C-phosphoniophosphaalkenes as precursors of Iσ4, 3σ2-diphosphaallenes: Scope and limitations

Article abstract of DOI:10.1002/ejic.200500014

The study of a general synthetic route to 1σ⁴, 3σ²-diphosphaallenes involving the reaction of LiHMDS with C-phosphoniophosphaalkenes is reported. The choice of the base is critical since the precursors are highly electrophilic species that react cleanly with methyl-, butyl-, mesityl-, or tert-butyllithium to afford C- phosphanylphosphonium ylides. The role of the substituents at the σ⁴-phosphorus centre has also been studied. The resulting phosphaallenes react cleanly with a Lewis acid and undergo [3+2] cycloaddition with azides to afford a five-membered heterocycle in a three-step process. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.

Full text of DOI:10.1002/ejic.200500014

FULL PAPER
C-Phosphoniophosphaalkenes as Precursors of 1σ4,3σ2-Diphosphaallenes:
Scope and Limitations
David Martin,[a,b] Heinz Gornitzka,[a] Antoine Baceiredo,*[a] and Guy Bertrand*[a,b]
Keywords: Phosphorus / Phosphaalkenes / Phosphacumulenes / Phosphorus ylides
The study of a general synthetic route to 1σ4,3σ2-diphos-
phaallenes involving the reaction of LiHMDS with C-phos-
phoniophosphaalkenes is reported. The choice of the base is
critical since the precursors are highly electrophilic species
that react cleanly with methyl-, butyl-, mesityl-, or tert-butyl-
lithium to afford C-phosphanylphosphonium ylides. The role
of the substituents at the σ4-phosphorus centre has also
been studied. The resulting phosphaallenes react cleanly
with a Lewis acid and undergo [3+2] cycloaddition with
azides to afford a five-membered heterocycle in a three-step
process.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2005)
Introduction
Among the possible neutral heterocumulenes featuring
the PCP sequence, 1σ4,3σ4-diphosphaallenes (carbodiphos-
phoranes) A[1] and 1σ2,3σ2-diphosphaallenes B[2] have been
known for many years. Recently, we reported the synthesis
and characterisation of the first 1σ4,3σ2-diphosphaallene C
(Scheme 1), which features two different types of phospho-
rus–carbon “double” bonds.[3,4] Derivative C was prepared
by elimination of N2 from the phosphanyl(chlorophos-
phanyl)diazomethane D, which first leads to the corre-
sponding transient carbene that then undergoes a 1,3-chlo-
rine shift from one phosphorus to the other. However, the
scope of this synthetic strategy is very limited in terms of
starting materials (diazo precursors and chlorine migrating
group).
Although phosphoniophosphaalkenes E can be readily
prepared in high yields,[5] their reactivity has not been ex-
plored in detail. In particular, C-hydrogenophosphoni-
ophosphaalkenes could afford the desired heterocumulene
C by a simple deprotonation. Herein, we describe our re-
sults concerning this new and more general synthetic way
to 1σ4,3σ2-diphosphaallenes.
Scheme 1.
Results and Discussion
Phosphoniophosphaalkenes 3 were prepared in two steps
by the method described by Grützmacher et al.[5] Two
equivalents of phosphonium ylides 1 react with bis(diiso-
propylamino)chlorophosphane to give the corresponding
C-phosphanyl phosphorus ylides 2, with one equivalent of
ylide 1 acting as a base to deprotonate the transiently
formed C-phosphanylphosphonium salts. In the second
step, the heterolytic cleavage of a P–N bond is achieved by
addition of two equivalents of BF3·OEt2, which affords the
corresponding phosphoniophosphaalkenes 3 in good yields
(72–95%) (Scheme 2). In the 31P NMR spectra, compounds
3 display an AX system, with a low-field signal (δ Ϸ
300 ppm) characteristic of the phosphaalkene moiety, and
a phosphorus–phosphorus coupling constant of about
130 Hz. In the 13C NMR spectra, the signal for the PCP
carbon atom appears as a doublet of doublets, with chemi-
cal shifts in the range δ = 95–100 ppm.
[a] Laboratoire Hétérochimie Fondamentale et Appliquée, (UMR,
5069), Université Paul Sabatier,
118 Route de Narbonne, 31062 Toulouse Cedex 04, France
Fax: +33-5-61-55-82-04
E-mail: baceired@chimie.ups-tlse.fr
[b] UCR-CNRS Joint Research Chemistry Laboratory (UMR,
2282), Department of Chemistry, University of California
Riverside, CA 92521-0403, USA
Fax: +1-951-827-2725
E-mail: gbertran@mail.ucr.edu
Eur. J. Inorg. Chem. 2005, 2619–2624
DOI: 10.1002/ejic.200500014
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D. Martin, H. Gornitzka, A. Baceiredo, G. Bertrand
FULL PAPER
ing characteristic of a phosphaalkene moiety (Table 1). This
new diphosphaallene 8a was isolated as yellow crystals from
a pentane solution in 55% yield, and its structure was un-
ambiguously established by a single-crystal X-ray diffrac-
tion study (Figure 1).
