Cycloaddition reactions of 1-Alkyl-3,4,5-triphenyl-1,2-diphosphacyclopenta- 2,4-dienes in the coordination sphere of tungsten carbonyl

Article abstract of DOI:10.1134/S1070328410120043

1-Alkyl-3,4,5-triphenyl-1,2-diphosphacyclopenta-2,4-dienes react with tungsten hexacarbo-nyl under the conditions of "indirect" replacement of the carbonyl group to give 1 : 1 complexes; [4+2] cycloaddition reactions of these complexes with maleic acid de

Full text of DOI:10.1134/S1070328410120043

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2010, Vol. 36, No. 12, pp. 891–896. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © V.A. Milyukov, A.A. Zagidullin, E. HeyꢀHawkins, O.G. Sinyashin, 2010, published in Koordinatsionnaya Khimiya, 2010, Vol. 36, No. 12, pp. 903–908.
Cycloaddition Reactions of 1ꢀAlkylꢀ3,4,5ꢀtriphenylꢀ1,2ꢀ
diphosphacyclopentaꢀ2,4ꢀdienes in the Coordination Sphere
of Tungsten Carbonyl
V. A. Milyukova, *, A. A. Zagidullina, E. HeyꢀHawkinsb, and O. G. Sinyashina
a Arbuzov Institute of Organic and Physical Chemistry, Kazan Research Center, Russian Academy of Sciences,
ul. akademika Arbuzova 8, Kazan, 420083 Tatarstan, Russia
b Institute of Inorganic Chemistry, Leipzig University,
Johannisallee 29, 04103 Leipzig, Germany
*Eꢀmail: miluykov@iopc.knc.ru
Received March 19, 2010
Abstract—1ꢀAlkylꢀ3,4,5ꢀtriphenylꢀ1,2ꢀdiphosphacyclopentaꢀ2,4ꢀdienes react with tungsten hexacarboꢀ
nyl under the conditions of “indirect” replacement of the carbonyl group to give 1 : 1 complexes; [4+2]
cycloaddition reactions of these complexes with maleic acid derivatives and substituted acetylenes afford
tungsten carbonyl complexes containing 10ꢀalkylꢀ1,10ꢀdiphosphatricyclo[5.2.1.02.6]decaꢀ8ꢀeneꢀ3,5ꢀ
diones and 1ꢀalkylꢀ2,3ꢀdiphenylphosphirenes, respectively.
DOI: 10.1134/S1070328410120043
Transition
metal
complexes
with complexes with η1ꢀ [20], η4 [21], or η5ꢀtype of coordiꢀ
ꢀ
1ꢀalkyl(aryl)phosphacyclopentaꢀ2,4ꢀdienes (phospꢀ nation [22], depending on the metal nature.
holes) fix the attention of researchers because they
allow a series of chemical transformations that are
unknown with free phospholes. For instance, heating
or irradiation of a mixture of M(CO)6 (M = Cr, Mo, or
W) and 1ꢀphenylphosphole gives complexes containꢀ
ing dimeric diphosphole as a ligand (this dimer results
from a [2+2] cycloaddition, which is not typical of free
The goal of this study was to examine the complexꢀ
ing properties of 1ꢀalkylꢀ1,2ꢀdiphosphacyclopentaꢀ
2,4ꢀdienes (I) in reactions with tungsten carbonyl, to
identify the types of coordination in the resulting comꢀ
plexes, and to study their reactivities toward various
dienophiles (maleic acid derivatives and substituted
acetylenes).
