An unusual reaction of cyclopropenylphosphonium bromide with sodium polyphosphides - A novel approach to sodium 3,4,5-triphenyl-1,2-diphosphacyclopentadienide

Article abstract of DOI:10.1016/j.jorganchem.2008.08.006

1,2,3-Triphenylcyclopropenylphosphonium bromide reacts with sodium polyphosphides to give sodium 3,4,5-triphenyl-1,2-diphosphacyclopentadienide in high yield.

Full text of DOI:10.1016/j.jorganchem.2008.08.006

Journal of Organometallic Chemistry 693 (2008) 3318–3320
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Communication
An unusual reaction of cyclopropenylphosphonium bromide with sodium
polyphosphides – A novel approach to sodium 3,4,5-triphenyl-1,
2-diphosphacyclopentadienide
a
a
a
Ilya Bezkishko a, Vasily Miluykov a, , Alexander Kataev , Igor Litvinov , Dmitry Krivolapov ,
*
Oleg Sinyashin a, Evamarie Hey-Hawkins b,1
a A.E. Arbuzov Institute of Organic and Physical Chemistry, Russian Academy of Sciences, Arbuzov Street 8, Kazan 420088, Russia
b Institut für Anorganische Chemie der Universität Leipzig, Johannisallee 29, Leipzig, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 17 June 2008
Received in revised form 23 July 2008
Accepted 4 August 2008
Available online 11 August 2008
1,2,3-Triphenylcyclopropenylphosphonium bromide reacts with sodium polyphosphides to give sodium
3,4,5-triphenyl-1,2-diphosphacyclopentadienide in high yield.
Ó 2008 Elsevier B.V. All rights reserved.
Keywords:
Triphenylcyclopropenyl bromide
Phosphonium salt
Sodium polyphosphides
1,2-Diphosphacyclopentadienide anion
Ph
Ph
Ph
Ph
Ph
1. Introduction
NaxPy
X
P
Phosphonium salts are useful reagents in organic synthesis [1]
and have found broad application for the preparation of a variety
of Wittig reagents, which are widely used for the conversion of
ketones and aldehydes to alkenes [2]. Furthermore, cyclopropenyl-
phosphonium cations react with different nucleophiles to give
cyclic compounds such as furans [3] and cyclopentenones [4] due
to intermolecular Wittig reactions. Ring-opening reactions of
cyclopropene also take place in reactions with different amines
[5,6], aryl magnesium bromides [7], and phosphites [8]. We are
interested in the reactivity of phosphonium salts of cyclopropenes
toward sodium polyphosphides as a possible route to sodium
1,2-diphosphacyclopentadienide [9], which was recently obtained
by reaction of cyclopropenyl nickel complexes with different
polyphosphides such as NaP5 [10] and Na3P7 [11].
P
Br
Na+(diglyme)2
Ph
(2)
PR3
NaxPy
Ph
Ph
PR3+Br-
Ph
1
1a: PR3 = PPh3, 1b: PR3 = PMe2Ph
We have found that triphenylcyclopropenyl bromide reacts
with tertiary phosphines to form novel phosphonium salts 1 in
high yield (Eq. (1))
ð1Þ
The structure of 1 was confirmed by NMR spectroscopy, and addi-
tionally by X-ray analysis for 1b (see Fig. 1). To the best of our
knowledge, 1b is the first structurally characterized cyclopropenyl-
phosphonium salt. The cyclopropenyl ring and the two phenyl rings
at the C–C double bond of the cyclopropenyl ring are almost copla-
nar. The P1–C1 bond length (1.824(4) Å) is slightly longer than a
P–C single bond. The C–C distances of the cyclopropenyl ring in
1b differ: one bond is short (C@C, C2–C3 1.315(5) Å) and two are
* Corresponding author. Fax: +7 843 2752253.
E-mail addresses: miluykov@iopc.knc.ru (V. Miluykov), hey@rz.uni-leipzig.de
(E. Hey-Hawkins).