Scheme 2.
Phosphoniophosphaalkenes 3 are highly electrophilic
species; they can be regarded as phosphenium salts substi-
tuted by a phosphonium ylide fragment (3Ј). Addition of
methyl-, n-butyl- and mesityllithium to 3a did not lead to
the expected cumulenes; instead, the quantitative formation
of the C-phosphanylphosphonium ylides 4–6 was observed
(Scheme 3). This was indicated by the NMR spectroscopic
data, in particular the disappearance of the characteristic
low-field signal for the σ2-phosphorus atom of compounds
3a in the 31P NMR spectrum. When the more sterically
demanding tert-butyllithium was used, the C-phosphanyl-
phosphonium ylide 7,[6] featuring a P–H bond, was ob-
tained in near quantitative yield. In the 31P 1H-coupled
NMR spectrum, derivative 7 presents a characteristic doub-
Scheme 4.
Table 1. 31P and 13C NMR spectroscopic data (δ in ppm and J in
Hertz), and selected structural parameters [bond lengths (pm) and
bond angles (°)] for derivatives 8a, 8b and 8d.[4]
31
δ
13
δ
(JP,P
)
(JP,C
)
(σ4)P–C (σ2)P–C P–C–P
P
C
8a 313, 41 (190) 167 (37, 14)
8b 295, 59 (166) 163 (70)
8d 303, 61 (240) 170 (37, 10)
168.4
166.9
165.0
164.1
162.9
164.3
115.0
125.3
120.9
1
let of doublets (2JP,P = 160, JP,H = 220 Hz) at high-field (δ
= –18 ppm) for the σ3-phosphorus atom.
Figure 1. Structure of diphosphaallene 8a (thermal ellipsoids
drawn at 50% probability for non-hydrogen atoms; hydrogen atoms
omitted for clarity).
Scheme 3.
In order to prevent the nucleophilic attack at the σ2-
phosphorus atom we turned our attention to the bulky, but
Taking this result into account, one equivalent of
not reducing, lithium hexamethyldisilazide (LiHMDS). Ad- LiHMDS was added to phosphoniophosphaalkene 3b, in
dition of one equivalent of this strong base to a THF solu- which one phenyl group has been replaced by a diisopro-
tion of 3a afforded a mixture of compounds 8a and 9a in a pylamino substituent, as one would expect to have a more
70:30 ratio (Scheme 4). The spectroscopic data for 9a are stabilized phosphonium fragment, and thus a less electro-
again indicative of a phosphanylphosphonium ylide struc- philic σ2-phosphorus centre. However, similar results were
ture resulting from the addition of LiHMDS to the σ2- observed, and we isolated the phosphacumulene 8b and the
phosphorus atom of 3a. However, the major compound 8a phosphanylphosphonium ylide 9b in a 40:60 ratio (Table 1).
displays an AX system at δ = 313 and 41 ppm (2JP,P
190 Hz) in the 31P NMR spectrum, the low-field signal be- solution, and its structure was established by an X-ray dif-
=
Diphosphaallene 8b was crystallised from a cold pentane
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C-Phosphoniophosphaalkenes as Precursors of 1σ4,3σ2-Diphosphaallene
FULL PAPER
fraction study (Figure 2). With the more acidic phospho- nium ylides. The absence of symmetry is probably due to
niophosphaalkene 3c, in which the σ4-phosphorus atom is the pyramidalisation of both the phosphane and the ylidic
substituted by three phenyl groups, we did not observe any carbons, which appear as doublets of doublets at δ =
addition reaction. However, the expected cumulene 8c was 94 ppm (JP,C = 137 and 23 Hz) in the 13C NMR spectrum.
also not detected, even at low temperature, and the four- Heterocycle 15 was also obtained (75%) when half an equiv-
membered ring 10[3] was characterised in solution. In this alent of trimethylsilyl azide was added to 8a.
case the steric protection is probably not sufficient, and 8c
undergoes a head-to-tail dimerisation to afford heterocycle
10,[3] as demonstrated by the presence of an A2X2 spin sys-
tem at δ = 49 and 9 ppm (2JP,P = 120 Hz) in the 31P NMR
spectrum.
Figure 2. Structure of diphosphaallene 8b (thermal ellipsoids
drawn at 50% probability for non-hydrogen atoms; hydrogen atoms
omitted for clarity).
Scheme 5.
Derivatives 8a and 8b present very similar NMR spectro-
scopic data (Table 1) to those observed for the already
Conclusions
known diphosphacumulene 8d, which features two diiso-
propylamino and a chloro group bonded to the σ4-phos-
phorus atom.[4] Their molecular structures are also very
similar, with very short (σ2)P–C bond lengths (162.9–
164.1 pm); the values of the PCP angles (115.0–125.3°) are
in good agreement with an sp2-hybridized carbon atom.
