Novel pyranylidene complexes from group 6 transition metals and β-ethynyl α,β-unsaturated carbonyl compounds

Article abstract of DOI:10.1021/om0006763

The reaction of conjugated enyne-carbonyl compounds such as 1-(alkoxycarbonyl)-2-ethynylcyclo-alkenes and 1-carbamoyl-2-ethylnylcycloalkenes with Mo(CO)₅·NEt₃ and W(CO)₅·THF gave the corresponding 6-alkoxy- and 6-amino-2H-pyranylidene-molybdenum and -tungsten complexes, respectively. The cycloisomerization reaction of the conjugated vinylidene-ene-carbonyl complexes generated from 1-(alkoxycarbonyl)-or 1-carbamoyl-2-ethynylcycloalkenes and metals is a key route to these Fischer-type oxacarbene complexes. The crystal structure of the 6-methoxy-2H-pyranylidene-tungsten complex 2b has been determined by X-ray diffraction. New pyranylidene complexes undergo [4 + 2] cycloaddition reactions with acetylenes to give aromatic rings together with the liberation of metal hexacarbonyls.

Full text of DOI:10.1021/om0006763

Organometallics 2000, 19, 5525-5528
5525
Novel P yr a n ylid en e Com p lexes fr om Gr ou p 6 Tr a n sition
Meta ls a n d â-Eth yn yl r,â-Un sa tu r a ted Ca r bon yl
Com p ou n d s
Kouichi Ohe,* Koji Miki, Tomomi Yokoi, Fumiaki Nishino, and Sakae Uemura*
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering,
Kyoto University, Sakyo-ku, Kyoto 606-8501, J apan
Received August 7, 2000
Sch em e 1
Summary: The reaction of conjugated enyne-carbonyl
compounds such as 1-(alkoxycarbonyl)-2-ethynylcyclo-
alkenes and 1-carbamoyl-2-ethynylcycloalkenes with
Mo(CO)5‚NEt3 and W(CO)5‚THF gave the corresponding
6-alkoxy- and 6-amino-2H-pyranylidene-molybdenum
and -tungsten complexes, respectively. The cycloisomer-
ization reaction of the conjugated vinylidene-ene-
carbonyl complexes generated from 1-(alkoxycarbonyl)-
or 1-carbamoyl-2-ethynylcycloalkenes and metals is a key
route to these Fischer-type oxacarbene complexes. The
crystal structure of the 6-methoxy-2H-pyranylidene-
tungsten complex 2b has been determined by X-ray
diffraction. New pyranylidene complexes undergo [4 + 2]
cycloaddition reactions with acetylenes to give aromatic
rings together with the liberation of metal hexacarbonyls.
structure of 2 represents the R-metallo analogue of
R-pyrone.6 Although the reactivity as well as the
structural feature is of much interest, the studies on
pyranylidene-metal complexes are still limited.7,8 Thus,
we also describe the synthetic application of these
pyranylidene-metal complexes 2 as an enophile to
[4 + 2] cycloaddition reactions.
(4) For reviews on vinylidene transition-metal complexes, see: (a)
Bruce, M. I.; Swincer, A. G. Adv. Organomet. Chem. 1983, 22, 59. (b)
Bruce, M. I. Chem. Rev. 1991, 91, 197. (c) Bruneauu, C.; Dixneuf, P.
H. Acc. Chem. Res. 1999, 32, 311.
In tr od u ction
Fischer-type carbene complexes of the group 6 metals
Cr, Mo, and W are versatile and useful organometallic
reagents in organic synthesis.1 Typical oxacarbene
complexes (MdC(OR′)R) are readily prepared by the
reaction of the metal hexacarbonyl with a range of
organolithium reagents. It has also been demonstrated
that nucleophilic addition of an alcoholic O-H bond to
the R- and â-carbons of a vinylidene-metal complex
(MdCRdCâ, M ) Cr, Mo, W), generated from an
ω-alkynol, provides new access to oxacarbene complexes
as intermediates in catalytic reactions and isolable
intermediates in stoichiometric reactions.2,3 We report
herein a new approach for the pyranylidene-metal
compound 2 as a group 6 oxacarbene complex via a
nucleophilic attack with a carbonyl oxygen at an R-
carbon of a vinylidene-metal species (A) produced
from the conjugated compound 1 (Scheme 1).4,5 The
(5) For leading references dealing with transformation of vinylidene-
metal intermediates in conjugate systems, see: (a) Wang, Y.; Finn,
M. G. J . Am. Chem. Soc. 1995, 117, 8045. (b) Ohe, K.; Kojima, M.;
Yonehara, K.; Uemura, S. Angew. Chem., Int. Ed. Engl. 1996, 35, 1823.
