Rearrangement of carbiminium carbonylmetalates by mutual exchange of alkoxy- and amino functionalities (M = W, Cr)* Crystal structure analyses

Article abstract of DOI:10.1016/S0022-328X(00)00602-1

Reaction of (l-alkynyl)carbene complexes (CO)₅M=C(OEt)C=CPh (1a,b) (M = Cr, W) with enamines R′(R₂N)C=CHR″ (4a-d) (R₂N = morpholine) yielded carbiminium carbonylmetalates ^-(OC)₅M-C(OEt)=C[C(=N+R2)R']C(Ph)=C:HR″ (5) by metathesis of the (N)C=C at the C=C bond. Compounds 5 are stable in solid state, but in solution they undergo a mutual exchange of the ethoxy- and the amino functionality to give isomers ^-(OC)₅M-C(=N⁺R ₂)]C[=C(OEt)R']C(Ph)=CHR′ (6).

Full text of DOI:10.1016/S0022-328X(00)00602-1

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 617–618 (2001) 322–328
Rearrangement of carbiminium carbonylmetalates by mutual
exchange of alkoxy- and amino functionalities (M=W, Cr)ꢀ
Crystal structure analyses
Rudolf Aumann *, Klaus Roths, Roland Fro¨hlich
Organisch-Chemisches Institut, Uni6ersita¨t Mu¨nster, Corrensstrasse 40, D-48149 Mu¨nster, Germany
Received 13 July 2000; accepted 23 August 2000
Abstract
Reaction of (1-alkynyl)carbene complexes (CO)5MꢀC(OEt)CꢁCPh (1a,b) (M=Cr, W) with enamines R%(R2N)CꢀCHR%% (4a–d)
(R2N=morpholine) yielded carbiminium carbonylmetalates −(OC)5MꢂC(OEt)ꢀC[C(ꢀN+R2)R%]C(Ph)ꢀCHR%% (5) by metathesis of
the (N)CꢀC at the CꢁC bond. Compounds 5 are stable in solid state, but in solution they undergo a mutual exchange of the
ethoxy- and the amino functionality to give isomers −(OC)5MꢂC(ꢀN+R2)]C[ꢀC(OEt)R%]C(Ph)ꢀCHR%% (6). © 2001 Elsevier
Science B.V. All rights reserved.
Keywords: Carbene complexes; Metallahexatrienes; Carbiminium carbonylmetalates; Chromium and tungsten complexes; Enamines
enamines with alkynes, e.g. propargylic esters, in which
cyclobutene derivatives are generated in the first reac-
tion step and subsequently undergo ring opening to
butadiene derivatives [6,7], reactions of enamines with
(1-alkynyl)carbene complexes 1 leading to formation of
stable ‘cross-conjugated’ metallatrienes of type (1E)-5
instead of conjugated 1-metalla-1,3,5-trienes (3) had not
been reported [8].
1. Introduction
(1-Alkynyl)carbene complexes, e.g. (CO)5MꢀC(OEt)-
CꢁCPh (1a,b) (M=Cr, W) are potentially useful
reagents for the synthesis of organic compounds [1]. It
was shown only recently that secondary enaminones,
e.g. compounds 2 [2a,b] as well as tertiary cyclic enam-
ines ꢀCHꢀC(NR2)ꢀ [2c,d,e] undergo a 4-addition to
the CꢁC bond of (1-alkynyl)carbene complexes 1a,b
under exceedingly mild conditions to afford conjugated
6-amino-1-metalla-1,3,5-hexatrienes (OC)5MꢀCCꢀCCꢀ
C(N), e.g. compounds 3 (Scheme 1), which could be
further transformed into p- and a-cyclisation products
[3]. Whilst pursuing these studies, a second reaction
mode significantly different from the forementioned one
was found, which yields ‘cross conjugated’ metallahexa-
trienes (OC)5MꢀCC[ꢀC(NR2)]CꢀC, e.g. compounds
(1E)-5 (Scheme 1) by dichotomy of the (N)CꢀC bond at
the CꢁC bond instead of conjugated metallahexatrienes,
e.g. compounds 3 by a Michael-type addition [4,5].
Although there is ample precedence for reactions of
2. Results and discussion
It has been found that carbiminium carbonylmeta-
lates (1E)-5 containing a pyrrolidine unit (R2NꢀC4H8N)
would undergo a (1E/1Z) isomerisation, which appears
to be reversible and seems to be governed by the dipole
moment of the corresponding isomers (Scheme 2) [4b].
We now wish to report that this type of (1E/1Z)
rearrangement strongly depends on the type of amine
substituent. Whilst it was found to be the major reac-
tion of pyrrolidine derivatives 5 it became a minor side
reaction in case of compounds (1E)-5 containing a (less
basic) morpholine unit (R2NꢀC4H8NO) instead of a
(more basic) pyrrolidine moiety, since it was outrun by
a mutual exchange of the ethoxy- and the morpholine
group to give compounds 6.
ꢀ Part 108 of the series: Organic Syntheses via Transition Metal
Complexes. For preceding paper see Ref. [11].
* Corresponding author. Fax: +49-251-8336502.
E-mail address: aumannr@uni-muenster.de (R. Aumann).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00602-1

R. Aumann et al. / Journal of Organometallic Chemistry 617–618 (2001) 322–328
323
It is suggested that the transformation of carbi-
minium carbonylmetalates (1E)-5 into (thermodynami-
Scheme 3. Reaction path suggested for a 1,3 shift of the iminium
functionality of carbiminium carbonylmetalates (1E)-5.
cally more stable) isomers
6 would involve an
equilibrium between zwitterionic intermediates A and C
via formation of vinylidene complexes B (Scheme 3).