1
Fax: +49 341 9739319.
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.08.006

I. Bezkishko et al. / Journal of Organometallic Chemistry 693 (2008) 3318–3320
3319
long (C1–C3, 1.526(5) and C1–C2 1.517(5) Å), in contrast to [cyclo-
2. Experimental
(CPh)3] ClO4 [12] and [cyclo-(CNMe2)3]ClO4 [13], in which all three
C–C bonds are equivalent (1.373(5) and 1.363(7), respectively).
No aromaticity of cyclopropene ring of 1 was found in solution,
as is apparent from the 13C NMR spectrum, which exhibits a dou-
blet at ca. 31 ppm for C1, characteristic for an sp3-hybridized
carbon atom.
Phosphonium salts 1a and 1b were treated with mixture of
polyphosphides, obtained in situ from sodium and white
phosphorus and containing mainly NaP5 and Na3P7 [14]. Only
the signals of sodium 3,4,5-triphenyl-1,2-diphosphacyclopenta-
dienide (2) and the tertiary phosphine were detected in the 31P
NMR spectrum of the reaction mixture after refluxing for 3 h
(Eq. (1)).
All reactions and manipulations were carried out under dry pure
N2 in standard Schlenk apparatus. All solvents were distilled from
sodium/benzophenone and stored under nitrogen before use. The
NMR spectra were recorded on a Bruker AVANCE DRX 400 or an
MSL-400 (1H 400 MHz, 31P 121.7 MHz, 13C 100.6 MHz). SiMe4 was
used as internal reference for 1H and 13C NMR chemical shifts,
and 85% H3PO4 as external reference for 31P. PMe2Ph [16] and
[C3Ph3]Br [17] were prepared according to literature procedures.
2.1. (1,2,3-Triphenylcyclopropenyl)triphenylphosphonium bromide
(1a)
Compound 2 can easily be isolated from the reaction mixture by
filtration. After washing with n-hexane 2 is obtained in good
purity and can be used for following reactions without further
purification.
So reaction of phosphonium salts 1 with sodium polyphosp-
hides affords a new convenient method for preparation of 2. In
contrast, no sodium 3,4,5-triphenyl-1,2-diphosphacyclopentadie-
nide 2 was formed in reaction of 1,2,3-triphenylcyclopropenyl bro-
mide with sodium polyphosphides without tertiary phosphines or
at presence of catalytic amount tertiary phosphines. Recently we
have proposed that the first stage of formation of sodium 3,4,5-tri-
phenyl-1,2-diphosphacyclopentadienide in reaction of cycloprope-
A
mixture of triphenylcyclopropenyl bromide (0.34 g,
0.01 mmol) and PPh3 (0.26 g, 0.01 mmol) in THF (20 mL) was re-
fluxed for 3 h. The precipitate was collected by filtration and
washed with cold THF to give 1,2,3-triphenylcyclopropenyl)tri-
phenylphosphonium bromide (1a) as white crystals (0.54 g, 90%).
M.p.: 169 °C.
1H NMR ([D6]DMSO): d = 7.38 (d, 6H, Ph, JHH = 6.82 Hz), 7.3 (d,
3
3
2H, Ph, JHH = 6.9 Hz), 7.42–7.54 (m, 8H, Ph), 7.62 (t, 2 H, Ph,
3JHH = 7.02 Hz), 7.69 (t, 2H, Ph, JHH = 7.34 Hz), 7.79 (t, 2H, Ph,
3
3JHH = 7.34 Hz), 7.94 (d, 8H, Ph, JHH = 6.82 Hz). 31P NMR
3
([D6]DMSO): d = 30.4 (s). 13C NMR ([D6]DMSO): d = 30.04 (d, C1,
1JPC = 74.5 Hz), 112.33 (C@C), 121.24 (p-C, Ph-C1), 121.69 (p-C,
nyl complexes of nickel with sodium polyphosphides is
a
3
Ph-P), 123.55 (d, m-C, Ph-P, JCP = 2.4 Hz), 127.23 (p-C, Ph),
nucleophilic attack polyphosphide-anion to one of carbon of
C3-ring [11,15]. The absence of aromaticity of cyclopropene ring
of 1 allow to explain the difference of reactivity of 1,2,3-triphenyl-
cyclopropenyl bromide and phosphonium salts 1 towards sodium
polyphosphides – the positive charged carbon atom C1 facilities
the nucleophilic attack of polyphosphide-anion to one of carbon
of cyclopropenilium ring.