Thanks to its ylidic character, compound 8a readily re-
acts with Lewis acids, such as BF3, to afford the corre-
sponding complex 11, which was characterised by multinu-
clear NMR spectroscopy. Of particular interest is the qua-
druplet observed in the 19F NMR spectrum at δ = –49 ppm
(1JF,B = 40 Hz), which is characteristic of alkylfluoroborate
complexes (Scheme 5).[7] On the other hand, the P=C π-
bond of 8a acts as a dipolarophile upon treatment with tri-
methylsilyl azide to afford the [3+2]-cycloadduct 12, which
was detected by 31P NMR spectroscopy at low temperature
(δ = 110 and 31 ppm, JP,P = 200 Hz). Above –20°C, com-
pound 12 undergoes a clean fragmentation into iminophos-
In conclusion, we have demonstrated that phosphonio-
phosphaalkenes 3 are convenient precursors for 1σ4,3σ2-di-
phosphaallenes of type C. The presence of bulky substitu-
ents at the σ4-phosphorus centre is required to prevent di-
merisation. Future work will focus on the preparation of
new types of cumulenes using the potential reactivity of the
σ2-phosphorus atom of these phosphoniophosphaalkenes.
Experimental Section
General Remarks: All manipulations were performed under an inert
atmosphere of argon using standard Schlenk techniques. Dry, oxy-
gen-free solvents were employed. 1H, 13C and 31P NMR spectra
were recorded on Bruker AC80, AC200, WM250 or AMX400 spec-
1
trometers. H and 13C chemical shifts are reported in ppm relative
to Me4Si as external standard. 31P NMR downfield chemical shifts
are expressed with a positive sign, in ppm, relative to external 85%
H3PO4. 19F chemical shifts are reported in ppm relative to
F3CCO2H as external standard. IR spectra were recorded on a Per-
kin–Elmer spectrometer.
= 283 ppm)[8] and diazomethylenephos-
31P
phane 13 (δ
phorane 14 (δ = 23 ppm; IR: ν = 2200 cm–1).[9] Note that
31P
˜
14 can also act as a 1,3-dipole for the diphosphacumulene
8a to afford heterocycle 15,[10] which was isolated as a deep-
red oil in 80% yield. In the 31P NMR spectrum, compound
15 displays a doublet of doublets at δ = 5.9 ppm (2JP,P = 157
and 148 Hz) for the phosphane fragment and two doublets
Preparation of C-Phosphanyl Phosphorus Ylides 2a,c: In a typical
experiment, a THF solution of bis(diisopropylamino)chlorophos-
phane (0.2 g, 1 mmol) was added dropwise at –78 °C to a THF
solution of two equivalents of ylide 1a,c. The mixture was then
centred at δ = 30 ppm for the two inequivalent phospho- warmed to room temperature. After stirring overnight, the solvent
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D. Martin, H. Gornitzka, A. Baceiredo, G. Bertrand
FULL PAPER
was removed under vacuum and the product was extracted with
pentane. Compounds 2a,c were purified by recrystallisation from
hot acetonitrile.
solvent was removed under vacuum. The resulting product was ex-
tracted with pentane and dried under vacuum. Derivatives 4–7 were
obtained as orange oils and used without further purification.
2a: Yield: 0.47 g (89%), orange crystals, m.p. 98–100 °C. 1H NMR
4: Yield: 0.43 g (97%). 1H NMR (C6D6): δ = 1.01 (d, 3JH,H = 7 Hz,
2
2
(C6D6): δ = 1.90 (dd, JP,H = 4, JP,H Ͻ 1 Hz, 1 H, PCHP), 1.06
3
3
6 H, CHCH3), 1.05 (d, JH,H = 6 Hz, 6 H, CHCH3), 1.14 (d, JH,H
3
3
(d, JH,H = 7 Hz, 12 H, NCCH3), 1.12 (d, JH,H = 7 Hz, 12 H,
3
= 7 Hz, 6 H, CHCH3), 1.16 (d, JH,H = 5 Hz, 6 H, CHCH3), 1.43
3
2
NCCH3), 1.28 (d, JH,H = 7 Hz, 12 H, NCCH3), 3.6 (d sept, JP,H
= 7, 3JH,H = 7 Hz, 4 H, NCH), 4.0 (sept, 3JH,H = 7 Hz, 2 H, NCH),
7.80 (m, 4 H, Haro), 7.12 (m, 6 H, Haro) ppm. 13C{1H} NMR
(d, JP,H = 7 Hz, 3 H, PCH3), 1.65 (dd, JP,H = 9 and 3 Hz, 1 H,
PCHP), 3.5 (m, 4 H, NCH), 7.1 (m, 6 H, Haro), 7.7 (m, 4 H, Haro
)
