A practical synthesis of the first P-phosphinoylmethyl-λ5-phosphazenes

Article abstract of DOI:10.1055/s-2000-8729

The new N-aryl-P,P-diphenyl-P-(diphenylphosphinoyl)methyl-λ⁵-phosphazenes 2 have been prepared by three different approaches starting from the commercially available bis(diphenylphosphino)methane. Either oxidation of the mono-λ⁵-phosphazenes 3 or imination of the monoxide 4 yielded compounds 2 in moderate yields. The third method involved deprotonation of the easily accesible aminophosphonium salts 5.

Full text of DOI:10.1055/s-2000-8729

PAPER
2085
A Practical Synthesis of the First P-Phosphinoylmethyl-l5-phosphazenes
M. Alajarín,*a C. López-Leonardo,a P. Llamas-Lorente,a D. Bautistab
a Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain
Fax +34(968)364149; E-mail: alajarin@um.es
b Servicio Universitario de Instrumentación Científica, Edificio SACE, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia,
Spain
Received 31 July 2000; revised 19 August 2000
Dedicated to Professor J. Elguero
search revealed that compounds 1, of the type dppmSN,
Abstract: The new N-aryl-P,P-diphenyl-P-(diphenylphosphi-
are the only reported examples of this class.7 Much to our
noyl)methyl-l5-phosphazenes 2 have been prepared by three differ-
surprise, dppmON compounds such as the N-aryl deriva-
tives 2, are unknown species (Figure 1). Herein we report
ent approaches starting from the commercially available
bis(diphenylphosphino)methane. Either oxidation of the mono-l5-
phosphazenes 3 or imination of the monoxide 4 yielded compounds the first successful preparation of N-aryl-P,P-diphenyl-P-
(diphenylphosphinoyl)methyl-l5-phosphazenes
2
by
2 in moderate yields. The third method involved deprotonation of
the easily accesible aminophosphonium salts 5.
three different approaches, starting from the commercial-
ly available dppm.
Key words: azides, oxidations, phosphazenes, phosphorus, ylides
The synthesis of heterodifunctional ligands for the devel-
opment of homogeneus catalysis applications1 is often
considered to be the major barrier to the progress of this
valuable technique. The versatility of methylene-bridged
phosphane derivatives for coordinating to early as well as
late transition metals have caused an increasing academic
Ph2P
N
PPh2
S
Ph2P
N
PPh2
O
Ar
Ar
1
2
Ar = 4-CH3C6H4, 4-CH3OC6H4
Figure 1 Structures of compounds 1 and 2
interest
lately.1d
Complexes
of
the
type
RhCl(CO)(PPh2CH2CH2PPh2=O), containing a fluxional
ligand,2
and
related
complexes
with
It has been reported7 that the Staudinger reaction8 of dppm
with one equivalent amount of aryl azides yielded mono-
l5-phosphazenes 3, accompained by significant amounts
of CH2(PPh2=NAr)2 (up to 19%). In our hands, a slight
modification of the reaction conditions employed therein,
from toluene/60 ∞C to acetonitrile/25 ∞C, gave the N-aryl-
P,P-diphenyl-P-(diphenylphosphino)methyl-l5-phosp-
hazenes 3 in yields over 92% (determined by 1H NMR),
which were used without purification in the next step. Fur-
ther oxidation of 3 with H2O2 in acetone provided com-
pounds 2 in moderate yields (46-69%, two steps)
(Method A, Scheme, Table 1).
P,O
R2P(CH2)nPR1 =NR2 ligands,3 have proven to be active
2
catalysts in the carbonylation of methanol. Additional ad-
vantages could be provided by making modifications to
the reactivity of the ligand by systematic alteration of its
substituents, a flexibility that could strongly influence the
design of catalytic complexes with appropriate chemical
selectivity and stereoselectivity.
In this context, bis(chalcogenophosphoranyl)methane
ligands CH2(PPh2=X)2 (X = O, S, Se),4 usually abbreviat-
ed as dppmX2, and bis(iminophosphoranyl)methane
ligands CH2(PPh2=NR)2 (R = SiMe3, aryl)1d,5 are known
species of growing interest in organometallic chemistry.
Whereas the synthesis of symmetrically disubstituted het-
erodifunctional bis(diphenylphosphino)methane deriva-
tives CH2(PPh2=X)2 (dppmX2) from the parent
bis(diphenylphosphino)methane (dppm) is straightfor-
A second approach to the access of compounds 2 consist-
ed of the sequential oxidation-imination of dppm. Diphe-
nyl[(diphenylphosphino)methyl]phosphane oxide (4) can
be easily prepared in 56% yield by selective mono-oxida-
tion of dppm in a two-step reaction (treatment with benzyl
bromide and further hydrolysis), following a reported pro-
cedure.6b Staudinger reaction of compounds 4 with aryl
azides afforded the corresponding l5-phosphazenes 2
(71-83% yield, Method B, Scheme, Table 1).
ward,
the
formation
of
mono-derivatives
Ph2PCH2(PPh2=X) (X = O, S, Se, NSiMe3 or N-aryl)
(dppmX) needs careful control of the reaction condi-
tions.4b,6
With regard to unsymmetrically disubstituted bis(phos-
phane) derivatives of the type CH2(PPh2=X)(PPh2=Y)
(dppmXY) the three cases where X and Y are chalcogen
atoms (X, Y = O, S and Se) have been reported,4c whereas
the combination of the iminophosphoranyl and chalco-
genophosphoranyl functions (X = NR; Y = O, S, Se) on
these compounds is rare. Thus, an exhaustive literature
In attempts to improve the yield of the oxidation step 3 Æ
2, we carried out the reaction of 3 with bromine or iodine
in wet benzene. In fact, this reaction resulted in the oxida-
tion of the P(III) atom of 3, but also in the protonation of
the iminophosphoranyl unit giving rise to the aminophos-
phonium salts 5 (X = Br, I) in 38-64% yield. These
Synthesis 2000, No. 14, 2085–2091 ISSN 0039-7881 © Thieme Stuttgart · New York