(c) Merlic, C. A.; Pauly, M. E. J . Am. Chem. Soc. 1996, 118, 11319. (d)
Manabe, T.; Yanagi, S.; Ohe, K.; Uemura, S. Organometallics 1998,
17, 2942. (e) Maeyama, K.; Iwasawa, N. J . Am. Chem. Soc. 1998, 120,
1928. (f) Maeyama, K.; Iwasawa, N. J . Org. Chem. 1999, 64, 1344.
(6) For reviews, see: (a) Afarinkia, K.; Vinader, V.; Nelson, T. D.;
Posner, G. H. Tetrahedron 1992, 48, 9111. (b) Woodard, B. T.; Posner,
G. H. Advances in Cycloaddition; J AI: Greenwich, CT, 1999; Vol. 5, p
47.
(7) Moreto´ reported that the reaction of diethoxyacrylate with
alkynylalkoxycarbene-metal complexes eventually leads to 6-ethoxy-
2H-pyranylidene-chromium and -tungsten carbene complexes; see:
Camps, F.; Moreto´, J . M.; Ricart, S.; Vin˜as, J . M.; Molins, E.;
Miravitlles, C. J . Chem. Soc., Chem. Commun. 1989, 1560. J ordi, L.;
Moreto´, J . M.; Ricart, S.; Vin˜as, J . M.; Molins, E.; Miravitlles, C. J .
Organomet. Chem. 1993, 444, C28. For preparation of other pyran-2-
ylidene carbene complexes which have mainly alkyl or aryl moieties
as substituents on the pyranylidene ring, see: (a) Rees, C. W.; von
Angerer, E. J . Chem. Soc., Chem. Commun. 1972, 420. (b) Gilchrist,
T. L.; Livingston, R.; Rees, C. W.; von Angerer, E. J . Chem. Soc., Perkin
Trans. 1 1973, 2535. (c) J uneau, K. N.; Hegedus, L. S.; Roepke, F. W.
J . Am. Chem. Soc. 1989, 111, 4762. For preparation from Fischer-type
oxacarbene complexes, see: (d) Aumann, R.; Heinen, H. Chem. Ber.
1987, 120, 537. (e) Faron, K. L.; Wulff, W. D. J . Am. Chem. Soc. 1990,
112, 6419. (f) Wang, S. L. B.; Wulff, W. D. J . Am. Chem. Soc. 1990,
112, 4550. (g) Aumann, R.; Roths, K.; La¨ge, M.; Krebs, B. Synlett 1993,
667. (h) Aumann, R.; Roths, K.; J asper, B.; Fro¨hlich, R. Organometallics
1996, 15, 1257. (i) Aumann, R.; Meyer, A. G.; Fro¨hlich, R. J . Am. Chem.
Soc. 1996, 118, 10853. (j) Yu, Z.; Aumann, R.; Fro¨hlich, R.; Roths, K.;
Hecht, J . J . Organomet. Chem. 1997, 541, 187.
(1) Hegedus, L. S. Transition Metals in the Synthesis of Complex
Organic Molecules; University Science Books: Mill Valley, CA, 1994;
p 151.
(2) For a review, see: McDonald, F. E. Chem. Eur. J . 1999, 5, 3103.
(3) For leading references, see: (a) Fischer, E. O.; Plabst, D. Chem.
Ber. 1974, 107, 3326. (b) Casey, C. P.; Anderson, R. L. J . Chem. Soc.,
Chem. Commun. 1975, 895. (c) Parlier, A.; Rudler, H. J . Chem. Soc.,
Chem. Commun. 1986, 514. (d) Do¨tz, K. H.; Sturm, W.; Alt, H. G.