ppm. 13C{1H} NMR (C6D6): δ = 22.8 (dd, JP,C = 131 and 10 Hz,
PCP), 23.0 (dd, JP,C = 14 and 20 Hz, PCH3), 23.4 (s, CHCH3), 23.7
(d, JP,C = 2 Hz, CHCH3), 24.6 (s, CHCH3), 24.8 (s, CHCH3), 44.6
(d, JP,C = 8 Hz, NCH), 47.0 (d, JP,C = 5 Hz, NCH), 127.7 (s, Ca-
roH), 130.0 (dd, JP,C = 6 and 2 Hz, CaroH), 132.0 (d, JP,C = 8 Hz,
CaroH), 132.9 (dd, JP,C = 9 and 2 Hz, CaroH), 135.0 (dd, JP,C = 92
1
1
3
(C6D6): δ = 20.1 (dd, JC,P = 134 and 13 Hz, PCP), 24.2 (d, JC,P
= 3 Hz, NCHCH3), 25.0 (d, 3JC,P = 5 Hz, NCHCH3), 46.0 (d, 2JC,P
= 11 Hz, NCH), 127.8 (s, CHp), 130.0 (d, 3JC,P = 3 Hz, CHm), 132.9
2
4
1
3
(dd, JC,P = 93, JC,P = 3 Hz, CHo), 134.0 (dd, JC,P = 100, JC,P
= 3 Hz, Ci) ppm. 31P{1H} NMR (C6D6): δ = 50 and 35 (d, JP,P
=
2
190 Hz).
2
and 3 Hz, Ci) ppm. 31P{1H} NMR (CDCl3): δ = 35 and 6 (d, JP,P
1
2b: Yield: 0.53 g (96%), yellow powder, m.p. 113–115°C. H NMR
(C6D6): δ = 1.12 (d, JH,H = 7 Hz, 12 H, NCCH3), 1.24 (d, JH,H
= 107 Hz).
3
3
5: Yield: 0.44 g (90%). 1H NMR (C6D6): δ = 0.8–1.1 (m, 33 H,
butyl and CH3), 2.57 (dd, JP,H = 9 and 8 Hz, 1 H, PCHP), 3.40 (d
sept, JH,H = 8 Hz and JP,H = 10 Hz, 2 H, NCH), 3.60 (m, 2 H,
NCH), 7.1 (m, 4 H, Haro), 7.8 (m, 6 H, Haro) ppm. 13C{1H}
NMR(C6D6): δ = 14.4 (s, CH3), 21.7 (dd, JP,C = 114 and 16 Hz,
PCHP), 23.3 (broad, NCHCH3), 23.7 (s, NCHCH3), 24.7 (s, CH2),
29.5 (d, JP,C = 17 Hz, CH2), 36.9 (dd, JP,C = 17 and 7 Hz, PCH2),
44.8 (d, JP,C = 8 Hz, NCH), 47.0 (d, JP,C = 5 Hz, NCH), 127.7 (s,
CaroH), 130.1 (dd, JP,C = 9 and 3 Hz, CaroH), 132.6 (d, JP,C = 9 Hz,
3
= 7 Hz, 12 H, NCCH3), 1.28 (d, JH,H = 7 Hz, 12 H, NCCH3),
1.40 (d, 3JH,H = 7 Hz, 12 H, NCCH3), 1.8 (dd, 2JP,H = 9 and 2 Hz,
2
3
1 H, PCHP), 3.86 (d sept, JP,H = 6, JH,H = 7 Hz, 4 H, NCH),
2
3
4.13 (d sept, JP,H = 13, JH,H = 7 Hz, 4 H, NCH), 7.1 (m, 2 H,
Haro), 8.0 (m, 3 H, Haro) ppm. 31P{1H} NMR (CDCl3): AB system
centred at 56.0 (2JP,P = 137 Hz).
2c: Spectroscopic data were identical to those reported in the litera-
ture.[5]
Preparation of C-Phosphoniophosphaalkenes 3a,c: In a typical ex- CaroH), 134.2 (dd, JP,C = 103 and 8 Hz, Cipso) ppm. 31P{1H} NMR
2
periment, a freshly distilled BF3·OEt2 solution (2 equiv.) was added
dropwise at –78 °C to a CH2Cl2 solution of ylide 2a,c (1 mmol).
The mixture was warmed to room temperature and the volatile
materials were removed under vacuum. The crude product was dis-
solved in CH2Cl2 and precipitated by vigorous stirring with Et2O.
The resulting powder was washed with Et2O and dried under vac-
uum. Compounds 3a,c were recrystallised from a CH2Cl2/Et2O
mixture at –30 °C.
(C6D6): δ = 38 and 15 (d, JP,P = 150 Hz).