2086
M. Alajarín et al.
PAPER
Table 2 Aminophosphonium Salts 5 and their Deprotonation to 2
a)
Ph2P
N
PPh2
Yield (%)a mp (°C)
Ph2P
PPh2
Product
5a
Ar
X
Br
Br
Br
Br
Br
Br
I
(92-95%)
e)
Ar
Ph
55
44
40
64
39
42
38
55
53
56
60
64
58
279-281
146-148
237-239
228-230
283-285
248-250
170-172
3
(38-64%)
5b
5c
4-MeC6H4
4-MeOC6H4
2,6-(i-Pr)2C6H3
4-ClC6H4
4-BrC6H4
4-MeOC6H4
Ph
Ph2P
NH
PPh2
Method A
b)
c)
(56%)
(46-69%)
O
X
Ar
5
Method C
f)
5d
5e
Method B
d)
Ph2P
PPh2
O
Ph2P
PPh2
O
(53-64%)
N
(71-83%)
Ar
5f
2
4
5g
Reagents and conditions: a) Ar-N3/MeCN, 25 ∞C, 2 h; b) H2O2/ace-
tone, 25 ∞C, 3-4 h; c) i. PhCH2Br/toluene, 80 ∞C, 5 h; ii. 1 N KOH,
25 ∞C, 3 h; d) Ar-N3/CH2Cl2/Et2O, 25 ∞C, 7 h; e) Br2 or I2/benzene,
0 Æ 25 ∞C, then Et3N/benzene; f) NaNH2/liq. NH3, -33 ∞C
b
2a
-
-
b
2b
2c
4-MeC6H4
4-MeOC6H4
2,6-(i-Pr)2C6H3
4-ClC6H4
4-BrC6H4
-
-
Scheme
b
-
-
b
2d
2e
-
-
species could be easily deprotonated by treatment
with sodium amide in liquid ammonia to provide the
N-aryl-P,P-diphenyl-P-(diphenylphosphinoyl)methyl-l5-
phosphazenes 2 in moderate yields (53-64%) (Method C,
Scheme, Table 2).
b
-
-
b
2f
-
-
a Yield of pure product.
b See Table 2.
Analytical and spectral data of 2 were consistent with
their presumed structures (Tables 3 and 4). It is noticeable
that in their 1H NMR spectra the methylene hydrogens ap-
pear as a triplet in most of the cases, due to the virtual
equivalence of their two 2JHP coupling constants. Two dif-
ferent types of Ph2P groups are neatly apparent in their 13C
NMR spectra. The 31P NMR spectra consist of two
well-separated doublets, centered near d = 23 ppm and
-1 ppm, which are assigned to the phosphane oxide and
phosphazene functions respectively, the P=N center lying
typically upfield from the P=O one.9
compounds 2. The X-ray crystallographic analysis of
compound 2a is shown in Figure 2.12
It could be envisaged that the polarity of the P=O and P=N
bonds of compounds 2 would render their methylene hy-
drogens prone to tautomerization, similarly to what has
been reported for bis(methylenephosphoranyl)methanes10
and (S=Ph2P)2CH(PPh2=N-tolyl-4).11 The above dis-
cussed NMR data unequivocally discard the existence of
this kind of tautomeric equilibrium in CDCl3 solutions of
Table 1 Compounds 2 Prepared from 3 or 4
Product Ar
Yield of 2 (%)a
mp (°C)
from 3
from 4
80
Figure 2 X-ray structure of l5-phosphazene 2a
2a
2b
2c
2d
2e
2f
Ph
53
46
51
54
56
69
190-192
170-172
90-92
The conformation of 2a in the solid state, which is charac-
terized by a N-P(1)···P(2)-O dihedral angle of 86.10∞, is
similar to the ones shown by CH2(PPh2=N-tolyl-4)213 and
CH3CH(PPh2=N-tolyl-4)2,14 (dihedral angles of 86.35 and
99.17∞, respectively) and markedly different to that of the
sulfur analog 1 (Ar = 4-CH3C6H4) with an arrangement of
the P=N and P=S groups nearly antiperiplanar (dihedral
angle of 176.11∞).7
4-MeC6H4
4-MeOC6H4
2,6-(i-Pr)2C6H3
4-ClC6H4
4-BrC6H4
71
79
83
168-170
194-196
198−200
-
-
a Yield of pure product.
Synthesis 2000, No. 14, 2085–2091 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
A Practical Synthesis of the First P-Phosphinoylmethyl-l5-phosphazenes
2087
Table 3 1H NMR and 31P NMR Data of λ5-Phosphazenes 2
Prod-
uct
1H NMR (300 MHz, CDCl3/TMS)
31P NMR (121.4 MHz, CDCl3/H3PO4)
d, J (Hz)
d, J (Hz)
CH2
Ar
Ph
P=N
P=O
2a
2b
3.62 (t, 2JHP
13.9)
=
=
6.62–6.67 (m, 3 H, H-2 + H-4),
6.99–7.04 (m, 2 H, H-3)
7.25–7.43 (m, 12 H), 7.55–7.63
(m, 4 H), 7.8–7.87 (m, 4 H)
–0.1 (d, 2JPP
14.4)
=
=
24.5 (d, 2JPP
14.4)
=
=
3.64 (t, 2JHP
13.9)
2.21 (s, 3 H, CH3), 6.57 (d, 2 H,
7.27–7.43 (m, 12 H), 7.57–7.62
(m, 4 H), 7.64–7.89 (m, 4 H)
–0.1 (d, 2JPP
13.5)
24.7 (d, 2JPP
13.5)
3JHH = 8.1), 6.85 (d, 2 H, 3JHH
=
8.1)
2c
3.60 (t, 2JHP
13.9)
=
3.70 (s, 3 H, OCH3), 6.56 (d, 2 H,
7.26–7.44 (m, 12 H), 7.55–7.62
(m, 4 H), 7.79–7.86 (m, 4 H)
–1.0 (d, 2JPP
13.9)
=
24.6 (d, 2JPP
13.9)
=
=
3JHH = 9.1), 6.62 (d, 2 H, 3JHH
=
9.1)
2d
3.59 (dd, 2JHP
15.6, 12.4)
=
0.94 (d, 12 H, 3JHH = 6.8, CH3),
3.27 (m, 2 H, CH), 6.81 (t, 1 H,
3JHH = 7.6, H-4), 6.96 (d, 2 H,
3JHH = 7.6, H-3)
7.24–7.39 (m, 12 H), 7.47–7.54
(m, 4 H), 7.73–7.8 (m, 4 H)
–11.0 (d, 2JPP
13.7)
=
22.4 (d, 2JPP
13.7)
2e
2f
3.59 (t, 2JHP
13.9)
=
=
6.48 (d, 3JHH = 8.7), 6.91 (d,
3JHH = 8.7)
7.3–7.45 (m, 12 H), 7.56–7.63
(m, 4 H), 7.76–7.84 (m, 4 H)
0.7 (d, 2JPP = 13.7) 24.3 (d, 2JPP
=
=
13.7)
3.59 (t, 2JHP
13.9)
6.44 (d, 3JHH = 8.8), 7.05 (d,
3JHH = 8.8)
7.31–7.45 (m, 12 H), 7.56–7.63
(m, 4 H), 7.76–7.84 (m, 4 H)
1.0 (d, 2JPP = 12.8) 24.3 (d, 2JPP
12.8)
N-Aryl-P,P-diphenyl-P-(diphenylphosphinoyl)methyl-l5-phos-
phazenes 2; General Procedures
Compounds 2 are indefinitely stable in the solid state but
1
slowly decompose in CDCl3 solution. H and 31P NMR
Method A: A solution of the appropriate aryl azide (0.78 mmol) in
anhyd MeCN (20 mL) was added dropwise, under N2, to a suspen-
sion of bis(diphenylphosphino)methane (300 mg, 0.78 mmol) in an-
hyd MeCN (30 mL). At the end of the reaction (ca. 3 h, IR
monitoring) the solvent was evaporated in vacuo and the crude
monitoring of CDCl3 solutions of compounds 2 showed,
after some hours, the appearance of new signals which
could be attributed to at least two different emerging spe-
cies and the simultaneous decrease of the signals corre-
sponding to 2. This decomposition process is now under
investigation in our laboratory.
