Synthesis of functionalized mono-, di-, tri-, and tetraphosphines: Attempted application to prepare hyperbranched polymers and dendrimers built with phosphines at each branching point

Article abstract of DOI:10.1055/s-2000-6402

The synthesis of several functionalized mono-, di-, tri-, and tetraphosphines is described. These compounds are used for the attempted preparation of hyperbranched polymers and dendrimers possessing free phosphino groups at each branching point within the structure. Theses attempts were not fully successful, but several phosphaacetylenic derivatives have been isolated.

Full text of DOI:10.1055/s-2000-6402

726
PAPER
Synthesis of Functionalized Mono-, Di-, Tri-, and Tetraphosphines: Attempted
Application to Prepare Hyperbranched Polymers and Dendrimers Built with
Phosphines at Each Branching Point
Vincent Huc, Anna Balueva,# Rosa-Maria Sebastian, Anne-Marie Caminade,* Jean-Pierre Majoral*
Laboratoire de Chimie de Coordination, CNRS, 205 route de Narbonne, F-31077 Toulouse Cedex 4, France
Fax +33(5)61553003; E-mail: caminade@lcc-toulouse.fr or majoral@lcc-toulouse.fr
Received 5 November 1999; revised 22 December 1999
paraformaldehyde, that we have already applied to graft
Abstract: The synthesis of several functionalized mono-, di-, tri-,
phosphines on the surface of dendrimers in quantitative
and tetraphosphines is described. These compounds are used for the
attempted preparation of hyperbranched polymers and dendrimers
possessing free phosphino groups at each branching point within the
yields.3d,3i In order to obtain a hyperbranched polymer,
both NH and PH functions should be gathered in a single
structure. Theses attempts were not fully successful, but several compound, one of them being in double amount to ensure
phosphaacetylenic derivatives have been isolated.
the branching. A target molecule corresponding to this de-
scription is the 4-N-methylaminophenylphosphine (4).
This compound is obtained in four steps from 4-bromo-N-
methylaniline (Scheme 1). The first step is the reaction
with three equivalents of butyllithium which affords the
dilithium salt 1 as an intermediate used in situ. The next
step is the reaction with ClP(NEt2)2, which leads to the
formation of compound 2, isolated by distillation. Etha-
nolysis of 2 leads to the phosphonite 3, also isolated by
distillation. The last step of the synthesis is the reduction
of the phosphonite by LiAlH4, leading to the target mole-
cule 4-N-methylaminophenylphosphine (4) after distilla-
tion, with an overall yield of 7.8% from 1. Compound 4 is
characterized by a triplet at d = -124.6 with 1JPH = 200.3
Hz in the 31P NMR spectrum, which is typical for a prima-
ry phosphine.
Key words: dendrimers, hyperbranched polymer, phosphorus,
phosphine, alkynes, Grignard reagents
A special type of macromolecules named dendrimers at-
tracts a considerable attention since more than one decade
due to the unique properties of these highly branched
compounds.1 Most of the initial work in this field was de-
voted to the synthesis of organic dendrimers, but silicon-
and phosphorus-containing dendrimers rapidly became an
important part of this field.2 We are interested since five
years in the synthesis, the study of reactivity and proper-
ties of phosphorus-containing dendrimers,3 as well as
those of phosphorus-containing hyperbranched poly-
mers.4 In all cases, tetracoordinated pentavalent phospho-
rus atoms constitute the branching point. We thought that
it could be interesting to build dendrimers with tricoordi-
nated trivalent phosphorus atoms at each branching point,
owing to the unique complexation and catalytic properties
of phosphines. Very few papers describe the synthesis of
dendrimers including phosphines at each layer of the skel-
eton; only a third generation dendrimer possessing 15 free
phosphines5 and a fourth generation dendrimers possess-
ing 46 complexed phosphines6 have been described up to
now. We report here our attempts to build hyperbranched
polymers and dendrimers possessing functionalized phos-
phines at the branching points.
Me
Me
N
Li
+ 3 BuLi
Br
N
Li
-LiBr
-BuH
-BuBu
H
1
2 ClP(NEt2)2
P(NEt2)2
Me
N
(Et2N)2P
2
EtOH (excess)
P(OEt)2
Me
H
Me
H
LiAlH4
N
PH2
N
4
3
Scheme 1
The well-known propensity of most tricoordinated phos-
phorus atoms to oxidize in air incited us to try first to ob-
tain hyperbranched polymers. Indeed, hyperbranched
polymers are synthesized in one step, whereas dendrimers
need many steps to be synthesized, increasing the risk of
oxidation. Furthermore, the structure of both types of
compounds is close, even if the polydispersity is much
higher for hyperbranched polymers than for dendrimers.