1Rꢀphospholes) [1]. Dimerization of phospholes in
[2+2], [4+2], and [4+4] cycloaddition reactions has
also been observed in the coordination spheres of
other metals: nickel [2, 3], platinum [4], palladium
[5], and ruthenium [6–8]. Intramolecular reactions of
1ꢀphenylphospholes with vinylphosphines [9–12],
2ꢀvinylpyridine [13], phenyl vinyl sulfoxide [14], and
ethyl vinyl ketone [15] in the coordination spheres of
ruthenium or palladium compounds have been
employed for the template synthesis of chiral bidentate
ligands. In addition, 7ꢀphosphanorbornadienes
obtained by [4+2] cycloaddition reactions of a tungꢀ
sten complex with 1ꢀphenylphosphole and dimethyl
acetylenedicarboxylate have been successfully used to
generate highly reactive phosphorus species, namely,
phosphinidenes, which are the phosphorus analogs of
carbenes [16–18].
EXPERIMENTAL
All manipulations dealing with the preparation of
the starting reagents and the synthesis and isolation of
products were carried out under an inert gas in a stanꢀ
dard Schlenk vessel. All solvents were distilled over
Na/benzophenone immediately before use. NMR
spectra were recorded for 10–20% solutions in inert
solvents (C6D6 and CDCl3) on a Bruker MSLꢀ400
spectrometer (400 (1H), 161.97 (31P), and 100.6 MHz
(13C)) with tetramethylsilane as the internal standard
(1H, 13C) and with 85% H3PO4 as the external stanꢀ
dard (31P). IR spectra were recorded on a Bruker Vecꢀ
torꢀ22 FTIR pulse spectrometer in the 400–4000 cm–1
range.
Commercial reagents (tungsten hexacarbonyl,
maleic anhydride, maleimide, dimethyl acetylenediꢀ
carboxylate, and diphenylacetylene) were used withꢀ
out preliminary purification. 1ꢀAlkylꢀ3,4,5ꢀtriphenylꢀ
1,2ꢀdiphosphacyclopentaꢀ2,4ꢀdienes were prepared
as described in [23].
It should be noted that the complexing properties
of phospholes substantially depend on the number of
P atoms in the ring since sequential replacement of the
CR fragment by a phosphorus atom enhances the aroꢀ
maticity of phospholes [19]. For instance, 1ꢀ[bis(trimꢀ
ethylsilyl)methyl]ꢀ3,5ꢀdiꢀtertꢀbutylꢀ1,2,4ꢀtriphospꢀ
Synthesis of (1ꢀRꢀ3,4,5ꢀtriphenylꢀ1,2ꢀdiphosꢀ
hole reacts with transition metal compounds to give phacyclopentaꢀ2,4ꢀdiene)pentacarbonyltungsten
891

892
MILYUKOV et al.
Elemental analysis data, melting temperatures, and yields of complexes II–IV*
Content (found/calculated), %
Complex
(empirical formula
Тm
,
°С
Yield, g (%)
)
C
H
P
IIa (C28H20O5P2W)
IIb (C30H24O5P2W)
IIc (C30H24O5P2W)
IIIa (C32H22O8P2W)
IIIb (C34H26O8P2W)
IIIc (C34H26O8P2W)
IVa (C32H23NO7P2W)
IVb (C34H27NO7P2W)
IVc (C34H27NO7P2W)
128
130
130
142
150
153
144
152
155
0.61 (89)
0.64 (90)
0.64 (91)
0.32 (80)
0.33 (80)
0.34 (83)
0.32 (82)
0.35 (86)
0.34 (84)
49.01 (49.29)
50.34 (50.73)
50.54 (50.73)
49.12 (49.26)
50.32 (50.52)
50.28 (50.52)
49.14 (49.32)
50.39 (50.58)
50.44 (50.58)
3.23 (2.95)
4.13 (3.41)
4.17 (3.41)
2.45 (2.84)
3.36 (3.24)
3.16 (3.24)
2.56 (2.97)
3.18 (3.37)
3.22 (3.37)
9.19 (9.08)
8.99 (8.72)
8.87 (8.72)
7.77 (7.94)
7.48 (7.66)
7.29 (7.66)
7.45 (7.95)
7.39 (7.67)
7.59 (7.67)
* Complexes IIa–IIc are dark red powders; complexes IIIa–IIIc and IVa–IVc are yellow powders.
