1,2-azaphosphol-5-ene complexes through metal-assisted synthesis

Article abstract of DOI:10.1021/om060344j

Thermal ring opening of {[2-bis(trimethylsilyl)methyl-3-phenyl-2H- azaphosphirene-kP]pentacarbonyltungsten(0)} (1) in toluene in the presence of 1-piperidino carbonitrile (2) and various mono- and disubstituted alkenes, i.e., ethyl acrylate (4), E-stilbene (6), fumaronitrile (7), and maleic anhydride (10), was investigated. Special emphasis was placed on the dependence of the regio- and stereoselectivity of the transiently formed nitrilium phosphane-ylide complex 3 on the electronic properties of the alkenes. Three-component reaction of 1, 2, and 4 yielded regioselectively a 1:1 mixture of the diastereomeric 4-ethoxycarbonyl-substituted 1,2-azaphosphol-5-ene complexes 5a,b; the constitution of 5a was unambiguously established by single-crystal X-ray diffraction. Whereas E-stilbene (6) gave no reaction with complex 3, fumaronitrile (7) reacted with transient 3 to furnish the diastereomeric 1,2-azaphosphol-5-ene complexes 8a,b together with the 2H-1,3,2-diazaphosphole complex 9; the product ratio of 2:1:1 was determined by ³¹P{ ¹H} NMR spectroscopy. Reaction of 1, 2, and maleic anhydride (10) resulted in a complicated product mixture, whereby the constitution of the spirocyclic complexes 11a,b (bearing a 1,3,2-oxazaphosphol-3-ene moiety) is based on their NMR data. Further examination showed that the C-O double bond system of 10 did not participate in a [3+2] cycloaddition reaction if the thermal decomposition of complex 1 was carried out in neat benzonitrile, thus showing the preference of the transiently formed C-phenyl-substituted nitrilium phosphane-ylide complex 12 for the C-C double bond of 6: In this case, the bicyclic complexes 13a,b were formed exclusively.

Full text of DOI:10.1021/om060344j

4830
Organometallics 2006, 25, 4830-4834
1,2-Azaphosphol-5-ene Complexes through Metal-Assisted Synthesis
Rainer Streubel,*,† Hendrik Wilkens,‡ Frank Ruthe,‡ and Peter G. Jones‡
Institut fu¨r Anorganische Chemie, Rheinische Friedrich-Wilhelms-UniVersita¨t Bonn,
Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany, and Institut fu¨r Anorganische und Analytische Chemie,
Technische UniVersita¨t Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
ReceiVed April 18, 2006
Thermal ring opening of {[2-bis(trimethylsilyl)methyl-3-phenyl-2H-azaphosphirene-κP]pentacarbon-
yltungsten(0)} (1) in toluene in the presence of 1-piperidino carbonitrile (2) and various mono- and
disubstituted alkenes, i.e., ethyl acrylate (4), E-stilbene (6), fumaronitrile (7), and maleic anhydride (10),
was investigated. Special emphasis was placed on the dependence of the regio- and stereoselectivity of
the transiently formed nitrilium phosphane-ylide complex 3 on the electronic properties of the alkenes.
Three-component reaction of 1, 2, and 4 yielded regioselectively a 1:1 mixture of the diastereomeric
4-ethoxycarbonyl-substituted 1,2-azaphosphol-5-ene complexes 5a,b; the constitution of 5a was unambigu-
ously established by single-crystal X-ray diffraction. Whereas E-stilbene (6) gave no reaction with complex
3, fumaronitrile (7) reacted with transient 3 to furnish the diastereomeric 1,2-azaphosphol-5-ene complexes
8a,b together with the 2H-1,3,2-diazaphosphole complex 9; the product ratio of 2:1:1 was determined by
31P{1H} NMR spectroscopy. Reaction of 1, 2, and maleic anhydride (10) resulted in a complicated product
mixture, whereby the constitution of the spirocyclic complexes 11a,b (bearing a 1,3,2-oxazaphosphol-
3-ene moiety) is based on their NMR data. Further examination showed that the C-O double bond
system of 10 did not participate in a [3+2] cycloaddition reaction if the thermal decomposition of complex
1 was carried out in neat benzonitrile, thus showing the preference of the transiently formed C-phenyl-
substituted nitrilium phosphane-ylide complex 12 for the C-C double bond of 6: In this case, the bicyclic
complexes 13a,b were formed exclusively.