For stability reasons, we wanted to obtain only com-
pounds in which phosphorus is linked to three carbon at-
oms, even if the yield of the synthesis of such compounds
is rarely quantitative. Thus, we decided to use the Man-
nich-type reaction between NH and PH functions, and
With compound 4 in our hands, we tried to react it with
paraformaldehyde (Scheme 2). A reaction occurred, as in-
dicated by the disappearance of the signal at d = -124.6 in
the 31P NMR spectrum, but many other peaks appeared,
pointing out that the reaction does not lead cleanly to the
hyperbranched polymer 5. The low yield of synthesis of
compound 4 did not allow us to try to vary the reaction
conditions. Consequently, we decided to foresake this
method and to try to find a way to obtain dendrimers in-
cluding phosphines in their skeleton.
Synthesis 2000, No. 5, 726–730 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Synthesis of Functionalized Mono-, Di-, Tri-, and Tetraphosphines
727
(PPh2), and a quadruplet at d = -87.5 (2JPP = 4.8 Hz). The
large shielding of the signal at d = -87.5 is consistent with
the chemical shift reported for P(C∫CH)3 (d = -91).9
The structure of compound 12 is confirmed by 1H and 13C
NMR and by FAB mass spectra ([M + 1]+ = 659, 100%).
The formation of the tetraphosphine 12 is rather surprising
since it implies a desulfuration, a type of reaction which is
not common with organolithium derivatives. Obviously,
we tried to obtain 12 using PCl3 instead of PSCl3, but this
reaction leads to a complex mixture of compounds in
which 12 is undetectable.
Me
N
Me
N
PH2
CH2
CH2
P
P
Me
N
H
4
+
C
H2
P
(CH2O)n
N
Me
x
5
Scheme 2
In fact, we were interested in having not only phosphines
but also other functions as building blocks of the dendrim-
er. The richness of the chemistry of acetylenic derivatives,
and the fact that they have been used only a few times in
dendrimer chemistry7 encouraged us to try to combine
phosphine and acetylene functions in a single compound.
Thus, the ethynyldiphenylphosphine 8 appears as a suit-
able building block for this purpose. Compound 8 is ob-
tained by reacting ethynylmagnesium bromide (6) with
diphenylchlorophosphine (7), using slight modifications
of a method already reported for the synthesis of 88
(Scheme 3). The next step consists of functionalizing the
acetylenic group of 8. In order to try to find the best way
to build a dendrimer with this compound, we decided first
to synthesize several functional derivatives of 8 and to test
their reactivity toward various chlorophosphine deriva-
tives. In this perspective, we synthesized the lithium and
Grignard derivatives 9 and 10, respectively. The stannyl
derivative 11 was prepared via the magnesium derivative
10 (Scheme 3). The three compounds were not isolated
but used in situ.
The Grignard derivative 10 was then reacted with PSCl3
or PCl3 under various conditions. In all cases, the tetra-
phosphine 12 can be detected in 31P NMR in a higher pro-
portion when PCl3 is used. In this case, 12 can be isolated
by column chromatography (35% yield). Thus, the mag-
nesium derivative 10 seems to give better results than the
lithium derivative 9. To confirm this assumption, 10 was
reacted with POCl3, having in mind the higher stability of
the P=O bond compared to the P=S bond, which should
prevent the reduction (the dissociation energy of P=X
bond is 510 KJmol-1 for Cl3P=O and 293 KJmol-1 for
Cl3P=S).10 The major product of the crude reaction mix-
ture is compound 13 as expected, even if it is finally iso-
lated in low yield (17%). Compound 13 gives two signals
in 31P NMR, a doublet at d = -34 (PPh2) and a quadruplet
at d = - 58 (P=O) (3JPP = 4.7 Hz). The value at -58 ppm
is unusual for a phosphine oxide, but it is consistent with
that reported for OP(C∫CH)3 (d = -56).9 The structure of
compound 13 is also confirmed by FAB mass spectrome-
try ([M + 1]+ = 675, 100%). We also tried to obtain com-
pound 13 using the stannyl derivative 11, but this reaction
leads only to the formation of polymers (Scheme 3).