Organometallics 1987, 6, 1424. (e) McDonald, F. E.; Connolly, C. B.;
Gleason, M. M.; Towne, T. B.; Treiber, K. D. J . Org. Chem. 1993, 58,
6952. (f) Quayle, P.; Rahman, S.; Ward, E. L. M.; Herbert, J .
Tetrahedron Lett. 1994, 35, 3801. (g) McDonald, F. E.; Gleason, M. M.
J . Am. Chem. Soc. 1996, 118, 6648. (h) Schmidt, B.; Kocienski, P.; Reid,
G. Tetrahedron 1996, 52, 1617. (i) Bernasconi, C. F. Chem. Soc. Rev.
1997, 26, 299. (j) McDonald, F. E.; Zhu, H. Y. H. J . Am. Chem. Soc.
1998, 120, 4246. (k) McDonald, F. E.; Reddy, K. S.; D´ıaz, Y. J . Am.
Chem. Soc. 2000, 122, 4304.
(8) In the course of our study Iwasawa and co-workers have reported
the formation of benzopyranylidene-tungsten complexes from o-
ethynylphenyl ketones and tungsten carbonyl and its application to
[4 + 2] cycloaddition reactions with electron-rich alkenes; see: Shido,
M.; Maeyama, K.; Kusama, H.; Iwasawa, N. 78th Annual Meeting of
the Chemical Society of J apan, Funabashi, J apan, March 29, 2000;
Abstracts Vol. II, p 1026. Note Added in Proof: Iwasawa, N.; Shido,
M.; Maeyama, K.; Kusama, H. J . Am. Chem. Soc. 2000, 122, 10226.
10.1021/om0006763 CCC: $19.00 © 2000 American Chemical Society
Publication on Web 11/14/2000

5526 Organometallics, Vol. 19, No. 25, 2000
Notes
Ta ble 1. P r ep a r a tion of P yr a n ylid en e-Meta l
Com p lexes fr om Con ju ga ted En yn e-Ca r bon yls
a n d th e Gr ou p 6 Meta lsa
F igu r e 1. ORTEP drawing of the complex 2b.
gave better yields of 2a , in 51% (2.0 equiv of W) and
75% yields (3.0 equiv of W), respectively (entries 2 and
3). Although the condition of THF reflux was required,
the reaction of 2-ethynyl-1-(methoxycarbonyl)cyclohex-
1-ene (1b) with W(CO)5‚THF was complete within 0.5
h to give the corresponding pyranylidene-tungsten
complex 2b in 63% yield as well (entry 4). Among other
group 6 metals examined, the similar pyranylidene-
molybdenum complex 3b was obtained in 35% yield
from 1b and preformed Mo(CO)5‚NEt311 (entry 5), while
11
the reaction with the chromium complex Cr(CO)5‚NEt3
gave only a trace amount of an isolable complex. An
amide compound, 2-ethynyl-1-(N,N-diethylcarbamoyl)-
cyclohex-1-ene (1c), also reacted with W(CO)5‚THF at
reflux temperature in THF to give the 6-(diethylamino)-
pyranylidene complex 2c in 68% yield (entry 6). The
formation of pyranylidene-metal complexes 2d ,e from
1d ,e demonstrated the tolerance of an ω-alkenyl or an
internal alkynyl moiety in the substrate (entries 7 and
8). The simplest substrate, 2-phenylethyl (Z)-pent-2-en-
4-ynoate (1f), was reacted with W(CO)5‚THF to give the
6-((2-phenylethyl)oxy)pyranylidene-tungsten complex
2f in 58% yield (entry 9).
a
Reactions were carried out with 1 (0.2-0.5 mmol) under Ar.
b
The solution of M(CO)5‚L was prepared by irradiating a THF or
Et2O solution of M(CO)6 for 4 h with a high-pressure Hg lamp.
Resu lts a n d Discu ssion
As a first attempt to investigate our idea, we under-
took the reaction of a conjugate â-ethynyl R,â-unsatur-
ated carbonyl compound with group 6 metals, which are
capable of the formation of stable Fischer-type carbene
complexes. When 2-ethynyl-1-(methoxycarbonyl)cyclo-
pent-1-ene (1a ;9 0.5 mmol) was treated with 1.2 equiv
of preformed W(CO)5‚THF10 at room temperature, the
corresponding pyranylidene-tungsten complex 2a was
isolated in 38% yield (eq 1). The complex 2a is stable
These are all new R,γ-dienyl Fischer-type carbene
complexes, and the structure of one of them was
unambiguously determined by X-ray diffraction. An
ORTEP drawing of the complex 2b is shown in Figure
1. The figure shows that the tungsten pentacarbonyl
fragment presents the carbene carbon with a wall of CO.