1
product 3 (yields over 92%, determined by H NMR), which was
used in the next step without purification, was dissolved in acetone
(15 mL). A solution of H2O2 (30%, 88 mg, 0.78 mmol) was then
added and the mixture was stirred for 4 h at r.t. The solvent was re-
moved under reduced pressure and the residue was taken up in Et2O
(10 mL) at 0 ∞C to give 2 as a yellow solid that was purified by crys-
tallization from CH2Cl2/Et2O.
In summary, we have synthesized the new (iminophos-
phoranyl)(phosphinoyl)methanes 2 by three different ap-
proaches starting from the commercially available
bis(diphenylphosphino)methane. From the synthetic point
of view the most suitable method is the imination-oxida-
tion sequence (Method A). This route provided the best
overall yields and is shorter (two steps in a one-pot reac-
tion) than the alternative oxidation-imination (Method B),
which consists of three steps from the same starting mate-
rial, similar to the third procedure which involves the in-
termediacy of salts 5 (Method C).
Method B: A solution of the corresponding aryl azide (0.5 mmol) in
anhyd Et2O (5 mL) was added to a solution of 4 (200 mg, 0.5 mmol)
in a mixture of anhyd CH2Cl2 (10 mL) and anhyd Et2O (15 mL). The
mixture was stirred for 7 h and the solvent was evaporated in vacuo.
After treatment of the residue with Et2O (10 mL) at 0 ∞C, the yellow
solid was filtered off, dried and crystallized from CH2Cl2/Et2O to
give 2.
2a
IR (nujol): n = 1593, 1487, 1438, 1348, 1171, 1113, 810, 787, 760,
728, 696 cm-1.
All reactions which are sensitive to moisture were carried out under
N2. All solvents were purified by distillation and dried, if necesary,
prior to use. Aryl azides15 and P,P-diphenyl-P-[(diphenylphosphi-
no)methyl]phosphane oxide (4)6b were prepared by published meth-
ods. Some products were purified by flash column chromatography
on silica gel (40-63 mm). Melting points were determined on a Kof-
ler hot-plate melting point apparatus and are uncorrected. Mi-
croanalyses were performed with a Pelkin-Elmer 240C instrument.
NMR spectra were recorded on a Bruker AC-200 and Varian UNI-
TY-300 spectrometers. Chemical shifts refer to signals of TMS in
MS (EI, 70 eV): m/z (%) = 492 ([M]+ + 1, 62), 491 ([M]+, 100), 400
(50), 290 (33), 276 (56), 215 (22), 201 (73), 199 (96), 185 (34), 183
(70), 121 (89), 77 (56).
Anal. calcd for C31H27NOP2 (491.5): C, 75.75; H, 5.54; N, 2.85;
Found C, 75.59; H, 5.49; N 2.89.
Crystal Structure Analysis of 2a
Crystal Data: C31H27NOP2, Mr = 491.48, triclinic, space group P-1,
a = 3.5800(10) Å, b = 9.5480(10) Å, c = 16.3750(10) Å,
the case of 1H and 13C spectra and to 85% H3PO4 in the case of 31
P
a = 80.610(10)∞,
b = 81.830(10)∞,
g = 75.270(10)∞.
spectra. MS were recorded on a VG-Autospec spectrometer at
70 eV ionization voltage. IR spectra were measured on a Nicolet
Impact 400 spectrophotometer.
Volume = 1272.9(2) Å3, Z = 2, Calculated density = 1.282 Mg/m3.
Synthesis 2000, No. 14, 2085–2091 ISSN 0039-7881 © Thieme Stuttgart · New York