The transformation of the 4- into 2-carbiminium
complexes, (1E)-5 and 6, respectively, was followed by
1H-NMR spectra. Characteristic spectral changes in-
clude a significant high-field shift of the signals OCH2
[e.g. (1E)-5a: l 4.21; 6a: AB-system l 3.73 and 3.27], a
strong diastereotopic splitting of the methylene protons
[e.g. NCH2 and OCH2 of 6a: l 5.70–3.30] as well as of
the corresponding carbon signals [e.g. (1E)-5a: l
(OCH2CH3) 73.9; (OCH2 morpholine) 66.1; (NCH2
morpholine) 51.8. 6a: 67.6, 67.0, 64.2, 63.0 and 53.3].
The chemical shifts of the carbene carbon atoms of
compounds (1E)-5a–d and 6a–d are in a range typi-
cally observed for carbiminium carbonylmetalates [e.g.
(1E)-5a: l (WꢂC) 254.4, 6a: 254.7], at somewhat higher
field than observed for 4-amino-tungsta-1,3-butadienes
[e.g. (OC)5WꢀC(OEt)CHꢀC(NMe2)Ph l 269.7). Fur-
thermore, a relative high field shift of 4-H is observed
for compounds 6 compared to iminium complex (1E)-5
[e.g. (1E)-5a: l 5.90; 6a: 5.41]. The transformation of
compounds (1E)-5a into 6a involves a configurational
change of C3ꢀC4 leading to a NOE enhancement of
OCH2 (morpholine) as well as of ortho-phenyl on irra-
diation of 4-H.
Scheme 1. Different reaction modes of secondary enaminones and
tertiary enamines, respectively, with (1-alkynyl)carbene complexes 1
(M=W, Cr); chemical yields and characteristic NMR shifts of
carbiminium carbonylmetalates (1E)-5 (in CDCl3 at 242 K).
Structural details of compounds (1Z)-5a were pro-
vided by a crystal structure analysis (Fig. 1). The
compound shows a carbiminium carbonylmetalate unit,
which is characterized by a pattern of alternating bond
distances of the WꢂCꢀCꢂCꢀN+ backbone [WꢂC2
,
2.292(5) A, C2ꢀC3 1.418(7), C3ꢂC6 1.463(7), C6ꢀN1
1.312(7)], a slightly distorted cisoid arrangement of the
WꢂC2ꢀC3ꢂC6 moiety [dihedral angle −34.4(7)°] and a
stronger distortion of the transoid C2ꢀC3ꢂC6ꢀN1 unit
[dihedral angle 143.3(6)°]. Especially the latter feature
excludes the presence of an enamino unit, since this
would imply a planar C3ꢀC6 double bond. The
Scheme 2. Thermal (1E/1Z) isomerisation of 4-iminium carbonyl-
metalates 5 and formation of 2-iminium carbonylmetalates 6 by a 1,3
shift of the imino unit.

324
R. Aumann et al. / Journal of Organometallic Chemistry 617–618 (2001) 322–328
C2ꢀC3ꢂC4ꢀC5 portion of the molecule adopts a tran-
soid conformation [dihedral angle 140.1(6)°], and shows
an essential planar cis arrangement of the C3ꢂC4ꢂ
C5ꢂC51 −9.2(10) group as well as a slightly distorted
ester functionality [dihedral angle C4ꢂC5ꢂC51ꢂO51
−20.7(10)].
Carbiminium carbonylmetalates 6 were characterized
by NMR spectra and a crystal structure analysis of
compound 6a (Fig. 2). The latter compound exhibits a
long distance between C2ꢂC3 1.514(15) and a short
distance C2ꢀN2 1.318(13) as well as a strong distortion
of WꢂC2ꢂC3ꢀC6 96.3(9)° [N2ꢂC2ꢂC3ꢀC6 −80.5(12)].
The C6ꢀC3ꢂC4ꢀC5ꢂC51 diene portion of the molecule
shows alternating bond distances [C3ꢀC6 1.331(14),
C3ꢂC4 1.464(14), C4ꢂC5 1.38(2) and C5ꢂC51 1.44(2)]
and adopts a transoid conformation, C6ꢀC3ꢂC4ꢀC5
148.7(11)°, C3ꢂC4ꢂC5ꢂC51 175.6(11) and C4ꢂC5ꢂ
C51ꢂO51 −21.3(23).
3. Experimental
Fig. 2. Molecular structure of carbiminium carbonyltungstate 6a.
