Organic syntheses via transition metal complexes. 83.1 cis-1-metalla-1,3,5-hexatrienes (butadienylcarbene complexes) of tungsten via ring opening of pyranylidene complexes

Article abstract of DOI:10.1021/om950741m

Aminolysis of the 2H-pyran-2-ylidenetungsten complex 3 affords amino-1-tungsta-1,3,5-hexatrienes with different structures, depending on the reaction temperature and the type of amine involved. Addition of primary amines RNH₂ (4a-d) (R = allyl, n-Bu, CH₂Ph, i-Pr) to 3 at -15 °C yields salt-type (3Z)-6-amino-1-tungsta-1,3,5-hexatrienes 5a-d by reversible ring opening of the pyranylidene ring. Addition of 4a-c at 20 °C affords (3Z)-2-amino-1-tungsta-1,3,5-hexatrienes 6a-c by an irreversible ring opening of the pyranylidene ring. Secondary amines RR¹NH 8a-c [RR¹N = Me₂N, 2-(hydroxymethyl)pyrrolidine, pyrrolidine] undergo an irreversible ring opening to 2-amino-1-tungsta-1,3,5-hexatrienes 9a-c. Aminolysis of 3 in the presence of Me₃SiCl/Et₃N affords acetimino pyranylidene complexes 10, from which (3Z)-2,6-diamino-1-tungsta-1,3,5-hexatrienes 11 are derived upon aminolysis. Thermolysis of 6a in THF/pyridine affords the captodative 1-amino-1,3-hexadien-5-one 12. 2H-Pyran-2-ylidene complex 3, C₁₉H₁₂O₇W, was characterized by X-ray diffraction.

Full text of DOI:10.1021/om950741m

Organometallics 1996, 15, 1257-1264
1257
Or ga n ic Syn th eses via Tr a n sition Meta l Com p lexes. 83.1
cis-1-Meta lla -1,3,5-h exa tr ien es (Bu ta d ien ylca r ben e
Com p lexes) of Tu n gsten via Rin g Op en in g of
P yr a n ylid en e Com p lexes†
Rudolf Aumann,* Klaus Roths, Beate J asper, and Roland Fro¨hlich
Organisch-Chemisches Institut der Universita¨t Mu¨nster, Corrensstrasse 40,
D-48149 Mu¨nster, Germany
Received September 18, 1995X
Aminolysis of the 2H-pyran-2-ylidenetungsten complex 3 affords amino-1-tungsta-1,3,5-
hexatrienes with different structures, depending on the reaction temperature and the type
of amine involved. Addition of primary amines RNH2 (4a -d ) (R ) allyl, n-Bu, CH2Ph, i-Pr)
to 3 at -15 °C yields salt-type (3Z)-6-amino-1-tungsta-1,3,5-hexatrienes 5a -d by reversible
ring opening of the pyranylidene ring. Addition of 4a -c at 20 °C affords (3Z)-2-amino-1-
tungsta-1,3,5-hexatrienes 6a -c by an irreversible ring opening of the pyranylidene ring.
Secondary amines RR1NH 8a -c [RR1N ) Me2N, 2-(hydroxymethyl)pyrrolidine, pyrrolidine]
undergo an irreversible ring opening to 2-amino-1-tungsta-1,3,5-hexatrienes 9a -c. Ami-
nolysis of 3 in the presence of Me3SiCl/Et3N affords acetimino pyranylidene complexes 10,
from which (3Z)-2,6-diamino-1-tungsta-1,3,5-hexatrienes 11 are derived upon aminolysis.
Thermolysis of 6a in THF/pyridine affords the captodative 1-amino-1,3-hexadien-5-one 12.
2H-Pyran-2-ylidene complex 3, C19H12O7W, was characterized by X-ray diffraction.
Sch em e 1. P yr a n ylid en e Com p lex 3 by
Con d en sa tion of th e 1,3-Dik eton e 2 w ith th e
Alk yn ylca r ben e Com p lex 1
2H-P yr a n -2-ylid en e Com p lexes. Ring-opening re-
actions of six-membered rings provide a convenient
means for the generation of open-chain products with
cis stereochemistry. While we were pursuing ring
precursors of (conjugated) cis-1-tungsta-1,3,5-hexatrienes
(CO)5WdCXCRdCRCRdCRY (X, Y ) OR′, NR′2; R )
hydrogen, alkyl, aryl),2 our attention was drawn to 2H-
pyran-2-ylidene complexes, e.g., compound 3, as poten-
tial starting materials. Among several routes available
for the generation of pyranylidene complexes2-11 the
condensation of enolizable carbonyl compounds, e.g., 2,4-
pentanedione (2), with a 1-alkynylcarbene complex, e.g.,
† Dedicated to Prof. Max Herberhold on the occasion of his 60th
birthday.
(CO)5WdC(OEt)CtCPh (1), appeared to be the best
suited in view of its high versatility.6
X Abstract published in Advance ACS Abstracts, February 1, 1996.
(1) Part 82: Meyer, A.; Aumann, R. Synlett 1995, 1011.
(2) For earlier preparation of such compounds, see: (a) Aumann,
R.; Roths, K.; Grehl, M. Synlett 1993, 669. (b) Aumann, R.; Ko¨ssmeier,
M.; Roths, K.; Fro¨hlich, R. Synlett 1994, 1041. (c) Aumann, R.;
Ko¨ssmeier, M.; Roths, K. Unpublished. (d) Aumann, R.; Roths, K.;
Laege, M.; Krebs, B. Synlett 1993, 667.
Condensation of 2 with 1 is induced by catalytic
amounts of triethylamine in pentane and affords a 90%
yield of crystalline complex 3 directly from the reaction
mixture. This reaction most probably proceeds via the
2-ethoxy-1-metalla triene A, which due to the presence
of base rapidly undergoes ring closure2a,b to the pyra-
nylidene complex 3 by elimination of EtOH. Therefore,
the reverse reaction, i.e., an attempt to generate 2-ethoxy-
1-metalla trienes by ring opening of compound 3 with
EtOH, does not appear to be promising.
We have previously demonstrated that a Michael-type
addition of enamines to the alkynylcarbene complex 1
affords 6-amino-2-ethoxy-1-tungsta-1,3,5-hexatrienes.2b,c
These compounds are quite stable and can be isolated
in crystalline form in high yields. Since Fischer carbene
complexes are known to become more stable if oxy
substituents are replaced by amino substituents, we
anticipated that aminolysis of pyranylidene complex 3
would provide an entry to stable 2-amino-1-tungsta-
1,3,5-hexatrienes.
(3) (a) Rees, Ch. W.; von Angerer, E. J . Chem. Soc., Chem. Commun.
1972, 420. (b) Gilchrist, T. L.; Livingstone, R.; Rees, Ch. W.; von
Angerer, E. J . Chem. Soc., Perkin Trans. 1 1973, 2535.
(4) Berke, H.; Ha¨rter, P.; Huttner, G.; Zsolnai, L. Z. Naturforsch.
1981, 36b, 929.
(5) Aumann, R.; Heinen, H. Chem. Ber. 1987, 120, 537.
(6) (a) Wang, S. L. B.; Wulff, W. D. J . Am. Chem. Soc. 1990, 112,
4551. (b) Faron, K. L.; Wulff, W. D. J . Am. Chem. Soc. 1990, 112, 6419.
(7) (a) Camps, F.; Moreto´, J . M.; Ricart, S.; Vin˜as, J . M.; Molins, E.;
Miravitlles, C. J . Chem. Soc., Chem. Commun. 1989, 1560. (b) Camps,
F.; J ordi, L.; Moreto´, J . M.; Ricart, S.; Castan˜o, Echavarren, A. M. J .
Organomet. Chem. 1992, 436, 189. (c) J ordi, L.; Moreto´, J . M.; Ricart,
S.; Vin˜as, J . M.; Molins, E.; Miravitlles, C. J . Organomet. Chem. 1993,
444, C28. (d) J ordi, L.; Camps, F.; Ricart, S.; Vin˜as, J . M.; Moreto´, J .
M.; Mejias, M.; Molins, E. J . Organomet. Chem. 1995, 494, 53.
(8) J uneau, K. N.; Hegedus, L. S.; Roepke, F. W. J . Am. Chem. Soc.
1989, 111, 4762.
(9) Licandro, E.; Maiorana,S.; Papagni, A.; Zanotti Gerosa, A.;
Cariati, F.; Bruni, S.; Moret, M.; Chiesi Villa, A. Inorg. Chim. Acta
1994, 220, 233.
(10) (a) Adams, R. D.; Chen, L. J . Am. Chem. Soc. 1994, 116, 4467.
(b) Adams, R. D.; Chen, L.; Huang, M. Organometallics 1994, 13, 2696.
(11) Garlaschelli, L.; Malatesta, M. C.; Panzeri, S.; Albinati, A.;
Ganazzoli, F. Organometallics 1987, 6, 63.
Complex 3 can be considered to be a resonance hybrid
between a pyranylidene and a zwitterionic pyrylium
0276-7333/96/2315-1257$12.00/0 © 1996 American Chemical Society

1258 Organometallics, Vol. 15, No. 4, 1996
Aumann et al.
Sch em e 3. 2-Am in o-1-m eta lla Tr ien es 6 a n d
Dih yd r op yr id in ylid en e Com p lexes 7 by
Ir r ever sible Am in olysis of 3
F igu r e 1. Molecular structure of pyranylidene complex
3.