Scheme 1. λ3-Phospholanes (I-III), 1,2λ3-Azaphospholanes
(IV), and 1,2λ3-Azaphospholenes (V-IX) (lines denote
ubiquitous organic substituents)
Introduction
Metal-assisted synthesis is an important and well-established
concept in organometallic and coordination chemistry, in
general. This methodology was introduced to organophosphorus
chemistry through the fundamental work of Marinetti and
Mathey by demonstrating the selective use of phosphinideness
if stabilized as terminal phosphinidene complexessin phos-
phorus heterocyclic chemistry.1 Historically the background to
the chemistry of P-heterocycles2 such as phospholanes I,
phosphol-2-enes II, and phosphol-3-enes III (Scheme 1) was
spurred by the seminal discovery of the McCormack reaction
in 1953.3 Meanwhile, the matured chemistry has led to several
applications, e.g., phospholane-based ligands such as DuPHOS
in various catalytic industrial processes.2
The chemistry of 1,2λ3-azaphospholanes IV started around
1970 by the work of Pudovik4 and Oehme,5 who first reported
the use of cyclocondensation reactions, which were then used
for years as the method of choice. Recently, Malisch achieved
the synthesis of functionalized 1,2λ3-azaphospholanes in the
coordination sphere of a transition metal center using hydro-
phosphination reactions of a primary phosphine iron complex.6
In contrast to this, 1,2λ3-azaphospholenes V-IX (Scheme 1)
are still elusive species,7 because of a significant lack of
synthetic strategies for these ring systems. For example, there
are only two short communications on complexes having a
* Corresponding author. E-mail: r.streubel@uni-bonn.de. Fax: (49)228-
739616. Tel: (49)228-735345.
† Rheinische Friedrich-Wilhelms-Universita¨t Bonn.
‡ Technische Universita¨t Braunschweig.
(1) (a) Reviews: Mathey, F.; Tran Huy, N. H.; Marinetti, A. HelV. Chim.
Acta 2001, 84, 2938. (b) Lammertsma, K. Top. Curr. Chem. 2003, 229,
95.
(2) Review: Kee, T. P. In Phosphorus-carbon heterocyclic chemistry:
the rise of a new domain; Mathey, F., Ed.; Pergamon: Amsterdam, 2001;
Chapter 4, p 195, and references therein.
(3) McCormack, W. B. U.S. Pat. 2 663 737-38, 1953; Chem. Abstr.
1955, 49, 7602.
(4) Pudovik, A. N.; Kondrat’eva, R. M.; Khairullin, V. K. IzV. Akad.
Nauk, Ser. Khim. 1969, 9, 2076-2078.
(5) Oehme, H.; Thamm, R. Zeit. Chem. 1971, 11, 262-263.
(6) Malisch, W.; Klu¨pfel, B.; Schumacher, D.; Nieger, M. J. Organomet.
Chem. 2002, 661, 95-110.
(7) To the best of our knowledge, ring systems VIII and IX with a λ3-
phosphorus are experimentally unknown; for derivatives of type IX with a
λ5-phosphorus see for example: Schmidpeter, A.; Zeiss, W. Angew. Chem.
1971, 83, 397-398; Angew. Chem., Int. Ed. Engl. 1971, 10, 396-397.
Comment: the λ3 notation is used exclusively in the Introduction.
10.1021/om060344j CCC: $33.50 © 2006 American Chemical Society
Publication on Web 08/23/2006

1,2-Azaphosphol-5-ene Complexes
Organometallics, Vol. 25, No. 20, 2006 4831
1,2λ3-azaphosphol-4-ene (V),8,9 some on 1,2λ3-azaphosphol-3-
enes (VI)seither free10 or in a P-ligated fashion11sand on 1,2λ3-
azaphosphol-3-enes (VII).12,13 Very recently, the latter, chiral
so-called Wilke’s-azaphospholene, has received increased at-
tention in catalysis.14,15
Scheme 2. Trapping of Transient 1,3-Dipole Complex 3
with Ethyl Acrylate (4)
Recently, we had shown that transient nitrilium phosphane-
ylides can be used efficiently as new 1,3-dipoles in the chemistry
of unsaturated five-membered phosphorus heterocycles, if the
phosphorus is coordinated to a transition metal.16,17 As we are
trying to exploit this continuously, we decided to investigate
their potential for the synthesis of complexes bearing 1,2λ3-
azaphosphol-5-ene ligands using our three-component reaction
protocol for the generation of such complexes and the results
obtained earlier by trapping reactions with alkynes.18 Here, we
report on metal-assisted synthesis, X-ray structure, and NMR
data of various mono- and bicyclic 1,2λ3-azaphosphol-5-ene
complexes with functional groups. Furthermore, we provide the
first strong spectroscopic evidence for C5-spirocyclic 1,3,2-
oxazaphosphol-3-ene complexes.
spectroscopy; complex 8b was tentatively assigned on the basis
of its 31P{1H} NMR spectroscopic data; selected NMR data of
8a are collected in Table 1 and will be discussed below together
with those of other products mentioned hereafter.