2088
M. Alajarín et al.
PAPER
Table 4 13C NMR Data of l5-Phosphazenes 2
Prod-
uct
13C NMR (75 MHz, CDCl3/TMS), d
Cm Cp
128.4 (d, 3JCP 131.6 (d,
CH2
Ci
Co
C-1
C-2
C-3
C-4
2a
32.1 (dd, 129.8 (d, 1JCP(N)
=
130.7 (d, 2JCP(O)
150.6 (d,
123.2 (d,
128.8
117.5
1JCP
58.0,
56.3)
=
98.6), 133.0 (dd,
= 9.3), 132.3 (d, = 12.8),
4JCP = 2.1),
128.5 (d, 3JCP 131.8 (d,
= 12.2)
4JCP = 2.3)
2JCP = 3.0) 3JCP
=
1JCP(O) = 130.7,
3JCP(N) = 1.8)
2JCP(N) = 9.9)
19.7)
2ba
2cb
2dc
2e
32.1 (dd, 130.0 (d, 1JCP(N)
=
=
130.7 (d, 2JCP(O)
128.4 (d, 3JCP 131.6 (d,
4JCP = 2.6),
128.5 (d, 3JCP 131.8 (d,
= 12.2)
4JCP = 2.6)
147.8 (d,
123.0 (d,
129.5
114.4
122.8
128.5
131.4
126.6
152.0
1JCP
=
58.3,
55.9)
98.7), 133.0 (d,
= 9.9), 132.4 (d, = 12.4),
2JCP = 3.1) 3JCP
=
1JCP(O) = 129.2)
2JCP(N) = 10.4)
19.3)
32.0 (dd, 130.2 (d, 1JCP(N)
130.7 (d, 2JCP(O)
128.4 (d, 3JCP 131.6 (d,
4JCP = 2.9),
128.5 (d, 3JCP 131.8 (d,
= 12.2)
4JCP = 2.9)
143.9 (d,
123.6 (d,
1JCP
58.3,
55.9)
=
98.6), 132.9 (d,
= 9.9), 132.4 (d, = 12.2),
2JCP = 3.1) 3JCP
=
1JCP(O) = 129.3)
2JCP(N) = 10.4)
18.0)
33.4 (dd, 132.4 (d, 1JCP
=
130.3 (d, 2JCP(O)
128.1 (d, 3JCP 131.4 (d,
4JCP = 2.3),
128.6 (d, 3JCP 131.5 (d,
= 12.2)
4JCP = 2.3)
143.4 (d,
142.6 (d,
119.4
1JCP
=
57.4,
53.3)
104.4), 133.7 (dd, = 9.3), 132.2 (d, = 12.8),
2JCP = 2.4) 3JCP = 7.0)
(d, 5JCP
= 2.6)
1JCP = 102.4, 3JCP
2JCP(N) = 9.9)
= 2.4)
31.9 (t,
=
57.7)
129.5 (d, 1JCP(N)
98.0), 132.6 (d,
1JCP(O) = 126.5)
=
130.6 (d, 2JCP(O)
128.4 (d, 3JCP 131.7 (d,
4JCP = 2.0),
128.6 (d, 3JCP 132.0 (d,
= 12.1)
4JCP = 2.1)
149.3
149.7
124.0 (d,
3JCP
122.2
109.5
1JCP
= 9.3), 132.2 (d, = 12.2),
=
2JCP(N) = 9.9)
19.1)
2f
31.9 (t,
=
57.9)
129.3 (d, 1JCP(N)
=
130.6 (d, 2JCP(O)
128.4 (d, 3JCP 131.7 (d,
4JCP = 2.4),
128.6 (d, 3JCP 132.0 (d,
= 12.2)
4JCP = 2.4)
124.6 (d,
1JCP
100.6), 132.7 (d,
= 9.9), 132.2 (d, = 11.6),
3JCP
=
1JCP(O) = 128.7)
2JCP(N) = 10.4)
19.1)
a 20.6 (CH3).
b 55.6 (OCH3).
c 23.8 (CH3), 28.7 (CH).
Data Collection: The data collection was performed using a Sie-
mens P4 at low temperature. Crystal size: 0.44 × 0.40 × 0.31 mm.
The measurement was made in the range 3.14 < q < 25.00∞,
l = 0.71073 MoKa (graphite monochromator), -9 £h £10, 0 £k £11,
-19 £l £19, a total of 4749 reflections, of which 4461 were indepen-
dent reflections.
Anal. calcd for C32H29NO2P2 (521.5): C, 73.70; H, 5.60; N, 2.69;
Found C, 73.82; H, 5.42; N 2.63.
2d
IR (nujol): n = 1591, 1456, 1436, 1305, 1262, 1209, 1145, 1123,
1033, 1001, 792, 760, 744 cm-1.
MS (EI, 70 eV): m/z (%) = 576 ([M + 1]+, 23), 575 ([M]+, 53), 532
(30), 400 (11), 374 (8), 360 (100), 323 (98), 275 (29), 214 (24), 201
(50), 199 (52), 185 (39), 183 (37), 161 (11), 121 (65).
Structure solution and refinement: The structure was solved using
direct methods (SHELXS-86)16 and refined with the full matrix
least-squares on F2 (SHELXL-93).17 The anisotropic refinement
converged at R1 = 0.0356 and wR2 = 0.0858 (all data). The differ-
ence Fourier synthesis on the basis of the final structural model
showed a maximum of 0.288 eA-3 and a minimun of -0.289 eA-3.
Anal. calcd for C37H39NOP2 (575.7): C, 77.20; H, 6.83; N, 2.43;
Found C, 76.99; H, 6.90; N 2.47.
2e
IR (nujol): n = 1587, 1492, 1441, 1369, 1361, 1198, 1123, 835, 788,
2b
744, 723, 701, 669 cm-1.
IR (nujol): n = 1604, 1508, 1460, 1438, 1353, 1209, 1171, 1113,
1049, 803, 728, 696 cm-1.
MS (EI, 70 eV): m/z (%) = 527 ([M + 2]+, 45), 526 ([M + 1]+, 47),
525 ([M]+, 99), 400 (15), 324 (8), 310 (14), 215 (17), 201 (59), 199
(100), 185 (16), 183 (42), 121 (73).
MS (EI, 70 eV): m/z (%) = 506 ([M + 1]+, 39), 505 ([M]+, 100), 400
(15), 304 (10), 290 (25), 215 (20), 201 (64), 199 (94), 185 (24), 183
(49), 121 (84), 107 (18), 91 (30).
Anal. calcd for C31H26ClNOP2 (526.0): C, 70.79; H, 4.98; N, 2.66;
Found C, 70.54; H, 4.88; N 2.59.
Anal. calcd for C32H29NOP2 (505.5): C, 76.03; H, 5.78; N, 2.77;
Found C, 76.16; H, 5.71; N 2.72.
2f
IR (nujol): n = 1577, 1485, 1438, 1358, 1202, 1166, 1121, 1049,
2c
830, 787, 755, 739, 669 cm-1.
IR (nujol): n = 1508, 1453, 1438, 1338, 1265, 1234, 1195, 1119,
1049, 828, 778, 743, 694, 667 cm-1.