6: Yield: 0.54 g (98%). 1H NMR (C6D6): δ = 0.88 (d, 3JH,H = 8 Hz,
3
3
6 H, CHCH3), 0.95 (d, JH,H = 8 Hz, 6 H, CHCH3), 1.03 (d, JH,H
3
= 5 Hz, 6 H, CHCH3), 1.08 (d, JH,H = 5 Hz, 6 H, CHCH3), 2.15
(s, 3 H, CaroCH3), 2.16 (s, 6 H, CaroCH3), 2.48 (dd, JP,H = 9 and
7 Hz, 1 H, PCHP), 3.4 (d sept, JH,H = 7, JP,H = 14 Hz, 2 H, NCH),
3.7 (m, 2 H, JCH), 6.8 (s, 2 H, Haro), 7.1 (m, 6 H, Haro), 7.8 (m, 4
H, Haro) ppm. 13C{1H} NMR (C6D6): δ = 21.6 (dd, JP,C = 151 and
47 Hz, PCP), 23.6 (s, CHCH3), 24 (m, CH3), 46.9 (d, JP,C = 5 Hz,
NCH), 47.0 (d, JP,C = 5 Hz, NCH), 47.4 (d, JP,C = 10 Hz, NCH),
3a: Yield: 0.37 g (72%), yellow crystals, m.p. 168 –170 °C. 1H NMR
3
(CDCl3): δ = 1.24 (d, JH,H = 7 Hz, 12 H, NCCH3), 3.6 (d sept,
3
2
2
2JP,H = 16, JH,H = 7 Hz, 4 H, NCH), 6.75 (dd, JP,H = 12, JP,H
=
127.3 (s, CaroH), 127.4 (s, CaroH), 130.7 (s, CaroH), 132.8 (d, JP,C =
8 Hz, CaroH), 129.9 (d, JP,C Ͻ 1 Hz, CaroH), 134 (m, Caro), 136.0
4 Hz, 1 H, PCHP), 7.80 (m, 10 H, Haro) ppm. 13C{1H} NMR
(CDCl3): δ = 23.4 (broad, NCHCH3), 49.2 (d, 2JC,P = 6 Hz, NCH), (s, Caro), 141.3 (d, JP,C = 18 Hz, Caro) ppm. 31P{1H} NMR (C6D6):
95.5 (dd, 1JC,P = 105 and 56 Hz, PCP), 124.5 (dd, 1JC,P = 106, 3JC,P
δ = 39 and 18 (d, JP,P = 202 Hz).
2
2
3
= 5 Hz, Ci), 129.8 (dd, JC,P = 13 Hz, CHaro), 133.2 (d, JC,P
=
1
3
7: Yield: 0.41 g (95%) ppm. H NMR (C6D6): δ = 1.06 (d, JH,H
=
10 Hz, CHaro), 134.2 (s, CHp) ppm. 31P{1H} NMR (CDCl3): δ =
3
7 Hz, 6 H, CHCH3), 1.11 (d, JH,H = 6 Hz, 6 H, CHCH3), 1.13 (d,
2
308 and 40 (d, JP,P = 133 Hz).
3JH,H = 7 Hz, 6 H, CHCH3), 1.19 (d, JH,H = 7 Hz, 6 H, CHCH3),
3
3b: Yield: 0.51 g (95%), colourless powder, m.p. 176–178 °C. 1H
NMR (CDCl3): δ = 1.28 (d, 3JH,H = 7 Hz, 12 H, NCCH3), 1.40 (d,
2.00 (pseudo t, JP,H = 9 Hz, 1 H, PCHP), 3.4 (m, 4 H, NCH), 6,01
(ddd, JP,H = 220, JH,H = 8 Hz, 1 H, PH), 7.1 (m, 6 H, Haro), 7.7
2
3
3JH,H = 7 Hz, 6 H, NCCH3), 3.7 (d sept, JP,H = 16, JH,H = 7 Hz,
(m, 4 H, Haro) ppm. 13C{1H} NMR(C6D6): δ = 20.0 (dd, JP,C
=
4 H, NCH), 3.9 (broad, 4 H, NCH), 6.22 (dd, 2JP,H = 12 and 6 Hz,
126 and 16 Hz, PCP), 23.3 (s, CHCH3), 23.4 (s, CHCH3), 24.0 (s,
1 H, PCHP), 7.7 (m, 10 H, Haro) ppm. 13C{1H} NMR (CDCl3): δ CHCH3), 24.1 (s, CHCH3), 24.2 (s, CHCH3), 24.3 (s, CHCH3),
= 23.6 (d, 2JC,P = 3 Hz, NCCH3), 24.2 (broad, NCHCH3), 48.7 (d, 47.7 (d, JP,C = 5 Hz, NCH), 49.2 (d, JP,C = 8 Hz, NCH), 128.4 (s,
2JC,P = 5 Hz, NCH), 50.0 (broad, NCH), 99.8 (dd, 1JC,P = 119 and CaroH), 130.7 (s, CaroH), 132.8 (d, JP,C = 8 Hz, CaroH), 133.1 (dd,
1
3
50 Hz, PCP), 124.2 (dd, JC,P = 125, JC,P = 3 Hz, Ci), 129.3 (d, JP,C = 7 and 2 Hz, CaroH), 134.5 (dd, JP,C = 53 and 4 Hz, Ci) ppm.