Experimental Results
Reacting 1, 2, and maleic anhydride (10) resulted in the
formation of spirocyclic 1,3,2-oxazaphosphol-3-ene complexes
11a,b together with two not yet firmly identified complexes20
in a 1:1:2:4 ratio (Scheme 4). In this case, product separation
using column chromatography failed. Nevertheless, the assign-
ment of these NMR data to the C5-spirocyclic 1,3,2-oxazaphos-
phol-3-ene complexes 11a,b can be achieved by comparison.
as the resonances at 196.5 ppm (|J(W,P)| ) 300.9 Hz) and at
188.1 (|J(W,P)| ) 309.0 Hz) are typical for this ring system,
as we know from our earlier studies. The only example of a
structurally confirmed 1,3,2-oxazaphosphol-3-ene complex,
obtained by reaction of complex 3′ (3′: NMe2 instead of
1-piperidino) with DMAD,19 shows data (191.6 ppm and
|J(W,P)| ) 305.9 Hz) that are in very good accordance with
those of 11a,b.
Further studies showed that this reaction can be tuned into a
selective one, meaning the C-O double bond system of alkene
10 was discarded if the thermal decomposition of complex 1
was carried out in neat benzonitrile, thus promoting the
formation of the transient C-phenyl-substituted nitrilium phos-
phane-ylide complex 12. In this case, exclusively the bicyclic
complexes 13a,b were formed, from which 13a was isolated
and fully characterized (Scheme 5; for selected NMR data see
Table 1). This result clearly underlines the preference of transient
complex 12 for the C-C double bond of 10.
First we studied the thermal reaction of 2H-azaphosphirene
complex 119 in toluene in the presence of 1-piperidino carbo-
nitrile (2) and ethyl acrylate (3), the latter as an example of an
electronically activated and sterically nondemanding monosub-
stituted alkene. In this case, we obtained a clean [3+2]
cycloaddition reaction of the transiently formed nitrilium
phosphane-ylide complex 4 to the alkene, thus yielding regio-
selectively a 1:1 mixture of the diastereomeric 4-ethoxycarbonyl-
substituted 1,2λ3-azaphospholene complexes 5a,b (Scheme 2);
no phosphirane complex formation was observed in this case.18
Although complexes 5a,b could not be separated by column
chromatography, their NMR data were recorded (Table 1) and
unambiguously assigned on the basis of DEPT experiments;
furthermore, the structure of isomer 5a was established by
single-crystal X-ray crystallography.
To our surprise, no reaction occurred between 2H-azaphos-
phirene complexes 1, 2, and E-stilbene (6), thus demonstrating
an electronic and/or steric mismatch of 6 with complex 3. In
marked contrast, complexes 1, 2, and fumaronitrile (7) reacted
with transient complex 3 to furnish the diastereomeric 1,2-
azaphosphol-5-ene complexes 8a,b together with the 2H-1,3,2-
diazaphosphole complex 9 in a ratio of 2:1:1 (determined by
31P{1H} NMR spectroscopy) (Scheme 3). Complexes 8a and 9
were isolated in pure form and fully characterized by NMR
Studies devoted to obtain nonligated 1,2-azaphosphol-5-enes
are currently underway.
(8) Streubel, R.; Wilkens, H.; Jones, P. G. Chem.sEur. J. 2000, 21,
3997-4000.
(9) Hoffmann, N.; Jones, P. G.; Streubel, R. Angew. Chem. 2002, 114,
1186-1188; Angew. Chem., Int. Ed. 2002, 41, 1226-1228.
(10) J. Alcaraz, M.; Svara, J.; Mathey, F. NouV. J. Chim. 1986, 10, 321-
326.
Discussion of Selected NMR Spectroscopic Data
The analytical data including elemental analyses, MS spec-
trometric data, and IR and NMR spectroscopic data readily
confirm the molecular structures of all compounds reported
herein, which had been separated (unless otherwise stated) and
purified by column chromatography at low temperature and
(11) Hoffmann, N.; Wismach, C.; Ernst, L.; Schiebel, H.-M.; Jones, P.
G.; Streubel, R. Eur. J. Inorg. Chem. 2003, 1815-1821.
(12) Angermund, K.; Eckerle, A.; Lutz, F. Z. Naturforsch. 1995, 50b,
488-502.
(13) Wilke, G. Angew. Chem. 1988, 100, 189-211; Angew. Chem., Int.
Ed. Engl. 1988, 27, 18-207.
(14) Boeing, C.; Francio, G.; Leitner, W. AdV. Synth. Catal. 2005, 347,
1537-1541.