Sch em e 2. 6-Am in o-1-m eta lla Tr ien es 5 by
Rever sible Am in olysis of 3 w ith P r im a r y Am in es 4
Ta ble 1. In flu en ce of Tem p er a tu r e a n d
Con cen tr a tion of a P r im a r y Am in e 4 on th e
Equ ilibr iu m Ra tio of 3:5
4 and 5
R
+20 °Ca
-30 °Ca
-30 °Cb
a
b
c
d
allyl
>20:1
>20:1
>20:1
>20:1
2:1
1:10
<1:20
<1:20
<1:20
<1:20
n-Bu
CH2Ph
i-Pr
2:1
c
a
Molar ratio of compounds 3:5 according to 1H NMR measure-
ments in CDCl3 at the temperature indicated in the presence of 2
ylide (Scheme 1). The pyrylium character is indicated
by the pattern of nonalternating bond distances between
the ring atoms [C2-O1 136.8(6), O1-C6 135.3(7), C2-
C3 140.1(7), C3-C4 138.1(7), C6-C5 137.4(8), and C4-
C5 142.0(7) pm, found by X-ray structural analysis
(Figure 1, Tables 5-8)]. Furthermore, the distance
W-C2 ) 219.3(5) pm is significantly longer than the
distance WdC ) 205 pm in (CO)5WdC(OMe)Ph.12
Little, if any, π-conjugation of the acetyl group with the
π-electron system of the pyranylidene ring is expected
since ν(CdO) is 1702.4 cm-1 in the IR spectrum, and
C4-C5-C51-C52 ) 60.4° was found by X-ray analysis.
Further indication of the pyrylium character of 3 is
based upon the strong deshielding of NMR signals of
C6 (δ 173.9) and 3-H (δ 8.05) and a significant upfield
shift of C2 (δ 258.4) compared to the carbene carbon
atom of (CO)5WdC(OEt)Ph (δ 319.6).13 In line with the
pyrylium character of 3, both ring carbon atoms at-
tached to the oxygen atom (i.e., C2 and C6) are expected
to be the most susceptible to nucleophilic attack by, for
example, an amine.
6-Am in o-1-m eta lla Tr ien es 5 fr om 3 via Rever s-
ible Rin g Op en in g w ith P r im a r y Am in es 4. It is
plausible to suggest that the addition of an amine 4 to
the pyrylium ligand of 3 should initially occur at C6 and
give a zwitterion B (Scheme 2),2a which provides a better
delocalization of negative charge than zwitterion C
(Scheme 3), resulting from the addition of 4 to the
carbene carbon atom C2. Direct experimental proof is
provided by NMR studies with primary alkylamines
4a -d . Hence, the addition of excess i-PrNH2 (4d ) to a
b
equiv of 4. Molar ratio of compounds 3:5 if an excess of 4 equiv
of 4 is applied. c Not determined.
(dark red) solution of 3 in diethyl ether did not produce
an obvious change in color within 20 min at 20 °C;
however, at -15 °C the solution immediately turned
yellow, and yellow crystals of compound 5d began to
precipitate within minutes. These crystals were isolated
by decantation and dried at -15 °C, but were found to
be unstable at 20 °C and formed a dark-red solution in
CDCl3, which (at 20 °C) exhibited 1H NMR signals of
an apparent 4:2:3 mixture of 4d , 3, and Et2O. At -30
°C this solution turned yellow, and (at this temperature)
1H NMR signals of the 1-metalla triene 5d were
observed (Table 1). The structure assigned to com-
pounds 5a -d is based on the stoichiometry in the solid
state as well as on NMR measurements in solution. The
signal of the carbene carbon atom lies within the range
expected for related carbenetungsten complexes [5d , δ
290.2; e.g. (CO)5WdC(ONMe4)Tol, δ 278.114 ] and is
shifted by 32 ppm to lower field than C2 of the ylide-
type pyranylidene precursor 3 (δ 258.4).13 Nuclear
Overhauser effects were observed between the o-hydro-
gen atoms of the phenyl group and both methyl groups
of 5d , in line with the open-chain structure suggested
for 5d . The presence of an (NH) amino enone unit [5d :
δ(CdO) 195.1, δ [dC(NHR)CH3] 162.8] and a hydrogen
bridge between the NH and CdO groups [5d , δ(NH)
11.73] is also clearly indicated by the NMR spectra.
Formation of a hydrogen bridge in 5a -d seems to
provide the driving force for the reversible ring opening
of the pyranylidene ring of 3, since aminolysis of this
type is not observed with secondary amines 8 (vide
infra).
(12) Mills, O. S.; Redhouse, A. D. Angew. Chem. 1965, 77, 1142;
Angew. Chem., Int. Ed. Engl. 1965, 4, 1142.
(13) For similar effects, see: Aumann, R.; Hinterding, P. Chem. Ber.
1992, 125, 2765-2772.
(14) Fischer, E. O.; Weiss, K. Chem. Ber. 1976, 109, 1128-1139.

Organic Syntheses via Transition Metal Complexes
Organometallics, Vol. 15, No. 4, 1996 1259
Ta ble 2. 2-Am in o-1-m eta lla Tr ien es 6 a n d
Dih yd r op yr id in ylid en e Com p lexes 7 by Am in olysis
of 3 w ith Am in es 4a -d a t 20 °C
Sch em e 4. 2-Am in o-1-m eta lla Tr ien es 9 by
Ir r ever sible Am in olysis of 3 w ith Secon d a r y
Am in es 8
4, 6
R
6 + 7 (%)a
(Z)-6:(E)-6b:7c
a
b
c
d
allyl
84
52
50
d
10:1:1
10:1:2
10:1:2
n-Bu
CH2Ph
i-Pr
a
Isolated total yield of compounds 6 and 7 (vide infra) in
b
percent. Compounds (E)-6 are formed by thermal isomerization
of (Z)-6. c A dihydropyridinylidene complex 7 (vide infra) is the
d
purported product of cyclization of syn-(Z)-6. Formation of 6d is
not observed at 20 °C within 24 h.
2-Am in om eta lla Tr ien es 6 by Ir r ever sible Am i-
n olysis of 3 w ith P r im a r y Am in es 4. Concomitant
with the (fast reversible) formation of salt-type 6-amino-
metalla trienes 5 by the addition of primary alkylamines
4a -d to C6 of the pyranylidene ring of 3 (Scheme 2),
2-aminometalla trienes 6a -c are generated by a slow
but irreversible aminolysis of compound 3 via an
intermediate C resulting from amine addition to C2
(Scheme 3). This reaction is influenced by the bulkiness
of the amine 4 and is strongly retarded by R-branched
alkyl substituents (e.g., R ) i-Pr).
2-Amino-1-tungsta-1,3,5-hexatrienes (Z)-6a-c are gen-
erated from the cyclic precursor 3 at 20 °C, with the
retention of configuration at the central CdC bond.
These compounds are expected to form syn and anti
stereoisomers (with respect to the configuration of the
amino function). The isomers anti-(Z)-6a -c are isolated
as major products (Scheme 3, Table 2). The anti
configuration seems to be a consequence of the, presum-
ably, anti periplanar arrangement of the N+-R versus
the C2-W bond in the zwitterionic intermediate C.
Stereoisomers syn-(Z)-6 are not detected, but in addition
pyranylidene complexes 7 are obtained, which could
possibly result from a (base-induced) cyclization of syn-
(Z)-6. Due to the slow E/ Z isomerization of anti-(Z)-
6a -c at the central CdC bond, the isomers anti-(E)-
6a -c are obtained as byproducts in amounts increasing
with reaction time and temperature.
The structure assignment of compounds 6a -c is
based on the chemical shift of the carbene carbon atom
in the 13C NMR spectrum, which unambiguously lies
within the range expected for aminocarbenetungsten
complexes [e.g., anti-(Z)-6b, δ 251.6; anti-(E)-6b, δ
252.8]. In line with the pyridinium ylide character of
compounds 7a -c, the signal of the carbon atom at-
tached to the tungsten atom is shifted upfield ap-
preciably2a,c,13 (e.g., 7b, δ 211.1). The (E) and (Z)
configurations of 6 are distinguished by 1H NMR
spectra, since the vinyl proton 3-H is strongly deshielded
by the anisotropic influence of the neighboring phenyl
ring [e.g., anti-(Z)-6a , δ 6.66; anti-(E)-6a , δ 5.96]. A
positive NOE enhancement is observed between 3-H
and the COCH3 group in anti-(E)-6a . An anti configu-
ration is assigned to the amino function due to the
upfield shift observed for the NCH2 signal [e.g., anti-
(Z)-6a , δ 2.98; expected for syn-(Z)-6a , δ 4.00] and the
overall downfield shift of the NH signal by the aniso-
tropic influence of the (CO)5W moiety.15 For vinyl
proton 3-H, only minor changes are induced by E/ Z
configurational changes of the central CdC bond [e.g.,
anti-(Z)-6a , δ 8.03; anti-(E)-6a , δ 8.17].
Ta ble 3. Con figu r a tion a n d Ch em ica l Yield of
2-Am in o-1-tu n gsta Tr ien es 9
8, 9
NRR1
9 (%)
(Z)/(E)-9
a
b
c
NMe2
81
89
83
(Z) only
(Z) only
(E) only
2-(hydroxymethyl)pyrrolidino
pyrrolidino
2-Am in om eta lla Tr ien es 9 by Ir r ever sible Am i-
n olysis of 3 w ith Secon d a r y Am in es 8. The observed
reversible generation of 6-aminotungsta-1,3,5-hexatrienes
5 from 1 upon the addition of primary amines 4a -d to
pyranylidene complex 3 (Scheme 2) could not be estab-
lished with secondary amines 8. The overall reaction
of secondary amines 8a -c with compound 3 is faster
than the irreversible aminolysis of these compounds
with primary amines [e.g., the addition of HNMe2 (8a )
to 3 was complete within 20 min at 20 °C] and afforded
2-amino-1-tungsta trienes 9 (Scheme 4, Table 3).
Compounds 9a ,b are isolated isomerically pure in the
(Z) configuration, while the pyrrolidine derivative 9c
acquired the (E) configuration. An apparently rapid
configuration change of (Z)-9c to (E)-9c may be initiated
by deprotonation to give an anionic intermediate D, in
which rotation at the crucial C-C bond is expected to
be a facile process (Scheme 4). Stereocontrol seems to
be governed not only by the bulkiness of the amine but
also by hydrogen bridge interactions. The latter may
play an important role in retaining the (Z) configuration
of the anion derived from 9b.