127.64 (p-C, Ph), 128.46 (m-C, Ph-C1), 129.04 (m-C, Ph), 129.11
(m-C, Ph), 129.13 (o-C, Ph-C1), 129.53 (o-C, Ph), 129.56 (o-C, Ph),
130.33 (ipso-C, Ph), 131.55 (ipso-C, Ph), 131.61 (d, o-C, Ph-P,
2JCP = 9.61 Hz), 133.5 (ipso-C, Ph-C1), 133.45 (d, ipso-C, Ph-P,
1JCP = 25.2 Hz). Anal. Calc. for C39H30BrP (609.54): C, 76.85; H,
4.96; P, 5.08. Found: C, 76.62; H, 4.86; P, 5.19%.
In summary we have found that 1,2,3-triphenylcyclopropenyl-
phosphonium salts react cleanly with sodium polyphosphides to
give sodium 3,4,5-triphenyl-1,2-diphosphacyclopentadienide in
good yield.
2.2. (1,2,3-Triphenylcyclopropenyl)dimethylphenylphosphonium
bromide (1b)
Compound (1b) was prepared in a similar manner to 1a and was
obtained as white crystals in 85% yield. M.p.: 144 °C. Crystals suit-
able for X-ray analysis were growth from a saturated solution of 1b
in CHCl3 at ꢀ30 °C.
2
1H NMR ([D6]DMSO): d = 2.39 (d, 6H, Me, JHP = 13.5 Hz), 7.34
3
3
(d, 3H, Ph, JHH = 7.0 Hz), 7.46 (d, 2H, Ph, JHH = 6.9 Hz), 7.49–7.58
3
(m, 8H, Ph), 7.69 (t, 1 H, Ph, JHH = 7.15 Hz), 7.75 (t, 1H, Ph,
3JHH = 7.52 Hz), 7.77 (t, 1H, Ph, JHH = 7.15 Hz), 7.82 (d, 4H, Ph,
3
3JHH = 6.60 Hz). 31P NMR ([D6]DMSO): d = 29.8 (s). 13C NMR
1
([D6]DMSO) d = 8.02 (d, Me, JCP = 52.9 Hz), 31.04 (d, C1,
1JCP = 74.5 Hz), 112.46 (C@C), 121.27 (p-C, Ph-C1), 121.8 (p-C, Ph-
3
P), 124.59 (d, m-C, Ph-P, JCP = 2.4 Hz), 128.35 (p-C, Ph), 128.46
(p-C, Ph), 128.94 (m-C, Ph-C1), 129.25 (m-C, Ph), 129.35 (m-C,
Ph), 129.54 (o-C, Ph-C1), 129.64 (o-C, Ph), 129.97 (o-C, Ph),
130.83 (ipso-C, Ph), 131.21 (ipso-C, Ph), 131.79 (d, o-C, Ph-P,
2JCP = 9.61 Hz), 134.1 (ipso-C, Ph-C1), 136.56 (d, ipso-C, Ph-P,
1JCP = 25.2 Hz). Anal. Calc. for C29H26BrP (485.40): C, 71.76, H,
5.40, P, 6.38. Found: C, 71.10, H, 5.24, P, 6.57%.