(R = Et (IIa), Bu (IIb), and isoꢀBu (IIc)). A solution of
13C NMR (C6D6,
δ
, ppm): 152.12 t (2JCP
=
=
2
tungsten hexacarbonyl (0.35 g, 1 mmol) in THF 13.14 Hz), 161.14 dd (2JCP = 10.34 Hz, JCP
(100 ml) was exposed to UV light in a quartz 4.87 Hz), 189.93 dd (2
reaction vessel under argon at 5°C for 3 h. The resultꢀ
J
CP = 51.12 Hz, 2
JCP = 14.99 Hz).
IR (hexane,
IIb (R = Bu).
1H NMR (C6D6,
ν
(CO), cm–1): 1945, 2023, 2124, 2146.
ing solution was lemonꢀcolored. A solution of 1ꢀRꢀ
3,4,5ꢀtriphenylꢀ1,2ꢀdiphosphacyclopentaꢀ2,4ꢀdiene
(1 mmol) in THF (10 ml) was added and the reaction
mixture was stirred for 12 h. The solvent was removed
in vacuo and the product was extracted with hexane.
The elemental analysis data, melting temperatures,
and yields of complexes II are given in table.
IIa (R = Et).
δ
, ppm): 0.64 t (3H, CH3, 3JHH
=
7.09 Hz), 0.77 m (2H, CH2), 1.04 m (2H, CH2),
1.71 m (2H, CH2), 6.9–7.8 m (15H, Ph).
31P NMR (C6D6,
δ, ppm): 213.47 d ( JPP
=
=
1
2
1
234.3 Hz, JPW = 268.14 Hz), 48.37 d ( JPP
234.3 Hz, 1
JPW = 210.36 Hz).
1H NMR (C6D6,
δ
, ppm): 1.14 dt (3H, CH3,
13C NMR (C6D6,
δ
, ppm): 148.77 t (3JCP
=
3
3JHH = 7.14 Hz, JHP = 13.1 Hz), 2.13 m (2H, CH2),
13.34 Hz), 165.99 dd (3
193.21 dd (3
J
CP = 7.12 Hz, 3
J
CP = 2.10 Hz),
3
3
7.34 d (Ph, JHP = 7.12 Hz), 6.96 t (4H, Ph, JHP
=
J
CP = 51.07 Hz, 3
J
CP = 12.02 Hz).
6.12 Hz), 7.00 d (4H, Ph, 3
JHP = 4.81 Hz), 7.03 d (2H,
Ph, 3 HP = 5.82 Hz), 7.07 d (4H, Ph, 3
J JHP = 7.13 Hz),
IR (hexane,
ν
(CO), cm–1): 1932, 2070, 2134, 2145.
7.23 d (2H, Ph, 3
8.49 Hz).
J
HP = 5.13 Hz), 7.31 t (1H, Ph, 3JHP
=
IIc (R = isoꢀBu).
δ =
1H NMR (C6D6, , ppm): 0.92 d (6H, CH3, 3JHH
31P NMR (C6D6,
δ
, ppm): 209.56 d ( JPP
=
1
241.3 Hz, 2
J
PW = 279.2 Hz), 36.55 d ( 1
JPP = 241.3 Hz, 6.23 Hz), 1.14 m (1H, CH), 1.72 m (2H, CH2), 6.9–
1JPW = 212.3 Hz).
7.8 m (15H, Ph).
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 36
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CYCLOADDITION REACTIONS
893
1
31P NMR (C6D6,
δ
, ppm): 208.31 d ( JPP
=
8.80 Hz), 6.68 d (2H, Ph, 3
J
HH = 6.85 Hz), 6.82 t (3H,
246.3 Hz, 2
J
PW = 271.2 Hz), 33.13 d ( 1
J
PP = 246.3 Hz, Ph, 3
J
HH = 7.09 Hz), 6.87 d (2H, Ph, 3
J
HH = 7.34 Hz),
1JPW = 203.1 Hz).