It is interesting to note that only one single isomer,
(Z)-9b, is obtained from the addition of the unsym-
metrical 2-(hydroxymethyl)pyrrolidine (8b) to complex
3. According to NMR measurements of (Z)-9b, the
NCH(CH2OH) group is arranged syn to the metal unit
[δ[NCH(CH2OH)] 3.65, δ[NCH(CH2OH)] 63.2; (E)-9c, δ
(syn-NCH2) 3.72 and 3.35; δ(syn-NCH2) 62.3]. This
configuration seems to result from the orientation of
amine 8b in the precursor (of type C) under the
directing influence of a N···H···O hydrogen bridge. The
structures suggested for the 6-amino-1-tungsta-1,3,5-
hexatrienes 9a -c are in line with spectroscopic evidence
that is similar to that outlined earlier for compounds
6a -c.
Acet im in o P yr a n ylid en e Com p lexes 10. The
acetyl group of pyranylidene complex 3 is not subjected
to direct attack by an amine for kinetic reasons, since
the addition to C6 and/or C2 (resulting in the formation
of 1-tungsta trienes 5, 6, and 9, respectively) is a much
faster process. Nevertheless, iminoacetyl compounds
10a -d are derived from 3 in smooth reaction with
(15) Moser, E.; Fischer, E. O. J . Organomet. Chem. 1969, 16, 275-
282; 1968, 13, 387-398.

1260 Organometallics, Vol. 15, No. 4, 1996
Aumann et al.
Ta ble 6. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 3
Sch em e 5. Gen er a tion of Acetim in o Com p lex 10
fr om Acetylp yr a n ylid en e Com p lex 3
W-C(2)
2.193(5)
1.368(6)
1.401(7)
1.381(7)
1.420(7)
1.474(7)
C(5)-C(6)
1.374(8)
1.503(7)
1.353(7)
1.481(8)
1.207(7)
1.503(9)
C(2)-O(1)
C(2)-C(3)
C(3)-C(4)
C(4)-C(5)
C(4)-C(41)
C(5)-C(51)
C(6)-O(1)
C(6)-C(61)
C(51)-O(53)
C(51)-C(52)
O(1)-C(2)-C(3)
O(1)-C(2)-W
114.2(4)
118.0(3)
127.6(4)
123.8(4)
118.6(5)
119.0(4)
122.5(4)
117.7(5)
117.7(5)
C(4)-C(5)-C(51)
O(1)-C(6)-C(5)
O(1)-C(6)-C(61)
C(5)-C(6)-C(61)
C(6)-O(1)-C(2)
O(53)-C(51)-C(52)
O(53)-C(51)-C(5)
C(52)-C(51)-C(5)
124.6(5)
120.9(5)
111.0(5)
128.0(5)
124.8(4)
123.0(6)
120.2(6)
116.7(5)
C(3)-C(2)-W
C(4)-C(3)-C(2)
C(3)-C(4)-C(5)
C(3)-C(4)-C(41)
C(5)-C(4)-C(41)
C(6)-C(5)-C(4)
C(6)-C(5)-C(51)
Ta ble 4. Acetim in o P yr a n ylid en e Com p lexes by
Am in olysis of 3 w ith P r im a r y Am in es 4a -d in
P r esen ce of Me3SiCl/Et3N
Ta ble 7. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t P a r a m eter s (Å2
× 103) for 3a
4, 10
R
10 (%)
anti/ syn-10
a
b
c
d
allyl
91
90
70
90
1:1a
1:1a
n-Bu
CH2Ph
i-Pr
x
y
z
U(eq)
1:1a
W
C(2)
C(3)
C(4)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(5)
7325(1)
7363(8)
8558(8)
8293(7)
9567(8)
11699(8)
12932(10)
12018(11)
9888(12)
8666(9)
2201(1)
194(5)
-99(5)
3783(1)
3057(4)
2383(3)
1868(3)
1141(4)
1351(4)
682(5)
-221(5)
-453(5)
229(4)
2049(4)
2737(4)
3208(3)
3097(5)
1559(4)
1699(7)
1122(4)
5065(5)
5783(4)
4355(5)
4656(4)
4229(5)
4444(5)
3336(5)
3106(4)
2521(4)
1820(4)
23(1)
24(1)
26(1)
24(1)
26(1)
32(1)
42(1)
46(1)
47(2)
36(1)
28(1)
30(1)
30(1)
45(2)
39(1)
58(2)
55(1)
37(1)
60(2)
37(1)
61(1)
37(1)
60(2)
34(1)
51(1)
32(1)
51(1)
>10:1
a
anti/ syn equilibrium of compound 10 after contact with silica
gel.
1382(5)
1557(5)
-899(5)
1020(6)
-1824(7)
-2491(8)
-2371(6)
-2481(5)
-2203(5)
-919(4)
-3173(7)
-3933(6)
4579(7)
4544(5)
2006(7)
1938(7)
4101(6)
5161(5)
1322(7)
881(7)
Ta ble 5. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for 3
formula
mol wt
C19H12O7W
536.14
cryst color
cryst system
space group (no.)
a (Å)
red-purple
triclinic
P1h(2)
6.667(1)
6773(8)
5658(9)
5969(6)
C(6)
O(1)
C(61)
C(51)
C(52)
O(53)
C(11)
O(11)
C(12)
O(12)
C(13)
O(13)
C(14)
O(14)
C(15)
O(15)
4098(11)
6338(10)
8151(13)
4576(7)
9150(10)
10132(9)
7241(10)
7163(8)
4648(10)
3123(9)
9992(10)
11494(8)
5517(9)
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
10.282(1)
14.279(2)
97.45(1)
100.45(1)
103.23(1)
921.9(2)
Z
D
2
calc (g cm-3
)
1.931
0.63
0.71073
512
µ (cm-1
)
wavelength (Å)
F(000) (e)
3059(6)
3533(6)
2388(6)
2491(6)
diffractometer
scan mode
[(sin θ)/λ]max (Å-1
T (°C)
abs corr
transm
no. of measd reflcns
no. of indep reflcns
no. of obsd reflcns [>2σ(I)]
Rav
Enraf-Nonius MACH3
ω-2θ
4510(9)
)
0.62
a
-50
U(eq) is defined as one-third of the trace of the orthogonalized
ψ-scan (empirical)
60.9 S 99.9%
3896 ((h, (k, +l)
3738
Uij tensor.
is accelerated appreciably upon contact with silica gel
(Table 4). The isomers can be easily distinguished by
their 1H NMR spectra. In compounds syn-10, the
dNCH signal is shifted upfield compared to the corre-
sponding signal of the anti isomer due to the anisotropic
influence of the pyranylidene ring, whereas the NCCH3
group in syn-10 appears to be less shielded than in the
anti product [e.g., anti-10a , δ(dNCH) 3.58, δ(NCCH3)
0.86; syn-10a , δ(dNCH) 3.36, δ (NCCH3) 1.42]. Dy-
namic line-broadening is observed for the signals of the
diastereotopic methyl group of the isopropyl unit in anti-
10d (but not in syn-10d ), which is due to racemization
by (an apparently fast) rotation of the acetimino group
against the pyranylidene ring.
2,6-Dia m in o-1-m eta lla Tr ien es via Acetim in o
Com p lexes 10. 2,6-Diamino-1-metalla trienes have
been previously obtained by aminolysis of 2-ethoxy-6-
amino-1-metalla trienes.2b,c An alternate route for the
generation of such compounds is based on the aminoly-
sis of acetimino pyranylidene complexes 10. For ex-
ample, the addition of Me2NH (8a ) to compound 10a
3510
0.018
no. of refined params
R(all data/obsd data)
wR2 (all data/obsd data)
246
0.036/0.033
0.095/0.094
1.78 (-2.92)
calculated, riding
EXPRESS, SHELX-86,
SHELXL-93, SCHAKAL-92
resid elec dens (e Å-3
H-atoms
)
programs used
primary amines 4a -d in the presence of Me3SiCl/Et3N
(Scheme 5, Table 4). The condensation reaction is
presumed to proceed via an intermediate E, involving
initial O-silylation of a 1-tungsta triene 5 (Scheme 2)
and subsequent ring closure2 by elimination of a tri-
methylsiloxy unit.
According to NMR measurements, the acetimino
derivatives 10a -d are generated in an anti configura-
tion with respect to the CdN bond initially, but they
form an anti/ syn mixture in solution. The anti/ syn
equilibration is slow in neutral solution at 20 °C, but it

Organic Syntheses via Transition Metal Complexes
Organometallics, Vol. 15, No. 4, 1996 1261
°C. After 2 h at 20 °C, crystallization was continued at -15
°C for 12 h to give (additional) compound 3 (482 mg, 90%, Rf
) 0.5, 1:1 diethyl ether/pentane, rust-brown powder from
pentane, violet needles from diethyl ether, mp 106 °C): 1H
NMR (CDCl3) δ 8.05 (1 H, s, 3-H), 7.54 (3 H, m, o- and m-H,
Ph), 7.40 (2 H, m, o-H, Ph), 2.67 (3 H, s, 6-CH3), 1.92 (3 H, s,
OCCH3); 13C NMR (CDCl3) δ 258.4 (WdC), 204.5 and 198.6
[trans- and cis-CO, W(CO)5], 204.5 (Cq, CdO), 173.9 (Cq, C6),
143.1 (Cq, C4), 141.5 (CH, C3), 135.4 (Cq, i-C, Ph), 131.5, 129.9,
and 128.2 (CH each, Ph), 127.9 (Cq, C5), 31.7 (6-CH3), 19.8
(OCCH3); IR (diffuse reflection, cm-1) 2060.3, 1975.4, 1900.0,
1702.4, 1589.8; MS (70 eV, 184W) m/ e (relative intensity) 536
(20) [M+], 395 (40) [M+ - 5CO], 212 (20) [ligand+], 179 (100).
Sch em e 6. 2,6-Dia m in o-1-m eta lla Tr ien e 11 by
Am in olysis of 10
Sch em e 7. En a m in e 12 fr om Meta lla Tr ien e 9
Anal. Calcd for
C19H12O7W (536.2): C, 42.56; H, 2.26.