MS (EI, 70 eV): m/z (%) = 572 ([M + 3]+, 27), 571 ([M + 2]+, 75),
570 ([M + 1]+, 38), 569 ([M]+, 73), 400 (10), 354 (13), 215 (18), 201
(56), 199 (100), 185 (23), 183 (47), 121 (77).
MS (EI, 70 eV): m/z (%) = 522 ([M + 1]+, 70), 521 ([M]+, 74), 400
(10), 321 (9), 215 (17), 201 (60), 199 (100), 185 (25), 183 (49), 121
(64).
Anal. Calcd. for C31H26BrNOP2 (570.4): C, 65.28; H, 4.59; N, 2.46;
Found C, 65.01; H, 4.56; N 2.52.
Synthesis 2000, No. 14, 2085–2091 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
A Practical Synthesis of the First P-Phosphinoylmethyl-l5-phosphazenes
2089
For yields and other physical data of l5 -phosphazenes 2, see Tables
1, 3 and 4.
IR (nujol): n = 3373, 1508, 1450, 1442, 1232, 1188, 1122, 747, 692
cm-1.
1H NMR (CDCl3): d = 3.66 (s, 3 H, OCH3), 5.08 (dd, 2 H,
2JHH = 17.1, 12.3 Hz, CH2), 6.60 (d, 2 H, 3JHH = 8.8 Hz, Harom), 6.79
Arylaminophosphonium Bromides 5a-f and Iodide 5g; General
Procedure
3
(d, 2 H, JHH = 8.8 Hz, Harom) 7.34-7.46 (m, 10 H, Ph2), 7.56-7.6
2
A solution of Br2 or I2 (0.52 mmol) in benzene (10 mL) was added
dropwise to a solution of 3 (0.52 mmol), generated in situ from
bis(diphenylphosphino)methane and aryl azides as above, in ben-
zene (20 mL) at 0 °C. The mixture was allowed to warm up to r.t.
for 0.5 h and then Et3N (50 mg, 0.52 mmol) in benzene (1 mL) was
added. The white precipitate of triethylammonium halide was sepa-
rated by filtration and the crude product was purified by flash chro-
matography (EtOAc/EtOH) and then crystallized from MeOH/Et2O
to give the salts 5a-g (X = Br and I).
(m, 2 H, Ph2), 7.84-8.0 (m, 8 H, Ph2), 9.52 (d, 1 H, JHP = 6.9 Hz,
NH).
1
1
13C NMR (CDCl3): d = 28.7 (dd, JCP(O) = 61.1, JCP(+) = 55.5 Hz,
1
CH2), 55.3 (OCH3), 114.5 (C-3), 119.4 (d, JCP(+) = 98.6 Hz, Ci),
122.1 (d, 3JCP(+) = 7.0 Hz, C-2), 128.9 (d, 3JCP = 12.8 Hz, Cm), 129.5
3
2
(d, JCP = 13.3 Hz, Cm), 130.5 (d, JCP(O) = 10.4 Hz, Co), 130.9 (d,
2JCP(+) = 1.8 Hz, C-1), 131.4 (dd, 1JCP(O) = 106.3, 3JCP(+) = 3.6 Hz, Ci),
132.3 (d, 4JCP(O) = 2.9 Hz, Cp), 133.6 (d, 2JCP(+) = 11.6 Hz, Co), 134.8
(d, 4JCP(+) = 2.9 Hz, Cp), 156.1 (C-4).
5a
2
31P NMR (CDCl3): d = 25.6 (d, JPP = 8.5 Hz, P=O), 33.2 (d,
Rf 0.52 (EtOAc/EtOH, 8:2).
2JPP = 8.5 Hz, P+).
IR (nujol): n = 3385, 1601, 1588, 1495, 1440, 1235, 1180, 1119,
MS (EI, 70 eV): m/z (%) = 522 (25), 521 (71), 400 (7), 323 (32), 321
(30), 306 (53), 215 (25), 201 (100), 199 (80), 185 (24), 183 (52),
121 (65), 91 (17).
970, 804, 782, 749, 692 cm-1.
2
1H NMR (CDCl3): d = 5.14 (dd, 2 H, JHP = 16.7, 13.5 Hz, CH2),
6.88 (d, 2 H, 3JHH = 7.6 Hz, H-2), 6.93 (t, 1 H, 3JHH = 7.6 Hz, H-4),
7.07 (t, 2 H, 3JHH = 7.6 Hz, H-3), 7.29-7.48 (m, 10 H, Ph2), 7.57-
7.63 (m, 2 H, Ph2), 7.86-8.03 (m, 8 H, Ph2), 9.69 (d, 1 H, 2JHP = 7.3
Hz, NH).
Anal. calcd for C32H30BrNO2P2 (602.5): C, 63.80; H, 5.02; N, 2.32;
Found C, 63.85; H, 5.15; N 2.13.
5d
Rf 0.57 (EtOAc/EtOH, 8:2).
1
1
13C NMR (CDCl3): d = 28.9 (dd, JCP(O) = 61.2, JCP(+) = 55.4 Hz,
CH2), 118.9 (d, JCP(+) = 98.6 Hz, Ci), 119.8 (d, 3JCP(+) = 7.0 Hz, C-
1
IR (nujol): n = 3413, 1585, 1435, 1364, 1258, 1164, 1153, 1121,
2), 123.6 (C-4), 129.0 (d, 3JCP = 13.3 Hz, Cm), 129.3 (C-3), 129.7 (d,
1095, 795, 750, 689 cm-1.
3JCP = 13.9 Hz, Cm), 130.6 (d, JCP(O) = 11.0 Hz, Co), 130.7 (dd,
2
1H NMR (CDCl3): d = 0.90 (d, 12 H, 3JHH = 6.8 Hz, CH3), 2.98 (m,
1JCP(O) = 106.5, JCP(+) = 3.0 Hz, Ci), 132.4 (d, JCP(+) = 2.9 Hz, Cp),
133.5 (d, 2JCP(+) = 11.6 Hz, Co), 135.0 (d, 4JCP(O) = 2.9 Hz, Cp), 137.9
(C-1).