H
C
6
C
+
MgBr
-10°C
BuLi
Li
9
C
C
PPh2
PCl3
H
C C PPh2
Thus, the Grignard reagent 10 appears to be the most suit-
able starting material to try to obtain dendrimers, even if
the reactions observed with it were not, so far, quantita-
tive. Under these circumstances, the convergent method
of synthesis of dendrimers appears more appropriate than
the divergent one.11 In the divergent method, the dendrim-
er is grown by grafting a large number of small molecules
on the surface of the macromolecule. In the convergent
method, the dendrimer is built by reacting one small mol-
ecule with the core of two of three macromolecules. Thus,
the number of reactive sites at each step is much lower and
the weight difference between perfect and imperfect den-
drimer is much greater with the convergent method, facil-
itating the workup when using non-quantitative reactions.
8
Ph2PCl
7
(S)PCl3
EtMgBr
Ph2P
PPh2
C
C
C
C
C
(O)PCl3
(O)PCl3
PCl3
C
Ph2P
C
C P
O
BrMg C
C PPh2
P C
C
C
PPh2
12
PPh2
C
10
or P(S)Cl3
13
Ph2P
ClSnPh3
Ph3Sn C
C PPh2
11
Scheme 3
Our first attempts consisted of reacting the lithium deriv-
ative 9 with PSCl3, because we thought that the presence
of a tetracoordinated phosphorus atom should enhance the
stability of the product and facilitate the workup. In fact in
almost all cases, varying the stoechiometry of reagents,
the temperature and the solvent, mainly polymers are ob-
tained, but a surprising result is observed with a 2:1 sto-
ichiometry of 9/PSCl3. In this case, beside polymers, the
tetraphosphine derivative 12 is obtained and isolated by
column chromatography (8% yield). This compound has
been first characterized by 31P NMR, which indicated the
presence of two types of signals: one doublet at d = -31.4
The type of convergent synthesis we intended to use ne-
cessitates the repetition of four steps to build one genera-
tion (Scheme 4). The first one is the CHÆCMgBr
transformation previously described, leading to 10. The
second one consists of reacting Me2NPCl2 with two
equivalents of 10, which affords the triphosphine 14 in
80% yield. Compound 14 is characterized by 31P NMR
(one doublet at d = -33.5 (PPh2) and one triplet at d =
+6.7 (PN) with 3JPP = 4 Hz), and by FAB mass spectrom-
etry ([M + 1]+ = 494, 100%). The third step is the P-NMe2
Æ P-Cl transformation (14 Æ 15). We first tried to use
Synthesis 2000, No. 5, 726–730 ISSN 0039-7881 © Thieme Stuttgart · New York

728
V. Huc et al.
PAPER
PCl3 as the chlorinating agent; monitoring the exchange known. Dendrimers derived from 16 would have a [PC4]n
reaction by 31P NMR which indicates the formation of the formulae (except for the surface), and could be considered
expected compound 15, but it is unstable under the condi- as “nude” dendrimers on which could be grafted various
tions of the reaction, and polymerizes rapidly. Then, we functions, either on the acetylenic groups, or on the phos-
used 2 equivalents of HCl in diethyl ether, one to cleave phine groups, depending on the properties expected. Any-
the P-N bond, the second one to trap Me2NH, in order to way, our attempts allowed us to isolate several new
avoid side reactions. These conditions lead cleanly to mono-, di-, tri-, and tetraphosphine derivatives which
compound 15, characterized in 31P NMR spectrum by one could find uses as functionalized ligands, in view of the
doublet at d = -32.9 (PPh2), and one triplet at d = +11.1 wide use of simple phosphinoalkynes for the synthesis of
3
(PCl) with JPP = 4 Hz. Compound 15 is stable for a few organometallic complexes containing two or more transi-
hours in solution after removal of the precipitate, but we tion metals.12
did not try to isolate it. Thus, the fourth step is performed
in situ, by adding BrMgC∫CH to 15. 31P MNR spectra in-
All reactions were carried out in the absence of air, under argon, us-
dicate the formation of the first generation of the dendrim-
ing standard Schlenk techniques and vacuum-line manipulations.