Found: C, 42.81; H, 2.46.
Allyla m m on iu m (3Z)-5-Acetyl-6-(a llyla m in o)-4-p h en yl-
1-p en ta ca r bon yltu n gsta h ep ta -1,3,5-tr ien -2-a te (5a ). To
a freshly prepared solution of pentacarbonyl(5-acetyl-6-methyl-
4-phenyl-2H-pyran-2-ylidene)tungsten (3) (134 mg, 0.25 mmol)
in 1 mL of CD2Cl2 was added allylamine (4a ) (57 mg, 1.00
mmol) at -30 °C (with a microsyringe). A yellow solution
formed; NMR spectra were taken at -30 °C. TLC indicated
the presence of a very polar yellow compound, from which the
(violet) pyranylidene complex 3 was eluted due to the redis-
sociation of 5 on silica gel into 3 and 4: 1H NMR (CD2Cl2, 243
K, signals of the allylammonium species render prominent
leads to ring opening and formation of the 2,6-diamino-
1-metalla triene (Z)-11 in 78% yield (Scheme 6).
This aminolytic ring opening of compound 10a is
highly regioselective and provides a means for the
introduction of two different amino functions into a
1-metalla-1,3,5-hexatriene skeleton.
3
intensity) δ 11.63 (1 H, t, J ) 5 Hz, O‚‚‚HsN), 7.52 (2 H, d,
o-H, Ph), 7.52 (1 H, s, 3-H), 7.37 and 7.29 (2:1 H, m each, m-
and p-H, Ph), 5.95 (m, N+H3 and N+CH2CHdCH2), 5.20 (m,
N+CH2CHdCH2), 5.77 (1 H, m, CHdCH2, 6-allyl), 5.13 (2 H,
m, CHdCH2, 6-allyl), 3.80 (2 H, m, NCH2, 6-allyl), 3.47 (m,
N+CH2), 1.98 (3 H, s, OCCH3), 1.77 (3 H, s, NCCH3); 13C NMR
(CD2Cl2, 243 K) δ 292.5 (WdC), 207.3 and 202.4 [trans- and
cis-CO, W(CO)5], 195.8 (Cq, CdO), 164.6 (Cq, dCN), 149.2 (CH,
C3), 141.8 (Cq, C4), 134.8 (N+CH2CHdCH2), 133.9 (CHdCH2,
6-allyl), 128.5, 127.4, and 126.7 (CH each, Ph), 123.2 (Cq, i-C,
Ph), 116.9 (N+CH2CHdCH2), 116.0 (CHdCH2, 6-allyl), 104.3
(Cq, C5), 45.5 (NCH2, 6-allyl), 42.9 (N+CH2), 28.2 (OCCH3),
16.4 (NCCH3).
En am in e 12 via 2-Am in o-1-m etalla Tr ien es. Since
2-amino-1-metalla trienes are easily accessible com-
pounds, we initiated studies on their applicability to
2
organic synthesis.1,
Here we wish to illustrate an
example for the formation of a captodative 1-amino-1,3-
hexadienone 12 by base-induced ligand disengagement.
Thermolysis of (E/ Z)-9a in THF in the presence of
pyridine (Py) at 90 °C for 1.5 h afforded the enamine
12 together with (pyridine)W(CO)5. The reaction most
probably involves the formation of an anionic intermedi-
ate16 such as F , which after loss of CO may give an
anionic tungstacyclopropene17 G, from which the enam-
ine 12 is eliminated after protonation16c (Scheme 7).
n -Bu tyla m m on iu m (3Z)-5-Acetyl-6-(n -bu tyla m in o)-4-
p h en yl-1-p en t a ca r b on ylt u n gst a h ep t a -1,3,5-t r ien -2-a t e
(5b). Pentacarbonyl(5-acetyl-6-methyl-4-phenyl-2H-pyran-2-
ylidene)tungsten (3) was reacted as described earlier with 4
equiv of n-butylamine (4b) to give a solution of 5b: 1H NMR
(CD2Cl2, 243 K, 600 MHz, signals of the n-butylammonium
species render prominent intensity) δ 11.71 (1 H, t, 3J ) 5 Hz,
O‚‚‚HsN), 7.52 (2 H, d, o-H, Ph), 7.37 (1 H, s, 3-H), 7.29 and
7.22 (2:1 H, m each, m- and p-H, Ph), 4.37 (m, NH3+), 3.47
and 3.15 (m each, 6-NCH2 and N+CH2), 1.91 (3 H, s, OCCH3),
1.77 (3 H, s, NCCH3), 1.51 and 1.45 (m each, 6-NCH2CH2 and
N+CH2CH2), 1.33 and 1.30 [m each, N+(CH2)2CH2 and
6-N(CH2)2CH2], 0.91 and 0.89 [t each, N+(CH2)3CH3 and
5-N(CH2)3CH3]; 13C NMR (CD2Cl2, 243 K) δ 289.9 (WdC), 207.7
and 202.6 [1:4, trans- and cis-CO, W(CO)5], 195.0 (Cq, CdO),
163.7 (Cq, dCN), 149.4 (CH, C3), 142.4 (Cq, C4), 128.5, 127.3,
and 126.8 (2:1:2, CH each, Ph), 123.1 (Cq, i-C, Ph), 103.5 (Cq,
C4), 43.5 and 40.3 (5-NCH2 and N+CH2), 34.2 and 31.9 (N+-
CH2CH2 and 5-NCH2CH2), 28.3 (OCCH3), 20.9 and 20.2 [N+-
(CH2)2CH2 and 6-N(CH2)2CH2], 15.5 (NCCH3), 13.7 and 13.5
[6-N(CH2)3CH3 and N+(CH2)3CH3].
Exp er im en ta l Section
All operations were performed under argon. Solvents were
dried by distillation from sodium/benzophenone. Melting
points are uncorrected. Instrumentation: 1H NMR and 13C
NMR spectra were obtained with Bruker WM 300 and WP 360
spectrometers. (Multiplicities were determined by DEPT.
Chemical shifts refer to δTMS ) 0.00 ppm.) Other analyses:
IR Digilab FTS 45; MS Finnigan MAT 312; elemental analysis,
Perkin-Elmer 240 elemental analyzer; column chromatogra-
phy, Merck-Kieselgel 100; TLC, Merck DC-Alufolien Kieselgel
60 F 254. Rf values refer to TLC tests. Complex 3 has been
prepared by a modified procedure given in the literature.6
P en ta ca r bon yl(5-a cetyl-6-m eth yl-4-p h en yl-2H-p yr a n -
2-ylid en e)tu n gsten (3). To pentacarbonyl(1-ethoxy-3-phen-
yl-2-propyn-1-ylidene)tungsten (1) (482 mg, 1.00 mmol) in a
5-mL screw-top vessel was added a solution of pentane-2,4-
dione (2) (100 mg, 1.00 mmol) and triethylamine (50 mg, 0.50
mmol) in 4 mL of pentane with vigorous stirring at 20 °C until
a dark solution was obtained (after 3-5 min), from which rust-
brown crystals of 3 began to precipitate within 10 min at 20
Ben zyla m m on iu m (3Z)-5-Acetyl-6-(n -ben zyla m in o)-4-
ph en yl-1-pen tacar bon yltu n gstah epta-1,3,5-tr ien -2-ate (5c).
Pentacarbonyl(5-acetyl-6-methyl-4-phenyl-2H-pyran-2-ylidene-
)tungsten (3) is reacted as described earlier with 4 equiv of
benzylamine (4c) to give 5c: 1H NMR (CD2Cl2, 243 K, 600
MHz, signals of benzylammonium the species render promi-
(16) See also: (a) Kreiter, C. G. Angew. Chem. 1967, 79, 900; Angew.
Chem., Int. Ed. Engl. 1967, 6, 879. (b) Casey, C. P.; Anderson, R. L. J .
Chem. Soc., Chem. Commun. 1975, 895. (c) Bernasconi, C. F.; Flores,
F. X.; Sun, W. J . Am. Chem. Soc. 1995, 117, 4875.
(17) For a review on metallacyclopropenes, see: Templeton, J . L.
Adv. Organomet. Chem. 1989, 29, 71. For an X-ray structure of a stable
chromacyclopropene of related type, see: Aumann, R.; Heinen, H.;
Kru¨ger, C.; Betz, P. Chem. Ber. 1990, 123, 599.
3
nent intensity) δ 11.94 (1 H, t, J ) 5 Hz, O‚‚‚HsN), 7.67 (2
H, d, o-H, 4-Ph), 7.62 (1 H, s, 3-H), 7.45-7.18 (m, m- and p-H,
4-Ph, 6-NCH2Ph and N+CH2Ph), 6.62 (H3N+), 4.29 and 3.69
(m each, 6-NCH2 and H3N+CH2), 2.05 (3 H, s, OCCH3), 1.88
(3 H, s, NCCH3); 13C NMR (CD2Cl2, 243 K), δ 291.4 (WdC),
207.6 and 202.7 [1:4, trans- and cis-CO, W(CO)5], 196.3 (Cq,

1262 Organometallics, Vol. 15, No. 4, 1996
Aumann et al.
CdO), 163.4 (Cq, dCN), 149.4 (CH, C3), 142.0 (Cq, C4), 139.8
and 137.8 (Cq, i-C, CH2Ph and N+CH2Ph), 129.3-126.3 (CH
each, 2 Ph and N+CH2Ph), 123.3 (Cq, i-C, 4-Ph), 104.5 (Cq,
C5), 44.5 and 43.4 (NCH2 and N+CH2), 28.4 (OCCH3), 16.8
(NCCH3).