1
4
2
2 H, CH), 5.35 (dd, 2 H, JHP = 16.8, 11.2 Hz, CH2), 6.91 (d, 2 H,
3JHH = 7.8 Hz, H-3), 7.11 (t, 1 H, 3JHH = 7.8 Hz, H-4), 7.26-7.5 (m,
12 H, Ph2), 7.69-7.93 (m, 8 H, Ph2), 8.33 (d, 1 H, 2JHP= 7.2 Hz, NH).
2
31P NMR (CDCl3): d = 27.2 (d, JPP = 9.9 Hz, P=O), 32.8 (d,
13C NMR (CDCl3): d = 23.4 (CH3), 29.5 (CH), 29.6 (dd,
2JPP = 9.9 Hz, P+).
1
1
1JCP(O) = 64.1, JCP(+) = 56.9 Hz, CH2), 119.8 (d, JCP(+) = 102.2 Hz,
3
MS (EI, 70 eV): m/z (%) = 492 (40), 491 (100), 490 (29), 400 (26),
290 (44), 276 (38), 215 (25), 201 (82), 199 (83), 185 (23), 183 (60),
121 (58), 77 (51).
Ci), 123.8 (C-3 and C-4), 128.9 (d, JCP = 13.6 Hz, Cm) 129.0 (d,
3JCP = 13.1 Hz, Cm), 130.2 (d, JCP(+) = 5.0 Hz, C-2) 130.5 (d,
3
2JCP(O) = 10.1 Hz, Co), 131.7 (dd, JCP(O) = 106.3, JCP(+) = 3.0 Hz,
Ci), 132.2 (d, 4JCP(O) = 2.5 Hz, Cp), 133.6 (d, 2JCP(+) = 11.1 Hz, Co),
134.5 (d, 4JCP(+) = 3.0 Hz, Cp), 147.4 (d, 2JCP(+) = 3.0 Hz, C-1).
1
3
Anal. calcd for C31H28BrNOP2 (572.4): C, 65.05; H, 4.93; N, 2.45;
Found C, 65.21; H, 5.03; N 2.57.
31P NMR (CDCl3): d = 24.4 (d, JPP = 7.8 Hz, P=O), 37.2 (d,
2
5b
2JPP = 7.8 Hz, P+).
Rf 0.41 (EtOAc/EtOH, 8:2).
MS (EI, 70 eV): m/z (%) = 576 (6), 575 (13), 400 (6), 374 (6), 360
(47), 323 (100), 215 (11), 201 (26), 200 (27), 199 (32), 185 (19),
183 (22), 121 (46).
IR (nujol): n = 3397, 1610, 1508, 1450, 1290, 1195, 1129, 747, 686
cm-1.
1H NMR (CDCl3): d = 2.18 (s, 3 H, CH3), 5.12 (dd, 2 H, 2JHH = 17.1,
Anal. calcd for C37H40BrNOP2 (656.6): C, 67.69; H, 6.14; N, 2.13;
Found C, 67.53; H, 6.21; N 2.20.
3
12.3 Hz, CH2), 6.76 (d, 2 H, JHH = 8.5 Hz, Harom), 6.87 (d, 2 H,
3JHH = 8.5 Hz, Harom), 7.33-7.46 (m, 10 H, Ph2), 7.57-7.6 (m, 2 H,
Ph2), 7.86-8.03 (m, 8 H, Ph2), 9.71 (d, 1 H, 2JHP = 6.9 Hz, NH).
5e
Rf 0.58 (EtOAc/EtOH, 7:3).
1
13C NMR (CDCl3): d = 20.5 (CH3), 29.0 (dd, JCP(O) = 60.6,
1
1JCP(+) = 54.8 Hz, CH2), 119.3 (d, JCP(+) = 98.1 Hz, Ci), 119.9 (d,
IR (nujol): n = 3385, 1490, 1450, 1438, 1278, 1113, 1091, 947, 904,
3
3JCP(+) = 7.1 Hz, C-2), 128.9 (d, JCP = 12.8 Hz, Cm), 129.5 (d,
755, 734, 669 cm-1.
2
3JCP = 13.7 Hz, Cm), 129.8 (C-3), 130.5 (d, JCP(O) = 10.4 Hz, Co),
2
1H NMR (CDCl3): d = 5.12 (dd, 2 H, JHP = 17.1, 12.5 Hz, CH2),
131.4 (dd, 1JCP(O) = 106.1, 3JCP(+) = 3.3 Hz, Ci), 132.3 (d, 4JCP(O) = 2.9
3
3
6.84 (d, 2 H, JHH = 8.8 Hz, Harom), 7.02 (d, 2 H, JHH = 8.8 Hz,
2
Hz, Cp), 133.2 (C-4), 133.5 (d, JCP(+) = 11.9 Hz, Co), 134.8 (d,
H
arom), 7.29-7.48 (m, 10 H, Ph2), 7.59-7.66 (m, 2 H, Ph2), 7.81-
4JCP(+) = 3.0 Hz, Cp), 135.3 (d, 2JCP(+) = 2.5 Hz, C-1).
7.88 (m, 4 H, Ph2), 7.94-8.02 (m, 4 H, Ph2), 10.02 (d, 1 H, 2JHP = 6.8
2
31P NMR (CDCl3): d = 25.7 (d, JPP = 8.0 Hz, P=O), 32.5 (d,
Hz, NH).
2JPP = 8.0 Hz, P+).
1
1
13C NMR (CDCl3): d = 29.0 (dd, JCP(O) = 60.9, JCP(+) = 55.1 Hz,
CH2), 118.7 (d, JCP(+) = 98.6 Hz, Ci), 121.0 (d, 3JCP(+) = 7.0 Hz, C-
1
MS (EI, 70 eV): m/z (%) = 506 (36), 505 (100), 504 (17), 400 (9),
304 (12), 290 (21), 215 (13), 201 (55), 199 (71), 185 (15), 183 (40),
136 (20), 121(66) 91 (21).
2), 129.0 (d, 3JCP = 13.3 Hz, Cm), 129.2 (C-3), 129.7 (d, 3JCP = 13.3
2
Hz, Cm), 130.1 (C-4), 130.5 (d, JCP(O) = 11.0 Hz, Co), 131.3 (dd,
1JCP(O) = 106.0, 3JCP(+) = 3.2 Hz, Ci), 132.4 (d, 4JCP(O) = 2.0 Hz, Cp),
133.6 (d, 2JCP(+) = 12.2 Hz, Co), 135.0 (d, 4JCP(+) = 3.1 Hz, Cp), 136.7
(C-1).