,
Selected bond lengths (A) and angles (°): WꢂC2 2.247(9), C2ꢂN2
All operations were performed under argon. Dried
solvents were used in all experiments. Melting points
1.318(13), C2ꢂC3 1.514(15), N2ꢂC10 1.479(14), N2ꢂC14 1.480(14),
C11ꢂC10 1.49(2), C3ꢂC6 1.331(14), C3ꢂC4 1.464(14), C6ꢂO1
1.379(12), C6ꢂC7 1.51(2), O1ꢂC8 1.413(14), C8ꢂC9 1.46(2), C4ꢂC5
1.38(2), C4ꢂC41 1.48(2), C5ꢂC51 1.44(2), C51ꢂO51 1.256(14),
C51ꢂO52 1.288(14), O52ꢂC53 1.41(2); N2ꢂC2ꢂC3 114.4(9),
N2ꢂC2ꢂW 129.8(8), C3ꢂC2ꢂW 115.7(6), C2ꢂN2ꢂC10 124.6(9),
C2ꢂN2ꢂC14 125.2(10), C10ꢂN2ꢂC14 110.3(9), N2ꢂC14ꢂC13
109.9(11), N2ꢂC10ꢂC11 109.1(10), C6ꢂC3ꢂC4 123.2(10), C6ꢂC3ꢂC2
119.4(9), C4ꢂC3ꢂC2 117.4(9), C3ꢂC6ꢂO1 118.8(9), C3ꢂC6ꢂC7
124.2(10), O1ꢂC6ꢂC7 116.7(10), C6ꢂO1ꢂC8 118.8(9), C5ꢂC4ꢂC3
115.8(10), C5ꢂC4ꢂC41 123.8(10), C3ꢂC4ꢂC41 120.5(9), C42ꢂC41ꢂC4
1
are not corrected. Instrumentation: H- and 13C-NMR
spectra were obtainend with Bruker ARX 300, Bruker
120.8(11),
C46ꢂC41ꢂC4
120.3(9),
C4ꢂC5ꢂC51
128.3(11),
O51ꢂC51ꢂO52 121.7(11), O51ꢂC51ꢂC5 125.3(12), O52ꢂC51ꢂC5
113.0(11), C51ꢂO52ꢂC53 122.8(12).
AM 360 und Varian U 600 spectrometers. Chemical
shifts refer to lTMS=0.00 ppm. Other analyses: IR
Digilab FTS 45; MS Finnigan MAT 312; elemental
analysis with Perkin–Elmer 240 elemental analyzer;
TLC with Merck DC-Alufolien Kieselgel 60 F254. Rf
values refer to TLC tests. Column chromatographic
purifications were achieved with Merck Kieselgel 100.
Pentacarbonyl(1-ethoxy-3-phenyl-2-propin-1-ylidene)-
tungsten (1a) and -chromium (1b) were prepared ac-
cording to the procedure given in Ref. [1].
Fig. 1. Molecular structure of carbiminium carbonyltungstate (1Z)-
,
5a. Selected bond distances (A) and angles (°): WꢂC2 2.292(5),
C2ꢂO1 1.355(6), C2ꢂC3 1.418(7), O1ꢂC13 1.441(7), C13ꢂC14
1.490(9), C3ꢂC6 1.463(7), C3ꢂC4 1.499(8), C4ꢂC5 1.328(8), C5ꢂC51
1.466(8), C51ꢂO51 1.212(7), C51ꢂO52 1.324(7), O52ꢂC53 1.436(7),
C6ꢂN1 1.312(7), C6ꢂC7 1.491(8), N1ꢂC8 1.483(7), N1ꢂC12 1.482(8),
C8ꢂC9 1.472(11), C9ꢂO10 1.413(12), O10ꢂC11 1.420(9), C11ꢂC12
1.494(9); O1ꢂC2ꢂC3 106.1(5), O1ꢂC2ꢂW 124.5(4), C3ꢂC2ꢂW
127.7(4), C2ꢂO1ꢂC13 123.8(4), O1ꢂC13ꢂC14 108.7(5), C2ꢂC3ꢂC4
120.4(5), C2ꢂC3ꢂC6 120.8(5), C4ꢂC3ꢂC6 118.8(5), C5ꢂC4ꢂC41
117.9(5), C3ꢂC4ꢂC5 123.8(5), C3ꢂC4ꢂC41 118.1(5), C4ꢂC41ꢂC42
121.0(6), C4ꢂC41ꢂC46 121.4(5), C4ꢂC5ꢂC51 128.9(6), C5ꢂC51ꢂO51
3.1. Pentacarbonyl[1-ethoxy-5-methoxy-2-(1-
morpholinium-1-ethylidene)-5-oxo-3-phenyl-penta-
1,3-dien-1-yl]tungstate [(1E)- and (1Z)-5a] and
pentacarbonyl[2-(1-ethoxy-ethylidene)-5-methoxy-1-
morpholinium-5-oxo-3-phenyl-3-penten-1-yl]tungstate
(6a)
126.4(6),
C5ꢂC51ꢂO52
111.6(6),
O51ꢂC51ꢂO52
122.0(6),
C51ꢂO52ꢂC53 117.5(5), C3ꢂC6ꢂN1 121.0(5), C3ꢂC6ꢂC7 120.2(5),
N1ꢂC6ꢂC7 118.5(5), C6ꢂN1ꢂC8 124.6(6), C6ꢂN1ꢂC12 125.3(5),
C8ꢂN1ꢂC12 110.1(5), N1ꢂC8ꢂC9 111.1(6), C8ꢂC9ꢂO10 114.2(9),
C9ꢂO10ꢂC11 109.1(7), O10ꢂC11ꢂC12 110.4(7), C11ꢂC12ꢂN1
111.1(6).
A
mixture of pentacarbonyl(1-ethoxy-3-phenyl-2-
propin-1-ylidene)tungsten (1a, 482 mg, 1.00 mmol) and

R. Aumann et al. / Journal of Organometallic Chemistry 617–618 (2001) 322–328
325
(100) [w(CꢁO], 1710.2 (20) [w(CꢀO]. X-ray crystal
structure analysis of compound (1Z)-5a: formula
C25H25NO9W, M=667.31, red crystal 0.25×0.20×
3-morpholino-but-2-enoic acid methylester (4a, 185
mg, 1.00 mmol) in 20 ml of n-pentane is vigorously
stirred in a centrifuge tube for 1 h at 20°C to give a
yellow precipitate of compound (1E)-5a, which is iso-
lated by centrifugation and washed twice with 5 ml of
n-pentane each [606 mg, 98%, m.p. (dec.) 74°C, Rf =
0.1 in diethyl ether–pentane (1:1)]. (1E)-5a in CDCl3
solution undergoes an isomerisation to a 1:6 mixture
of compounds (1Z)-5a and 6a, which is completed
within 24 h at 20°C.