202.8 (Cq, CdO), 147.9 (Cq, C6), 146.8 (CH, C3), 140.2 (Cq,
C4), 136.3 (Cq, i-C, Ph), 135.2 (Cq, C5), 131.9 (CHdCH2); 128.5,
128.3, and 127.7 (CH each, Ph), 117.8 (CHdCH2), 67.3 (NCH2),
32.2 (OCCH3), 18.2 (6-CH3); IR (n-hexane, cm-1) 2059.6 (20),
1985.9 (5), 1922.4 (100); IR (diffuse reflection, cm-1): 1705.2
(60) [ν(CdO)] and 1585.4 (50); MS (70 eV, 184W) m/ e (relative
intensity) 575 (40) [M+], 547 (40), 519 (30), 491 (40), 463 (50),
435 (100), 365 (40), 250 (70), 197 (60), 167 (80), 57 (100). Anal.
Calcd for C22H17NO6W (575.2): C, 45.91; H, 2.98; N, 2.44.
Found: C, 46.15; H, 3.10; N, 2.54.
Isopr opylam m on iu m (2Z)-5-Acetyl-6-(isopr opylam in o)-
4-p h e n yl-1-p e n t a ca r b on ylt u n gst a h e p t a -1,3,5-t r ie n -2-
ate (5d). Pentacarbonyl(5-acetyl-6-methyl-4-phenyl-2H-pyran-
2-ylidene)tungsten (3) was reacted as described earlier with 4
equiv of isopropylamine (4d ) to give 5d : 1H NMR (CD2Cl2, 243
K, signals of the isopropylammonium species render prominent
5-Acetyl-2-(n -bu tyla m in o)-6-h yd r oxy-4-p h en yl-1-p en -
ta ca r bon yltu n gsta h ep ta -1,3,5-tr ien e [(Z)-6b a n d (E)-6b]
a n d P en ta ca r bon yl(5-a cetyl-1-bu tyl-6-m eth yl-4-p h en yl-
1,2-d ih yd r op yr id in -2-ylid en e)tu n gsten (7b). Pentacarbo-
nyl(5-acetyl-6-methyl-4-phenyl-2H-pyran-2-ylidene)tungsten (3)
(536 mg, 1.00 mmol) in 5 mL of dry ethyl ether was reacted
as described earlier with n-butylamine (4b) (95 mg, 1.30 mmol)
for 24 h at 20 °C to afford a mixture of (Z)-6b:(E)-6b:7b )
10:1:2. Chromatography on silica gel with pentane/dichlo-
romethane (4:1-1:1) afforded yellow 7b (81 mg, 14%, Rf ) 0.8
in 5:1 pentane/dichloromethane), followed by an orange frac-
tion of (Z/ E)-6b (234 mg, 38%, Rf ) 0.5 in 5:1 pentane/
dichloromethane).
3
intensity) δ 11.73 (1 H, t, J ) 5 Hz, O‚‚‚HsN), 7.52 (2 H, d,
o-H, 4-Ph), 7.41 (1 H, s, 3-H), 7.30 (2 H, m, m-H, Ph), 7.23 (1
H, m, p-H, Ph), 5.05 (H3N+), 3.66 and 3.20 (m each, NCH and
H3N+), 1.96 (3 H, s, OCCH3), 1.81 (3 H, s, NCCH3), 1.16 and
3
1.13 [d each, J ) 6.6 Hz, NCH(CH3)2 and N+CH(CH3)2]; 13C
NMR (CD2Cl2, 243 K) δ 290.2 (WdC), 207.5 and 202.7 [1:4,
trans- and cis-CO, W(CO)5], 195.1 (Cq, CdO), 162.8 (Cq, dCN),
149.5 (CH, C3), 142.4 (Cq, C4), 128.5, 127.3, and 126.8 (2:1:2,
CH each, Ph), 122.9 (Cq, i-C, Ph), 103.6 (Cq, C5), 44.9 and
43.4 (NCH and N+CH), 28.5 (OCCH3), 23.8 and 23.5 [CH3 each,
NCH(CH3)2], 24.1 [N+CH(CH3)2], 16.3 (NCCH3).
5-Acet yl-2-(a llyla m in o)-6-h yd r oxy-4-p h en yl-1-p en t a -
ca r bon yltu n gsta h ep ta -1,3,5-tr ien e [(Z)-6a a n d (E)-6a ]
a n d P en ta ca r bon yl(5-a cetyl-1-a llyl-6-m eth yl-4-p h en yl-
1,2-d ih yd r op yr id in -2-ylid en e)t u n gst en (7a ). To penta-
carbonyl(5-acetyl-6-methyl-4-phenyl-2H-pyran-2-ylidene)tung-
sten (3) (536 mg, 1.00 mmol) in 5 mL of dry ethyl ether was
added allylamine (4a ) (74 mg, 1.30 mmol) with stirring. After
4 h at 20 °C, compound 3 was consumed completely and the
color of the initially violet solution had become yellow. Ac-
cording to a 1H NMR spectrum in C6D6, a mixture of (Z)-6a :
(E)-6a :7a ) 10:1:1 was formed. Chromatography on silica gel
with pentane/dichloromethane (2:1-1:1) afforded (greenish)
yellow 7a (40 mg, 7%, Rf ) 0.8 in 1:1 pentane/dichloromethane,
yellow crystals); elution with dichloromethane/diethyl ether
(10:1) yielded orange (Z)-6a (403 mg, 70%, Rf ) 0.3 in 1:1
pentane/dichloromethane, Rf ) 0.7 in dichloromethane, orange
oil) and yellow (E)-6a (40 mg, 7%, Rf ) 0.1 in 1:1 pentane/
dichloromethane, yellow oil).
1
(Z)-6b: H NMR (CDCl3) δ 17.05 (1 H, s, dCOH‚‚‚O), 8.52
(1 H, s broad, HN), 7.50-7.10 (5 H, m, Ph), 6.98 (1 H, s, 3-H),
3.25 (2 H, m, NCH2), 1.91 (6 H, s, OCCH3), 1.63 (2 H, m,
NCH2CH2), 1.38 [2 H, m, N(CH2)2CH2], 0.95 [3 H, t, N(CH2)3-
CH3; 13C NMR (CDCl3) δ 251.6 (WdC), 201.8 and 198.3 [1:4,
trans- and cis-CO, W(CO)5], 191.9 (2 Cq, CdO and dCOH‚‚‚O),
140.9 (Cq, C5), 138.2 (CH, C4), 134.0 (Cq, i-C, Ph), 129.2, 128.8,
and 126.9 (CH each, Ph), 110.9 (Cq, C6), 51.9 (NCH2), 31.1
(NCH2CH2), 24.7 (OCCH3), 19.8 [N(CH2)2CH2], 13.5 [N(CH2)3-
CH3].
1
(E)-6b: H NMR (CDCl3) δ 16.78 (1 H, s, dCOH‚‚‚O), 8.52
(1 H, s broad, HN), 7.50-7.10 (5 H, m, Ph), 6.43 (1 H, s, 3-H),
3.42 and 3.00 (1 H each, m each, diastereotopic NCH2), 2.07
(6 H, s, 2CCH3), 1.50 (2 H, m, NCH2CH2), 1.27 (2 H, m, NCH2-
CH2CH2), 0.87 [3 H, t, N(CH)3CH3]; 13C NMR (CDCl3) δ 252.8
(WdC), 201.6 and 198.2 [1:4, trans- and cis-CO, W(CO)5], 191.9
(2 Cq, CdO and dCOH‚‚‚O), 140.9 (Cq, C5), 139.9 (CH, C4),
134.0 (Cq, i-C, Ph), 128.9, 128.7, and 128.4 (CH each, Ph),
114.9 (Cq, C6), 51.2 (NCH2), 30.4 (NCH2CH2), 24.2 (OCCH3),
19.9 [N(CH2)2CH2], 13.4 [N(CH2)3CH3]; IR (diffuse reflection,
cm-1) 2060.1, 1970.2, 1915.4 [ν(CtO)], 1598.7 [ν(CdO)], 1530.2
[ν(CdC)]; MS (70 eV, 184W) m/ e (relative intensity) 609 (10)
[M+], 469 (20) [M+ - 5CO], 285 (30) [ligand+], 57 (100); exact
mass calcd for C23H23NO7W 609.098823, found 609.10021.
1
(Z)-6a : H NMR (C6D6) δ 17.05 (1 H, s, O‚‚‚HsO), 8.03 (1
H, s broad, NH), 7.05 and 7.03 (2:3 H, m each, Ph), 6.66 (1 H,
3
s, 3-H), 5.07 (1 H, ddt, J ) 17.0, 10.0, and 4.5 Hz, CHdCH2),
4.83 and 4.81 (1 H each, m each, CHdCH2), 2.98 (2 H, m,
NCH2), 1.90 (6 H, s, 6-CH3 and OCCH3); 13C NMR (C6D6) δ
253.0 (WdC), 201.8 and 198.7 [trans- and cis-CO, W(CO)5],
192.0 (Cq, CdO and dCOH‚‚‚O), 141.3 (Cq, C4), 138.0 (CH,
C3), 135.5 (Cq, i-C, Ph), 130.5 (CHdCH2), 129.5, 128.8, and
126.9 (2:1:1, CH each, Ph), 118.6 (CHdCH2), 111.0 (Cq, C5),
53.4 (NCH2), 24.6 (2 CH3); IR (diffuse reflection, cm-1) 3356.3
[ν(NsH) bridge], 3289.6 [ν(NsH) carbene], 2060.1 (25), 1970.1
(10), 1942.6 (60), 1899.5 (100) [ν(CtO)], 1599.8 (40) [ν(CdO)],
1519.4 (50) [ν(CdC)]; MS (70 eV, 184W) m/ e (relative intensity)
593 (30) [M+], 565 (10), 537 (5), 509 (15), 481 (20), 453 (60),
210 (80), 57 (100). Anal. Calcd for C22H19NO7W (593.3): C,
44.54; H, 3.23; N, 2.36. Found: C, 44.72; H, 3.40; N, 2.43.