The W-Ccarb bond length (2.215(6) Å) is almost equal
to the W-Ccarb bond (2.02-2.22 Å) in typical tungsten-
oxacarbene complexes.12 The Ccarb-O bond length of
1.430(7) Å indicates the lack of multiple bonding be-
tween pyran oxygen and the carbene carbon, other
typical oxacarbene complex Ccarb-O bond lengths being
in the range of 1.30-1.35 Å.12,13 On the other hand, the
O(1)-C(9) and C(9)-O(2) bond lengths, 1.321(7) and
1.316(7) Å, respectively, indicate substantial multiple
enough to be purified by silica gel column chromatog-
raphy. The reaction conditions were further optimized,
and the generality of the reaction of â-ethynyl R,â-
unsaturated carbonyl compounds with group 6 metal
carbonyls was examined. The results are shown in Table
1. Reactions of 1a with excess amounts of W(CO)5‚THF
(11) (a) Wrighton, M. Chem. Rev. 1974, 74, 401. (b) McDonald, F.
E.; Schultz, C. C. J . Am. Chem. Soc. 1994, 116, 9363.
(12) (a) Guy, M. P.; Guy, J . T.; Bennett, D. W. Organometallics 1986,
5, 1696. (b) Alvarz, C.; Pacreau, A.; Parlier, A.; Rudler, H.; Daran,
J .-C. Organometallics 1987, 6, 1057.
(13) Typical organic ethers exhibit C-O bond lengths of around 1.43
Å, while the CdO distances in ketones average about 1.22 Å: Gordon,
A. J .; Ford, R. A. The Chemist’s Companion; Wiley: New York, 1972;
p 108.
(9) â-Ethynyl R,â-unsaturated carbonyl compounds were prepared
from the corresponding 2-bromo-1-cycloalkenecarboxylic acids. Proce-
dures for the preparation of these compounds and their spectral data
are reported in the Supporting Information.
(10) Strohmeier, W.; Gerlach, K. Chem. Ber. 1961, 94, 398.

Notes
Organometallics, Vol. 19, No. 25, 2000 5527
formed with silica gel 60 Merck F-254 plates. Column chro-
matography was performed with Merck silica gel 60. The NMR
spectra were measured for solutions in CDCl3 with Me4Si as
an internal standard (1H and 13C), and the following abbrevia-
tions are used: s, singlet; d, doublet; t, triplet; q, quartet; quint,
quintet; m, multiplet. IR spectra were recorded with an FT-
IR spectrometer. Melting points are uncorrected. Elemental
analyses were performed at the Microanalytical Center of
Kyoto University. All new compounds 1 were prepared and
fully characterized. Procedures for the preparation of 1 and
the precursors of 1 are reported in the Supporting Information.
Typ ica l P r oced u r e for Syn th esis of th e P yr a n ylid en e-
Tu n gsten Com p lex 2. P yr a n ylid en e-Tu n gsten Com p lex
2a . A solution of W(CO)6 (0.53 g, 1.5 mmol) in THF (10 mL)
under Ar was irradiated by an Hg lamp (350 nm) at room
temperature for 4 h. To this yellow solution under Ar was
added a solution of 1a (75 mg, 0.50 mmol) in THF (1 mL) by
a syringe. The solution was stirred at room temperature for 4
h. The solvent was removed under reduced pressure, and the
residue was subjected to column chromatography on SiO2 with
hexane/AcOEt (10:1 v/v) as an eluent to afford 2a (0.18 g, 0.38
mmol, 75% yield) as a yellow solid: mp 106.1 °C dec; IR (KBr)
Sch em e 2
bonding in complex 2b. 13C NMR chemical shifts of
carbene carbons of the complexes 2 were all observed
in the higher field range of 220-235.4 ppm compared
with those observed at 321-347 ppm for typical oxa-
carbene complexes.12 These data strongly support the
contribution of the resonance structures shown in
Scheme 2.