(20) 31P{1H} NMR data: a resonance at 105.4 ppm with a |J(W,P)| of
279.3 Hz and at 114.5 ppm with a |J(W,P)| of 276.8 Hz was recorded; the
data could be in accordance with two isomeric 1,2-azaphosphol-5-ene
complexes.
(21) Wilkens, H.; Ruthe, F.; Jones, P. G.; Streubel, R. J. Chem. Soc.,
Chem. Commun. 1998, 1529-1530. Comment on the X-ray data of 16:
only data of one of the two crystallographically independent molecules were
used for this comparison.
(15) Boeing, C.; Francio, G.; Leitner, W. J. Chem. Soc., Chem. Commun.
2005, 1456-1458.
(16) Review: Streubel, R. Top. Curr. Chem. 2002, 223, 91-109.
(17) Wilkens, H.; Ruthe, F.; Jones, P. G.; Streubel, R. J. Chem. Soc.,
Chem. Commun. 1998, 1529-1530.
(18) Wilkens, H.; Ostrowski, A.; Jeske, J.; Ruthe, F.; Jones, P. G.;
Streubel, R. Organometallics 1999, 18, 5627-5642.
(19) Streubel, R.; Ostrowski, A.; Priemer, S.; Rohde, U.; Jeske, J.; Jones,
P. G. Eur. J. Inorg. Chem. 1998, 257-261.
(22) Sheldrick, G. M. SHELXL-97, program for crystal structure refine-
ment; Universita¨t Go¨ttingen, 1997.

4832 Organometallics, Vol. 25, No. 20, 2006
Streubel et al.
Table 1. Comparison of Selected 31P and 13C NMR Dataa of 1,2-Azaphosphol-5-ene Complexes 5a,b, 8a, 13a, and 148
δ(31P) (1J(P,W))
δ(13C3) (1J(P,C))
δ(13C4) ((2+3)J(P,C))
δ(13C5) ((2+3)J(P,C))
5a
5b
8a
96.4 (260.2)
92.7 (256.9)
119.5 (284.4)
134.7 (272.3)
158.5 (306.7)
35.0 (9.0)
39.6 (nr)
40.5 (nr)
59.1 (13.0)
54.1 (27.6)
50.7 (6.5)
50.8 (6.2)
40.9 (nr)
51.1 (mc, br)
49.6 (20.6)
160.2 (nr)
161.2 (nr)
152.8 (8.7)
164.9 (3.9)
144.9 (10.7)
13a
148
a CDCl3, δ [ppm], J [Hz]; only coupling magnitudes; nr ) not resolved.
Scheme 3. π-Substrate Competition of Alkene 7 in [3+2]
Scheme 5. π-Selective Reaction of Transient Nitrilium
Phosphane-ylide Complex 12 with Alkene 10 under
Formation of Bicyclic 1,2-Azaphosphol-5-ene Complexes
13a,b
Cycloaddition Reactions with Transient Complex 3
Scheme 4. Formation of C5-Spirocyclic
1,3,2-Oxazaphosphol-3-ene Complexes 11a,b
phol-5-ene complex 14, which displayed a resonance at 158.5
ppm.8 It also became apparent through this study that the
substitution pattern also significantly effects the phosphorus-
tungstensand phosphorus-carbonscoupling constants but to
an extent hardly foreseeable: the difference between complex
5b and 14 is about 50 Hz! Another somewhat surprising result
was that the resonances of the C5 atoms would become more
shielded if the number of electron-withdrawing groups at C3
and C4 increases.
Discussion of Selected X-ray Structural Data of
Complex 5a
subsequent crystallization in most cases. NMR data will be
discussed hereafter; for further analytical data see the Experi-
mental Section. The assignment of the resonances to the carbon
atoms of the heterocyclic system in 2H-1,2-azaphosphol-5-ene
complexes is obvious, if the carbon atoms are bonded either to
phosphorus or to hydrogen, leading in the first case to
significantly greater magnitudes of |J(P,C)| (in general) and/or
to characteristic spectra, if DEPT experiments were performed.