1
7b: H NMR (CDCl3) δ 8.46 (1 H, s, 3-H), 7.45 (3 H, m, m-
and p-H, Ph), 7.33 (2 H, m, o-H, Ph), 4.87 (2 H, s dynamically
broadened, NCH2), 2.61 (3 H, s, 6-CH3), 1.93 (3 H, s, OCCH3),
1.79 (2 H, m, NCH2CH2), 1.53 [2 H, m, N(CH2)2CH2], 1.01 [3
H, t, N(CH2)3CH3]; 13C NMR (CDCl3) δ 211.1 (WdC), 203.4
and 199.2 [1:4, trans- and cis-CO, W(CO)5], 202.8 (Cq, CdO),
147.0 (Cq, C6), 146.9 (CH, C3), 139.9 (Cq, C4), 136.5 (Cq, i-C,
Ph), 135.4 (Cq, C5), 129.9, 129.3, and 128.5 (CH each, Ph),
64.3 (NCH2), 32.7 (NCH2CH2), 32.2 (OCCH3), 19.8 [N(CH2)2CH2],
1
(E)-6a : H NMR (C6D6) δ 16.90 (1 H, s, O‚‚‚HsO), 8.17 (1
18.9 (6-CH3), 13.7 [N(CH2)3CH3]; IR (diffuse reflection, cm-1
)
H, s broad, NH), 7.05 and 7.02 (2:3 H, m each, Ph), 5.96 (1 H,
2057.0, 1985.1, 1898.2 [ν(CtO)], 1705.6 [ν(CdO)], 1584.7 [ν-
(CdC)]; MS (70 eV, 184W) m/ e (relative intensity) 591 (10) [M+],
451 (10) [M+ - 5CO], 267 (40) [ligand+], 196 (100); exact mass
calcd for C23H21NO6W 591.087840, found 591.08660.
3
s, 3-H), 4.95 (1 H, ddt, J ) 17.0, 10.0, and 4.5 Hz, CHdCH2),
4.76 and 4.71 (1 H each, m each, CHdCH2), 3.30 and 2.86 (1
H each, s each, dynamically broadened, NCH2), 2.01 and 1.70
(3 H each, s each, dynamically broadened, 6-CH3 and OCCH3);
IR (diffuse reflection, cm-1) m/ e (relative intensity) 3351.8 (10,
sharp) and 3287.8 (15, broad) [ν(NsH and OsH)], 2060.5 (30),
1971.7 (50), 1945.2 (100) [ν(CtO)], 1598.6 (30) [ν(CdO)],
1520.0 (30) [ν(CdC)].
5-Acet yl-2-(b en zyla m in o)-6-h yd r oxy-4-p h en yl-1-p en -
ta ca r bon yltu n gsta h ep ta -1,3,5-tr ien e [(Z)-6c a n d (E)-6c]
a n d P en ta ca r bon yl(5-a cetyl-1-ben zyl-6-m eth yl-4-p h en yl-
1,2-d ih yd r op yr id in -2-ylid en e)tu n gsten (7c). Pentacarbo-
nyl(5-acetyl-6-methyl-4-phenyl-2H-pyran-2-ylidene)tungsten (3)
(536 mg, 1.00 mmol) in 5 mL of dry ethyl ether was reacted
as described earlier with benzylamine (4c) (139 mg, 1.30 mmol)
to afford a mixture of (Z)-6c:(E)-6c:7c ) 10:1:2. Chromatog-
raphy on silica gel with pentane/dichloromethane (1:1-2:1)
afforded (greenish) yellow 7c (81 mg, 13%, Rf ) 0.8 in 5:1
pentane/dichloromethane); elution with dichloromethane/di-
1
7a : H NMR (C6D6) δ 8.71 (1 H, s, 3-H), 7.22 and 7.00 (2:3
H, m each, Ph), 5.45 (1 H, ddt, 3J ) 17.0, 10.0, and 4.5 Hz,
CHdCH2), 5.05 (2 H, s broad, NCH2), 4.86 and 4.40 (1 H each,
3
4
dt each, J ) 10.0 and 17.0 Hz, J ) 2.0 Hz, dCH2), 2.32 and
1.48 (3 H each, s each, 6-CH3 and OCCH3); 13C NMR (CDCl3)
δ 212.9 (WdC), 203.1 and 198.8 [trans- and cis-CO, W(CO)5],

Organic Syntheses via Transition Metal Complexes
Organometallics, Vol. 15, No. 4, 1996 1263
ethyl ether (10:1) yielded an orange mixture of 6c (Z/ E ) 10:
1) (237 mg, 37%, Rf ) 0.5 in 5:1 pentane/dichloromethane).
(Z)-6c: H NMR (CDCl3) δ 17.10 (1 H, s, O‚‚‚HsO), 8.52 (1
(Cq each, CdO and dCOH‚‚‚O), 145.4 (CH, C3), 143.3 (Cq,
C4), 129.3 (Cq, i-C, Ph), 129.0, 128.3, and 126.5 (2:1:2, CH
each, Ph), 111.2 (Cq, C6), 66.2 (CH2OH), 63.2 (NCHCH2OH),
61.1 (NCH2), 27.3 and 22.2 (CH2 each, pyrrolidine), 26.6 and
24.8 (CCH3 each); IR (n-hexane, cm-1) 2060.1 (30), 1988.5 (10),
1924.9 (100) [ν(CtO)]; IR (diffuse reflection, cm-1) 3500.0 [ν-
(OsH)], 2057.1, 1988.4, 1894.7 [ν(CtO)], 1593.0 [ν(CdO)],
1503.2 [ν(CdC)]; MS (70 eV, 184W) m/ e (relative intensity) 637
(10) [M+], 497 (10) [M+ - 5CO], 252 (30), 303 (5) [ligand+],
298 (80), 296 (60), 182 (100). Anal. Calcd for C24H23NO8W
(637.1): C, 45.21; H, 3.64; N, 2.20. Found: C, 45.44; H, 3.70;
N, 2.32.
1
H, s broad, HN), 7.40 (10 H, m, 2 Ph), 7.08 (1 H, s, 3-H), 4.46
(2 H, m, NCH2), 1.95 (6 H, s, OCCH3); 13C NMR (CDCl3) δ
252.6 (WdC), 201.7 and 198.0 [1:4, trans- and cis-CO, W(CO)5],
191.9 (2 Cq, CdO and dCOH‚‚‚O), 140.9 (Cq, C5), 138.1 (CH,
C4), 135.1 and 133.7 (Cq each, i-C, 2 Ph), 130-126 (CH each,
2 Ph), 110.9 (Cq, C6), 55.9 (NCH2), 24.2 (OCCH3); IR (diffuse
reflection, cm-1) 2060.2, 1970.9, 1909.3 [ν(CtO)], 1597.2
[ν(CdO)], 1522.5 [ν(CdC)]; MS (70 eV, 184W) m/ e (rela-
tive intensity) 643 (10) [M+], 503 (10) [M+ - 5CO], 319
(10) [ligand+], 91 (100); exact mass calcd for C26H21NO7W
643.082755, found 643.08086.
5-Acet yl-2-p yr r olid in o-6-h yd r oxy-4-p h en yl-1-p en t a -
ca r bon yltu n gsta h ep ta -1,3,5-tr ien e [(E)-9c]. Pentacarbo-
nyl(5-acetyl-6-methyl-4-phenyl-2H-pyran-2-ylidene)tungsten (3)
(536 mg, 1.00 mmol) in 1 mL of dichloromethane was reacted
with pyrrolidine (8c) (70 mg, 1.00 mmol) as described earlier
to give yellow (E)-9c (504 mg, 83%, Rf ) 0.5 in 2:1 pentane/
dichloromethane, yellow crystals from ether at -15 °C): 1H
NMR (C6D6) δ 17.80 (1 H, s broad, O‚‚‚HsO), 7.20 (2 H, d,
o-H, Ph), 7.05 (3 H, m, m- and p-H, Ph), 6.51 (1 H, s, 3-H),
3.72 and 3.35 (1 H each, s broad each, diastereotopic syn-
NCH2), 2.46 (2 H, m, anti-NCH2), 1.87 and 1.54 (2 H each, s
broad each, NCH2CH2CH2), 1.23 and 1.00 (3 H each, s broad
each, CCH3 each); 13C NMR (CDCl3) δ 243.0 (WdC), 202.3 and
198.9 [trans- and cis-CO, W(CO)5], 194.4 and 189.3 (Cq each,
CdO and dCOH‚‚‚O), 143.0 (CH, C3), 142.6 (Cq, C4), 132.4
(Cq, i-C, Ph), 129.3, 128.4, and 126.9 (2:1:2, CH each, Ph),
111.4 (Cq, C6), 62.3 and 54.7 (NCH2 each), 25.5 and 24.2 (CH2
each, pyrrolidine), 25.8 and 23.5 (CCH3 each); IR (n-hexane,
cm-1) 2059.6 (30), 1987.7 (10), 1925.3 (100) [ν(CtO)]; IR
(diffuse reflection, cm-1) 3500.0 [ν(OsH)], 2057.1, 1988.5,
1890.0 [ν(CtO)], 1597.3 [ν(CdO)], 1500.0 [ν(CdC)]; MS (70
eV, 184W) m/ e (relative intensity) 607 (10) [M+], 589 (20), 551
(10), 523 (40), 495 (40), 467 (40) [M+ - 5CO], 283 (30) [ligand+],
268 (80), 266 (60), 224 (100). Anal. Calcd for C23H21NO7W
(607.3): C, 45.49; H, 3.49; N, 2.31. Found: C, 45.64; H, 3.70;
N, 2.52.
1
(E)-6c: H NMR (CDCl3) δ 16.75 (1 H, s, O‚‚‚H-O), 8.82 (1
H, s broad, HN), 7.50-7.00 (10 H, m, 2 Ph), 6.49 (1 H, s, 3-H),
5.57 and 3.95 (1 H each, m each, NCH2), 2.01 (6 H, s, OCCH3);
13C NMR (CDCl3) δ 253.6 (WdC), 202.0 and 198.1 [1:4, trans-
and cis-CO, W(CO)5], 191.9 (2 Cq, CdO and dCOH‚‚‚O), 140.9
(Cq, C5), 139.9 (CH, C4), 138.2 and 133.5 (Cq each, i-C each,
2 Ph), 130-126 (CH each, 2 Ph), 114.9 (Cq, C6), 55.3 (NCH2),
24.7 (OCCH3).