All solvents were dried, distilled and degassed before use, silica gel
er 16, with the presence of one doublet at d = -32.5 (PPh2)
(3JPP = 4.5 Hz), and one shielded triplet at d = -89.5, typ-
was degassed prior to use. Instrumentation: Bruker AC80, AC200,
1
or AM250 for H, 13C, 31P NMR, Perkin Elmer 1725X for FT-IR,
Finniganmat TSQ 700 for FAB mass spectra. 4-Bromo-N-methyla-
niline was synthesized according to a published procedure.13
ical for a phosphine linked to three acetylenic functions.
However, we observed also the presence of a few other
compounds, and above all, a large amount of precipitate
corresponding to the formation of polymers. The small
quantity of compound 16 formed prevented its isolation,
thus the synthesis was stopped at this step (the first gener-
ation), and we did not try to obtain the second generation
by repeating the four steps on the C-H bond of compound
16 (Scheme 4).
Bis(diethylamino)-4-[N-bis(diethylamino)phosphino-N-methy-
lamino]phenylphosphonite (2)
BuLi (1.6 M in hexane, 35.2 mL, 56.32 mmol) was added dropwise
to
a stirred solution of 4-bromo-N-methylaniline (3.49 g,
18.7 mmol) in Et2O (40 mL) between –40 °C and -50 °C. The tem-
perature was slowly increased up to r.t. for 3 h. The mixture was
stirred overnight at r.t., then refluxed for 4 h and then cooled again
to -50 °C. A solution of bis(diethylamido)chlorophosphite (7.92 g,
37.6 mmol) in Et2O (15 mL) was added dropwise at this tempera-
ture. The resulting mixture was stirred for 1 h at -50 °C, then the
temperature was slowly increased up to r.t., whence a white precip-
itate appeared. After stirring overnight, the precipitate was removed
by filtration, and the filtrate was evaporated in vacuo. The residue
was dissolved in pentane and filtered again, and concentrated. The
residue was fractionnaly distilled in vacuo to give 3.99 g (47%) of
2 as a very viscous yellow liquid; bp 172-176 °C/0.01 Torr.
H
C
C
PPh2
8
first step
EtMgBr
BrMg C
C
PPh2
10
Me2NPCl2
second step
PPh2
C
C
C
Me2N
P
14
C
PPh2
31P{1H}NMR (pentane): d = 99.37 (s, ArP), 111.65 (s, PNMe).
1H NMR (CDCl3): d = 1.03 (t, 3JHH = 7.1 Hz, 12 H, CH3CH2), 1.09
third step
2 HCl
PPh2
15
C
C
C
P
3
Cl
(t, JHH = 7.0 Hz, 12 H, CH3CH2), 2.91 (s, 3 H, CH3N), 2.98-3.17
C
(m, 16 H, CH3CH2N), 7.14 (ddd, 3JHH = 8.7 Hz, 4JHP = 4JHP = 2.3 Hz,
PPh2
H
fourth step
BrMg C
C
2 H, H3Ar), 7.25 (dd, 3JHH = 8.7 Hz, 3JHP = 5.4 Hz, 2 H, H2Ar).
6
2
13C{1H}NMR (CDCl3): d = 13.78 (d, JCP = 3.3 Hz, CH3CH2),
PPh2
C
C
14.54 (d, 2JCP = 3.5 Hz, CH3CH2), 31.78 (d, 2JCP = 5.8 Hz, CH3N),
P
C
H
C
16
C
2
2
C
39.36 (d, JCP = 19.0 Hz, CH3CH2), 42.47 (d, JCP = 17.3 Hz,
PPh2
first generation
CH3CH2), 116.85 (dd, JCP = 17.7 Hz, 3JCP = 3.6 Hz, C-3, arom),
3
130.02 (d, 1JCP = 8.9 Hz, C-1, arom), 131.36 (d, 2JCP = 16.2 Hz, C-2,
arom), 149.46 (d, 2JCP = 22.2 Hz, C-4, arom).
PPh2
C
C
C
P
P
C
C
C
PPh2
PPh2
C
C
Diethyl (4-Methylamino)phenylphosphonite (3)
H
C
C
P
Undistilled 2 can be used for the synthesis of 3. In this case, the so-
lution of crude 2 was filtered, then evaporated in vacuum at 40 °C
for 4 h. Undistilled 2 (16.77 g, 36.85 mmol) and EtOH (40 mL)
were stirred together in a sealed Schlenk flask at 80-86 °C for 30 h.