Furthermore, because of the unambiguously established structure
of complex 5a (for X-ray structure analysis see next chapter),
we assign the resonances in the range 160-165 ppm having
small |J(P,C)| values to the C5 atom (Table 1). A comparison
of the NMR spectroscopic data of the 2H-1,2-azaphosphol-5-
The molecular structure of the 1,2-azaphosphol-5-ene com-
plex 5a was confirmed for the solid state by X-ray crystal-
lography (Figure 1). Comparison of the most interesting
structural features of the complexes 5a and 1519 (Figure 2)
reveals that complex 5a has a nonplanar five-membered ring
system (in contrast to 15), whereby the phosphorus atom lies
36 pm out of the plane of N(1)-C(6)-C(7)-C(8) (rms
deviation 3.6 pm: cf. 15: ∆ ) 0.362 Å). The planar environment
at N(2) (angle sum 357.3°) (15: 359.9°) together with a
shortened C(6)-N(2) distance of 134.8(6) pm (15: 133.7(4)
pm) indicate a pπ-pπ electron interaction between the lone pair
of the nitrogen center of the diorganoamino group and the C-C
double bond of the 1,2-azaphosphol-5-ene ring in complex 5a,
very similar to that in 15.
ene complexes 5a,b, 8a, and 13a reveals for all derivatives 31
P
NMR resonances in the range 92-135 ppm, which clearly
indicate the presence of electron-withdrawing groups at the
neighboring endocyclic carbon centers. That such groups may
have a surprisingly strong effect on the phosphorus shieldings
and thus the chemical shiftswas already observed in the case
of the related 3,3′,4,4′-tetracyano-substituted 2H-1,2-azaphos-
Interestingly, the endocyclic nitrogen-carbon double-bond
distance is shorter in 5a (128.0(6) pm) than in 15 (130.1(4) pm);
there is also a slight difference in the W-P distance, which is
251.06(14) pm in complex 5a and 247.48(9) pm in complex
15.

1,2-Azaphosphol-5-ene Complexes
Organometallics, Vol. 25, No. 20, 2006 4833
tography at low temperature. The κP notation in the nomenclature
is intended to differentiate between P- and N-coordination of the
appropriate heterocycle to the metal.
{Pentacarbonyl[2-bis(trimethylsilyl)methyl-4-ethoxycarbonyl-
5-(1-piperidino)-1,2-azaphosphol-5-ene-κP]tungsten(0)} (5a,b).
2H-Azaphosphirene tungsten complex 1 (0.62 g, 1 mmol) was
dissolved in 3.0 mL of toluene together with 0.2 mL of 1-piperidino
nitrile (2 mmol), and 2 mmol of the alkene 4 was added. After
heating the solution at 75 °C for 1.5 h with slow stirring, the solution
was evaporated to dryness. Low-temperature chromatography of
the residues afforded the products (SiO2, 10 × 2 cm, -20 °C; petrol
ether (40/60)/diethyl ether 95:5); complex 5a was crystallized from
n-pentane at -20 °C.
Yield: 430 mg (62%) of a pale red solid. Mp: 112 °C (dec).
3
13C{1H} NMR (CDCl3): δ 2.5 (d, J(P,C) ) 1.2 Hz, SiMe3), 2.6
3
(s, SiMe3), 2.7 (s, SiMe3), 2.9 (d, J(P,C) ) 1.7 Hz, SiMe3), 14.1
(s, CH2CH3), 14.2 (s, CH2CH3), 22.3 (s, NCH2CH2CH2), 22.4 (s,
NCH2CH2CH2), 25.6 (s br, NCH2CH2CH2), 28.1 (d, 1J(P,C) ) 3.5
Hz, CH(SiMe3)2), 29.8 (s, CH(SiMe3)2), 35.0 (d, 1J(P,C) ) 9.0 Hz,
PCH2), 39.6 (mc, PCH2), 48.0 (s br, NCH2CH2CH2), 50.7 (d,
(2+3)J(P,C) ) 6.5 Hz, PCH2CH), 50.8 (d, (2+3)J(P,C) ) 8.2 Hz,
PCH2CH), 61.9 (s, CH2CH3), 62.2 (s, CH2CH3), 160.2 (s, PNC),
161.2 (s, PNC), 170.2 (d, 3J(P,C) ) 4.3 Hz, CO2Et), 171.4 (d, 3J-
(P,C) ) 8.1 Hz, CO2Et), 198.2 (d, 2J(P,C) ) 7.9 Hz, cis-CO), 198.5
(d, 2J(P,C) ) 7.8 Hz, cis-CO), 201.3 (d, 2J(P,C) ) 22.1 Hz, trans-
CO), 202.0 (d, 2J(P,C) ) 22.8 Hz, trans-CO). 31P{1H} NMR
(CDCl3): δ 92.7 (s, 1J(P,W) ) 256.9 Hz), 96.4 (s, 1J(P,W) ) 260.2
Hz). IR (KBr): ν˜ 2067 (s), 1978 (s), 1903 (vs, br) cm-1 (CO);
1729 (s) cm-1 (CO2); 1567 (vs, sh), cm-1 (CdN). MS (70 eV, EI),
Figure 1. Molecular structure of 5a (ellipsoids represent 50%
probability level; hydrogen atoms are omitted for clarity). Selected
bond lengths (pm) and angles (deg): P-N(1) 169.8(4), N(1)-C(6)
128.0(6), C(6)-C(7) 155.5(6), C(7)-C(8) 153.9(2), P-C(8) 181.5-
(5), P-C(9) 182.6(5), P-W 251.06(14); W-P-C(9) 117.42(16),
N(1)-P-C(8) 94.1(2), C(6)-N(1)-P 113.7(3), N(1)-C(6)-C(7)
117.8(4), C(6)-C(7)-C(8) 105.6(4), C(7)-C(8)-P 105.1(3).