6.93–7.09 m (3H, Ph), 7.15 d (3H, Ph, JHH
9.29 Hz), 7.34 d (2H, Ph, 3
HH = 6.85 Hz).
31P NMR (CDCl3,
, ppm): 80.12 d ( JPP
207.1 Hz), 1.7 d ( 1 PP = 207.1 Hz, 1
=
3
13C NMR (C6D6,
δ
, ppm): 149.77 t (3JCP
=
CP = 2.10 Hz),
CP = 12.02 Hz).
(CO), cm–1): 1933, 2072, 2163, 2178.
J
1
13.34 Hz), 164.99 dd (3
J
CP = 7.12 Hz, 3
J
δ
=
188.99 dd (3
J
CP = 51.07 Hz, 3
J
J
JPW = 259.3 Hz).
13C NMR (CDCl3,
δ, ppm): 77.01 dd (C–Ph,
IR (hexane,
ν
2
1JCP = 26.26 Hz, JCP = 4.14 Hz), 141.48 dd (1JCP
=
=
Reactions of 1ꢀRꢀ1,2ꢀdiphosphole complexes II
with maleic acid derivatives. A solution of complex II
(1 mmol) and a maleic acid derivative (1 mmol) in tolꢀ
2
27.91 Hz, JCP = 18.40 Hz), 157.99 dd (2JCP
2
18.19 Hz, JCP = 4.14 Hz), 169.23 s (CO), 171.53 s
(CO).
uene (20 ml) was heated at 100°С for 3 h. On cooling,
IVa (R = Et; maleimide).
the solution was filtered and concentrated in vacuo to
a small volume (5 ml). Hexane (30 ml) was added and
the resulting precipitate was filtered off and dried in
vacuo. The complexes obtained were pentacarboꢀ
nyl(10ꢀRꢀ7,8,9ꢀtriphenylꢀ4ꢀoxaꢀ1,10ꢀdiphosphatriꢀ
cyclo[5.2.1.02.6]decaꢀ8ꢀeneꢀ3,5ꢀdione)tungsten
(R = Et (IIIa), Bu (IIIb), and isoꢀBu (IIIc)) and penꢀ
tacarbonyl(10ꢀRꢀ7,8,9ꢀtriphenylꢀ4ꢀazaꢀ1,10ꢀdiphosꢀ
phatricyclo[5.2.1.02.6]decaꢀ8ꢀeneꢀ3,5ꢀdione)tungꢀ
sten (R = Et (IVa), Bu (IVb), and isoꢀBu (IVc)). The
elemental analysis data, melting temperatures, and
yields of complexes III and IV are given in table.
IIIa (R = Et; maleic anhydride).
1H NMR (CDCl3,
δ
, ppm): 0.72 dt (3H, CH3,
HP = 16.44 Hz), 1.32 ddq (2H, CH2,
3JHH = 7.82 Hz, 2JHP = 49.16 Hz, 3
HP = 1.46 Hz), 4.24
dd (1H, CH, 3 HH = 7.38 Hz, 2JHP = 10.99 Hz), 4.57 d
3JHH = 7.82 Hz, 3
J
J
J
3
3
(1H, CH, JHH = 7.38 Hz), 6.16 d (4H, Ph, JHH
9.12 Hz), 7.15 d (4H, Ph, 3
HH = 7.27 Hz), 7.07 d (4H,
Ph, 3 HH = 6.82 Hz), 7.14 d (2H, Ph, 3
HH = 6.23 Hz),
7.36 d (1H, Ph, 3
HH = 6.77 Hz), 9.02 s (1H, NH).
31P NMR (CDCl3,
204.5 Hz), 3.0 d ( 1 PP = 204.5 Hz, 1
=
J
J
J
J
1
δ
, ppm): 81.45 d ( JPP
=
J
JPW = 251.7 Hz).