Anal. calcd for C32H30BrNOP2 (586.5): C, 64.54; H, 5.16; N, 2.39;
Found C, 64.71; H, 5.11; N 2.23.
5c
2
31P NMR (CDCl3): d = 25.3 (d, JPP = 7.6 Hz, P=O), 33.2 (d,
Rf 0.45 (EtOAc/EtOH, 7:3).
2JPP = 7.6 Hz, P+).
Synthesis 2000, No. 14, 2085–2091 ISSN 0039-7881 © Thieme Stuttgart · New York

2090
M. Alajarín et al.
PAPER
MS (EI, 70 eV): m/z (%) = 527 (22), 526 (32), 525 (48), 400 (11),
275 (12), 215 (47), 201 (100), 200 (25), 199 (79), 185 (29), 183
(66), 121 (50).
(10 mL) was added to obtain 2 as a yellow solid, which was filtered,
dried and crystallized from CH2Cl2/Et2O.
For yields of l5-phosphazenes 2, see Table 2.
Anal. calcd for C31H27BrClNOP2 (606.9): C, 61.35; H, 4.48; N,
2.31; Found C, 61.52; H, 4.57; N 2.17.
Acknowledgement
5f
Rf 0.57 (EtOAc/EtOH, 7:3).
This work was supported by the Dirección General de Enseñanza
Superior (Project PB95-1019), Fundación Séneca (Project PB/2/FS/
99), and Acedesa (a division of Takasago). One of us (P. L.-L.) also
thanks Fundación Séneca for a fellowship.
IR (nujol): n = 3423, 1594, 1490, 1456, 1441, 1278, 1234, 1182,
1125, 967, 746, 731, 694, 670 cm-1.
1H NMR (CDCl3): d = 5.11 (dd, 2 H, JHP = 17.3, 12.3 Hz, CH2),
2
3
3
6.80 (d, 2 H, JHH = 8.9 Hz, Harom), 7.17 (d, 2 H, JHH = 8.9 Hz,
H
arom), 7.34-7.49 (m, 10 H, Ph2), 7.61-7.66 (m, 2 H, Ph2), 7.82-
References
7.88 (m, 4 H, Ph2), 7.95-8.02 (m, 4 H, Ph2), 10.05 (d, 1 H, 2JHP = 7.4
(1) (a) Katti, K. V.; Cavell, R. G. Inorg. Chem. 1989, 28, 413, and
references cited therein.
Hz, NH).
13C NMR (CDCl3): d = 29.0 (dd, JCP(O) = 60.9, JCP(+) = 55.0 Hz,
1
1
(b) Katti, K. V; Cavell, R. G. Organometallics 1989, 8, 2147,
and references cited therein.
1
CH2), 116.4 (C-4), 118.6 (d, JCP(+) = 98.0 Hz, Ci), 121.3 (d,
3JCP(+) = 7.5 Hz, C-2), 129.0 (d, JCP = 13.3 Hz, Cm), 129.7 (d,
3
(c) Katti, K. V; Batchelor, R. J.; Einstein, F. W. B.; Cavell, R.
G. Inorg. Chem. 1990, 29, 808, and references cited therein.
(d) Avis, M. W.; Vrieze, K.; Kooijman, H.; Veldman, N.;
Spek, A. L.; Elsevier, C. J. Inorg. Chem. 1995, 34, 4092, and
references cited therein.
3JCP = 13.9 Hz, Cm), 130.4 (d, JCP(O) = 10.4 Hz, Co), 131.6 (dd,
2
1JCP(O) = 103.4, JCP(+) = 3.1 Hz, Ci), 132.2 (C-3), 132.4 (d,
3
4JCP(O) = 2.9 Hz, Cp), 133.5 (d, JCP(+) = 12.2 Hz, Co), 135.0 (d,
2
4JCP(+) = 2.9 Hz, Cp), 137.3 (C-1).
31P NMR (CDCl3): d = 25.2 (d, JPP = 7.5 Hz, P=O), 33.0 (d,
2
(2) Wegman, R. W.; Abatjoglou, A. G.; Harrison, A. M. J. Chem.
Soc., Chem. Commun. 1987, 1891.
2JPP = 7.5 Hz, P+).
(3) Cavell, R. G.; Katti, K. V. Can Pat. Appl. CA 2024284, 1992;
Chem. Abstr. 1992, 117, 251564.
(4) (a) Davison, A.; Reger, D. L. Inorg. Chem. 1971, 9, 1967.
(b) Wheatland, D. A.; Clapp, C. H.; Waldron, R.W. Inorg.
Chem. 1972, 11, 2340.
MS (EI, 70 eV): m/z (%) = 571 (28), 569 (27), 553 (29), 551 (22),
400 (10), 370 (44), 368 (36), 354 (13), 215 (41), 201 (100), 199
(54), 185 (37), 183 (71), 121 (42).
Anal. calcd for C31H27Br2NOP2 (651.3): C, 57.17; H, 4.18; N, 2.15;
Found C, 57.01; H, 4.28; N 2.32.
(c) Grim, S. O.; Walton, E. D. Inorg. Chem. 1980, 19, 1982.
(d) Laguna, A.; Laguna. M.; Rojo, A.; Fraile, M. N. J.
Organomet. Chem. 1986, 315, 269.
(e) Berry, D. E.; Browning, J.; Dixon, K. R.; Hilts, R. W.;
Pidcock, A. Inorg. Chem. 1992, 31, 1479.
5g
Rf 0.56 (AcOEt/EtOH, 8:2).
IR (nujol): n = 3434, 1594, 1512, 1452, 1442, 1230, 1187, 1132,
1019, 980, 815, 791, 753, 693 cm-1.
(f) Browning, J.; Bushnell, G. W.; Dixon, K. R.; Hilts, R. W.
J. Organomet. Chem. 1992, 434, 241.
1H NMR (CDCl3): d = 3.67 (s, 3 H, OCH3), 5.00 (dd, 2 H,
2JHP = 16.0, 12.1 Hz, CH2), 6.62 (d, 2 H, 3JHH = 8.9 Hz, Harom), 6.78
(d, 3JHH = 8.9 Hz, Harom), 7.34-7.47 (m, 10 H, Ph2), 7.57-7.61 (m,
2 H, Ph2), 7.9-8.1 (m, 8 H, Ph2), 8.80 (br s, 1 H, NH).
(5) (a) Imhoff, P.; Gülpen, J. H.; Vrieze, K.; Smeets, W. J. J.;
Spek, A. L.; Elsevier, C. J. Inorg. Chim. Acta 1995, 235, 77.