(
184W); m/z (%): 724 (10) [M+•], 668 (100) [(M - 2 CO)+•], 584
(65) [(M - 5 CO)+•], 73 (20) [(SiMe3)+•]. Anal. Calcd for
C22H35N2O7PSi2W (724.5): C 38.13, H 5.15, N 3.87. Found: C
38.19, H 5.21, N 3.82.
{Pentacarbonyl[2-bis(trimethylsilyl)methyl-3,4-cyano-5-(1-pi-
peridino)-1,2-azaphosphol-5-ene-κP]tungsten(0)} (8a). 2H-Aza-
phosphirene tungsten complex 1 (0.62 g, 1 mmol) was dissolved
in 3.0 mL of toluene together with 0.2 mL of 1-piperidino nitrile
(2 mmol), and 2 mmol of the alkene 6 was added. After heating
the solution at 75 °C for 1.5 h with slow stirring, the solution was
evaporated to dryness. Low-temperature chromatography of the
residues afforded the products (SiO2, 10 × 2 cm, -20 °C; petrol
ether (40/60)/diethyl ether 90:10).
Figure 2. Complex 15.19
Conclusions
Our investigations of the thermolysis of the 2H-azaphos-
phirene complex 1 in toluene in the presence of piperidino nitrile
and various, electronically different alkenes (1) led to new
mono- and bicyclic 1,2-azaphosphol-5-ene derivatives with
functional groups, (2) revaled a significant effect of the
C-substituent of transiently generated nitrilium phosphane-ylide
complexes 3 and 12 and the alkene substitution pattern on the
reaction course, whereby (3) complex 3 tended to avoid
sterically congested ring systems and/or is significantly less
π-selective than complex 12. In total, it provides further insight
into the chemistry of these phosphorus-containing 1,3-dipoles.
Yield: 150 mg (22%) of a pale brown, amorphous solid. Mp:
1
188 °C (dec). H NMR (CDCl3): δ 0.26 (s, 9 H, SiMe3), 0.37 (d,
4J(P,H) ) 0.2 Hz, 9 H, SiMe3), 1.69 (s br, 6 H, NCH2CH2CH2),
3.54 (mc, 4 H, NCH2CH2CH2), 3.78 (dd, 3J(P,H) ) 6.2 Hz, 3J(H,H)
2
3
) 7.4 Hz, 1 H, PCHCH), 4.22 (dd, J(P,H) ) 2.0 Hz, J(H,H) )
7.4 Hz, 1 H, PCHCH). 13C{1H} NMR (CDCl3): δ 2.8 (s, SiMe3),
2.8 (d, 3J(P,C) ) 2.2 Hz, SiMe3), 24.0 (s, NCH2CH2CH2), 25.6 (s
1
br, NCH2CH2CH2), 31.1 (d, J(P,C) ) 9.1 Hz, PCHCH), 40.5 (s,
CH(SiMe3)2), 40.8 (s, PCHCH), 48.9 (s br, NCH2CH2CH2), 115.4
(d, 2J(P,C) ) 4.1 Hz, CN), 117.6 (d, 3J(P,C) ) 6.9 Hz, CN), 152.8
(d, (2+3)J(P,C) ) 8.7 Hz, PNC), 197.0 (d, 2J(P,C) ) 7.8 Hz, 1J(C,W)
) 126.3 Hz, cis-CO), 199.4 (d, 2J(P,C) ) 17.4 Hz, trans-CO). 31P-
{1H} NMR (CDCl3): δ 119.5 (s, 1J(P,W) ) 284.4 Hz). IR (KBr):
ν˜ 2071 (s), 1987 (s), 1944 (vs), 1930 (vs) cm-1 (CO); 1598 (s br),
cm-1 (CdN). MS (70 eV, EI), (184W); m/z (%): 704 (20) [M+•],
646 (25) [(M - 2 CO)+•], 590 (30) [(M - 4 CO)+•], 562 (100)
[(M - 5 CO)+•], 73 (50) [(SiMe3)+•]. Anal. Calcd for C22H35N4O7-
PSi2W (702.5): C 37.61, H 4.45, N 7.98. Found: C 36.55, H 4.87,
N 6.95. HR-EI-MS (182W): ber. 700.1080; gef. 700.1046 ( 2.