13C NMR (CDCl3,
δ, ppm): 74.85 dd (C–Ph,
2
1JCP = 24.32 Hz, JCP = 2.81 Hz), 140.98 dd (C=C,
1H NMR (CDCl3,
3JHH = 7.9 Hz, 3
HP = 15.08 Hz), 1.28 ddq (2H, CH2,
3JHH = 7.9 Hz, 2JHP = 51.9 Hz, 3
HP = 1.8 Hz), 4.31 dd
(1H, CH, 3 HP = 8.0 Hz, 2JHP = 9.9 Hz), 4.79 d (1H,
CH, 3 HP = 8.80 Hz), 6.72 d (2H, Ph, 3
HH = 6.85 Hz),
δ, ppm): 0.9 dt (3H, CH3,
1JCP = 27.72 Hz, 2JCP = 19.23 Hz), 157.97 dd (C=C,
2
2JCP = 18.31 Hz, JCP = 4.06 Hz), 174.89 s (CO),
J
J
177.99 s (CO).
J
IVb (R = Bu; maleimide).
1H NMR (CDCl3,
δ
, ppm): 0.79 t (3H, CH3,
J
J
3
3JHH = 6.85 Hz), 0.82 m (2H, CH2), 1.13 m (2H,
6.87 t (2H, Ph, JHH = 7.34 Hz), 6.89 d (1H, Ph,
3JHH = 6.85 Hz), 7.01 m (3H, Ph), 7.12 m (5H, Ph),
3
CH2), 1.69 m (2H, CH2), 4.50 dd (CH, JHH
=
3
2
3
7.23 d (3H, Ph, JHH = 5.87 Hz), 7.37 d (2H, Ph,
8.80 Hz, JHP = 25.43 Hz), 4.78 d (CH, JHH = 8.34
Hz), 6.75 d (5H, Ph, 3
HH = 9.29 Hz), 6.99 d (5H, Ph,
3JHH = 7.34 Hz), 7.07 d (5H, Ph, 3
HH = 6.85 Hz), 7.36
d (2H, Ph, 3
HH = 6.85 Hz), 9.02 s (1H, NH).
31P NMR (CDCl3,
214.5 Hz), 3.7 d ( 1 PP = 214.5 Hz, 1
3JHH = 6.85 Hz).
J
1
31P NMR (CDCl3,
δ
, ppm): 82.04 d ( JPP
=
J
201.5 Hz), 3.4 d ( 1
J
PP = 201.5 Hz, 1
J
PW = 253.3 Hz).
J
13C NMR (CDCl3,
δ
, ppm): 76.86 dd (1JCP
=
=
=
1
δ, ppm): 82.6 d ( JPP
=
26.47 Hz, JCP = 4.14 Hz), 140.91 dd (1JCP
27.50 Hz, 2JCP = 18.40 Hz), 158.13 dd (2JCP
1
J
JPW = 244.4 Hz).
13C NMR (CDCl3,
δ
, ppm): 73.14 d (1JCP
=
=
=
17.99 Hz, 2JCP = 3.93 Hz), 169.19 s (CO), 171.55 s
(CO).
27.71 Hz), 165.48 dd (1JCP = 27.91 Hz, JCP
2
15.40 Hz), 172.39 dd (2JCP = 18.19 Hz, JCP
2
2
IIIb (R = Bu; maleic anhydride).
4.14 Hz), 189.33 d (CO, JCP = 10.62 Hz), 192.81 d
1H NMR (CDCl3,
δ
, ppm): 0.78 t (3H, CH3,
(CO, 3
IVc (R = isoꢀBu; maleimide).
JCP = 6.20 Hz).