The structure of 2b represents a canonical form of
R-pyrone. Therefore, we envisaged cycloaddition reac-
tions of these pyranylidene complexes with dienophiles.
The reaction of 2b with an excess amount of dimethyl
acetylenedicarboxylate (DMAD; 15 equiv) gave the
tetralin derivative 4b in 27% isolated yield (eq 2). The
1909, 1957, 2058 cm-1 1H NMR (300 MHz, 25 °C) δ 2.10
;
(quint, J ) 7.8 Hz, 2H), 2.75 (t, J ) 7.8 Hz, 2H), 2.81 (t, J )
7.8 Hz, 2H), 4.30 (s, 3H), 7.61 (s, 1H); 13C NMR (75 MHz, 25
°C) δ 23.8, 27.0, 33.8, 56.9, 114.4, 132.2, 166.0, 170.1, 199.1,
204.0, 235.4. Anal. Calcd for C14H10O7W: C, 35.47; H, 2.13.
Found: C, 36.39; H, 2.28. HRMS (FAB): calcd for C14H10O7W
(M+), 473.9933; found, 473.9938.
P yr a n ylid en e-Tu n gsten Com p lex 2b. The reaction was
carried out in THF at reflux temperature for 0.5 h: yellow
solid, 63% yield; mp 103.8-105.6 °C; IR (KBr) 1882, 1920,
1
1962, 2059 cm-1; H NMR (300 MHz, 25 °C) δ 1.77-1.78 (m,
use of solvent, i.e., toluene, did not positively affect the
reaction, giving the product only in 9% yield. The
carbene complex 2c also reacted with DMAD to give the
corresponding tetralin derivative 4c in 25% yield. The
transformation was explained by assuming a [4 + 2]
cycloaddition reaction between 2 and the acetylene
followed by a pericyclic demetalation of a tungsten
hexacarbonyl (Scheme 3). The demetalation step is quite
similar to the decarboxylation step in the [4 + 2]
cycloaddition of R-pyrones.
4H), 2.43-2.50 (m, 2H), 2.55-2.65 (m, 2H), 4.30 (s, 3H), 7.34
(s, 1H); 13C NMR (75 MHz, 25 °C) δ 20.5, 21.1, 21.3, 29.2, 57.1,
109.3, 135.7, 157.1, 171.1, 199.2, 203.9, 228.1. Anal. Calcd for
C
15H12O7W: C, 36.91; H, 2.48. Found: C, 36.82; H, 2.57.
P yr a n ylid en e-Tu n gsten Com p lex 2c: yellow solid, 68%
yield; mp 99.0-101.8 °C; IR (KBr) 1881, 1894, 1922, 1964, 2053
cm-1; H NMR (300 MHz, 25 °C) δ 1.35 (t, J ) 7.2 Hz, 6H),
1
1.70-1.77 (m, 4H), 2.45-2.53 (m, 2H), 2.53-2.61 (m, 2H), 3.60
(q, J ) 7.2 Hz, 4H), 6.97 (s, 1H); 13C NMR (100 MHz, 25 °C)
δ 13.7, 21.1, 22.6, 25.6, 29.6, 44.9, 109.4, 133.1, 153.1, 169.1,
199.7, 204.3, 220.0. Anal. Calcd for C18H19NO6W: C, 40.85;
H, 3.62; N, 2.65. Found: C, 41.10; H, 3.70; N, 2.64.
Sch em e 3
P yr a n ylid en e-Tu n gsten Com p lex 2d : yellow liquid,
55% yield; IR (neat) 1907, 1915, 1965, 2058 cm-1 1H NMR
;
(300 MHz, 25 °C) δ 1.74-1.80 (m, 4H), 1.99 (quint, J ) 6.9
Hz, 2H), 2.20-2.27 (m, 2H), 2.35-2.42 (m, 2H), 2.45-2.55 (m,
2H), 4.65 (t, J ) 6.9 Hz, 2H), 5.02-5.09 (m, 2H), 5.75-5.88
(m, 1H), 7.31 (s, 1H); 13C NMR (75 MHz, 25 °C) δ 20.6, 21.1,
21.3, 27.7, 29.1, 29.7, 70.2, 109.3, 116.1, 135.5, 136.5, 157.1,
170.8, 199.2, 204.0, 227.4. Anal. Calcd for C19H18O7W: C,
42.09; H, 3.35. Found: C, 43.50; H, 3.57. HRMS (FAB): calcd
for C19H18O7W (M+), 542.0562; found, 542.0554. (This complex
is unstable to air and light to obtain the correct elemental
analytical data.)