0.15 mm, a=19.737(1), b=10.662(1), c=25.249(1)
3
,
,
A, i=107.56(1)°, V=5065.7(6) A , zcalc=1.750 g
cm−3, v=46.14 cm−1, empirical absorption correc-
tion via „-scan data (0.9575C50.999), Z=8, mon-
,
oclinic, space group C2/c (no. 15), u=0.71073 A,
T=293 K, ꢀ–2q scans, 5279 reflections collected
(−h, −k, 9l), [(sin q)/u]=0.62 A−1, 5129 independent
,
(Rint=0.023) and 3548 observed reflections [I]
2|(I)], 328 refined parameters, R=0.033, wR2=
0.070, max. residual electron density 1.49 (−1.14) e
−3
,
A
close to tungsten, hydrogen calculated and
refined as riding atoms [10].
1H-NMR (CDCl3): l 7.27 (5H, s, C6H5), 5.90 (1H,
3
s, 4-H), 4.21 (3H, q, J=7 Hz, OCH2CH3), 3.72 (4H,
m, 2OCH2, morpholine), 3.57 (3H, s, OCH3), 3.53
(4H, m, 2NCH2, morpholine), 2.31 (3H, s, NꢀCCH3),
1.15 (3H, t, OCH2CH3). 13C-NMR (CDCl3, 242 K): l
254.4 (WꢂC), 202.8 and 199.4 [1: 4, trans- and cis-
CO W(CO5], 180.5 (Cq, CꢀN+), 166.6 (Cq,
COOCH3), 156.5 (Cq, C3), 138.8 and 134.8 (Cq each,
C2 and iC Ph), 128.7–127.5 (5CH Ph), 118.7 (CH,
C4), 73.9 (OCH2CH3), 66.1 (broad, 2 diastereotopic
OCH2 of morpholine), 51.8 (broad, 2NCH2 morpho-
line), 51.1 (OCH3), 26.7 (OCH2CH3), 14.9 (NCCH3).
IR (diffuse reflection), cm−1: 2051.0 (10), 1921.5
(100) and 1897.4 (80) [w(CꢁO], 1712.6 (20) [w(CꢀO].
1H-NMR (CDCl3: l 7.27 (5H, m, Ph), 5.41 (1H, s,
4-H), 5.70–3.30 (8H, m, 2OCH2 and 2NCH2 morpho-
line), 3.73 and 3.27 (1H each, diastereotopic
OCH2CH3), 3.50 (3H, s, OCH3), 1.79 [3H, s,
ꢀC(OEt)CH3], 0.63 (3H, t, OCH2CH3). 13C-NMR
(CDCl3) l 254.7 (WꢂCꢀN+), 202.8 and 198.6 [1:4,
trans- and cis-CO W(CO5], 166.2 (Cq, COOCH3);
148.6, 146.0 and 140.1 (Cq each; C1%, C2 and C3),
137.5 (Cq, iC Ph), 127.9 and 127.7 (CH each, Ph),
120.1 (CH, C4); 67.6, 64.2 and 63.0 (OCH2 each, Et
and morpholine), 53.3 (broad, 2NCH2 morpholine),
51.5 (OCH3), 17.1 (CH3, C2%), 15.6 (OCH2CH3). IR
(diffuse reflection), cm−1: 2058.9 (30), 1908.8 (100)
[w(CꢁO], 1724.3 (20) [w(CꢀO]. MS (70 eV, m/e (%)
184W: 667 (10) [M+], 315 (35) [ligand], 314 (100).
Anal. Found: C, 44.78; H, 4.02; N, 2.10. Calc. for
C25H25NO9W (667.3): C, 45.00; H, 3.78; N, 2.10%.
X-ray crystal structure analysis of compound 6a: for-
mula C25H25NO9W, M=667.31, yellow–red crystal
0.40×0.20×0.10 mm, a=8.312(2), b=11.362(3),
1H-NMR (CDCl3: l 7.52 (2H, m, o-H Ph), 7.30
(3H, m, m- and p-H Ph), 6.27 (1H, s, 4-H), 4.39 (2H,
q, OCH2CH3), 3.84 (4H, m, 2OCH2 morpholine), 3.79
(3H, s, OCH3), 3.60 (4H, m, 2NCH2 morpholine),
2.46 (3H, s, NꢀCCH3), 1.18 (3H, t, OCH2CH3). 13C-
NMR (CDCl3) l (WꢂC) [9], 203.4 and 200.1 [1:4,
trans- and cis-CO, W(CO5], l [9] (Cq, CꢀN+), 166.8
(Cq, COOCH3) 157.4 (Cq, C3), 143.7 (Cq, C2), l [9]
(Cq, iC Ph); 129.7, 129.0 and 128.6 (CH each, Ph),
117.8 (CH, C4), 75.1 (OCH2CH3), 66.6 (broad,
2OCH2 morpholine), 52.8 (broad, 2NCH2 morpho-
line), 51.5 (OCH3) 25.8 (OCH2CH3), 15.6 (NCCH3).