The volatile components of the reaction mixture were removed in
vacuum, and the residue was distilled under reduced pressure to
C
C
C
second generation
C
PPh2
Scheme 4
give 4.36 g (52%) of
3 as a viscous pale yellow liquid;
bp 100-102 °C/0.01 Torr)
31P{1H}NMR (CDCl3): d = 158.95 (s).
Our attempts to build hyperbranched polymers and den-
drimers including phosphines at each branching point
were not crowned with success, essentially because of the
low yield at each step of the synthesis. This fact is not re-
ally surprising, particularly for the multiacetylenic deriv-
atives, whose sensitivity toward polymerization is well
1H NMR (CDCl3): d = 1.25 (t, JHH = 7.0 Hz, 6 H, CH3CH2), 2.84
3
(br s, 3 H, CH3N), 3.71-3.98 (m, 5 H, CH3CH2, NH), 6.61 (dd,
4
3
3JHH = 8.5 Hz, JHP = 1.1 Hz, 2 H, H3Ar), 7.42 (dd, JHH = 8.5 Hz,
3JHP = 6.4 Hz, 2 H, H2Ar).
Synthesis 2000, No. 5, 726–730 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Synthesis of Functionalized Mono-, Di-, Tri-, and Tetraphosphines
729
3
13C{1H}NMR (CDCl3): d = 17.13 (d, JCP = 3.9 Hz, CH3CH2),
THF (4 mL). The resulting colourless solution of 11 was used im-
mediately.
31P{1H}NMR (THF): d = -31.
2
30.37 (s, CH3N), 61.88 (d, JCP = 10.1 Hz, CH3CH2), 111.80 (d,
3JCP = 7.0 Hz, C-3, arom), 128.23 (d, JCP = 15.6 Hz, C-1, arom),
1
131.15 (d, 2JCP = 21.6 Hz, C-2, arom), 150.64 (s, C-4, arom).
({Bis[(diphenylphosphino)ethynyl]phosphino}ethynyl)(diphe-
nyl)phosphine (12)
N-Methyl-4-phosphinoaniline (4)
A solution of 3 (6.08 g, 26.78 mmol) in Et2O (18 mL) was added
dropwise to a stirred suspension of LiAlH4 (1.26 g, 33.15 mmol) in
Et2O (20 mL) maintained between -40 °C and -45 °C. The mixture
was stirred for 1 h at this temperature, then for 2 h at 0 °C and for 2
d at r.t. (the increase in temperature from -40 °C to 0 °C was ac-
companied by formation of a very strong foam which complicated
the stirring). The mixture was diluted by Et2O (20 mL), and then
H2O (5mL) was added dropwise. The precipitate was removed by
filtration, the filtrate dried overnight (Na2SO4), filtered and evapo-
rated to dryness. Distillation of the residue under reduced pressure
gave 1.2 g (32%) of 4 as a colourless liquid; bp 63-67 °C/0.03 Torr.
Method 1: To a solution of PSCl3 (0.210 mL, 2.03 mmol) in THF
(5 mL) at -85 °C was added dropwise a 0.279 M solution of
Ph2PC∫CLi (14.54 mL, 4.06 mmol) in THF. The resulting mixture
was allowed to slowly reach the r.t. and was stirred overnight to give
a black solution. This solution was evaporated to dryness, then ex-
tracted with a 70:30 mixture pentane/CH2Cl2(4 × 20 mL). The com-
bined organic fractions are concentrated. Chromatography of the
dark residue over silica gel (eluent: pentane/CH2Cl2, 70:30) gave
0.104 g (8%) of 12 as a thick colourless oil.
Method 2: To a solution of PCl3 (0.069 mL, 0.79 mmol) in THF (3
mL) at -90 °C was added dropwise a 0.44 M solution of
Ph2PC∫CMgBr (10) (5.38 mL) in THF. The resulting mixture was
allowed to slowly reach the r.t. and stirred overnight to give a black
solution. This solution was evaporated to dryness, then extracted
with a 70:30 mixture pentane/CH2Cl2 (4 × 20 mL). The combined
organic fractions were concentrated. Chromatography of the dark
residue over silica gel (eluent: pentane/CH2Cl2, 70:30) gave 0.182 g
(35%) of 12 as a thick colourless oil.
31P NMR (CDCl3): d = -124.62 (t, 1JPH = 200.3 Hz).