1
7c: H NMR (CDCl3) δ 8.60 (1 H, s, 3-H), 7.50-7.24 (8 H,
m, Ph, m- and p-H, benzyl), 6.97 (2 H, m, o-H, benzyl), 6.29 (2
H, s dynamically broadened, NCH2), 2.40 (3 H, s, 6-CH3), 1.91
(3 H, s, OCCH3); 13C NMR (CDCl3) δ 214.5 (WdC), 203.0 and
198.7 [1:4, trans- and cis-CO, W(CO)5], 202.6 (Cq, CdO), 148.3
(Cq, C6), 146.5 (CH, C3), 140.5 (Cq, C4), 136.3 and 134.6 (Cq
each, i-C each, 2 Ph), 135.5 (Cq, C5), 129.9, 129.4, 128.6, 128.2,
and 125.6 (CH each, 2 Ph), 63.4 (NCH2), 32.2 (OCCH3), 19.3
(6-CH3); IR (diffuse reflection, cm-1) 2058.7, 1966.6, 1899.8 [ν-
(CtO)], 1704.3 [ν(CdO)], 1585.5 [ν(CdC)]; MS (70 eV, 184W)
m/ e (relative intensity) 625 (10) [M+], 485 (30) [M+ - 5CO],
301 (30) [ligand+], 91 (100); exact mass calcd for C26H19NO6W
625.072191, found 625.06959.
(3Z)-5-Acetyl-2-(d im eth yla m in o)-6-h yd r oxy-4-p h en yl-
1-p en ta ca r bon yltu n gsta h ep ta -1,3,5-tr ien e (9a ). To pen-
tacarbonyl(5-acetyl-6-methyl-4-phenyl-2H-pyran-2-ylidene)-
tungsten (3) (536 mg, 1.00 mmol) in 1 mL of dichloromethane
was added dimethylammonium dimethylaminocarbamate (8a )
(134 mg, 1.00 mmol) with stirring. A yellow solution was
obtained after 20 min at 20 °C, from which yellow crystals
began to precipitate after the addition of 3 mL of pentane (470
mg, 81%, Rf ) 0.2 in 1:1 pentane/dichloromethane, yellow
crystals, mp 121 °C): 1H NMR (C6D6) δ 16.80 (1 H, s broad,
O‚‚‚HsO), 7.19 (1 H, s, 3-H), 7.13 and 7.00 (2:3, m each, Ph),
2.45 and 2.12 (3 H each, s each, NMe2), 2.00 and 1.30 (3 H
each, s dynamically broadened each, CCH3 each); 13C NMR
(CDCl3) δ 250.3 (WdC), 200.6 and 198.7 [trans- and cis-CO,
W(CO)5], 193.6 and 191.2 (Cq each, CdO and dCOH‚‚‚O),
141.3 (CH, C3), 141.2 (Cq, C4), 129.1 (Cq, i-C, Ph), 129.0, 128.4,
and 126.0 (2:1:2, CH each, Ph), 110.6 (Cq, C6), 54.0 and 45.9
(NCH3 each), 24.8 and 24.7 (CCH3 each); IR (diffuse reflection,
cm-1) 2059.2, 1988.2, 1908.7; MS (70 eV, 184W) m/ e (relative
intensity) 581 (10) [M+], 441 (20) [M+ - 5CO], 257 (30)
[ligand+], 198 (100), 165 (90), 115 (100). Anal. Calcd for
P e n t a c a r b o n y l[1-(N -a lly la c e t i m i n o )-6-m e t h y l-4-
p h en ylp yr a n -2-ylid en e]tu n gsten (10a ). To a freshly pre-
pared suspension of pentacarbonyl(5-acetyl-6-methyl-4-phenyl-
2H-pyran-2-ylidene)tungsten (3) (536 mg, 1.00 mmol) and
allylamine (4a ) (57 mg, 1.00 mmol) in 1 mL of dry ethyl ether
in a 5-mL screw-top vessel was added a solution of trimeth-
ylchlorosilane (308 mg, 3.00 mmol) and triethylamine (409 mg,
4.00 mmol) in 3.5 mL of dry diethyl ether with stirring.
Stirring was continued at 20 °C until a (homogeneous) solution
was obtained. According to TLC, complex 3 was consumed
completely after 24 h at 20 °C, and maroon polar compound
10a formed. Solvent was removed (20 °C, 1 Torr) and the
residue was extracted with small portions of toluene.
A
1H
NMR spectrum, which was taken immediately after (a fast)
workup, indicated the presence of anti-10a only. Anti/ syn
isomerization to give a 1:1 mixture was observed upon stand-
ing in solution or upon chromatography (523 mg, 91%, red oil,
Rf ) 0.2 in 1:1 pentane/diethyl ether, on silica gel). anti-10a
1
C
21H19NO7W (581.2): C, 41.25; H, 2.73; N, 2.53. Found: C,
{syn-10a }: H NMR (C6D6) δ 8.10 {8.00} (1 H, s, 3-H), 7.05-
6.90 {6.95-6.90} (5 H, m, Ph), 5.90 {5.82} (1 H, ddt, 3J ) 17.0,
10.0, and 4.5 Hz, CHdCH2), 5.18 and 5.04 {5.12 and 5.00} (1
41.38; H, 2.95; N, 2.72.
5-Acetyl-2-[2-(h yd r oxym eth yl)p yr r olid in o]-6-h yd r oxy-
4-p h en yl-1-p en ta ca r bon yltu n gsta h ep ta -1,3,5-tr ien e [(Z)-
9b]. Pentacarbonyl(5-acetyl-6-methyl-4-phenyl-2H-pyran-2-
ylidene)tungsten (3) (536 mg, 1.00 mmol) in 1 mL of di-
chloromethane was reacted with 2-(hydroxymethyl)pyrrolidine
(8b) (100 mg, 1.00 mmol) as described earlier to give yellow
(E)-9b (567 mg, 89%, Rf ) 0.5 in 1:1 pentane/diethyl ether):
1H NMR (C6D6) δ 17.63 (1 H, s broad, O‚‚‚HsO), 7.39 (1 H, s,
3-H), 7.26 (2 H, d, o-H, Ph), 7.10 (3 H, m, m- and p-H, Ph),
4.20 (1 H, s, CH2OH), 3.72 (2 H, m, CH2OH), 3.65 (1 H, m,
syn-NCHCH2OH), 2.82 (2 H, m, anti-NCH2), 2.00 and 1.40 (2
H each, s broad each, NCH2CH2CH2), 1.23 and 1.00 (3 H each,
s broad each, CH3 each); 13C NMR (CDCl3) δ 247.8 (WdC),
202.9 and 198.9 [trans- and cis-CO, W(CO)5], 193.7 and 190.9
3
2
H each, dd each, J ) 17.0 and 10.0 Hz, J ) 1.5 Hz, dCH2),
3.58 {3.36} (2 H each, m each, NCH2), 1.96 and 0.86 {1.63 and
1.42} (3 H each, s each, 6-CH3 and NCCH3); 13C NMR (C6D6)
δ 253.9 {255.7} (Cq, WdC), 204.4 and 199.2 {204.3 and 199.2}
[Cq, 1:4, trans- and cis-CO, W(CO)5], 174.8 {172.3} (Cq, C6),
163.1 {160.7} (Cq, C)N), 145.6 {145.2} (Cq, C4), 141.3 {141.4}
(CH, C3), 135.2 {136.1} (CHdCH2), 135.2 {135.0} (Cq, i-C, Ph),
129.4, 128.7, and 127.8 {129.2, 128.6, and 128.1} (2:2:1, CH
each, Ph), 130.8 {132.3} (Cq, C6), 115.8 {115.6} (dCH2), 56.6
{54.6} (NCH2), 19.0 and 18.8 {27.3 and 19.1} (6-CH3 and
NCCH3); IR (n-hexane, cm-1) 2060.6 (40), 1972.2 (5), 1930.3
(100) [ν(CtO)]; IR (diffuse reflection, cm-1) 1651.4 (15) [ν-
(CdN)], 1593.3 (60) [ν(CdC)]; MS (70 eV, 184W) m/ e (relative

1264 Organometallics, Vol. 15, No. 4, 1996
Aumann et al.
intensity) 575 (80) [M+], 547 (60), 519 (10), 491 (70), 463 (70),
435 (100). Anal. Calcd for C22H17NO6W (575.2): C, 45.91; H,
2.98; N, 2.44. Found: C, 46.05; H, 3.18; N, 2.62.
H, sept, NCHMe2), 2.43 (3 H, s, NCCH3), 1.43 (3 H, s, 6-CH3);
13C NMR (CDCl3) δ 253.5 (WdC), 204.9 and 198.8 [1:4, trans-
and cis-W(CO)5], 174.5 (Cq, C6), 160.9 (Cq, CdN), 145.9 (Cq,
C4), 141.4 (CH, C3), 135.8 (Cq, i-C, Ph), 130.8, 129.2, 128.5
(CH each, Ph), 129.6 (Cq, C5), 52.0 (NCHMe2), 22.8 [NCH-
(CH3)2], 19.6 and 19.1 (6-CH3 and NCCH3); IR (diffuse reflec-
tion, cm-1) 2059.0, 1973.6, 1903.9 [ν(CtO)], 1648.4 [ν(CdN)],
1593.5 [ν(CdC)]; MS (70 eV, 184W) m/ e (relative intensity) 577
(70) [M+], 437 (60) [M+ - 5CO], 253 (60) [ligand+], 80 (100).