2.3. Sodium bis(diglyme) 1,2-diphospha-3,4,5-
triphenylcyclopentadienide (2)
A mixture of Na (0.46 g, 2 mmol) and P4 (1.24 g, 1 mmol) in dig-
lyme (40 mL) was refluxed for 6 h to give a mixture of sodium
polyphosphides. The reaction mixture was cooled to RT, 1a (0.6 g,
1 mmol) was added, and the mixture was refluxed for an additional
3 h. The reaction mixture was filtered, and the solid was washed
twice with diglyme. The solvent was evaporated in vacuum and
Fig. 1. Molecular structure of 1b. Hydrogen atoms, bromide anion, and solvent
omitted for clarity; thermal ellipsoids drawn at 50% probability. Selected bond
lengths (Å) and angles (°): C1–C2 1.517(5), C1–C3 1.526(5), C2–C3 1.315(5), P1–C1
1.824(4), P1– C22 1.777(4), P1–C23 1.774(4), P1–C24 1.793(4); C2–C1–C4 121.3(3),
C3–C1–C4 121.9(3), C2–C1–C3 51.2(2), C3–C2–C1 64.8(3), C1–C3–C2 64.0(3), C1–
P1–C23 112.48(18), C1–P1–C22 108.6(2), C1–P1–C24 108.8(2).

3320
I. Bezkishko et al. / Journal of Organometallic Chemistry 693 (2008) 3318–3320
the remaining residue was washed three times with n-hexane
(20 mL) to give 2 (0.4 g, 65%) as a brown powder. M.p.: 125 °C
(decomp).
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
1H NMR ([D8]thf): d = 3.15 (s, 12H, MeO), 3.30 (t, 8H,
Acknowledgments
3
3JHH = 5.1 Hz, OCH2), 3.38 (t, 8H, JHH = 5.1 Hz, OCH2), 6.63 (t, 2H,
3JHH = 7.3 Hz, p-CH in Ph), 6.75 (br s, 9H, Ph), 6.93 (br d, 4H,
3JHH = 7.3 Hz, o-CH in Ph). 13C NMR ([D8]thf): d = 58.07 (s, MeO),
69.69 (s, OCH2), 71.39 (s, OCH2), 121.77 (s, m-C, Ph), 122.96 (s,
m-C, Ph), 125.91 (s, p-C, Ph), 126.20 (s, p-C, Ph), 129.73 (t,
2JCP = 4.9 Hz, ipso-C, Ph), 131.93 (s, ipso-C, Ph), 143.88 (s, o-C, Ph),
The authors thank the Deutsche Forschungsgemeinschaft and
RFBR (07-03-91556) for financial support of this work.
References
2
[1] J.I.G. Cadogan, Organophosphorus, Reagents in Organic Synthesis, AP, New
York, 1979.
144.27 (s, o-C, Ph), 147.02 (t, JCP = 8.9 Hz, C-Ph), 161.61 (ps.t,
1JCP + 2JCP = 28.5 Hz, C-Ph). 31P NMR ([D8]thf): d = 190.0 (s). Anal.
Calc. for C33H43NaO6P2 (620.60): C, 63.86; H, 6.98; P, 9.98. Found:
C, 64.10; H, 7.04; P, 9.57%.
[2] D.H. Valentine Jr., J.H. Hillhouse, Synthesis (2003) 317–334.
[3] W.G. Dauben, D.J. Hart, Tetrahedron Lett. (1975) 4353–4356.
[4] J.P. Marlno, R.C. Landick, Tetrahedron Lett. (1975) 4531–4534.
[5] S. Yoneda, H. Kojima, Bull. Chem. Soc. Jpn. 61 (1988) 1793–1794.
[6] H. Kojima, K. Ozaki, N. Matsumura, H. Inoue, J. Heterocyclic Chem. 27 (1990)
1845–1846.
[7] H. Kojima, K. Ozaki, N. Matsumura, H. Inoue, Bull. Chem. Soc. Jpn. 64 (1991)
2298–2299.
[8] H. Kojima, K. Ozaki, N. Matsumura, H. Inoue, J. Chem. Res. Synop. (1991) 324–
325.
[9] N. Maigrot, N. Avarvari, C. Charrier, F. Mathey, Angew. Chem., Int. Ed. Engl. 34
(1995) 590–592.