1H NMR (CDCl3): d = 2.83 (s, 3 H, CH3N), 3.75 (br s, 1 H, NH),
1
3
3.98 (d, JHP = 200.3 Hz, 2 H, PH2), 6.55 (dd, JHH = 8.6 Hz,
4JHP = 1.0 Hz, 2 H, H3Ar), 7.36 (ddt, JHH = 8.6 Hz, JHP = 7.3 Hz,
3
3
4JHH = 0.5 Hz, 2 H, H2Ar).
13C{1H}NMR (CDCl3): d = 30.49 (s, CH3N), 112.45 (d, JCP = 7.1
3
Hz, C-3, arom), 129.22 (s, C-1, arom), 136.79 (d, 2JCP = 17.4 Hz, C-
3
2, arom), 149.64 (s, C-4, arom).
31P{1H} NMR (THF): d = -87.5 (q, JPP = 4.8 Hz, Ph2PC∫CP),
-31.4 (d, 3JPP = 4.8 Hz, PC∫CPPh2).
1H NMR (CDCl3): d = 7.34 (m, 18 Harom ), 7.63 (m, 12 Harom).
Diphenylethynylphosphine (8)
To a 0.5 M solution of HC∫CMgBr in THF (100 mL, 0.05 mol) at
-10 °C was added dropwise a solution of Ph2PCl (8.97 mL,
0.05 mol) in THF (60 mL). The resulting mixture was stirred for 1
h at r.t., then aq 2% AcOH (50 mL), and solid NaHCO3 was added
to neutralizit. The organic phase was separated, and the aqueous
phase was extracted with pentane (4 × 20 mL). The pentane extracts
were combined with the organic phase and dried overnight
(MgSO4), filtered and evaporated to dryness. Chromatography of
the dark residue over silica gel (eluent: pentane) gave 7.35 g (70%)
of 8 as a white powder; mp 35 °C.
3
13C{1H}NMR (CDCl3): d = 128.19 (d, JCP = 7.8 Hz, m-CHarom),
2
128.71 (s, p-CHarom), 132.14 (d, JCP = 21.0 Hz, o-CHarom), 134.37
(d, 1JCP = 5.8 Hz, 4JCP = 1.6 Hz, i-Carom), (C∫C not detected).
MS (FAB+): m/z = 659 ([M + 1]+, 100%).
({Bis[(diphenylphosphino)ethynyl]phosphino}ethynyl)(diphe-
nyl)phosphine Oxide (13)
To a solution of POCl3 (0.067 mL, 0.715 mmol) in THF (3 mL) at
-100 °C was added dropwise a 0.26 M solution of Ph2PC∫CMgBr
(10) (5.43 mL) in THF. The resulting mixture was allowed to slowly
reach the r.t. and was stirred overnight to give a black solution,
which was then impregnated on 3 g of silica gel (40-60 m). Chro-
matography of the resulting powder (eluent gradient: pentane/
CHCl3, 50:50, then pure MeCN) gave 0.08 g (17%) of 13 as a thick
colourless oil.
31P{1H}NMR (THF):d = -34 (s).
1H NMR (CDCl3): d = 2.24 (s, 1 H, C∫CH), 7.25-7.38 (m, 6
Harom), 7.59-7.68 (m, 4 Harom).
13C{1H}NMR (C6D6): d = 81.80 (d, JCP = 11.0 Hz, HC∫CP),
1
95.94 (s, HC∫CP), 128.53 (s, p-CHarom), 129.07 (s, m-CHarom),
132.45 (d, 2JCP = 20.9 Hz, o-CHarom), 132.26 (d, 1JCP = 5.8 Hz, Car-
31P{1H}NMR (CDCl3): d = -60.5 (q, 3JPP = 5 Hz, P=O), -34.6 (d,
om).
3JPP = 5 Hz, PPh2).
1H NMR (CDCl3): d = 7.29 (m, 18 Harom), 7.53 (m, 12 Harom).
[(Diphenylphosphino)ethynyl]lithium (9)
3
13C{1H}NMR (CDCl3): d = 129.0 (d, JCP = 8.1 Hz, m-CHarom),
To a solution of Ph2PC∫CH (0.5 g, 2.38 mmol) in THF (6 mL) at
0 °C was added dropwise a 1.6 M solution of BuLi in hexane
(1.49 mL, 2.38 mmol). The resulting mixture became yellow and
was stirred for 30 min after the end of the addition. The solution of
9 was used immediately.