IR (diffuse reflection, cm−1: 2053.1 (20) and 1897.0
,
c=15.432(5) A, h=108.07(3), i=100.55(2), k=
3
93.37(2)°, V=1351.7(7) A , zcalc=1.640 g cm−3, v=
83.56 cm−1
empirical absorption correction via
„-scan data (0.5835C50.999), Z=2, triclinic, space
,
,
(
,
group P1 (no. 2), u=1.54178 A, T=293 K, ꢀ–2q
scans, 5894 reflections collected (+h, 9k, 9l),
[(sin q)/u]=0.62 A−1, 5497 independent (Rint=0.088)
,
and 4419 observed reflections [I]2|(I)], 329 refined
parameters, R=0.067, wR2=0.174, max. residual

326
R. Aumann et al. / Journal of Organometallic Chemistry 617–618 (2001) 322–328
−3
,
electron density 2.23 (−2.14) e A
hydrogen calculated and refined as riding atoms [10].
close to tungsten,
3.3. Pentacarbonyl[1-ethoxy-5-benzoxy-2-
(1-morpholinium-1-ethylidene)-5-oxo-3-phenyl-penta-
1,3-dien-1-yl]tungstate [(1E)- and (1Z)-5c] and
pentacarbonyl[2-(1-ethoxy-ethylidene)-5-benzoxy-1-
morpholinium-5-oxo-3-phenyl-3-penten-1-yl]tungstate
(6c)
3.2. Pentacarbonyl[1-ethoxy-5-methoxy-2-
(1-morpholinium-1-ethylidene)-5-oxo-3-phenyl-penta-
1,3-dien-1-yl]chromate [(1E)- and (1Z)-5b] and
pentacarbonyl[2-(1-ethoxy-ethylidene)-5-methoxy-
1-morpholinium-5-oxo-3-phenyl-3-penten-1-yl]chromate
(6b)
A
mixture of pentacarbonyl(1-ethoxy-3-phenyl-2-
propin-1-ylidene)tungsten (1a, 482 mg, 1.00 mmol)
and 3-morpholino-but-2-enoic acid benzylester (4b,
227 mg, 1.00 mmol) in 20 ml of n-pentane is reacted
as described above to give compound (1E)-5c [660
mg, 87%, m.p. (dec.) 80°C, Rf=0.1 in diethyl ether–
pentane (1:1)]. (1E)-5c in CDCl3 solution undergoes
an isomerisation within 24 h at 20°C to give com-
pound (1Z)-5c and 6c in a molar ratio 1:2.
A
mixture of pentacarbonyl(1-ethoxy-3-phenyl-2-
propin-1-ylidene)chromium (1b, 351 mg, 1.00 mmol)
and 3-morpholino-but-2-enoic acid methylester (4a,
185 mg, 1.00 mmol) in 20 ml of n-pentane is reacted
as described above to give compound (1E)-5b [487
mg, 78%, m.p. (dec.) 78°C, Rf=0.1 in diethyl ether–
pentane (1:1)]. (1E)-5b in CDCl3 solution undergoes
an isomerisation within 24 h at 20°C to give com-
pound 6b as the only isolated product.
3.3.1. (1E)-5c
1H-NMR (C6D6, 360 MHz, 242 K): l 7.40–7.00
(10H, m, Ph and CH2Ph), 5.98 (1H, s, 4-H), 4.96
(2H, s, OCH2Ph), 4.15 (2H, m, diastereotopic
OCH2CH3), 3.62 (4H, broad, 2OCH2 morpholine),
3.39 (4H, broad, 2NCH2 morpholine), 2.19 (3H, s,
NꢀCCH3), 1.12 (3H, OCH2CH3). 13C-NMR (C6D6,
360 MHz, 242 K): l [9] (WꢂC), 202.9 and 199.5 [1:
4, trans- and cis-CO, W(CO5], 180.2 (Cq, CꢀN+),
166.2 (Cq, COOCH2Ph), 157.1 (Cq, C3), 139.1 (Cq,
C2), 135.5 and 135.3 (Cq each, iC, Ph), 129–127
(5CH, Ph), 118.9 (CH, C4), 74.4 (OCH2CH3), 66.2
(2OCH2 morpholine), 65.7 (OCH2Ph), 51.9 (2NCH2
morpholine), 27.1 (OCH2CH3), 15.1 (NCCH3). IR
(diffuse reflection), cm−1: 2051.6 (20), 1919.5 (90) and
1876.2 (100) [w(CꢁO], 1712.6 (20) [w(CꢀO].
3.2.1. (1E)-5b
1H-NMR (CDCl3): l 7.29 (5H, s, Ph), 5.74 (1H, s,
4-H), 4.35 (2H, diastereotopic OCH2CH3), 3.61 (4H,
m, 2OCH2, morpholine), 3.57 (3H, s, OCH3), 3.31
(4H, m, 2NCH2, morpholine), 2.20 (3H, s, NCCH3),
1.31 (3H, t, OCH2CH3). 13C-NMR (CDCl3 242 K): l
[9] (CrꢀC), 224.0 and 218.6 [1: 4, trans- and cis-CO,
Cr(CO5], 174.7 (Cq, CꢀN+), 166.7 (Cq, COOCH3),
155.3 (Cq, C3), 138.3 (Cq, C2), 134.8 (Cq, iC Ph);
128.8, 127.6 and 127.3 (CH each, Ph), 118.4 (CH,
C4), 72.6 (OCH2CH3), 66.4 (broad, 2OCH2,, morpho-
line), 51.6 (broad, 2NCH2, morpholine), 51.3 (OCH3),
25.9 (OCH2CH3), 15.4 (NCCH3). IR (diffuse reflec-
tion, cm−1: 2049.1 (30), 1925.9 (100), 1898.6 (90)
[w(CꢁO], 1720.7 (20) [w(CꢀO].