3
2
2JC,P = 14 Hz, CHaro), 133.3 (d, JC,P = 6 Hz, CHaro), 134.4 (s,
31P{1H} NMR (C6D6): δ = 38 and –18 (d, JP,P = 160 Hz).
2
CHaro) ppm. 31P{1H} NMR (CDCl3): δ = 303 and 53 (d, JP,P
=
Reaction of LiMHDS with Phosphoniophosphaalkenes 3a,c: THF
(6 mL) was added to a solid mixture of phosphaalkene 3a,c
(1.9 mmol) and LiHMDS·Et2O (1.9 mmol), at –90 °C, and the
solution was warmed to room temperature. The solvent was re-
moved under vacuum and the crude product was immediately ex-
tracted with pentane.
125 Hz).
3c: Spectroscopic data were identical to those reported in the litera-
ture.[5]
General Procedure for the Synthesis of Adducts 4–7: In a typical
experiment, one equivalent of organolithium derivative (4: MeLi;
5: nBuLi; 6: MesLi; 7: tBuLi;) in solution in hexanes was added to
a THF solution of the phosphaalkene 3a (0.43 g, 1 mmol) at
–78 °C. The mixture was warmed to room temperature and the
8a: Yield: 0.45 g (55%), yellow needles from pentane/THF at 4 °C,
1
3
m.p. 64–66 °C. H NMR (C6D6): δ = 1.23 (d, JH,H = 7 Hz, 12 H,
3
NCCH3), 1.33 (br. d, JH,H = 7 Hz, 12 H, NCCH3), 3.5 (d sept,
2622
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C-Phosphoniophosphaalkenes as Precursors of 1σ4,3σ2-Diphosphaallene
FULL PAPER
3
2JP,H = 16, JH,H = 7 Hz, 4 H, NCH), 7.0 (m, 6 H, Haro), 7.9 (m, H, CHaro) ppm. 13C{1H} NMR (C6D6): δ = 24.1 (s, CH3), 24.8 (s,
4 H, Haro) ppm. 13C{1H} NMR (C6D6): δ = 23.3 (s, NCHCH3), CH3), 47.6 (d, JP,C = 5 Hz, NCH), 94.0 (dd, JP,C = 137 and 23 Hz,
47.6 (d, 2JC,P = 4 Hz, NCH), 128.1 (s, CHp), 130.0 (d, 3JC,P = 3 Hz,
CHm), 132.1 (dd, JC,P = 12, JC,P Ͻ 1 Hz, CHo), 135.0 (dd, JC,P
PCP), 130.1 (s, HCaro), 130.8 (s, HCaro), 133.0 (dd, JP,C = 108 and
75 Hz, Ci), 134.8 (d, JP,C = 50 Hz, HCaro), 134.9 (d, JP,C = 60 Hz,
2
4
1
3
1
2
= 93, JC,P = 3 Hz, Ci), 166.5 (dd, JC,P = 37 and 14 Hz, PCP) HCaro) ppm. 31P{1H} NMR (C6D6): δ = 30.0 (dd, JP,P = 157 and
ppm. 31P{1H} NMR (C6D6): δ = 313 and 41 (d, JP,P = 190 Hz)
148 Hz), 5.9 (dd, JP,P = 157 and 148 Hz) ppm.
2
2
ppm. C54H84N4OP4: calcd. C 69.80, H 9.11, N 6.03; found C 69.75,
H 9.04, N 6.10.
Crystallographic Data for 8a: C54H84N4OP4, M = 929.13, mono-
clinic, P21/c, a = 23.882(2), b = 7.920(1), c = 28.678(2) Å, β =
94.061(1)°, V = 5410.6(6) Å3, Z = 4, T = 173(2) K. 22828 Reflec-
tions (7276 independent, Rint = 0.0698) were collected. Largest elec-
tron density residue: 0.305 eÅ–3, R1 [for I Ͼ 2σ(I)] = 0.0641 and
9a: Yield: 0.28 g (25%). 1H NMR (C6D6): δ = 0.22 (s, 9 H, SiCH3),
3
0.41 (s, 9 H, SiCH3), 1.03 (d, JH,H = 6 Hz, 12 H, NCCH3), 1.07
3
3
(d, JH,H = 6 Hz, 12 H, NCCH3), 1.13 (d, JH,H = 6 Hz, 12 H,
NCCH3), 2.39 (dd, 2JP,H = 12 and 2 Hz, 1 H, PCHP), 3.73 (d sept,
2JP,H = 7, 3JH,H = 6 Hz, 4 H, NCH), 3.80 (d sept, 2JP,H = 14, 3JH,H
= 6 Hz, 2 H, NCH),7.2 (m, 6 H, Haro), 7.6 (m, 4 H, Haro) ppm.