In conclusion, we have demonstrated that a nucleo-
philic attack of carbonyl oxygen at a vinylidene-metal
intermediate, generated from terminal acetylenes and
the group 6 metal carbonyls, provides new entry to a
pyranylidene-metal complex. Further, we have dis-
closed the reactivity of newly prepared pyranylidene
complexes in [4 + 2] cycloadditions. Considering the
facile formation of a vinylidene-metal complex from a
terminal alkyne and the regeneration of a metal hexa-
carbonyl with [4 + 2] cycloaddition, this reaction
protocol will be applicable to catalytic reactions.
P yr a n ylid en e-Tu n gsten Com p lex 2e: yellow solid, 71%
yield; mp 73.6-75.4 °C dec; IR (KBr) 1896, 1923, 1976, 2059,
2366 (CtC) cm-1; 1H NMR (300 MHz, 25 °C) δ 1.10 (t, J ) 7.6
Hz, 3H), 1.78-1.79 (m, 4H), 2.15 (qt, J ) 2.6, 7.6 Hz, 2H),
2.39-2.53 (m, 2H), 2.53-2.71 (m, 2H), 2.75 (tt, J ) 2.6, 6.2
Hz, 2H), 4.69 (t, J ) 2.6 Hz, 2H), 7.35 (s, 1H); 13C NMR (75
MHz, 25 °C) δ 12.3, 13.9, 19.6, 20.5, 21.1, 21.3, 29.2, 68.7, 73.5,
84.5, 109.4, 135.8, 157.2, 170.6, 199.7, 203.9, 228.2. Anal. Calcd
for C20H18O7W: C, 43.34; H, 3.27. Found: C, 43.26; H, 3.18.
P yr a n ylid en e-Tu n gsten Com p lex 2f: orange solid, 58%
yield; mp 78.4-79.8 °C; IR (KBr) 1904, 1921, 1939, 1981, 2059
Exp er im en ta l Section
1
Gen er a l P r oced u r es. Tetrahydrofuran (THF) and diethyl
ether were distilled from sodium benzophenone-ketyl under
argon. Analytical thin-layer chromatography (TLC) was per-
cm-1; H NMR (400 MHz, 25 °C) δ 3.12 (t, J ) 6.8 Hz, 2H),
4.77 (t, J ) 6.8 Hz, 2H), 6.14 (d, J ) 8.0 Hz, 1H), 7.10-7.30
(m, 6H), 7.56 (d, J ) 8.0 Hz, 1H); 13C NMR (75 MHz, 25 °C) δ

5528 Organometallics, Vol. 19, No. 25, 2000
Notes
Ta ble 2. Selected In ter a tom ic Dista n ces (Å) a n d
An gles (d eg) for 2b
Ta ble 3. Su m m a r y of Cr ysta llogr a p h ic Da ta of 2b
empirical formula
fw
C15H12O7W
488.11
Bond Lengths
cryst syst
space group
cryst color
lattice params
a (Å)
b (Å)
c (Å)
monoclinic
P21/n (No. 14)
yellow
W(1)-C(1)
W(1)-C(12)
W(1)-C(14)
O(1)-C(1)
O(2)-C(9)
O(3)-C(11)
O(5)-C(13)
O(7)-C(15)
C(2)-C(3)
C(8)-C(9)
2.215(6)
2.018(8)
2.054(8)
1.430(7)
1.316(7)
1.146(9)
1.138(8)
1.145(8)
1.404(8)
1.382(9)
W(1)-C(11)
W(1)-C(13)
W(1)-C(15)
O(1)-C(9)
O(2)-C(10)
O(4)-C(12)
O(6)-C(14)
C(1)-C(2)
2.023(8)
2.042(8)
2.021(7)
1.321(7)
1.448(9)
1.153(9)
1.136(9)
1.362(9)
1.383(8)
16.141(6)
5.909(6)
18.592(5)
114.17(2)
1617(1)
4