3.3.2. (1Z)-5c
1H-NMR (CDCl3): l 7.46 (2H, m, o-H Ph), 7.30
and 7.00 (6:2H, m, Ph and CH2Ph), 6.24 (1H, s, 4-
H), 5.04 (2H, diastereotopic CH2Ph), 4.19 (2H,
diastereotopic, OCH2CH3), 3.64 (4H, m, 2OCH2 mor-
pholine), 3.42 (4H, m, 2NCH2 morpholine), 2.27 (3H,
s, NCCH3), 1.09 (3H, t, OCH2CH3). 13C-NMR
(CDCl3) l [9] (WꢂC), 203.2 and 199.7 [1: 4, trans-
and cis-CO, W(CO5] [9], (Cq, CꢀN+), 165.7 (Cq,
COOCH2Ph), 157.6 (Cq, C3), 142.2 (Cq, C2), [9] (Cq,
iC 3-Ph), 136.4 (Cq, iC CH2Ph), 129–127 (10CH, Ph
and CH2Ph), 117.3 (CH, C4), 73.9 (OCH2CH3), 65.9
(OCH2Ph), 61.9 (2OCH2, morpholine), 52.0 (2NCH2,
morpholine), 24.8 (NCCH3) 15.1 (OCH2CH3).
3.2.2. Compound 6b
1H-NMR (CDCl3): l 7.27 (5H, m, Ph), 5.31 (1H, s,
4-H), 4.70–3.10 (8H, m, OCH2 and NCH2, morpho-
line), 3.65 and 3.21 (1H, diastereotopic OCH2CH3),
3.48 (3H, s, OCH3), 1.73 [3H, s, ꢀC(OEt)CH3], 0.61
(3H, t, OCH2CH3). 13C-NMR (CDCl3):
l 273.7
(CrꢀC), 222.5 and 217.2 [1:4, trans- and cis-CO,
Cr(CO5], 165.6 (Cq, COOCH3); 148.1, 146.0 and
139.7 (Cq each; C1%, C2 and C3), 131.1 (Cq, iC Ph),
127.5–127.2 (5CH, Ph), 119.3 (CH, C4); 67.2, 63.6
and 60.3 (OCH2 each, OCH2CH3 and morpholine),
54.0 (2NCH2 morpholine), 51.0 (OCH3), 16.5
[ꢀC(OEt)CH3], 14.1 (OCH2CH3). IR (diffuse reflec-
tion), cm−1: 2050.2 (30), 1972.7 (90), 1905.2 (100)
[w(CꢁO], 1724.4 (20) [w(CꢀO]. MS (70 eV), m/e (%),
184W: 535 (4) [M+], 395 (20) [M+−5CO], 211 (20)
[ligand], 141 (95), 52 (100). Anal. Found: C, 55.94; H,
4.87; N, 2.82. Calc. for C25H25NO9Cr (535.5): C,
56.08; H, 4.71; N, 2.62%.
3.3.3. Compound 6c
1H-NMR (CDCl3): l 7.29–7.15 (10H, m, Ph and
CH2Ph), 5.39 (1H, s, 4-H), 5.14 (2H, diastereotopic
CH2Ph), 4.60–3.10 (10H, m, 2OCH2 and 2NCH2
morpholine each, and OCH2CH3), 1.70 [3H, s,

R. Aumann et al. / Journal of Organometallic Chemistry 617–618 (2001) 322–328
327
ꢀC(OEt)CH3], 0.56 (3H, t, OCH2CH3). 13C-NMR
(CDCl3): l 253.8 (WꢂC), 212.3 and 198.7 [1:4, trans-
and cis-CO, W(CO5], 165.3 (Cq, COOCH2Ph); 147.8,
146.2 and 139.6 (Cq each; C1%, C2 and C3), 135.7 and
131.9 (Cq each, iC Ph), 129–127 (CH, Ph and CH2Ph),
119.9 (CH, C4); 67.2, 66.6, 66.1, 63.8 and 62.6 (OCH2
each; morpholine, OCH2C6H5 and OCH2CH3), 52.9
(2NCH2, morpholine), 16.7 [ꢀC(OEt)CH3], 14.0
(OCH2CH3). IR (diffuse reflection), cm−1: 2058.3 (20),
1927.0 (90), 1902.1 (100) [w(CꢁO], 1721.3 (20) [w(CꢀO].
MS (70 eV, m/e (%), 184W: 419 (50) [M+ꢂW(CO5)], 339
(100), 91 (100) [CH2Ph+]. Anal. Found: C, 44.73; H,
4.16; N, 1.61. Calc. for (C31H29NO9W×CHCl3)
(862.8): C, 44.55; H, 3.50; N, 1.63%.
COOCMe3), 153.1 (Cq, C3), 139.9 and 135.8 (Cq each,
C2 and iC Ph); 128.1, 127.6 and 126.9 (CH each, Ph),
123.5 (CH, C4), 79.7 (CMe3), 74.1 (OCH2CH3), 66.2
(2OCH2, morpholine), 52.3 (2NCH2, morpholine), 27.5
[C(CH3)3], 25.8 (NCCH3), 15.3 (OCH2CH3). IR (dif-
fuse reflection), cm−1: 2058.6 (20), 1966.9 (90), 1935.6
(100) [w(CꢁO], 1708.7 (20) [w(CꢀO].