3JHH = 6.85 Hz), 0.82 m (2H, CH2), 1.14 m (2H,
3
1H NMR (CDCl3,
δ, ppm): 0.68 d (3H, CH3,
CH2), 1.78 m (2H, CH2), 4.49 dd (CH, JHH
=
=
2
3
3JHH = 6.85 Hz), 0.76 d (3H, CH3, JHH = 6.85 Hz),
3
8.80 Hz, JHP = 25.43 Hz), 4.73 d (CH, JHH
8.34 Hz), 6.8–7.5 m (15H, Ph).
1.03 m (2H, CH2), 1.48 m (1H, CH), 4.15 dd (1H,
1
31P NMR (CDCl3,
δ
, ppm): 86.45 d ( JPP
=
CH, 3 HH = 7.83 Hz, 2JHP = 10.27 Hz), 6.75 d (3H, Ph,
J
203.0 Hz), 9.79 d ( 1
13C NMR (CDCl3,
1JCP = 27.71 Hz), 167.48 dd (1
18.40 Hz), 170.39 dd (2JCP = 18.19 Hz, JCP
J
PP = 203.0 Hz, 1
J
PW = 254.81 Hz).
3JHH = 9.29 Hz), 6.99 d (4H, Ph, 3
JHH = 7.34 Hz), 7.07
3
3
δ
, ppm): 73.14 d (C–Ph,
d (3H, Ph, JHH = 6.85 Hz), 7.14 d (3H, Ph, JHH
=
CP = 27.91 Hz, 2JCP
=
=
6.36 Hz), 7.36 d (2H, Ph, 3
NH).
JHH = 6.85 Hz), 9.05 s (1H,
J
2
2
31P NMR (CDCl3,
δ
, ppm): 80.6 d ( JPP
PP = 212.2 Hz, 1
PW = 245.2 Hz).
13C NMR (CDCl3,
, ppm): 74.80 dd (C–Ph,
=
1
4.14 Hz), 194.33 d (CO, JCP = 10.62 Hz), 194.81 d
(CO, 3
CP = 6.20 Hz).
IIIc (R = isoꢀBu; maleic anhydride).
1H NMR (CDCl3, , ppm): 0.71 d (3H, CH3, 1JCP = 24.40 Hz, JCP = 2.89 Hz), 140.86 dd (1JCP
3JHH = 6.85 Hz), 0.78 d (3H, CH3, JHH = 6.85 Hz), 27.71 Hz, JCP = 19.02 Hz), 157.91 dd (2JCP
212.2 Hz), 1.9 d ( 1
J
J
J
δ
2
δ
=
=
3
2
2
1.8 m (1H, CH), 1.95 m (2H, CH2), 4.40 dd (CH, 18.40 Hz, JCP = 4.34 Hz), 174.78 s (CO), 177.76 s
3JHH = 8.80 Hz, 2JHP = 10.27 Hz), 4.65 d (CH, 3JHH
=
(CO).
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894
MILYUKOV et al.
Reactions of complexes II with dimethyl acetyleneꢀ
dicarboxylate. A mixture of complex IIb IIc) (0.71 g,
RESULTS AND DISCUSSION
(
For the synthesis of complexes of 1ꢀRꢀ1,2ꢀdiphosꢀ
phacyclopentadienes with W(CO)6, we used “indiꢀ
rect” photochemical replacement of the carbonyl
group. This technique involves irradiation of a solution
of tungsten hexacarbonyl in THF with UV light; the
resulting labile complex W(CO)5THF exists only in
solution. Addition to the latter of an appropriate
ligand allows irradiationꢀfree replacement of the THF
molecule to give monosubstituted carbonyl complexes
of tungsten.
1 mmol), dimethyl acetylenedicarboxylate (0.14 g,
1 mmol), and an excess of diphenylacetylene (0.54 g,
3 mmol) was heated in toluene (50 ml) at 50°C for 3 h.