(b) Kasani, A.; McDonald, R.; Cavell, R. G. Organometallics
1999, 18, 3775.
1
1
13C NMR (CDCl3): d = 28.9 (dd, JCP(O) = 60.8, JCP(+) = 53.1 Hz,
(c) Kasani, A.; McDonald, R.; Ferguson, M.; Cavell, R. G.
Organometallics 1999, 18, 4241.
(d) Babu, R. P. K.; McDonald, R.; Decker, S. A.;
Klobukowski, M.; Cavell, R. G. Organometallics 1999, 18,
4226.
1
CH2), 55.4 (OCH3), 114.7 (C-3), 119.3 (d, JCP(+) = 99.2 Hz, Ci),
122.4 (d, 3JCP(+) = 6.4 Hz, C-2), 129.0 (d, 3JCP = 12.8 Hz, Cm), 129.7
3
2
(d, JCP = 13.9 Hz, Cm), 130.0 (d, JCP(+) = 2.4 Hz, C-1), 130.6 (d,
1
3
2JCP(O) = 10.4 Hz, Co), 130.9 (dd, JCP(O) = 107.1, JCP(+) = 3.0 Hz,
Ci), 132.5 (d, JCP(O) = 2.8 Hz, Cp), 133.6 (d, 2JCP(+) = 12.2 Hz, Co),
4
(e) Kasani, A.; Ferguson, M.; Cavell, R. G. J. Am. Chem. Soc.
2000, 122, 726.
135.0 (d, 4JCP(+) = 2.5 Hz, Cp), 156.5 (C-4).
2
31P NMR (CDCl3): d = 27.4 (d, JPP = 11.0 Hz, P=O), 34.8 (d,
(6) (a) Grim, S. O.; Satek, L. C.; Tolman, C. A.; Jesson, J. P.
Inorg. Chem. 1975, 14, 656.
2JPP = 11.0 Hz, P+).
(b) Abatjoglou, A. G.; Kapicak, L. A. Eur Pat. Appl. EP 72560
(1983); Chem. Abstr. 1983, 98, 19842.
(c) Katti, K. V.; Pinkerton, A. A.; Cavell, R. G. Inorg. Chem.
1991, 30, 2631.
(d) Panduragi, R. S.; Katti, K. V.; Stillwell, L.; Barnes, C. L.
J. Am. Chem. Soc. 1998, 120, 11364.
MS (EI, 70 eV): m/z (%) = 522 (53), 521 (100), 400 (11), 323 (39),
321 (16), 306 (33), 215 (34), 201 (73), 199 (77), 185 (26), 183 (45),
121 (60).
Anal. calcd for C32H30INO2P2 (649.5): C, 59.18; H, 4.66; N, 2.16;
Found C, 58.99; H, 4.56; N 2.02.
For yields of aminophosphonium salts 5, see Table 2.
(7) Avis, M. W.; Goosen, M.; Elsevier, C. J.; Veldman, N.;
Kooijman, H.; Spek, A. L. Inorg. Chim. Acta 1997, 264, 43.
(8) Staudinger, H.; Meyer, J. Helv. Chim. Acta 1919, 2, 635.
(9) Handbook of Phosphorus-31 Nuclear Magnetic Resonance
Data; Tebby, J. C.; Ed.; CRC Press: Boca Raton, 1991.
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2063.
(b) Schmidbaur, H.; Deschler, U.; Zimmer-Gasser, B.;
Neugebauer, D.; Schubert, U. Chem. Ber. 1980, 113, 902.
(11) Grim, S. O.; Kettler, P. B. J. Chem. Soc., Chem. Commun.
1991, 979.
Deprotonation of Arylaminophosphonium Bromides 5a-f; Gen-
eral Procedure
Aminophosphonium salt 5 (0.6 mmol) was added to a solution of
NaNH2, prepared by the addition of Na (13.8 mg) to liquid ammonia
(25 mL) at -78 ∞C. The mixture was stirred for 4 h at -33 ∞C and
then allowed to stand until the ammonia was evaporated. The resi-
due was treated with CH2Cl2 (20 mL) and solid NaBr was filtered
off. The solvent was evaporated from the filtrate in vacuo, and Et2O
Synthesis 2000, No. 14, 2085–2091 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
A Practical Synthesis of the First P-Phosphinoylmethyl-l5-phosphazenes
2091
(12) Crystallographic data (excluding structure factors) for the
structure reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication No. CCDC 147252 (2a). Copies of the data can be
obtained free of charge on application to: CCDC, 12 Union
Road, Cambridge CB21EZ, UK (fax +44 122 3336033; e-
mail: deposit@ccdc.cam.ac.uk).
(13) (a) Imhoff, P.; van Asselt, R.; Elsevier, C. J.; Vrieze, K.;
Goubitz, K.; van Malssen, K. F.; Stam, C. H. Phosphorus
Sulfur 1990, 47, 401.
(15) (a) Herring, D. L. J. Org. Chem. 1961, 26, 3998.
(b) Smolinsky, G. J. Org. Chem. 1961, 26, 4106.
(16) Sheldrick, G. M., Fortran Program for the Solution of Crystal
Structures from Diffraction Data, Institute for Organic
Chemistry, University of Göttingen, 1986.
(17) Sheldrick, G. M., Fortran Program for Crystal Structure
Refinement, Institute for Organic Chemistry, University of
Göttingen, 1986.
(b) Elsevier, C. J.; Imhoff, P. Phosphorus Sulfur 1990, 49-50,
405.
Article Identifier:
1437-210X,E;2000,0,14,2085,2091,ftx,en;Z07200SS.pdf
(14) Avis, M. W.; Elsevier, C. J.; Veldman, N.; Kooijman, H.;
Spek, A. L. Inorg. Chem. 1996, 35, 1518.
Synthesis 2000, No. 14, 2085–2091 ISSN 0039-7881 © Thieme Stuttgart · New York