3.4.3. Compound 6d
1H-NMR (CDCl3): l 7.25 (5H, s, Ph), 5.26 (1H, s,
4-H), 4.60–3.10 (10H, m, OCH2 and NCH2 morpholine
each, and OCH2CH3), 1.78 [3H, s, ꢀC(OEt)CH3], 1.07
[9H, s, C(CH3)3], 0.59 (3H, t, OCH2CH3). 13C-NMR
(CDCl3): l 254.2 (WꢂC), 202.5 and 199.1 [1:4, trans-
and cis-CO, W(CO5], 165.6 (Cq, COOCMe3); 145.5,
145.0 and 140.6 (Cq each; C1%, C2 and C3), 131.2 (Cq,
iC Ph); 128.1, 127.6 and 126.9 (CH each, Ph), 122.7
(CH, C4), 80.2 (CMe3); 66.7, 66.3, 63.7 and 62.5
(2OCH2 and 1NCH2 morpholine each, and OCH2CH3),
52.8 (NCH2 morpholine), 27.8 [C(CH3)3], 16.6
[ꢀC(OEt)CH3], 14.1 (OCH2CH3). MS (70 eV), m/e (%),
184W: 709 (10) [M+], 569 (10) [M+ꢂ5CO], 385 (20)
[ligand], 57 (100). Anal. Found: C, 47.78; H, 4.21; N,
2.67. Calc. for C28H31NO9W (709.4): C, 47.41; H, 4.40;
N, 1.97%.
3.4. Pentacarbonyl[1-ethoxy-5-(t-butoxy)-2-
(1-morpholinium-1-ethylidene)-5-oxo-3-phenyl-
penta-1,3-dien-1-yl]tungstate [(1E)- and (1Z)-5d] and
pentacarbonyl[2-(1-ethoxy-ethylidene)-5-(t-butoxy)-
1-morpholinium-5-oxo-3-phenyl-3-penten-1-yl]tungstate
(6d)
A
mixture of pentacarbonyl(1-ethoxy-3-phenyl-2-
propin-1-ylidene)tungsten (1a, 482 mg, 1.00 mmol) and
3-morpholino-but-2-enoic acid t-butylester (4c, 203 mg,
1.00 mmol) in 20 ml of n-pentane is reacted as de-
scribed above to give compound (1E)-5d [631 mg, 89%,
m.p. (dec.) 99°C, Rf=0.1 in diethyl ether–pentane
(1:1)]. (1E)-5d in CDCl3 solution undergoes an isomeri-
sation within 24 h at 20°C to give compound (1Z)-5c
and 6c in a molar ratio 1:6.
3.5. Pentacarbonyl[1-ethoxy-5-(t-butoxy)-2-
(1-morpholinium-1-ethylidene)-5-oxo-3,4-bis(phenyl)-
penta-1,3-dien-1-yl]tungstate [(1E)-5e] and
pentacarbonyl[2-(1-ethoxy-ethylidene)-5-(t-butoxy)-
1-morpholinium-5-oxo-3,4-bis(phenyl)-3-penten-1-yl]
tungstate (6e)
3.4.1. (1E)-5d
1H-NMR (C6D6, 360 MHz): l 7.35 and 7.05 (2:3H,
Ph), 5.97 (1H, s, 4-H), 4.19 (2H, diastereotopic
OCH2CH3), 2.90 (4H, m, 2OCH2 morpholine), 2.80
(4H, m, NCH2 morpholine), 1.70 (3H, s, NCCH3) 1.30
[9H, s, C(CH3)3], 0.93 (3H, t, OCH2CH3). 13C-NMR
(CDCl3, 242 K): l 252.2 (WꢂC), 203.2 and 199.4 [1: 4,
trans- and cis-CO, W(CO5], 180.1 (Cq, CꢀN+), 165.9
(Cq, COOCMe3), 154.3 (Cq, C3), 139.4 and 134.6 (Cq
each, C2 and iC Ph); 128.9, 128.5 and 127.5 (CH each,
Ph), 123.1 (CH, C4), 79.9 (CMe3), 73.7 (OCH2CH3),
66.2 (2OCH2 morpholine), 51.7 (2NCH2 morpholine),
27.4 (CMe3), 26.2 (OCH2CH3), 15.2 (NCCH3). IR
(diffuse reflection), cm−1: 2050.6 (20), 1900.2 (100)
[w(CꢁO], 1703.6 (20) [w(CꢀO].
A mixture of pentacarbonyl(1-ethoxy-3-phenyl-2-
propin-1-ylidene)tungsten (1a, 482 mg, 1.00 mmol) and
2-morpholino-1-phenyl-propene (4d, 170 mg, 1.00
mmol) in 20 ml of n-pentane is reacted as described
above to give compound (1E)-5e (500 mg, 90%). (1E)-
5e in CDCl3 solution undergoes an isomerisation within
24 h at 20°C to give compound 6e as the only product.
3.5.1. (1E)-5e
1H-NMR (CDCl3): l 7.40–7.00 (10H, m, Ph), 6.80
(1H, s, 4-H), 4.28 (2H, q, OCH2CH3), 3.60 (4H, m,
diastereotopic OCH2 morpholine), 3.49 (4H, m,
diastereotopic NCH2 morpholine), 2.18 (3H, s,
NCCH3), 1.22 (3H, t, OCH2CH3).