The solution was filtered and concentrated to a
small volume. The residue was analyzed using 31P
NMR spectroscopy. Along with a signal for phosphaꢀ
benzene (
glet at
diphenylphosphirene)tungsten
172 ppm for pentacarbonyl(1ꢀisobutylꢀ2,3ꢀdipheꢀ
V
) at
–170 ppm for pentacarbonyl(1ꢀethylꢀ2,3ꢀ
VIa or at
δ 213 ppm, the spectrum shows a sinꢀ
δ
(
)
δ
⎯
nylphosphirene)tungsten (VIb), which agrees with the
literature data [17].
Complexes II were obtained as rufous powders in
89–91% yields.
OC
CO
CO W CO
Ph
P
Ph
Ph
CO
R
OC
PA
CO
W
CO
Ph
OC
OC
CO
OC
OC
P
Ph
Ph
h
ν, ТГФ
W
(I)
25°C
5°C
R
ТГФ
CO
PB
CO
CO
(II)
R = Et (a), Bu (b), isoꢀBu (c)
2
The structures of complexes II were determined geminal coupling constant JWP = 271.11 Hz is
from IR and 1H, 31P, a n d 13C NMR spectra and conꢀ
1
higher than the direct constant JWP = 203 Hz, thus
firmed by elemental analysis data. For instance, the
suggesting hyperconjugation in 1ꢀRꢀ1,2ꢀdiphosphole
complexes II. In the 13C NMR spectrum, the signal
for the carbon atom at the PB=C bond appears as a
doublet of doublets because of the couplings with two
nonequivalent P nuclei.
31Р{1H} NMR spectrum of complex IIc shows two
doublets at δР 208.3 and 33.1 ppm ( 1
JPP = 245 Hz) for
the PB and PA atoms, respectively. Note that a downꢀ
field shift by 29.7 ppm compared to the signals for the
starting ligand (δР 207.5 and 62.8 ppm) is observed
only for the P atom bearing the alkyl group, which
points to the coordination of tungsten through the PA
The coordination of the tungsten atom through the
PA atom was confirmed by the chemical behavior of
atom only. It should be noted that in complex IIc, the complexes II in cycloaddition reactions:
CO
CO
CO
CO
OC
OC
CO
W
O
X
CO W CO
[4+2]
toluene
100°C
Ph
OC
PA
+
PA
Ph
Ph
Ph
Ph
Ph
R
R
PB
HA
HB
O
PB
O
X
O
III: X = O, R = Et (а), Bu (b) isoꢀBu (c)
IV: X = NH, R = Et (а), Bu (b) изоꢀBu (c)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 36
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CYCLOADDITION REACTIONS
895
We found that complexes II react with maleic
anhydride and maleimide in hot toluene to give the
corresponding [4+2] cycloadducts III and IV, which
were isolated as yellow powders in high yields (80–
85%). The 31Р{1H} NMR spectrum of complex IIIc
shows two doublets at δР 82.4 and 3.4 ppm with a couꢀ
pling constant of 201.5 Hz. For the P–W bond, the
coupling constant is observed only for the PA atom
In [23], we have demonstrated that reactions of free
1ꢀRꢀ1,2ꢀdiphospholes ( ) with maleic acid derivatives
also follow the [4+2] cycloaddition pattern with high
regioꢀ and stereoselectivity. The reaction produces
only one diastereoisomer as two enantiomers, which
I
seems to be the case of complexes III and IV
.
It was interesting to carry out [4+2] cycloaddition
reactions of complexes II with substituted acetylenes.
In our opinion, the easier cleavage of the P–P bond
compared to the P–C one will allow generation of
alkylphosphinidene complexes under milder condiꢀ
(
1JWP = 253.3 Hz) directly attached to the tungsten
atom. This suggests the absence of hyperconjugation
in complexes III and IV. In the 13C NMR spectrum of
complex IIIc, the signals for the carbon atoms at the
C=C double bond appear as two doublets of doublets
at δC = 141.1 and 159.0 ppm because of the couplings
with two nonequivalent P nuclei.
tions than with monophospholes (110
that heating of tungsten complexes II with dimethyl
acetylenedicarboxylate and diphenylacetylene at 50
°С). We found
°С
gives complexes VI with 1ꢀalkylꢀ2,3ꢀdiphenylphosꢀ
phirenes as ligands.