Experimental Section
General Procedures. All reactions and manipulations were
carried out under an atmosphere of deoxygenated dry nitrogen, using
standard Schlenk techniques with conventional glassware, and
solvents were dried according to standard procedures. NMR spectra
were recorded on a Bruker AC-200 spectrometer (200 MHz for
1H; 50.3 MHz for 13C; 81.0 MHz for 31P) using [D]chloroform and
[D6]benzene as solvent and internal standard; shifts are given
relative to external tetramethylsilane (1H, 13C) and 85% H3PO4 (31P).
Mass spectra were recorded on a Finigan Mat 8430 (70 eV); apart
from m/z values of the molecule ions, only m/z values having
intensities of more than 20% are given. Infrared spectra were
recorded on a Biorad FT-IR 165 (selected data given). Melting
points were obtained on a Bu¨chi 535 capillary apparatus. Elemental
analyses were performed using a Carlo Erba analytical gas
chromatograph. All products were separated by column chroma-
8b: 31P{1H} NMR (CDCl3): δ 118.1 ppm, 1J(P,W) ) 283.2 Hz.
{Pentacarbonyl[2-bis(trimethylsilyl)methyl-4-(2-cyanoethenyl)-
5-(1-piperidino)-2H-1,3,2-diazaphosphole-κP]}tungsten(0)} (9).
1
Yield: 105 mg (15%) of a red oil. H NMR (CDCl3): δ 0.16 (s,
9 H, SiMe3), 0.21 (s, 9 H, SiMe3), 1.38 (d, 2J(P,H) ) 6.8 Hz, 1 H,
CH(SiMe3)2), 1.70 (s br, 6 H, NCH2CH2CH2), 3.42 (mc, 4 H, NCH2-

4834 Organometallics, Vol. 25, No. 20, 2006
Streubel et al.
CH2CH2), 6.50 (d, 3J(H,H) ) 16.0 Hz, 1 H, CH), 7.30 (d, 3J(H,H)
Hz, Caromat.), 133.6 (s, CHaromat.), 164.6 (d, (2+3)J(P,C) ) 14.3 Hz,
PNC), 164.9 (d, 2J(P,C) ) 14.3 Hz, CO2), 167.9 (d, 3J(P,C) ) 3.9
3
) 16.0 Hz, 1 H, CH). 13C{1H} NMR (CDCl3): δ 2.4 (d, J(P,C)
3
2
1
) 2.3 Hz, SiMe3), 2.6 (d, J(P,C) ) 2.1 Hz, SiMe3), 24.1 (s, CH-
Hz, CO2), 195.9 (d, J(P,C) ) 7.1 Hz, J(P,W) ) 126.2 Hz, cis-
CO), 198.6 (d, 2J(P,C) ) 27.8 Hz, trans-CO). 31P{1H} NMR
(CDCl3): δ 134.7 (s, 1J(P,W) ) 272.3 Hz). IR (KBr): ν˜ 2075 (vs),
1985 (vs), 1931 (vs, sh) cm-1 (CO); 1795 (m), 1778 (s) cm-1 (CO2);
1596 (m, sh), 1571 (m) cm-1 (CdN). MS (70 eV, EI), (184W); m/z
(%): 715 (25) [M+•], 687 (70) [(M - CO)+•], 659 (30) [(M - 2
CO)+•], 587 (55) [(M - CO - SiMe3)+•], 531 (65) [(M - 3 CO -
SiMe3)+•], 503 (65) [(M - 4 CO - SiMe3)+•], 73 (100) [(SiMe3)+•].
Anal. Calcd for C23H26NO8PSi2W (715.5): C 38.61, H 3.66, N 1,-
96. Found: C 38.55, H 3.67, N 1.93.
(SiMe3)2, NCH2CH2CH2), 25.5 (s, NCH2CH2CH2), 50.2 (s, NCH2-
4
CH2CH2), 108.3 (d, J(P,C) ) 1.8 Hz, NCHCH), 116.3 (s, CN),
140.9 (d, 3J(P,C) ) 23.0 Hz, NCHCH), 158.8 s, PNCN), 160.7 (d,
2
(2+3)J(P,C) ) 6.1 Hz, PNCC), 196.9 (d, J(P,C) ) 7.2 Hz, cis-
CO), 199.8 (d, 2J(P,C) ) 24.0 Hz, trans-CO). 31P{1H} NMR
(CDCl3): δ 155.0 (s, 1J(P,W) ) 257.5 Hz). Anal. Calcd for
C19H29N3O5PSi2W (650.4): C 35.08, H 4.49, N 6.46. Found: C
35.49, H 4.62, N 6.35.