129.85 (s, p-CHarom), 132.9 (d, 2JCP = 19.9 Hz, o-CHarom), 135.1 (d,
1JCP = 6 Hz, i-Carom), (C∫C not detected).
MS (FAB+): m/z = 675 ([M + 1]+, 100%).
31P{1H}NMR (THF): d = -30.
P,P-Bis[(diphenylphosphino)ethynyl]-N,N-dimethylphosphin-
ous Amide (14)
Bromo[(diphenylphosphino)ethynyl]magnesium (10)
To a solution of Ph2PC_CH (0.5 g, 2.38 mmol) in THF (6 mL) at r.t.
was added dropwise a 1.0 M solution of EtMgBr in THF (2.28 mL,
2.38 mmol). The resulting mixture became yellow and was stirred
for 15 min after the end of the addition. The solution of 10 was used
immediately.
To a solution of Me2NPCl2 (7.62 mmol) in THF (20 mL) cooled at
-80 °C was added dropwise a 0.276 M THF solution of
Ph2PC∫CMgBr (10) (13.81 mL, 3.81 mmol). The resulting mix-
ture was allowed to slowly reach the r.t. and was stirred overnight
to give a brown solution which was evaporated to dryness. The res-
idue was extracted with Et2O (3 × 20 mL). The organic phases were
combined and evaporated to give 0.749 g (80%) of 14 as a thick
brown oil.
31P{1H}NMR (THF): d = -30.
31P{1H}NMR (THF): d = -33.5 (d, 3JPP = 4 Hz, Ph2PC∫CP), 6.7 (t,
Diphenyl[(triphenylstannyl)ethynyl]phosphine (11)
To a 0.192 M solution of Ph2PC_CMgBr (10) (7.43 mL) in THF (6
mL) at -20°C was added dropwise a 0.36 M solution of ClSnPh3 in
3JPP = 4 Hz, PC∫CPPh2).
Synthesis 2000, No. 5, 726–730 ISSN 0039-7881 © Thieme Stuttgart · New York

730
V. Huc et al.
PAPER
1H NMR (CDCl3): d = 2.83 (d, 3JHP = 12.5 Hz, 6 H, CH3), 7.4 (m, 12
arom), 7.7 (m, 8 Harom).
(3) See for example:
H
(a) Launay, N.; Caminade, A. M.; Lahana, R.; Majoral, J. P.
Angew. Chem., Int. Ed. Engl. 1994, 33, 1589.
(b) Launay, N.; Caminade, A. M.; Majoral, J. P.
J. Am. Chem. Soc. 1995, 117, 3282.
(c) Galliot, C.; Prévoté, D.; Caminade, A. M.; Majoral, J. P.
J. Am. Chem. Soc. 1995, 117, 5470.
(d) Slany, M.; Bardají, M.; Casanove, M. J., Caminade, A. M.;
Majoral, J. P.; Chaudret, B. J. Am. Chem. Soc. 1995, 117,
9764.
(e) Larré, C.; Caminade, A. M.; Majoral, J. P. Angew. Chem.
Int. Ed. Engl. 1997, 36, 596.
2
13C{1H}NMR (CDCl3): d = 41.89 (d, JCP = 14.1 Hz, CH3), 104.6
1
1
(d, JCP = 17.2 Hz, C∫C), 105.52 (d, JCP = 21.1 Hz, C∫C),
128.19 (d, 3JCP = 7.8 Hz, m-CHarom), 128.71 (s, p-CHarom), 132.7 (d,
2JCP = 21.2 Hz, o-CHarom), 135.6 (d, 1JCP = 4.0 Hz, i-Carom).
MS (FAB+): m/z = 494 ([M + 1]+, 100%).
Bis[(diphenylphosphno)ethynyl]phosphinous Chloride (15)
To a solution of 14 in THF were added dropwise a 1 M solution of
HCl (2 equiv) in Et2O at r.t. The resulting mixture was stirred for
1 h, then filtered to afford 15 in Et2O solution which was used with-
out further purification.
(f) Galliot, C.; Larré, C.; Caminade, A. M.; Majoral, J. P.
Science 1997, 277, 1981.
3
(g) Larré, C.; Donnadieu, B.; Caminade, A. M.; Majoral, J. P.