3.4.2. (1Z)-5d
3.5.2. Compound 6e
1H-NMR (CDCl3): l 7.52 and 7.25 (2:3 H, m each,
Ph), 6.19 (1H, s, 4-H), 4.22 (2H, diastereotopic
OCH2CH3), 3.87 (4H, m, 2OCH2 morpholine), 3.75
(4H, m, 2NCH2 morpholine), 2.34 (3H, s, NCCH3),
1.45 [9H, s, C(CH3)3], 1.14 (3H, OCH2CH3). 13C-NMR
(CDCl3): l [9] (WꢂC), 202.9 and 199.8 [1: 4, trans- and
cis-CO, W(CO5], 178.0 (Cq, CꢀN), 165.9 (Cq,
1H-NMR (CDCl3): l 7.30–6.80 (10H, m, Ph), 6.04
(1H, s, 4-H), 4.70–3.00 (10H, m, OCH2 and NCH2,
morpholine each, and OCH2CH3), 1.76 (3H, s, CH3),
0.54 (3H, t, OCH2CH3). 13C-NMR (CDCl3): l 254.7
(WꢀC), 203.1 and 198.9 [1: 4, trans- and cis-CO,
W(CO)5]; 142.5, 141.0 and 133.7 (Cq each; C1%, C2 and
C3), 137.1 and 135.1 (Cq each, iC Ph), 131–126 (CH

328
R. Aumann et al. / Journal of Organometallic Chemistry 617–618 (2001) 322–328
[5] R. Aumann, I. Go¨ttker-Schnetmann, R. Fro¨hlich, O. Meyer, Eur.
J. Org. Chem. (1999) 2545.
each, C6H5 and C4); 67.7, 64.1, 63.8, 62.6 and 53.2
(2OCH2 and 2NCH2, morpholine each, OCH2CH3),
16.9 [ꢀC(OEt)CH3], 14.6 (OCH2CH3). IR (diffuse
reflection) cm−1: 2058.6, 1979.7 and 1892.2 [w(CꢁO)].
MS (70 eV), m/z (%), 184W: 685 (10) [M+], 545 (8)
[M+ −5CO], 361 (23) [ligand+], 332 (100).
[6] (a) A.G. Cook, Enamines: Synthesis, Structure and Reactions, in:
A.G. Cook (Ed.), Marcel Dekker, New York, 1969, pp. 230–1107.
(b) T. Nagasaka, H. Inoue, F. Hamaguchi Heterocycles 20 (1983)
1099. (c) T. Tokumitsu, Bull. Chem. Soc. Jpn. 59 (1986) 3871. (d)
R.J.M. Egberink, W. Verboom, P.H. Benders, S. Harkema, D.N.
Reinhoudt, Recl. Trav. Chim. Pays-Bas 107 (1988) 388. (e) W.K.
Gibson, D. Leaver, J. Chem. Soc. Sect. C (1966) 324. (f) A.
Halleux, H.G. Viehe, J. Chem. Soc. Sect. C (1968) 1726. (g) R.
Fuks, H.G. Viehe, Chemistry of the Acetylenes, in: H.G. Viehe
(Ed.), Marcel Dekker, New York, 1969, pp. 435–439.
4. Supplementary material
[7] (a) C.F. Huebener, L. Dorfman, M.M. Robinson, E. Donoghue,
W.G. Pierson, P. Strachan, J. Org. Chem. 28 (1963) 3134. (b) G.A.
Berchtold, G.F. Uhlig, J. Org. Chem. 28 (1963) 1459. (c) A.K.
Bose, G. Mina, M.S. Manhas, E. Rzucidlo, Tetrahedron Lett.
(1963) 1467. (d) A.J. Birch, E.G. Hutchinson, J. Chem. Soc. Sect.
C (1971) 3671. (e) D.N. Reinhoudt, C.G. Kouwenhoven, Tetrahe-
dron Lett. (1973) 3751. (f) G.J. Vos, P.H. Benders, D.N. Rein-
houdt, R.J.M. Egberink, S. Harkema, G.J. van Hummel, J. Org.
Chem. 51 (1986) 2004.
[8] For related reactions of enol ethers with compounds 1 see: (a) K.L.
Faron, W.D. Wulff, J. Am. Chem. Soc. 110 (1988) 8727. (b) F.
Camps, J.M. Moreto´, S. Ricart, J.M. Vin˜as, E. Molins, C.
Miravitlles, J. Chem. Soc. Chem. Commun. (1989) 1560. (c) L.
Jordi, J.M. Moreto´, S. Ricart, J.M. Vin˜as, E, Molins, C. Mira-
vitlles, J. Organomet. Chem. 444 (1993) C28. (d) L. Jordi, F.
Camps, S. Ricart, J.M. Vin˜as, J.M. Moreto´, M. Mejias, E. Molins,
J. Organomet. Chem. 494 (1995) 53. (e) For a recent review on
this topic see: W.D. Wulff, K.L. Faron, J. Su, J.P. Springer, A.L.
Rheingold, J. Chem. Soc., Perkin Trans. I (1999) 197.
[9] Signal not observed due to dynamic line broadening.
[10] Data sets were collected with Enraf Nonius CAD4 diffractometers.
Programs used: data collection EXPRESS (Nonius B.V. 1994), data
reduction MOLEN (K. Fair, Enraf-Nonius B.V. 1990), structure
solution SHELXS-93 (G.M. Sheldrick, Acta Crystallogr. Sect. A 46
(1990) 467), structure refinement SHELXL-93 (G.M. Sheldrick,
Universita¨t Go¨ttingen, Germany, 1997), graphics SCHAKAL (E.
Keller, Universita¨t Freiburg, 1997).
Crystallographic data (excluding structure factors)
for the structures reported in this paper have been
deposited with the Cambridge Crystallographic Data
Centre as supplementary publication CSD-147009 (5a),
and CSD-147010 (6a). Copies of the data can be ob-
tained free of charge from The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK (Fax: +44-
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
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