13C{1H} NMR (C6D6): δ = 4.22 (s, SiCH3), 4.48 (s, SiCH3), 23.2
wR2 = 0.1519 (all data) with R1 = Σ||Fo| – |Fc||/Σ|Fo| and wR2
=
[Σw(Fo – Fc ) /Σw(Fo2)2]0.5
.
2
2 2
Crystallographic Data for 8b: C25H47N3P2, M = 451.60, triclinic,
¯
P1, a = 8.158(1), b = 12.372(2), c = 15.531(2) Å, α = 112.822(2)°,
2
(s, NCHCH3), 23.8 (s, NCHCH3), 47.0 (d, JC,P = 5 Hz, NCH),
β = 95.436(2)°, γ = 102.054(2)°, V = 1385.8(4) Å3, Z = 2, T =
193(2) K. 9920 Reflections (5404 independent, Rint = 0.0336) were
collected. Largest electron density residue: 0.377 eÅ–3, R1 [for I Ͼ
2σ(I)] = 0.0457 and wR2 = 0.1180 (all data).
2
47.8 (d, JC,P = 4 Hz, NCH), 127.8 (d, JC,P = 6 Hz, CHaro), 129.8
(dd, JC,P = 15 and 3 Hz, CHaro), 130.0 (d, JC,P = 2 Hz, CHaro
)
2
ppm. 31P{1H} NMR (C6D6): δ = 80 and 40 (d, JP,P = 200 Hz)
ppm.
All data for both structures were collected at low temperatures
using an oil-coated shock-cooled crystal on a Bruker-AXS CCD
1000 diffractometer with Mo-Kα radiation (λ = 0.71073 Å). The
structure was solved by direct methods (SHELXS-97)[11] and all
non hydrogen atoms were refined anisotropically using the least-
squares method on F2.[12]
8b: Yield: 0.14 g (17%), yellow needles from pentane/THF, m.p.
3
80–82°C. 1H NMR (C6D6): δ = 1.20 (d, JH,H = 7 Hz, 24 H,
3
NCCH3), 1.35 (d, JH,H = 7 Hz, 12 H, NCCH3), 4.0 (m, 6 H,
NCH), 7.1 (m, 6 H, Haro), 8.0 (m, 4 H, Haro) ppm. 13C{1H} NMR
(C6D6): δ = 23.9 (s, NCHCH3), 24.5 (s, NCHCH3), 45.5 (broad,
2
NCH), 46.8 (d, JC,P = 5 Hz, NCH), 127.6 (s, CHaro), 129.5 (dd,
2
4
3JC,P = 8 and 2 Hz, CHaro), 132.4 (dd, JC,P = 10, JC,P Ͻ 1 Hz,
CCDC-259732 (for 8a) and -259733 (for 8b) contain the supple-
mentary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
CHaro), 136.0 (d, 1JC,P = 125 Hz, Ci), 162.4 (d, 1JC,P = 70 Hz, PCP)
ppm. 31P{1H} NMR (C6D6): δ = 295 and 59 (d, JP,P = 166 Hz)
2
ppm. C25H47N3P2: calcd. C 66.49, H 10.49, N 9.30; found C 66.55,
H 10.53, N 9.27.
9b: Yield: 0.46 g (40%), yellow needles from pentane/THF, m.p.
121–122 °C. H NMR (C6D6): δ = 0.53 (s, 9 H, SiCH3), 0.55 (s, 9
Acknowledgments
1
H, SiCH3), 1.06 (d, 3JH,H = 8 Hz, 12 H, NCCH3), 1.15 (d, 3JH,H
=
Thanks are due to the ACS/PRF (38192-AC4) and the CNRS for
financial support of this work.
3
8 Hz, 12 H, NCCH3), 1.24 (d, JH,H = 7 Hz, 6 H, NCCH3), 1.26
3
2
(d, JH,H = 7 Hz, 6 H, NCCH3), 1.79 (dd, JP,H = 9 and 2 Hz, 1
H, PCHP), 3.7–4.2 (m, 6 H, NCH), 7.2 (m, 3 H, Haro), 8.1 (m, 2
[1] a) F. Ramirez, N. B. Desai, B. Hansen, N. McKelvie, J. Am.
Chem. Soc. 1961, 83, 3539; b) O. I. Kolodiazhnyi, in Phospho-
rus Ylides (Ed.: O. I. Kolodiazhnyi), Wiley-VCH, Weinheim,
1999; c) A. W. Johnson, W. C. Kaska, K. A. O. Starzewski,
D. A. Dixon, in Ylides and Imines of Phosphorus (Ed.: A. W.
Johnson), Wiley-Interscience, New York, 1993; d) H. J. Best-
mann, R. Zimmermann, in Methoden Org. Chem. (Houben-
Weyl), 4th ed., vol. E1, 1982, pp.752–758.
[2] See for example: a) J. Escudié, H. Ranaivonjatovo, L. Rigon,
Chem. Rev. 2000, 100, 3639; b) M. Yoshifuji, K. Toyota, N.