{Pentacarbonyl[2-bis(trimethylsilyl)methyl-5-(1-piperidino)-
1,6-dioxa-3-aza-2-phosphaspiro[4.4]-3,3-diene-7-on-κP]}tungsten-
(0)} (11a,b). 2H-Azaphosphirene tungsten complex 1 (0.62 g, 1
mmol) was dissolved in 3.0 mL of toluene together with 0.2 mL
of 1-piperidino nitrile (2 mmol), and 2 mmol of the alkene 7 was
added. After heating the solution at 75 °C for 1.5 h with slow
stirring, the solution was evaporated to dryness. Neither low-
temperature chromatography nor extraction of the residue afforded
the products.
13b: 31P{1H} NMR (CDCl3): δ 122.0 (s, 1J(P,W) ) 271.6 Hz).
X-ray Crystallographic Analysis. Structure determination of
5a: Crystal data: C23H37N2O7PSi2W, M ) 724.55, P21/n, a )
1004.9(3) pm, b ) 1710.5(4) pm, c ) 1762.3(10) pm, â ) 95.50-
(4)°, V ) 3.015 nm3, Z ) 4, dcalc ) 1.596 M/m3, µ ) 4.0 mm-1
,
T ) 143 K. A yellow prism (0.60 × 0.45 × 0.30 mm) was used to
record 7116 intensities (2θmax 6-50°) using monchromated Mo KR
radiation on a Stoe STADI-4 diffractometer. After absorption
correction (psi-scans) 5306 were unique (Rint ) 0039) and were
used for all calculations (program SHELXL-97).21 Hydrogen atoms
were refined as rigid methyl groups or with a riding model. The
final wR(F2) was 0.082, with conventional R(F) 0.033, for 332
parameters and 47 restraints; highest peak 1089, hole -1803 e/nm3.
Crystallographic data for 5a (excluding structure factors) have
been deposited at the Cambridge Crystallographic Data Centre under
the number CCDC 297491. Copies may be requested free of charge
from the Director, CCDC, 12 Union Road, Cambridge CB2 1EZ,
England (E-mail: deposit@ccdc.cam.ac.uk).
31P{1H} NMR (CDCl3): δ 188.1 (1J(P,W) ) 309 Hz) and 196.5
(1J(P,W) ) 300.9 Hz).
{Pentacarbonyl[P-bis(trimethylsilyl)methyl-8-phenyl-1,5,4-
oxazaphosphabicyclo[3.3]oct-5-en-2,8-dione-κP]}tungsten(0)}
(13a,b). 2H-Azaphosphirene tungsten complex 1 (0.62 g, 1 mmol)
was dissolved in 3.0 mL of benzonitrile, and 2 mmol of the alkene
10 was added. After heating the solution at 75 °C for 1.5 h with
slow stirring, the solution was evaporated to dryness. In this case,
low-temperature column chromatography failed and only extraction
of the residue with small amounts of n-pentane at 0 °C yielded
13a.
Acknowledgment. We are grateful to the Fonds der Che-
mischen Industrie and the Deutsche Forschungsgemeinschaft
for support of this research. The X-ray data were recorded by
Mr. A. Weinkauf.
13a: Yield: 275 mg (40%) of a pale brown, amorphous solid.
1
Mp: 191 °C. H NMR (CDCl3): δ 0.12 (s, 9 H, SiMe3), 0.46 (s,
2
9 H, SiMe3), 1.71 (d, J(P,H) ) 10.0 Hz, 1 H, CH(SiMe3)2), 4.27
3
3
(dd, J(H,H) ) 5.2 Hz, J(P,H) ) 10.0 Hz, 1 H, PCCH),), 5.45
3
3
(dd, J(H,H) ) 5.2 Hz, J(P,H) ) 10.0 Hz, 1 H, PCH), 7.59 (mc,
Supporting Information Available: Crystallographic data for
5a. This material is available free of charge via the Internet at
http://pubs.acs.org.
3 H, CHaromat.), 8.08 (mc, 2 H, CHaromat.). 13C{1H} NMR (CDCl3):
3
δ 2.4 (d, J(P,C) ) 2.3 Hz, SiMe3), 2.5 (s, SiMe3), 28.5 (s, CH-
(SiMe3)2), 51.1 (mc, PCHCH), 59.1 (d, 1J(P,C) ) 13.0 Hz, PCHCH),
3
129.1 (s, CHaromat.), 130.9 (s, CHaromat.), 131.5 (d, J(P,C) ) 18.3
OM060344J