J. Am. Chem. Soc. 1998, 120, 4029.
(h) Majoral, J. P.; Caminade, A. M. Top. Curr. Chem. 1998,
197, 79.
(i) Caminade, A.M.; Laurent, R.; Chaudret, B.; Majoral, J.P.
Coord. Chem. Rev. 1998, 178-180, 793.
(j) Larré, C.; Bressolles, D.; Turrin, C.; Donnadieu, B.;
Caminade, A. M.; Majoral, J. P. J. Am. Chem. Soc. 1998, 120,
13070.
31P{1H}NMR (THF): d = -32.9 (d, JPP = 4 Hz, Ph2P), 11.1 (t,
3JPP = 4 Hz, ClP).
Bis[(diphenylphosphino)ethynyl](ethynyl)phosphine (16)
To a solution of 15 in THF was added a 0.5 M solution of
HC∫CMgBr (1 equiv) in THF at -10 °C. A precipitate appeared,
which was eliminated by filtration. Evaporation to dryness of the
solution followed by several washings did not allow to isolate com-
pound 16. Chromatography on silica gel resulted in the loss of com-
pound 16.
(4) Merino, S.; Brauge, L.; Caminade, A. M.; Majoral, J. P.;
Taton, D.; Gnanou, Y. , to be published.
(5) Miedaner, A.; Curtis, C. J.; Barkley, R.M.; DuBois, D. L.
Inorg. Chem. 1994, 33, 5482.
31P{1H}NMR (THF): d = -88.0 (t, JPP = 4.5 Hz, HC∫CP), -32.9
3
(d, 3JPP = 4.5 Hz, Ph2P).
(6) Petrucci-Samija, M.; Guillemette, V.; Dasgupta, M.; Kakkar,
A.K. J. Am. Chem. Soc. 1999, 121, 1968.
(7) (a) Xu, Z.; Moore, J. S. Angew. Chem. Int. Ed. Engl. 1993, 32,
1354.
Acknowledgement
Thanks are due to the Fundación Ramón Areces (Madrid, Spain) for
a grant to one of us (RMS), and to the CNRS for financial support.
(b) Kawaguchi, T.; Walker, K. L.; Wilkins, C. L.; Moore, J. S.
J. Am. Chem. Soc. 1995, 117, 2159.
(8) Charrier, C.; Chodkiewiecz, W.; Cadiot, P. Bull. Soc. Chim.
Fr. 1966, 1002.
(9) Rosenberg, D.; Drenth, W. Tetrahedron 1971, 27, 3893.
(10) Gilheany, D. G. In The Chemistry of Organophosphorus
Compounds, Hartley FR, Ed; Wiley: New York, 1992, Vol. 2,
Chap 1, pp 16-18.
(11) Hawker, C. J.; Fréchet, J. M. J. J. Am. Chem. Soc. 1990, 112,
7638.
(12) Ara, I.; Falvello, L.R.; Fernandez, S.; Forniés, J.; Lalinde, E.;
Martin, A.; Moreno, T. Organometallics 1997, 16, 5923 and
references cited therein.
References
# Present address: A. E. Arbuzov Institute of Organic and
Physical Chemistry, Russian Academy of Sciences, Kazan
Scientific Centre, Arbuzov Street 8, Kazan 420088, Russia
(1) For reviews, see for example:
(a) Tomalia, D. A.; Naylor, A. M.; Goddard, W. A. III Angew.
Chem., Int. Ed. Engl. 1990, 29, 138.
(b) Newkome, G. R.; Moorefield, C. N.; Vögtle, F. Dendritic
Molecules, VCH: Weinheim, 1996.
(c) Archut, A.; Vögtle, F. Chem. Soc. Rev. 1998, 27, 233.
(d) Chow, H. F.; Mong, T. K. K.; Nongrum, M. F.; Wan, C.W.
Tetrahedron 1998, 54, 8543.
(13) Krishnamurthy, S. Tetrahedron Lett. 1982, 23, 3315.
(e) Fischer, M.; Vögtle, F. Angew. Chem. Int. Ed. Engl.1999,
38, 884.
(2) Majoral, J. P.; Caminade, A. M. Chem. Rev. 1999, 99, 845.
Article Identifier:
1437-210X,E;2000,0,05,0726,0730,ftx,en;Z08299SS.pdf
Synthesis 2000, No. 5, 726–730 ISSN 0039-7881 © Thieme Stuttgart · New York