Inamoto, J. Chem. Soc., Chem. Commun. 1984, 689; c) H. H.
Karsh, H. U. Reisacher, G. Müller, Angew. Chem. Int. Ed. Engl.
1984, 23, 618; d) M. Gouygou, M. Koenig, J. Escudié, C. Co-
uret, Heteroatom Chem. 1991, 2, 221.
[3] H. P. Schrödel, G. Jochem, A. Schmidpeter, H. Nöth, Angew.
Chem. Int. Ed. Engl. 1995, 34, 1853.
[4] T. Kato, H. Gornitzka, A. Baceiredo, G. Bertrand, Angew.
Chem. Int. Ed. 2000, 39, 3319.
[5] H. Grützmacher, H. Pritzkow, Angew. Chem. Int. Ed. Engl.
1989, 28, 740.
H, Haro) ppm. 31P{1H} NMR (C6D6): δ = 83 and 54 (2JP,P
=
170 Hz) ppm.
BF3 Complex 11: One equivalent of BF3·OEt2 was added to a THF
solution (5 mL) of cumulene 8a (0.8 g, 2 mmol) at room tempera-
ture. After stirring the mixture for 1 h, the solvent was removed
under vacuum and the crude product was extracted with Et2O. The
solvent was removed under vacuum, and complex 11 was obtained
as a yellow powder (0.6 g, 62%). M.p. 89–91 °C. 1H NMR
3
(CDCl3): δ = 1.14 (br. d, JH,H = 7 Hz, 12 H, NCCH3), 1.17 (d,
3JH,H = 7 Hz, 12 H, NCCH3), 3.6 (br. m, 4 H, NCH), 4.0 (d sept,
3
2JP,H = 14, JH,H = 7 Hz, 4 H, NCH), 7.0 (m, 6 H, Haro), 7.9 (m,
4 H, Haro) ppm. 13C{1H} NMR (CDCl3): δ = 23.2 (s, NCHCH3),
2
49 (d, JC,P = 6 Hz, NCH), 128.1 (d, JC,P = 20 Hz, CHaro), 129.0
1
3
(dd, JC,P = 115, JC,P = 8 Hz, Ci), 131.9 (s, CHaro), 135.0 (d, JC,P
= 10 Hz, CHaro) ppm. 19F NMR (CDCl3): δ = –49 (q, JB,F
=
1
40 Hz) ppm. 31P{1H} NMR (CDCl3): δ = 326 (d, JP,P = 195 Hz),
2
2
3
57 (dq, JP,P = 195, JP,F = 8 Hz) ppm.
[6] a) E. J. Corey, S. M. Albonico, U. Koelliker, T. K. Schaaf,
R. K. Varmer, J. Am. Chem. Soc. 1971, 93, 1491; b) M. Soleil-
havoup, A. Baceiredo, G. Bertrand, Angew. Chem. Int. Ed.
Engl. 1993, 32, 1167.
[7] N. Kuhn, G. Henkel, T. Kratz, J. Kreutzberg, R. Boese, A. H.
Maulitz, Chem. Ber. 1993, 126, 2041.
[8] L. N. Markovskii, V. D. Romanenko, A. V. Ruban, Chemistry
of Acyclic Compounds of Two-Coordinate Phosphorus, Naukova
Dumka, Kiev, 1988.
Heterocycle 15: Freshly distilled Me3SiN3 (13 μL, 0.1 mmol) was
added to a THF solution (1 mL) of cumulene 8a (80 mg, 0.2 mmol)
at –78 °C. After warming to room temperature, the volatile materi-
als were removed under vacuum to give compound 15 as a deep-
red oil (110 mg (80%). 1H NMR (C6D6): δ = 1.07 (d, 3JH,H = 7 Hz,
3
12 H, NCCH3), 1.30 (d, JH,H = 7 Hz, 12 H, NCCH3), 1.60 (d,
3JH,H = 7 Hz, 12 H, NCCH3), 3.8 (d sept, 2JP,H = 16, 3JH,H = 7 Hz,
4 H, NCH), 7.0 (m, 6 H, CHaro), 8.0 (m, 4 H, CHaro), 8.4 (m, 4
Eur. J. Inorg. Chem. 2005, 2619–2624
www.eurjic.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2623

D. Martin, H. Gornitzka, A. Baceiredo, G. Bertrand
FULL PAPER
[9] J. M. Sotiropoulos, A. Baceiredo, G. Bertrand, J. Am. Chem.
Soc. 1987, 109, 4711.
[10] H.-P. Schroedel, A. Schmidpeter, Chem. Ber. 1997, 130, 1519.
[11] G. M. Sheldrick, Acta Crystallogr. Sect. A 1990, 46, 467–473.
[12] SHELXL-97, Program for Crystal Structure Refinement, G. M.
Sheldrick, University of Göttingen, Germany, 1997.
Received: January 6, 2005
Published Online: May 27, 2005
2624
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2005, 2619–2624