2.004
71.80
â (Å)
V (Å3)
C(3)-C(8)
Z
Dcalcd (g cm-3
)
µ(Mo KR) (cm-1
F(000)
)
Bond Angles
C(1)-W(1)-C(11)
C(1)-W(1)-C(13)
C(1)-W(1)-C(15)
C(11)-W(1)-C(13) 177.9(3) C(11)-W(1)-C(14)
C(11)-W(1)-C(15) 92.5(3) C(12)-W(1)-C(13)
C(12)-W(1)-C(14) 176.7(3) C(12)-W(1)-C(15)
C(14)-W(1)-C(15)
C(9)-O(2)-C(10)
W(1)-C(1)-C(2)
C(1)-C(2)-C(3)
C(3)-C(8)-C(9)
O(1)-C(9)-C(8)
W(1)-C(11)-O(3)
W(1)-C(13)-O(5)
W(1)-C(15)-O(7)
89.4(3) C(1)-W(1)-C(12)
88.5(3) C(1)-W(1)-C(14)
177.1(3) C(11)-W(1)-C(12)
92.8(3)
87.8(3)
86.4(3)
90.3(3)
93.3(3)
928
diffractometer
radiation
Rigaku AFC7R
MoKR (λ ) 0.71069 Å),
graphite monochromated
23.0
ω-2θ
55
total, 1280; unique,
1239 (Rint ) 0.045)
3142
direct methods (SIR92)
full-matrix least squares
220
14.28
0.031; 0.034
3.07
0.03
1.21
temp (°C)
scan type
max 2θ (deg)
no. of rflns measd
89.6(3)
90.0(3) C(1)-O(1)-C(9)
119.5(6) W(1)-C(1)-O(1)
133.2(5) O(1)-C(1)-C(2)
124.5(6) C(2)-C(3)-C(8)
115.6(6) O(1)-C(9)-O(2)
123.8(5) O(2)-C(9)-C(8)
178.1(8) W(1)-C(12)-O(4)
177.4(6) W(1)-C(14)-O(6)
178.7(7)
123.0(5)
113.8(4)
112.9(5)
120.1(6)
115.8(6)
120.3(6)
176.7(6)
179.3(7)
no. of observns (I > 3.00σ(I))
structure soln
refinement
no. of variables
rfln/param ratio
residuals: R; Rw
goodness of fit (GOF)
max shift/error in final cycle
max peak in final diff map (e Å-3
35.0, 71.2, 98.5, 127.2, 128.8, 128.9, 135.3, 136.1, 142.4, 173.7,
198.7, 203.0, 242.3. Anal. Calcd for C18H12O7W: C, 41.25; H,
2.31. Found: C, 40.76; H, 2.27. HRMS (FAB): calcd for
)
)
min peak in final diff map (e Å-3
-1.82
C
18H12O7W (M+), 524.0096; found, 524.0078.
Typ ica l P r oced u r e for [4 + 2] Cycloa d d ition of 2 w ith
Acetylen e. Dim eth yl 5,6,7,8-Tetr a h yd r o-1-m eth oxy-2,3-
n a p h th a len ed ica r boxyla te (4b). A mixture of complex 2b
(0.15 g, 0.30 mmol) and dimethyl acetylenedicarboxylate (0.55
mL, 4.5 mmol) in a sealed tube was stirred at 90 °C for 12 h
under N2. The mixture was subjected to column chromatog-
raphy on SiO2 with hexane/AcOEt (10:1 v/v) as an eluent to
afford 4b (22 mg, 0.080 mmol, 27% yield) as a colorless liquid:
IR (neat) 791, 1042, 1146, 1274, 1294, 1328, 1727 (CdO), 1738
Syn th esis of P yr a n ylid en e-Molybd en u m Com p lex 3b.
A solution of Mo(CO)6 (82 mg, 0.31 mmol) in Et2O (25 mL)
and Et3N (4 mL) under Ar was irradiated by an Hg lamp (350
nm) at room temperature for 1 h. A solution of 1b (42 mg,
0.26 mmol) in Et2O (1 mL) was added to this yellow solution.