[10] V. Miluykov, A. Kataev, O. Sinyashin, P. Lönnecke, E. Hey-Hawkins,
Organometallics 24 (2005) 2233–2236.
[11] V. Miluykov, A. Kataev, O. Sinyashin, E. Hey-Hawkins, Russ. Chem. Bull. 56
(2007) 304–306.
[12] M. Sundaralingam, L.H. Jensen, J. Am. Chem. Soc. 88 (1966) 198–204.
[13] A.T. Ku, M. Sundaralingam, J. Am. Chem. Soc. 94 (1972) 1688–1692.
[14] V. Miluykov, A. Kataev, O. Sinyashin, E. Hey-Hawkins, Russ. Chem. Bull. 55
(2006) 1297–1299.
2.4. X-ray analysis
Data were collected on a Bruker Smart Apex II CCD diffractom-
eter using graphite-monochromated Mo Ka (k = 0.71073 Å) radia-
tion. C29H26BrP ꢁ 2 CHCl3; M = 724.11; colorless prism; crystal size
ꢀ
0.30 ꢂ 0.30 ꢂ 0.30 mm; T = 273 K; triclinic; space group P1;
a = 9.549(2) pm, b = 12.301(4) pm, c = 14.997(7) pm,
a = 104.28
(3)°, ß = 92.65(3)°,
c
= 93.28(3)°; V = 1701.0(10) nm3; Z = 2;
q
calcd = 1.414 mg/m3; F(000) = 732; q range for data collection
2.65–26.29°; 0 6 h 6 11; ꢀ15 6 k 6 15; ꢀ18 6 l 6 18; 6796 reflec-
tions collected; 6404 independent reflections [R(int) = 0.0236];
F2 = 0.961; final R indices [I > 2r(I)]: R1 = 0.0609; wR2 = 0.0795; R
indices (all data) R1 = 0.1261; wR2 = 0.0956; largest difference
[15] V. Miluykov, A. Kataev, O. Sinyashin, E. Hey-Hawwkins, Phosphorus, Sulfur,
Silicon Relat. Elem. 183 (2008) 509–513.
peak/hole: 3 0.436/ꢀ0.380 e Å. Data were corrected for absorption
[16] P.D. Bartlett, G. Meguerian, J. Am. Chem. Soc. 78 (1956) 3710–3715.
[17] R. Breslow, H. Won Chang, J. Am. Chem. Soc. 83 (1961) 2367–2375.
using SADABS [18] program (l(Mo Ka
) = 1.749 mmꢀ1). All non-
[18] G.M. Sheldrik, SADABS
, Program for Empirical X-ray Absorption Correction,
hydrogen atoms were refined anisotropically. The hydrogen atoms
were calculated and refined as riding atoms. Data collection images
were indexed, integrated, and scaled using the APEX2 data reduction
package [19]. Structure solution and refinement with SIR [20],
SHELXL97 [21], WINGX [22] program. Pictures were generated with
ORTEP3 for Windows [23]. One of the two molecules of trichlorom-
ethane solvent is disordered in the crystal and was refined as
two equivalent molecules with the same occupancy value of 0.5.
Bruker-Nonis, 1990–2004.
[19] APEX
2
(Version 2.1), SAINTPLUS Data Reduction and Correction Program
(Version7.31A), Bruker Advanced X-ray Solutions, Bruker AXS Inc., Madison,
Wisconsin, USA, 2006.
[20] A. Altomare, G. Cascarano, C. Giacovazzo, D. Viterbo, Acta Crystallogr. Sect. A
47 (1991) 744–748.
[21] G.M. Sheldrick, SHELXL97
a Computer Program for Crystal Structure
Determination, University of Göttingen, 1997.
[22] L.J. Farrugia, J. Appl. Crystallogr. 32 (1999) 837–838.
[23] L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565.
Supplementary material
CCDC 666891 contains the supplementary crystallographic data
for 1b. These data can be obtained free of charge from The