Angew.
Chem. Int. Ed. Engl. 23 (1984) 587. (b) W.D. Wulff, in: Compre-
hensive Organic Synthesis, vol. 5, Pergamon Press, Oxford
(1991) 1065. (c) L.S. Hegedus, Tetrahedron 53 (1997) 4105. (d)
K.H. Do¨tz, J. Pfeiffer, in: M. Beller, C. Bolm (Eds.), Transition
Metals for Organic Synthesis, vol. 1, Wiley-VCH, Weinheim,
1998, p. 335. (e) F. Zaragoza-Do¨rwald, Metal Carbenes in
Organic Synthesis, Wiley-VCH, Weinheim, 1999.
[7] (a) C.C. Kreiter, Angew. Chem. 80 (1968) 402; Angew. Chem.
Int. Ed. Engl. 7 (1968) 390. (b) C.P. Casey, W.R. Brunsvold,
D.M. Scheck, Inorg. Chem. 16 (1977) 3059.
[8] (a) W.D. Wulff, S.R. Gilbertson, J. Am. Chem. Soc. 107 (1985)
503. (b) W.D. Wulff, Y.C. Xu, J. Org. Chem. 52 (1987) 3263. (c)
T.S. Powers, Y. Shi, K.J. Wilson, W.D. Wulff, A. Rheingold, J.
Org. Chem. 59 (1994) 6882.
[9] (a) E. Nakamura, K. Tanaki, T. Fujimura, S. Aoki, P.G.
Williard, J. Am. Chem. Soc. 115 (1993) 9015. (b) J. Barluenga,
J.M. Monserrat, J. Flo´rez, S. Gracia-Granda, E. Martin, Chem.
Eur. J. 1 (1995) 236. (c) W.D. Wulff, in: E.W. Abel, F.G.A.
Stone, G. Wilkinson (Eds.), Comprehensive Organometallic
Chemistry II, vol. 12, Pergamon Press, New York, 1995, p. 469.
[10] (a) W.D. Wulff, W.E. Bauta, R.W. Kaesler, P.J. Lankford, R.A.
Miller, C.K. Murray, D.C. Yang, J. Am. Chem. Soc. 112 (1990)
3642. (b) B.A. Anderson, W.D. Wulff, T.S. Powers, S. Tributt,
A.L. Rheingold, J. Am Chem. Soc. 114 (1992) 10784. (c) K.L.
Faron, W.D. Wulff, J. Am. Chem. Soc. 112 (1990) 6419. (d) K.S.
Chan, W.D. Wulff, J. Am. Chem. Soc. 108 (1986) 5229.
[11] Recent review: K.H. Do¨tz, P. Tomuschat, Chem. Soc. Rev. 28
(1999) 187.
7. Supplementary material
Crystallographic data (excluding structure factors) for
complexes 6 and 11 have been deposited with the
Cambridge Crystallographic Data Center as supplemen-
tary publication no CCDC-137307 (complex 6) and
CCDC-137306 (complex 11). Copies of the data can be
obtained free of charge on application to CCDC, 12
Union Road, Cambridge CB2 1EZ, UK (fax: (+44)1223-
336033; e-mail: deposit@ccdc.cam.ac.uk or http://
www.ccdc.cam.ac.uk).
[12] B.C. So¨derberg, L.S. Hegedus, M.A. Sierra, J. Am. Chem. Soc.
112 (1990) 4364.
[13] E.O. Fischer, T. Selmayr, F.R. Kreißl, Chem. Ber. 110 (1977)
2947.
[14] C.P. Casey, W.R. Brunsvold, J. Organomet. Chem. 118 (1976)
309.
[15] (a) A. Fu¨rstner, K. Langemann, J. Org. Chem. 61 (1996) 8746.
(b) S.J. Miller, S.-H. Kim, Z.-R. Chen, R.H. Grubbs, J. Am.
Chem. Soc. 117 (1995) 2108. (c) M. Delgado, J.D. Martin,
Tetrahedron Lett. 38 (1997) 6299.
Acknowledgements
Financial support from the Deutsche Forschungsge-
meinschaft (SFB 334 and Graduiertenkolleg Spek-

36
J. Su¨ltemeyer et al. / Journal of Organometallic Chemistry 606 (2000) 26–36
[16] (a) E.L. Eliel, S.H. Wielen, Stereochemistry of Organic Com-
pounds, Wiley, New York, 1994. (b) M.S. Visser, N.M.
Heron, M.T. Didiuk, J.F. Sagal, A.H. Hoveyda, J. Am. Chem.
Soc. 118 (1996) 4291 and references cited therein.
[25] (a) R. Hoffmann, Angew. Chem. 94 (1982) 725; Angew.
Chem. Int. Ed. Engl. 21 (1982) 711. (b) F.G.A. Stone, Angew.
Chem. 96 (1984) 85; Angew. Chem. Int. Ed. Engl. 23 (1984)
89.
[17] L. Lattuada, E. Licandro, S. Maiorana, A. Papagani, Gazz.
Chim. Ital. 123 (1993) 31.
[18] R.H. Smithers, J. Org. Chem. 45 (1980) 173.
[26] E.L. Eliel, Stereochemistry of Carbon Compounds, McGraw-
Hill, NewYork, 1962, p. 197.
[27] G.M. Sheldrick, SHELXS-90/97, Program for Structure Solu-
tion, Acta Crystallogr. Sect. A 46 (1990) 467.
[28] G.M. Sheldrick, SHELXL-97, Program for Crystal Structure
Refinement, Universita¨t Go¨ttingen, 1997.
[29] E.O. Fischer, A. Maasbo¨l, Chem. Ber. 100 (1967) 2445.
[30] A.C. Serra, C.M.M. da Silva, M.L.C. Vale, Tetrahedron 47
(1991) 9463.
[19] K.H. Do¨tz, H.-G. Erben, W. Staudacher, K. Harms, G.
Mu¨ller, J. Riede, J. Organomet. Chem. 335 (1988) 177.
[20] (a) Review: U. Schubert, Coord. Chem. Rev. 55 (1984) 261.
(b) O.S. Mills, A.D. Redhouse, J. Chem. Soc. A (1969) 1274.
[21] K.H. Do¨tz, A. Rau, K. Harms, J. Organomet. Chem. 439
(1992) 268.
[22] T.A. Kirkland, R.H. Grubbs, J. Org. Chem. 62 (1997) 7310.
[23] H.S. Overkleeft, U.K. Pandit, Tetrahedron Lett. 37 (1996) 547.
[24] L.A. Paquette, J. Mendez-Andino, Tetrahedron Lett. 40 (1999)
4301.
[31] J.A.H. Naesman, K.G. Pensar, Synthesis 8 (1985) 786.
[32] R.M. Moriarty, R.K Vaid, T.E. Hopkins, B.K. Vaid, O.
Prakash, Tetrahedron Lett. 31 (1990) 197.
.