The mixture was stirred at room temperature for 3 h. The
solvent was removed under reduced pressure, and the residue
was subjected to column chromatography on SiO2 with hexane/
AcOEt (10:1 v/v) as an eluent to afford 3b (35 mg, 0.090 mmol,
35% yield) as a yellow solid: mp 89.5-90.8 °C; IR (KBr) 1884,
(CdO), 2861, 2947, 3430 cm-1; H NMR (300 MHz, 25 °C) δ
1
1.77-1.84 (m, 4H), 2.74-2.82 (m, 4H), 3.79 (s, 3H), 3.86 (s,
3H), 3.94 (s, 3H), 7.52 (s, 1H); 13C NMR (75 MHz, 25 °C): δ
22.2, 22.4, 23.7, 29.3, 52.3, 52.6, 61.7, 125.3, 126.6, 127.2, 136.9,
140.4, 155.0, 165.8, 168.4. Anal. Calcd for C15H18O5: C, 64.74;
H, 6.52. Found: C, 64.79; H, 6.64.
Dim eth yl 1-(Dieth ylam in o)-5,6,7,8-tetr ah ydr o-2,3-n aph -
th a len ed ica r boxyla te (4c): yellow liquid, 25% yield; IR
(neat) 1141, 1277, 1731 (CdO), 1738 (CdO), 1916, 2341, 2360,
2859, 2933, 3436 cm-1; 1H NMR (300 MHz, 25 °C) δ 1.00 (t, J
) 7.2 Hz, 6H), 1.72-1.82 (m, 4H), 2.65-2.75 (m, 2H), 2.75-
2.86 (m, 2H), 2.90-3.12 (m, 4H), 3.85 (s, 3H), 3.89 (s, 3H), 7.57
(s, 1H); 13C NMR (75 MHz, 25 °C) δ 14.4, 22.4, 22.6, 26.6, 29.6,
47.4, 52.1, 52.2, 124.7, 128.1, 134.9, 139.4, 144.2, 146.8, 166.2,
169.8. Anal. Calcd for C18H25NO4: C, 67.69; H, 7.89; N, 4.39.
Found: C, 67.67; H, 7.86; N, 4.30.
1927, 1968, 2060 cm-1 1H NMR (300 MHz, 25 °C) δ 1.76-
;
1.79 (m, 4H), 2.42-2.46 (m, 2H), 2.58-2.62 (m, 2H), 4.31 (s,
3H), 7.30 (s, 1H); 13C NMR (75 MHz, 25 °C) δ 20.5, 21.2, 21.3,
29.1, 56.9, 109.1, 134.7, 155.8, 171.5, 207.4, 213.6. Anal. Calcd
for C15H12O7Mo: C, 45.02; H, 3.02. Found: C, 44.54; H, 2.87.
HRMS (FAB): calcd for C15H12O7Mo (M+), 401.9637; found,
401.9644.
X-r a y Cr ysta llogr a p h y of 2b. Yellow prismatic crystals
were obtained from a hexane solution at 23 °C. A crystal of
dimensions 0.20 × 0.20 × 0.20 mm was mounted on a glass
fiber. Bond lengths and bond angles are given in Table 2. Main
features of the refinement appear in Table 3. The intensity
data were measured on a Rigaku AFC-7R four-circle auto-
mated diffractometer with Mo KR radiation and a graphite
monochromator at 23 °C using the ω-2θ scan technique. The
structure was solved by direct methods (SIR92)14 and expanded
using Fourier techniques. All the calculations were performed
using the teXsan crystallographic software package. The final
cycle of full-matrix least-squares refinement was based on 3142
observed reflections (I > 3.00σ(I)) and 220 variable parameters
and gave R ) 0.031 and Rw ) 0.034. The value of the goodness-
of-fit indicator was 3.07. Lorentz and polarization corrections
and secondary extinction were applied for the structure.
Ack n ow led gm en t . We thank Mr. Yasuaki Hisa-
moto in our department for measuring HRMS spectra.
Su p p or tin g In for m a tion Ava ila ble: Text giving synthe-
sis details and characterization data for precursors of 1 and
tables of all X-ray crystal data, refinement parameters, atomic
coordinates, and bond distances and angles for 2b. This
material is available free of charge via the Internet at
http://pubs.acs.org.
(14) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A. J .
Appl. Crystallogr. 1993, 26, 343.
OM0006763