Anal. Calcd for C22H19NO6W (577.3): C, 45.78; H, 3.32; N,
2.43. Found: C, 45.93; H, 3.04; N, 2.68.
P e n t a ca r b on yl[5-(N -n -b u t yla ce t im in o)-6-m e t h yl-4-
p h en ylp yr a n -2-ylid en e]tu n gsten (10b). A freshly prepared
suspension of pentacarbonyl(5-acetyl-6-methyl-4-phenyl-2H-
pyran-2-ylidene)tungsten (3) (536 mg, 1.00 mmol) and n-
butylamine (4b) (73 mg, 1.00 mmol) in 1 mL of dry ethyl ether
was reacted as described earlier with trimethylchlorosilane/
triethylamine to give a 3:1 mixture of anti/ syn-10b . After
chromatography on silica gel, the anti:syn ratio was changed
to 1:1 (Rf ) 0.5 in 5:1 pentane/dichloromethane, 532 mg, 90%,
(3Z)-5-Acetyl-6-(allylam in o)-2-(dim eth ylam in o)-4-ph en -
yl-1-p en ta ca r bon yltu n gsta h ep ta -1,3,5-tr ien e (11). A mix-
ture of pentacarbonyl[5-(N-isopropylacetimino)-6-methyl-4-
phenylpyran-2-ylidene]tungsten (10d ) (577 mg, 1.00 mmol) in
3 mL of diethyl ether and dimethylammonium dimethylami-
nocarbamate (8a ) (134 mg, 1.00 mmol) was heated in a 5-mL
screw-top vessel for 1 h at 50 °C to give 11 (483 mg, 78%, Rf
) 0.5 in 10:1 dichloromethane/diethyl ether, yellow crystals,
mp 116 °C): 1H NMR (C6D6) δ 12.30 (1 H, s broad, NH bridge),
7.35 (1 H, s, 3-H), 7.40, 7.15, and 7.00 (2:2:1, m each, Ph), 5.42
(1 H, ddt, 3J ) 17.0, 10.0, and 4.5 Hz, CHdCH2), 4.93 (2 H, m,
dCH2), 3.20 (2 H, m, NCH2), 3.00 and 2.40 (3 H each, s each,
NMe2), 1.75 and 1.65 (3 H each, s dynamically broadened each,
CCH3 each); 13C NMR (CDCl3) δ 248.8 (WdC), 202.5 and 199.2
[trans- and cis-CO, W(CO)5], 194.8 (Cq, CdO), 163.1 (Cq,
dCsN), 142.6 (Cq, C4), 141.0 (CH, C3), 134.2 (CHdCH2),
132.6 (Cq, i-C, Ph), 129.0, 128.3, and 126.4 (2:1:2, CH each,
Ph), 115.7 (CHdCH2), 104.5 (Cq, C6), 53.4 and 45.3 (NCH3
1
red oil). anti-10b {syn-10b}: H NMR (CDCl3) δ 7.96 {8.01}
(1 H, s, 3-H), 7.51-7.24 (5 H, m, Ph), 3.36 {3.16} (2 H, m,
NCH2), 2.61 {2.50} (3 H, s, 6-CH3), 1.80 (2 H, m, NCH2CH2),
1.53 {1.96} (3 H, s, NCCH3), 1.36 {1.36} (2 H, m, NCH2-
CH2CH2), 0.95 {0.90} (3 H, t, NCH2CH2CH2CH3); 13C NMR
(CDCl3) δ 254.6 {256.3} (WdC), 204.4 {204.1} and 198.6
{198.5} [1:4, trans- and cis-W(CO)5], 173.8 {171.4} (Cq, C6),
163.1 {160.7} (Cq, CdN), 144.9 {144.3} (Cq, C4), 141.2 {141.1}
(CH, C3), 135.7 {134.9} (Cq, i-C, Ph), 130.3 {130.9}, 129.0
{129.3} and 128.2 {127.6} (CH each, Ph), 129.1 {124.2} (Cq,
C5), 52.1 {54.3} (NCH2), 32.4 {32.6} (NCH2CH2), 20.9 {20.9}
(NCH2CH2CH2), 19.9 and 19.5 {27.8 and 19.4} (6-CH3 and
NCCH3), 13.8 {13.8} (NCH2CH2CH2CH3); IR (diffuse reflection,
cm-1) 2058.9, 1973.2, 1938.0, 1898.5 [ν(CtO)], 1648.9 [ν-
(CdN)], 1592.8 [ν(CdC)]; MS (70 eV, 184W) m/ e (relative
intensity) 591 (20) [M+], 451 (40) [M+ - 5CO], 67 (40) [ligand+],
57 (100); exact mass calcd for C23H21NO6W (184W) 591.0882,
found 591.0866.
each), 28.7 and 17.4 (CCH3 each); IR (diffuse reflection, cm-1
2057.6, 1988.7, 1901.2 [ν(CtO)], 1593 [ν(CdO)]; MS (70 eV,
184W) m/ e (relative intensity) 620 (10) [M+], 480 (20) [M+
5CO], 196 (100), 165 (90), 57 (100). Anal. Calcd for C24H24
)
P e n t a ca r b on yl[5-(N -b e n zyla ce t im in o)-6-m e t h yl-4-
p h en ylp yr a n -2-ylid en e]tu n gsten (10c). A freshly prepared
suspension of pentacarbonyl(5-acetyl-6-methyl-4-phenyl-2H-
pyran-2-ylidene)tungsten (3) (536 mg, 1.00 mmol) and benzyl-
amine (4c) (107 mg, 1.00 mmol) in 1 mL of dry ethyl ether
was reacted as described earlier with trimethylchlorosilane/
triethylamine to give a 3:1 mixture of anti/ syn-10c. After
chromatography on silica gel, the anti:syn ratio was changed
to 1:1 (Rf ) 0.5 in 5:1 pentane/dichloromethane, 438 mg, 70%,
-
-
N2O6W (620.3): C, 46.47; H, 3.90; N, 4.50. Found: C, 46.29;
H, 3.85; N, 4.58.
3-Acetyl-6(E)-(d im eth yla m in o)-4-p h en yl-3,5-h exa d ien -
2-on e (12a ). Pentacarbonyl[(2Z)-4-acetyl-1-(dimethylamino)-
5-hydroxy-3-phenyl-2,4-hexadien-1-ylidene]tungsten (9a ) (290
mg, 0.50 mmol) in 1 mL of dry THF and pyridine (44 mg, 0.55
mmol) were heated in a 2-mL screw-top vessel. According to
a TLC test, starting material was consumed after 1.5 h at 90
°C. The solvent was removed and replaced by 2 mL of diethyl
ether, from which (pyridine)W(CO)5 (160 mg, 80%) could be
removed by crystallization at -45 °C: 1H NMR (CDCl3) δ
7.20-7.00 (5 H, m, Ph), 6.90 (1 H, d, 3J ) 13 Hz, dCHN), 5.98
1
red oil). anti-10c {syn-10c}: H NMR (CDCl3) δ 7.97 {8.05}
(1 H, s, 3-H), 7.50-7.24 (10 H, m, 2 Ph), 4.60 {4.44} (2 H, m
NCH2), 2.61 {2.46} (3 H, s, 6-CH3), 1.73 {2.03} (3 H, s, NCCH3);
13C NMR (CDCl3) δ 254.8 {256.8} (WdC), 204.4 {204.1} and
198.7 {198.6} [1:4, trans- and cis-W(CO)5], 173.9 {171.5} (Cq,
C6), 164.0 {162.3} (Cq, C)N), 144.9 {144.2} (Cq, C4), 141.3
{141.4} (CH, C3), 138.4 {138.2} and 135.7 {134.8} (Cq each,
i-C each, 2 Ph), 130.3, 129.0, 128.7, 128.2, 128.1, and 127.2
{130.9, 129.3, 128.5, 127.6, 127.5, and 127.2} (CH each, 2 Ph),
128.8 {123.9} (Cq, C5), 56.4 {57.8} (NCH2), 19.9 and 19.5 {27.9
and 19.4} (6-CH3 and NCCH3); IR (n-hexane, cm-1) 2059.5 (40),
3
(1 H, d, J ) 13.0 Hz, dCHC), 2.10-1.90 (12 H, dynamically
broadened, OCCH3 and NCH3); 13C NMR (CDCl3) δ 198.8 and
197.7 (Cq each, 2 8CdO), 154.1 (Cq, C3), 152.4 (dCHN), 139.9
(Cq, i-C, Ph), 130.3, 128.2, and 126.5 (CH each, Ph), 102.5 (CH,
C4), 100.2 (CH, C2), 50.6 (NCH3), 26.3 (2OCCH3); GC-MS (70
eV) m/ e (relative intensity) 257 (30) [M+], 256 (30) [M+ - 1],
242 (50), 213 (100) [M+ - COCH3], 200 (40), 180 (10), 170 (20)
[213 - NMe2], 158 (10), 141 (15), 128 (20), 115 (25), 43 (100).
1973.2 (5), 1945.8 (100) [ν(CtO)]; IR (diffuse reflection, cm-1
)
1648.3 (15) [ν(CdN)], 1592.6 (60) [ν(CdC)]; MS (70 eV, 184W)
m/ e (relative intensity) 625 (10) [M+], 548 (40) [M+ - 5CO],
301 (20) [ligand+], 91 (100); exact mass calcd for C26H19NO6W
(
184W) 625.07265, found 625.06959.
Ack n ow led gm en t. This work was supported by the
Deutsche Forschungsgemeinschaft (DFG) and the Fonds
der Chemischen Industrie.
P en ta ca r bon yl[5-(N-isop r op yla cetim in o)-6-m eth yl-4-
p h en ylp yr a n -2-ylid en e]tu n gsten (10d ). A freshly prepared
suspension of pentacarbonyl(5-acetyl-6-methyl-4-phenyl-2H-
pyran-2-ylidene)tungsten (3) (536 mg, 1.00 mmol) and isopro-
pylamine (4d ) (59 mg, 1.00 mmol) in 1 mL of dry ethyl ether
was reacted as described earlier with trimethylchlorosilane/
triethylamine to give anti-10d (Rf ) 0.5 in 5:1 pentane/
Su p p or tin g In for m a tion Ava ila ble: Tables of positional
and displacement parameters and bond distances and angles
(13 pages). Ordering information is given on any current
masthead page.
1
dichloromethane, 519 mg, 90%, red crystals, mp 155 °C): H
NMR (CDCl3) δ 7.74 (1 H, s, 3-H), 7.23 (5 H, m, Ph), 3.57 (1
OM950741M