CO
CO
CO
OC
CO
W
CO
OC
P
OC
CO
CO
Ph
W(CO)6
W
CO W CO
R
MeOOCC CCOOMe
PhC CPh
Δ
PA
CO
Ph
[4 + 2]
[1 + 2]
OC
PA
Ph
R P•
CO
•
Ph
R
Ph
Ph
Ph
COOMe
COOMe
PB
Ph
Ph
)
(В)
R
Ph
CCOOMe
(VI
P
PB
Ph
(V)
R = Et (a), isoꢀBu (b)
C
(II)
COOMe
(A)
2. Mercier, F., Mathey, F., Fischer,
J
., and Nelson,
J
J
.,
.,
Apparently, the first step involves [4+2] cycloaddiꢀ
tion leading to an unstable intermediate ( ). Cleavage
of the P–P and P–C bonds in complex results in the
formation of phosphabenzene ( ) and an alkylphosꢀ
phinidene complex ( ), which is “trapped” by dipheꢀ
J. Am. Chem. Soc., 1984, vol. 106, no. 2, p. 425.
A
A
3. Mercier, F., Mathey, F., Fischer,
J., and Nelson,
Inorg. Chem., 1985, vol. 24, no. 24, p. 4141.
4. Wilson, W.L., Rahn, .A., Alcock, N.W., et al., Inorg.
Chem., 1994, vol. 33, no. 1, p. 109.
5. Wilson, W.L., Fischer, ., Wasylishen, R.E., et al.,
Inorg. Chem., 1996, vol. 35, no. 6, p. 1486.
6. Redwine, K.D. and Nelson, .H., Organometallics
2000, vol. 19, no. 16, p. 3054.
7. BarthelꢀRosa, L.P., Nelson,
Fischer, ., Phosphorus, Sulfur, Silicon, Relat. Elem.
1996, vol. 109, nos. 1ꢀ4, p. 169.
i, H.L., Nelson, .H., DeCian, A., et al.,
nomet. Chem., 1997, vol. 529, nos. 1ꢀ2, p. 395.
9. Redwine, K.D. and Nelson, .H., . Organomet. Chem.,
2000, vol. 613, no. 2, p. 177.
10. Green, R.L., Nelson, H., and Fischer,
tallics, 1987, vol. 6, no. 10, p. 2256.
i, H.L., Nelson, .H., and Cian, A. De, et al., Organoꢀ
metallics, 1992, vol. 11, no. 5, p. 1840.
V
B
J
nylacetylene to form a tungsten complex with dipheꢀ
nylphosphirene (VI). The 31Р {1H} NMR spectrum
J
shows a signal for phosphabenzene
together with a signal for complex VI at
V
(
δ
δ
213 ppm)
–170 ppm,
J
,
which fully agrees with the previous data for this comꢀ
plex [17].
J.H., Catalano, V.
J., and
Thus, we found that tungsten(II) carbonyl comꢀ
plexes II with 1ꢀalkylꢀ3,4,5ꢀtriphenylꢀ1,2ꢀdiphosꢀ
phacyclopentaꢀ2,4ꢀdienes as ligands react with maleic
acid derivatives and diphenylacetylene according to
the [4+2] cycloaddition pattern to give tungsten comꢀ
plexes containing 10ꢀalkylꢀ1,10ꢀdiphosphatricyꢀ
J
,
8.
J
J
J. Orgaꢀ
J
J
clo[5.2.1.02.6]decaꢀ8ꢀeneꢀ3,5ꢀdiones (III
, IV) and
J
.
J., Organomeꢀ
1ꢀalkylꢀ2,3ꢀdiphenylphosphirenes (VI), respectively.
11.
J
J
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